JP2018160964A - Electric power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power system capable of suppressing disconnection from a power system by a reverse power relay. A photovoltaic power generation system PVS9 includes a power load L, a plurality of power conditioners PCSPVi, PCSBk, and a centralized management device MC9. A reverse power relay 51 is installed at the interconnection point between the photovoltaic power generation system PVS9 and the power system A. The centralized management device MC9 calculates the suppression index prPV and the charge/discharge index prB so that the interconnection point power becomes the target power. Each of the power conditioners PCSPVi and PCSBk calculates the individual target power based on the optimization problem using the suppression index prPV and the charge/discharge index prB, and controls the individual output power. In the photovoltaic power generation system PVS9 configured in this manner, the individual output power is reduced by changing the suppression index prPV and the charge/discharge index prB before the reverse power flow is detected by the reverse power relay 51. [Selection diagram] Fig. 27

Description

  The present disclosure relates to a grid-connected power system, and relates to a power system in which reverse power flow is prohibited.

  In recent years, power generation systems using renewable energy have become widespread. One example is a solar power generation system using sunlight. The solar power generation system includes a solar cell and a power conditioner. The solar cell generates DC power, and the power conditioner converts this DC power into AC power. The converted AC power is supplied to the power system. Solar power generation systems range from small households to large ones such as mega solar systems.

  A large-scale photovoltaic power generation system includes a plurality of power conditioners each connected to an electric power system. For example, the solar power generation system disclosed in Patent Document 1 includes a plurality of solar cells, a plurality of power conditioners, and a monitoring control system. The monitoring control system monitors and controls the plurality of power conditioners. Specifically, the supervisory control system performs control such as monitoring input / output power, input / output voltage, input / output current, etc. for a plurality of power conditioners and changing the output voltage.

JP 2012-205322 A

  In the solar power generation system, there is a self-consumption power system that operates in an interconnected manner with the power system and supplies all the generated power to the power load. In the power system, when reverse power flow is prohibited (not allowed), installation of a reverse power relay is required. The reverse power relay is a protective relay that disconnects the power system from the power system when a reverse power flow is detected. Normally, reverse power flow is prevented by controlling the power system. However, when sudden solar radiation fluctuations or load fluctuations occur, the control may not catch up and there may be a reverse power flow. In this case, the reverse power relay operates and disconnects the power system. When the power is disconnected by the reverse power relay, for example, calling a specialized contractor, the work for reconnecting to the power system is complicated. Such a problem occurs not only in a photovoltaic power generation system, but also in a power system in which a reverse power relay is installed.

  The power system according to the present disclosure has been created in view of the above circumstances. Then, the objective is to provide the electric power system which avoids being disconnected from an electric power grid | system by a reverse power relay.

  A power system provided by the present disclosure includes a power load, a distributed power source, and a centralized management device that manages the distributed power source, and a grid interconnection system linked to a power system, and the grid interconnection When a reverse power flow from the system to the power system is detected, the power system includes at least a reverse power relay that disconnects the distributed power source from the power system, and the centralized management device detects power to be adjusted An index for calculating an index for controlling the individual output power of the distributed power source based on the adjustment target power and the target power so that the adjustment target power becomes the target power Calculating means; and index transmitting means for transmitting the index to the distributed power source, wherein the distributed power source uses the index receiving means for receiving the index and the index. Based on an optimization problem, a target power calculation unit that calculates the individual target power of the distributed power source, and a control unit that controls the individual output power of the distributed power source to be the individual target power. The grid interconnection system is characterized in that the individual output power is reduced by changing the index before a reverse power flow is detected by the reverse power relay.

  In a preferred embodiment of the power system, the grid interconnection system further includes an auxiliary relay different from the reverse power relay, and the auxiliary relay includes the grid interconnection system and the power grid. And an electrical contact that operates based on interconnection power at the interconnection point, and when the electrical contact is activated, a contact signal indicating that the electrical contact is activated is transmitted to the distributed power source. The distributed power supply further includes a distributed power contact signal receiving means for receiving the contact signal, and the target power calculating means receives the contact signal by the distributed power contact signal receiving means. At this time, the value of the avoidance value to reduce the individual output power is set as the index.

  In a preferred embodiment of the power system, the target power calculation means uses the index received by the index reception means after continuing the calculation of the individual target power using the disconnection avoidance value for a predetermined time. The calculation of the individual target power that has been resumed is resumed.

  In a preferred embodiment of the power system, the auxiliary relay further transmits the contact signal to the central management device, and the central management device receives the contact signal. The index calculation means stops the calculation of the index when the contact signal receiving means for the centralized management device receives the contact signal, while the calculation of the index is stopped, The discontinuation avoidance value is used as the index.

  In a preferred embodiment of the power system, the index calculation means restarts the calculation of the index when a predetermined time has elapsed since the calculation of the index was stopped.

  In a preferred embodiment of the power system, the grid interconnection system includes a plurality of the distributed power sources, and the plurality of distributed power sources include a solar power generation device and a power storage device. The disengagement avoidance value for the solar power generation device is different from the disengagement avoidance value for the power storage device.

  The power system of the present disclosure includes a power grid, a distributed power source, a grid interconnection system including a centralized management device, and a reverse power relay. The centralized management apparatus calculates an index for controlling the individual output power of the distributed power supply so that the adjustment target power becomes the target power. The distributed power source calculates the individual target power of the distributed power source based on the optimization problem using the index, and sets the individual output power as the individual target power. In such a power system, the grid interconnection system reduces the individual output power by changing the index before a reverse power flow is detected by the reverse power relay. Thereby, since adjustment object electric power falls, it can avoid that a grid connection system is disconnected from an electric power grid by a reverse power relay.

It is a figure showing the whole solar power generation system composition concerning a 1st embodiment. It is a figure which shows the function structure regarding the output suppression control of the solar energy power generation system which concerns on 1st Embodiment. It is a figure which shows the model of the power conditioner assumed in simulation. It is a figure which shows the step response of the power control system of the power conditioner assumed in simulation. It is a figure which shows the verification result (case 1) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 2) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 3) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 4) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 5) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 6) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 7) by the simulation which concerns on 1st Embodiment. It is a figure which shows the whole structure of the solar energy power generation system which concerns on 2nd Embodiment. It is a figure which shows the function structure regarding the output suppression control of the solar energy power generation system which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 1) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 2) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 3) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the whole structure of the solar energy power generation system which concerns on 3rd Embodiment. It is a figure which shows the function structure regarding the output suppression control of the solar energy power generation system which concerns on 3rd Embodiment. It is a figure which shows the function structure regarding the peak cut control of the solar energy power generation system which concerns on 4th Embodiment. It is a figure which shows the function structure regarding the reverse power flow avoidance control of the solar energy power generation system which concerns on 5th Embodiment. It is a figure which shows the whole structure of the solar energy power generation system which concerns on 6th Embodiment. It is a figure which shows the function structure regarding the output suppression control of the solar energy power generation system which concerns on 6th Embodiment. It is a figure which shows the whole structure of the solar energy power generation system which concerns on 7th Embodiment. It is a figure which shows the function structure regarding the output suppression control of the solar energy power generation system which concerns on 7th Embodiment. It is a figure which shows the function structure regarding the schedule control of the solar energy power generation system which concerns on 8th Embodiment. It is a figure which shows the whole structure of the solar energy power generation system which concerns on 9th Embodiment. It is a figure which shows the function structure regarding the disconnection avoidance control of the solar energy power generation system which concerns on 9th Embodiment. It is a figure which shows the relationship between a suppression parameter | index and individual output electric power, and the relationship between a charging / discharging parameter | index and individual output electric power. It is a figure which shows the simulation result in the case where it does and the case where it does not perform disconnection avoidance control.

  Hereinafter, embodiments of the power system of the present disclosure will be described. The power system includes a grid interconnection system linked to a power grid, and a case where the grid interconnection system is a solar power generation system will be described as an example. In the following description, when the power at the interconnection point is positive, it is assumed that power is output from the photovoltaic power generation system to the power system (reverse power flow). On the other hand, when the power at the interconnection point is a negative value, the power is output from the power system to the photovoltaic power generation system.

FIG. 1 shows the overall configuration of a photovoltaic power generation system PVS1 according to the first embodiment. As shown in the figure, the photovoltaic power generation system PVS1 includes a plurality of solar cells SP _i (i = 1, 2,..., N; n is a positive integer), a plurality of power conditioners PCS _i , And it has the centralized management apparatus MC1. The photovoltaic power generation system PVS1 is a grid-connected reverse power flow system.

Each of the plurality of solar cells SP _i converts solar energy into electric energy. Each solar cell SP _i includes a plurality of solar cell panels connected in series and in parallel. A solar battery panel is a panel in which a plurality of solar battery cells made of a semiconductor such as silicon are connected and protected with a resin or tempered glass so that they can be used outdoors. The solar cell SP _i outputs the generated power (DC power) to the power conditioner PCS _i . The maximum amount of power that can be generated by the solar cell SP _i is defined as the power generation amount P _i ^SP of the solar cell SP _i .

Each of the plurality of power conditioners PCS _i converts the power (DC power) generated by the solar cell SP _i into AC power. Then, the converted AC power is output to the power system A. Each power conditioner PCS _i includes, for example, an inverter circuit, a transformer, a control circuit, and the like. The inverter circuit converts the DC power input from the solar battery SP _i into AC power synchronized with the power system A. The transformer boosts (or steps down) the AC voltage output from the inverter circuit. The control circuit controls an inverter circuit and the like. Each power conditioner PCS _i controls the individual output power P _i ^out which is the output power of its own device (power conditioner PCS _i ) by controlling an inverter circuit or the like. Note that the power conditioner PCS _i is not limited to the one configured as described above.

When the effective power output from the power conditioner PCS _i P _i ^out, the reactive power and Q _i ^out, the complex power of P _i ^out + jQ _i ^out from the power conditioner PCS _i is outputted. Therefore, the complex power of Σ _i P _i ^out + jΣ _i Q _i ^out is output to the connection point between the plurality of power conditioners PCS _i and the power system A. That is, the power at the interconnection point is the sum of the output power of each power conditioner PCS _i . The power at the interconnection point is defined as interconnection point power P (t). In this embodiment, no particular consideration is given to the output control of the reactive power Q _i ^out which is mainly used for suppressing voltage fluctuation at the interconnection point. That is, the connection point power P (t) is the sum (Σ _i P _i ^out ) of the active power P _i ^{out at} the connection point. Therefore, since the individual output power controlled by each power conditioner PCS _i is the active power P _i ^out , the individual output power is P _i ^out .

The central control device MC1 is to centralize plurality of power conditioners PCS _i. The central management device MC1 transmits and receives various types of information to and from each power conditioner PCS _i by wireless communication, for example. Note that wired communication may be used instead of wireless communication.

In the photovoltaic power generation system PVS1 configured as described above, the central management device MC1 monitors the predetermined adjustment target power, and adjusts the adjustment target based on the adjustment target power and the target power that is the target value of the adjustment target power. An index for setting the power to the target power is calculated. Then, this is transmitted to each power conditioner PCS _i . Each power conditioner PCS _i receives an index from the central management device MC1, and calculates an individual target power P _i ^ref that is a target value of the individual output power P _i ^out based on the received index. The individual output power P _i ^out is controlled based on the calculated individual target power P _i ^ref . The index is information for setting the adjustment target power as the target power, and is information for calculating the individual target power P _i ^ref .

In recent years, the number of solar power generation systems linked to the power system A has increased, and there is a possibility that the supply of power to the power system A will be excessive compared to the demand. In order to eliminate this excessive supply state, it is conceivable that an electric power company or the like instructs each photovoltaic power generation system to suppress individual output power. At this time, each photovoltaic power generation system needs to suppress the output power in accordance with the output suppression instruction. In this embodiment, as the output restriction instruction from the power company, it is assumed that the upper limit of the output power of the entire solar power system PVS1 output command value P ^C is indicated. Thus, solar systems PVS1, it is necessary to match the output power of the entire solar power system PVS1 the output command value P ^C.

Therefore, photovoltaic systems PVS1 according to this embodiment, the power conditioner PCS _i using the index distributed controls, consistent output power of the entire solar power system PVS1 the output command value P ^C I am letting. This is called “output suppression control”. In the photovoltaic power generation system PVS1, since all the individual output power P _i ^out of each power conditioner PCS _i is output to the connection point (power system A), the photovoltaic power generation system PVS1 is connected to the connection point power P ( t) is regarded as the output power of the entire photovoltaic power generation system PVS1, and output suppression control is performed. That is, photovoltaic systems PVS1 is matched linking point power P (t) to the output command value P ^C. Note that an index used in the output suppression control according to the present embodiment is a suppression index pr. Specifically, in photovoltaic systems PVS1, the central control device MC1 monitors the interconnection point power P (t), based on the linking point power P (t) and the output command value P ^C, continuous calculating the suppression indication pr for system point power P (t) to the output command value P ^C. Then, this is transmitted to each power conditioner PCS _i . Each power conditioner PCS _i receives the suppression index pr from the central management device MC1, and calculates the individual target power P _i ^ref based on the received suppression index pr. The individual output power P _i ^out is controlled based on the calculated individual target power P _i ^ref . Accordingly, it is made to coincide linking point power P (t) to the output command value P ^C. Thus, using the interconnection point power P (t) as the adjusted power is used the output command value P ^C as the target power.

FIG. 2 shows a functional configuration of a control system related to output suppression control of the photovoltaic power generation system PVS1 shown in FIG. In FIG. 2, the illustration of the solar cell SP _i is omitted. As a control system related to the output suppression control, each power conditioner PCS _i includes a receiving unit 11, a target power calculating unit 12, and an output control unit 13, as shown in FIG. In addition, the central management device MC1 includes a target power setting unit 21, an interconnection point power detection unit 22, an index calculation unit 23, and a transmission unit 24.

  The receiving unit 11 receives the suppression index pr transmitted from the central management device MC1. The receiving unit 11 receives the suppression index pr from the central management device MC1 by wireless communication, for example. Note that wired communication may be used instead of wireless communication.

The target power calculation unit 12 calculates the individual target power P _i ^ref of the own device (power conditioner PCS _i ) based on the suppression index pr received by the reception unit 11. Specifically, the target power calculation unit 12 calculates the individual target power P _i ^ref by solving the constrained optimization problem shown in the following equation (8). In the equation (8), P _i ^lmt represents the rated output (output limit) of each power conditioner PCS _i , and w _i represents the weight related to effective power suppression of the power conditioner PCS _i . The weight w _i related to the effective power suppression is stored in the target power calculation unit 12. Further, the weight w _i related to effective power suppression can be manually set by the user. Alternatively, each power conditioner PCS _i may be automatically set according to the condition (temperature, climate, reactive power amount, etc.) of the power conditioner PCS _i . Details of the following equation (8) will be described later.

The output control unit 13 controls the inverter circuit to control the individual output power P _i ^out . The output control unit 13 sets the individual output power P _i ^out to the individual target power P _i ^ref calculated by the target power calculation unit 12.

The target power setting unit 21 sets a target value for the interconnection point power P (t). In the present embodiment, the target power setting unit 21 sets a target power in the output suppression control. Specifically, the target power setting unit 21 acquires the output command value P ^C commanded from the power company, and sets the output command value P ^C as the target power. Target power setting unit 21 acquires, for example, the output command value P ^C from the power company through wireless communication. The output command value P ^C is not limited to the one that directly acquires from the electric power company. For example, the configuration may be such that the administrator manually inputs an output command value P ^C commanded from a power company into a predetermined computer, and the target power setting unit 21 acquires the output command value P ^C from the computer. . Alternatively, it relays the other communication device may be configured to acquire the output command value P ^C of commanded from the power company. The target power setting unit 21 outputs the set target power (output command value P ^C ) to the index calculation unit 23.

The target power setting unit 21 informs the indicator calculation unit 23 that there is no command when there is no output suppression command from the power company. The "when there is no command for output suppression from power company", does not suppress the output of the photovoltaic power generation system PVS1, it is when it outputs the most power solar SP _i is power. For example, when each power conditioner PCS _i operates at the maximum power point by the maximum power point tracking control, the maximum output is possible. In the present embodiment, the target power setting unit 21 outputs a numerical value −1 as the target power to the index calculation unit 23 when there is no output suppression command from the power company. Note that the method is not limited as long as it can be transmitted to the index calculation unit 23 that there is no instruction. For example, the target power setting unit 21 may acquire flag information indicating the presence / absence of an output suppression command from an electric power company or the like, and transmit the flag information to the index calculation unit 23. The flag information is, for example, “0” when there is no output suppression command and “1” when there is an output suppression command. Note that if there is a command for output suppression (when the flag information is "1"), to obtain the output command value P ^C together with the flag information.

In the present embodiment, illustrating a case where the target power setting unit 21 obtains the output command value P ^C as an example, but is not limited thereto. Specifically, it is also possible to obtain information of an output inhibition rate [%] instead of the output command value P ^C. At this time, the target power setting unit 21 sets the acquired output suppression rate [%] and the rated output of the entire photovoltaic power generation system PVS1 (that is, the total rated output of each power conditioner PCS _i ) Σ _i P _i ^lmt . based calculates the output command value P ^C. For example, the target power setting unit 21, when acquiring the command is 20% as an output inhibition rate, 80% of the rated output sigma _i P _i ^lmt photovoltaic systems PVS1 (= 100-20) the output command value P Calculate as ^C. Then, it outputs the calculated output command value P ^C in the index calculation unit 23 as the target power.

  The connection point power detection unit 22 detects the connection point power P (t). Then, the detected interconnection point power P (t) is output to the index calculation unit 23. In addition, you may comprise the connection point electric power detection part 22 as a detection apparatus different from the centralized management apparatus MC1. In this case, the detection device (interconnection point power detection unit 22) transmits a detection value of the connection point power P (t) to the central management device MC1 by wireless communication or wired communication.

The index calculation unit 23 calculates an index for setting the interconnection point power P (t) as the target power. In the present embodiment, since the output command value P ^C is input as the target power, the index calculation unit 23 calculates the suppression index pr for making the interconnection point power P (t) the output command value P ^C. . The index calculation unit 23 calculates a suppression index pr based on the following formula (9) and the following formula (10), where λ is a Lagrange multiplier, ε is a gradient coefficient, and t is time. However, the index calculation unit 23 as an output command value P ^C, when it is entered the numerical value -1 to indicate that there is no command output suppression from power company, the Lagrange multiplier λ is set to "0". That is, the suppression index pr is calculated as “0”. In the following formula (9), since the individual output power P _i ^out and the output command value P ^C are values that change with respect to time t, the individual output power is represented by P _i ^out (t) and the output command value, respectively. Is described as P ^C (t). Details of these formulas (9) and (10) will be described later.

The transmission unit 24 transmits the suppression index pr calculated by the index calculation unit 23 to each power conditioner PCS _i .

Next, in the output suppression control performed by the photovoltaic power generation system PVS1, the reason why the above equation (8) is used to calculate the individual target power P _i ^ref by the power conditioner PCS _i and the suppression index pr of the central management device MC1 The reason why the equation (9) and the equation (10) are used for the calculation will be described.

The photovoltaic power generation system PVS1 is configured to achieve the following three goals in the output suppression control. The first target (target 1-1) is “each power conditioner PCS _i calculates the individual target power in a distributed manner”. The second target (target 1-2) is “to match the output power (interconnection point power) at the connection point of the photovoltaic power generation system PVS1 with the output command value (target power) from the power company”. is there. The third target (target 1-3) is “to allow the output suppression amount to be adjusted for each power conditioner PCS _i ”. The output suppression amount is a difference between the maximum power value that can be output by the power conditioner PCS _i and the individual output power P _i ^out . The maximum power value that can be the output, when the power generation amount P _i ^SP> rated output P _i ^lmt solar cell SP _i is the rated output P _i ^lmt power conditioner PCS _i. On the other hand, when the power generation amount P _i ^SP of the solar cell SP _i ≦ the rated output P _i ^lmt , the power generation amount P _i ^SP of the solar cell SP _i .

First, consider a constrained optimization problem when the central management device MC1 intensively obtains the individual target power P _i ^ref . Then, the following equation (11) is obtained. Here, as described above, P _i ^ref represents the individual target power of each power conditioner PCS _i , P _i ^lmt represents the rated output (output limit) of each power conditioner PCS _i , and P ^C is Represents the output command value commanded by the electric power company. Note that the individual target power P _i ^ref which is the optimum solution of the following equation (11) is (P _i ^ref ) ^* . In the following equation (11), equation (11a) is the minimization of the output suppression amount of the individual output power P _i ^out , equation (11b) is the constraint due to the rated output P _i ^lmt , and equation (11c) is the interconnection point it represents respectively to match the power P (t) to the output command value P ^C.

This shows a case where the centralized management device MC1 obtains the individual target power (P _i ^ref ) ^* from the above equation (11). Therefore, in the case of the above formula (11), each power conditioner PCS _i does not calculate the individual target power (P _i ^ref ) ^* in a distributed manner, and thus the target 1-1 is not achieved.

Next, consider a constrained optimization problem when each power conditioner PCS _i obtains the individual target power P _i ^ref in a distributed manner. Then, the following formula (12) is obtained.

However, the individual target power, which is the optimal solution of the above equation (12), is the individual target power P _i ^ref obtained by each power conditioner PCS _i in a distributed manner, but the above equation (11c) is not taken into consideration. Therefore, the target 1-2 for matching the interconnection point power P (t) with the output command value P ^C from the power company cannot be achieved.

Therefore, consider achieving the target 1-2 by the following method. That is, each power conditioner PCS _i calculates the individual target power P _i ^ref in a distributed manner based on the suppression index pr received from the central management device MC1. Thereby, the target 1-2 is achieved. The constrained optimization problem when each power conditioner PCS _i obtains the individual target power P _i ^ref in a distributed manner using the suppression index pr can be expressed by the above equation (8). Note that equation (8) of the individual target power P _i ^ref which is the optimal solution with (P _i ^{ref) ♭.}

Here, the optimum solution (P _i ^ref ) ^* obtained by the above equation (11) and the optimum solution (P _i ^ref ) ^♭ obtained by the above equation (8) coincide with each other, so that the interconnection point power P ( t) can be matched with the output command value P ^C from the electric power company. That is, even if each power conditioner PCS _i solves the optimization problem in a distributed manner, the target 1-2 can be achieved. Therefore, focusing on the optimality of the steady state, a suppression index pr that satisfies (P _i ^ref ) ^* = (P _i ^ref ) ^♭ is considered. For that purpose, the KKT (Karush-Kuhn-Tucker) conditions of the above formula (11) and the above formula (8) are considered. Thus, the following expression (13) is obtained from the KKT condition of the above expression (11), and the following expression (14) is obtained from the KKT condition of the above expression (8). Note that μ is a predetermined Lagrange multiplier.

From these equation (13) and equation (14), it is assumed that pr = λ (the above equation (10)), so that the two optimum solutions (P _i ^ref ) ^* and (P _i ^ref ) ^一致 match. I understand. Accordingly, the central management device MC1 calculates the Lagrange multiplier λ, and presents (transmits) the calculated Lagrange multiplier λ as the suppression index pr to each power conditioner PCS _i so that each power conditioner PCS _i The individual target power (P _i ^ref ) ^♭ can be calculated from the equation (8). As a result, even if each power conditioner PCS _i obtains the individual target power P _i ^ref in a distributed manner, the connection point power P (t) and the output command value P ^C from the power company are matched. be able to. That is, the target 1-2 can be achieved.

Next, a method for calculating the Lagrange multiplier λ by the centralized management device MC1 will be described. In order for the central management device MC1 to obtain the Lagrange multiplier λ, first, h _{1, i} = −P _i ^ref and h _{2, i} = P _i ^ref −P _i ^lmt are set, and the inequality constraints of each power conditioner PCS _i are summarized. H _{j, i} (j = 1, 2, i = 1,..., N). Then, consider the following equation (15) which is a dual problem of the above equation (11).

Here, assuming that the optimum solution (P _i ^ref ) ^{求 め} determined by each power conditioner PCS _i is determined, the following equation (16) is obtained, which is the form of the maximization problem for the Lagrange multiplier λ. When the gradient method is applied to the following equation (16), the following equation (17) is obtained. Note that ε represents a gradient coefficient, and τ represents a time variable.

In the above equation (17), (P _i ^ref ) ^♭ is replaced with the individual output power P _i ^out of the corresponding power conditioner PCS _i . Further, the centralized management device MC1 does not individually observe the individual output power P _i ^out of each power conditioner PCS _i but observes the connection point power P (t) = Σ _i P _i ^out . Moreover, to have a valid sequential output command value P ^C from the power company. Then, the above equation (9) is obtained. Therefore, the central management device MC1 can calculate the Lagrange multiplier λ based on the interconnection point power P (t) and the output command value P ^C from the power company. Then, based on the above equation (10), the calculated Lagrangian multiplier λ is set as the suppression index pr.

From the above, in this embodiment, each power conditioner PCS _i uses the optimization problem shown in the above equation (8) when calculating the individual target power P _i ^ref . Further, the central management device MC1 uses the above formula (9) and the above formula (10) in order to calculate the suppression index pr.

  Next, in the photovoltaic power generation system PVS1 configured as described above, it was verified by simulation that the above three goals were achieved and the system was operating properly.

In the simulation, a solar power generation system PVS1 having _ten power conditioners PCS _i (i = 1 to 10; PCS _{1 to} PCS ₁₀ ) was assumed.

The model of the power system A (interconnection point voltage) was the following equation (18). In the following equation (18), R = R _L × L, X = X _L × L, R _L is a resistance component per unit length of the distribution line, and X _L is a reactance component per unit length of the distribution line. , L represents the length of the distribution line, and V ₁ represents the upper system voltage. In this simulation, the upper system voltage V ₁ is 6600 [V], the resistance component R _L per unit length of the wiring line is 0.220 [Ω / km], and the reactance component X _L per unit length of the distribution line Was 0.276 [Ω / km], and the length L of the distribution line was 5 [km].

The power conditioner PCS _i is assumed to have the model shown in FIG. 3, and PI control is performed to control the individual output power P _i ^out to the individual target power P _i ^ref . The current control system of the power conditioner PCS _i is designed to respond very quickly compared to the active / reactive power control system. Here, it is assumed that an appropriate control system design has been made in advance, and a first-order lag system with K = 1 and T = 10 ⁻⁴ is realized. The power control system, which is a higher-order control system of the current control system, assumes a time constant that the step response converges within 1 [s], and K _PP = K _PQ = 1.0 × 10 ⁻⁷ , K _IP = K _IQ = 1.2 × 10 ⁻³ . K _PP represents a proportional gain of active power, K _PQ represents a proportional gain of reactive power, K _IP represents an integral gain of active power, and K _IQ represents an integral gain of reactive power. The step response of the active / reactive power control system is shown in FIG.

5 to 11 show results when simulation is performed under a plurality of conditions using the above-described model photovoltaic power generation system PVS1. Each power conditioner PCS _i, when the power generation amount P _i ^SP is greater than the rated output P _i ^lmt of the connected solar cell SP _i is one that inhibits the rated output P _i ^lmt of the power conditioner PCS _i And

As a case 1, a simulation was performed in the case where all of the _ten power conditioners PCS _{1 to} PCS ₁₀ had the same conditions. This simulation is assumed to be simulation 1-1. In simulation 1-1, all of the ten power conditioners PCS _{1 to} PCS ₁₀ have a rated output P _i ^lmt of 500 [kW], a weight w _i relating to active power suppression of 1.0, and a power generation amount of the solar cell SP _i . It was assumed that P _i ^SP was 600 [kW]. Further, the output command value P ^C from the electric power company is assumed to be no command when 0 ≦ t <60 [s], and 3000 [kW] when 60 ≦ t [s]. Note that, when “there is no command for the output command value P ^C ”, as described above, the numerical value −1 indicating that there is no command is used as the output command value P ^C. In addition, the slope coefficient ε is 0.025, and each sampling time for updating the suppression index pr performed by the central management device MC1 and updating the individual target power P _i ^ref performed by each power conditioner PCS _i is 1 [s]. . In addition, all the power conditioners PCS _i are assumed to be operating at a power factor of 1 (reactive power target value = 0 [kvar]). FIG. 5 shows a simulation result in the simulation 1-1.

Figure 5 (a) ~ (e) is of the power conditioner PCS _i, photovoltaic SP generation amount P _i ^SP (dashed line) of _i, rated output P _i ^lmt (solid line), the individual target power P _i ^ref ( (Broken line) and individual output power P _i ^out (solid line) are shown. 5A shows the power conditioners PCS ₁ and PCS ₂ , FIG. 5B shows the power conditioners PCS ₃ and PCS ₄ , and FIG. 5C shows the power conditioners PCS ₅ and PCS ₆ . 5D shows the power conditioners PCS ₇ and PCS ₈ , and FIG. 5E shows the power conditioners PCS ₉ and PCS ₁₀ . In FIGS. 5A to 5E, the individual target power P _i ^ref (broken line) is slightly shifted upward for convenience of understanding. FIG. 5F shows the individual output powers P ₁ ^{out to} P ₁₀ ^out of the power conditioners PCS _{1 to} PCS ₁₀ in one graph. FIG. 5G shows the interconnection point power P (t) (solid line) and the output command value P ^C (broken line) from the power company. Incidentally, in FIG. 5 (g), the convenience of understanding, if there is no command output command value P ^C, outputs command the sum of the rated output P ₁ ^lmt ~P ₁₀ ^lmt of PCS ₁ ~PCS ₁₀ of the power conditioner Described as the value P ^C. FIG. 5H shows the Lagrangian multiplier λ calculated by the index calculation unit 23. FIG. 5I shows the suppression index pr calculated by the index calculation unit 23.

The following can be confirmed from FIG. That is, in the period from the start of the simulation to the output suppression command (0 ≦ t <60 [s]), as shown in FIGS. 5A to 5E, the individual power conditioners PCS _{1 to} PCS ₁₀ are individually displayed. output power P ₁ ^out ~P ₁₀ ^out is to reach 500 [kW] of the individual target power P ₁ ^ref ~P ₁₀ ^ref, rises and in response to the power generation amount P ₁ ^SP ~P ₁₀ ^SP solar cell SP _i Yes. When the individual target powers P ₁ ^{ref to} P ₁₀ ^ref reach 500 [kW], the individual output powers P ₁ ^{out to} P ₁₀ ^out thereafter become 500 [kW] of the individual target powers P ₁ ^{ref to} P ₁₀ ^ref. ] Can be confirmed. Further, after the output command value P ^C is commanded (60 ≦ t [s]), the Lagrange multiplier λ and the suppression index pr are updated as shown in FIGS. 5 (h) and 5 (i). I can confirm. Each power conditioner PCS ₁ ~PCS _10, based on the update of the suppression indicators pr, as shown in FIG. 5 (a) ~ (e) , by changing the individual target power P ₁ ^ref ~P ₁₀ ^ref Yes. Therefore, it can be confirmed that the individual output powers P ₁ ^{out to} P ₁₀ ^out are suppressed and follow the individual target powers P ₁ ^{ref to} P ₁₀ ^ref . Thus, as shown in FIG. 5 (g), the suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state.

As case 2, weights w ₅ and w ₆ relating to active power suppression set in two power conditioners PCS ₅ and PCS ₆ among the _ten power conditioners PCS _{1 to} PCS ₁₀ are the other power conditioners PCS _1. A case different from that of PCS ₄ and PCS _{7 to} PCS ₁₀ was simulated. This simulation is referred to as simulation 1-2. In the simulation 1-2, the weight w _i regarding the active power suppression of the two power conditioners PCS ₅ and PCS ₆ is set to 2.0. Other conditions are the same as those in the simulation 1-1. FIG. 6 shows a simulation result in the simulation 1-2. 6A to 6I are diagrams corresponding to FIGS. 5A to 5I in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIGS. 6A to 6E, the output suppression amounts of the power conditioners PCS ₅ and PCS _{6 in which} the weight w _i related to effective power suppression is changed as compared with the simulation 1-1 illustrated in FIG. However, it can be confirmed that it is half the output suppression amount of the other power conditioners PCS _{1 to} PCS ₄ and PCS _{7 to} PCS ₁₀ . At this time, as shown in FIG. 6 (h) and FIG. 6 (i), the Lagrange multiplier λ and the suppression index pr calculated by the central management device MC1 are also the values in the simulation 1-1 (FIG. 5 (h) and FIG. 5). It can also be confirmed that this is different from (i). Therefore, it is possible to give a difference to the output suppression amount by adjusting the weight w _i related to effective power suppression. Further, as shown in FIG. 6, the output suppression amounts of the other power conditioners PCS _{1 to} PCS ₄ and PCS _{7 to} PCS ₁₀ are reduced by the amount of the output suppression amount of the power conditioners PCS ₅ and PCS _6. by greater than -1, as shown in FIG. 6 (g), interconnection point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is appropriately operating in consideration of the weight w _i related to the effective power suppression set in the power conditioner PCS _i .

As a case 3, a simulation was performed in which weights w ₅ and w ₆ relating to active power suppression of two power conditioners PCS ₅ and PCS ₆ out of _ten power conditioners PCS _{1 to} PCS 10 were changed in the middle. . The simulation is referred to as simulation 1-3. In the simulation 1-3, the weights w ₅ and w ₆ regarding the active power suppression of the two power conditioners PCS ₅ and PCS ₆ are set to w ₅ = w ₆ = 1.0 at the start time (0 [s]). After 120 [s], w ₅ = w ₆ = 2.0. That is, in 60 ≦ t <120 [s] , while the weight w ₁ to w ₁₀ about the effective suppression of power each power conditioner PCS ₁ ~PCS ₁₀ as described above simulation 1-1 are all 1.0, 120 In ≦ t [s], the weights w ₅ and w ₆ relating to the active power suppression of the power conditioners PCS ₅ and PCS ₆ were changed to 2.0 as in the above simulation 1-2. Other conditions are the same as those in the simulation 1-1. FIG. 7 shows a simulation result in the simulation 1-3. 7A to 7I are diagrams corresponding to FIGS. 5A to 5I in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, before changing the weights w ₅ and w ₆ relating to the active power suppression of the power conditioners PCS ₅ and PCS ₆ to 2.0 (60 ≦ t <120 [s]), the same result as the simulation 1-1 is obtained. Yes, after changing the weights w ₅ and w ₆ relating to effective power suppression of the power conditioners PCS ₅ and PCS ₆ to 2.0 (120 ≦ t [s]), the same result as in the simulation 1-2 is obtained. Can be confirmed. Therefore, even in this way adjust the weights w _i relating active power suppression in the middle (change), continuously, it is possible to match the interconnection point power P (t) to the output command value P ^C.

As Case 4, each of the two inverters (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS ₁₀ ) generates power from the solar cell SP _i . The case where the amount P _i ^SP is different was simulated. The simulation is referred to as simulation 1-4. In the simulation 1-4, the solar cell SP _i for each of the two inverters (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS ₁₀ ) The power generation amounts P _i ^SP are respectively P ₁ ^SP , P ₂ ^SP = 600 [kW], P ₃ ^SP , P ₄ ^SP = 500 [kW], P ₅ ^SP , P ₆ ^SP = 400 [kW], P ₇ ^{SP, respectively.} , P ₈ ^SP = 300 [kW], P ₉ ^SP and P ₁₀ ^SP = 200 [kW]. Other conditions are the same as those in the simulation 1-1. FIG. 8 shows a simulation result in the simulation 1-4. 8A to 8I are diagrams corresponding to FIGS. 5A to 5I in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIGS. 8A to 8E, when the individual target power P _i ^ref is greater than or equal to the power generation amount P _i ^SP of the solar cell SP _i , it can be confirmed that output suppression is not performed. Further, as shown in FIG. ^8F, when the power generation amount P _i ^SP of the solar cell SP _i is different between the power conditioners PCS _{1 to} PCS ₁₀ having the same rated output P _i ^lmt , the power generation amount of the solar cell SP _i is different. P _i ^SP with less power conditioner PCS ₇ ~PCS ₁₀ it can be confirmed that that has not been output suppression. Furthermore, as shown in FIG. 8 (g), the suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state. Therefore, it can be said that the solar power generation system PVS1 is appropriately operating in consideration of the power generation amount P _i ^SP of the solar cell SP _i .

As Case 5, the rated output P _i ^lmt for each of the two ^inverters (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS ₁₀ ) Different cases were simulated. This simulation is referred to as simulation 1-5. In simulation 1-5, the rated output P _i ^{lmt for each of the two inverters} (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS ₁₀ ) , P ₁ ^lmt , P ₂ ^lmt = 500 [kW], P ₃ ^lmt , P ₄ ^lmt = 400 [kW], P ₅ ^lmt , P ₆ ^lmt = 300 [kW], P ₇ ^lmt , P ₈ ^lmt = 200 [kW], P ₉ ^lmt , and P ₁₀ ^lmt = 100 [kW]. Further, as an output command value P ^C from the electric power company, there is no command when 0 ≦ t <60 [s], and 2000 [kW] when 60 ≦ t [s], and the power generation amount P _i ^SP of the solar cell SP _i is The rated output was P _i ^lmt +100 [kW]. Other conditions are the same as those in the simulation 1-1. FIG. 9 shows a simulation result in the simulation 1-5. FIGS. 9A to 9I are diagrams corresponding to FIGS. 5A to 5I in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 9 (f), when the rated output P _i ^lmt is different, it can be confirmed that the output suppression amount is equal in each of the power conditioners PCS _{1 to} PCS ₁₀ . Further, as shown in FIG. 9G, it can be confirmed that the connection point power P (t) is suppressed and coincides with the output command value P ^C in a steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is appropriately operating in consideration of the rated output P _i ^lmt of the power conditioner PCS _i .

As a case 6, a case where the sampling time is increased was simulated. This simulation is referred to as simulation 1-6. In simulation 1-6, the sampling time was set to 60 [s] = 1 [min]. Further, the gradient coefficient ε was set to 0.0005, and the output command value P ^C from the electric power company was set to 3000 [kW] when 0 ≦ t <5 [min] and no command when 5 ≦ t [min]. Other conditions are the same as those in the simulation 1-1. FIG. 10 shows a simulation result in the simulation 1-6. FIGS. 10A to 10I are diagrams corresponding to FIGS. 5A to 5I in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 10 (g), when longer the sampling time, although the time to interconnection point power P (t) follows the output command value P ^C is longer than the above-described simulation 1-1 , is suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state.

In case 7, the case where the sampling time was made longer than the sampling time in case 6 was simulated. This simulation is referred to as simulation 1-7. In simulation 1-7, the sampling time was set to 180 [s] = 3 [min]. Further, the gradient coefficient ε was set to 0.0003, and the output command value P ^C from the electric power company was set to 3000 [kW] when 0 ≦ t <5 [min] and no command when 5 ≦ t [min]. Other conditions are the same as those in the simulation 1-1. FIG. 11 shows a simulation result in the simulation 1-7. FIGS. 11A to 11I correspond to FIGS. 5A to 5I in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 11 (g), even when the sampling time is set longer than the simulation 1-6, the connection point power P (t) is suppressed, and the output command value P ^C is reduced to a steady state. You can confirm that you are doing.

In addition to the results shown in FIGS. 5 to 11, the following can be confirmed by comparing FIGS. That is, as shown in (h) and (i) of each figure, the Lagrangian multiplier λ and the suppression index pr are the power generation amount P _i ^SP and the rated output P of the solar cell SP _i of the power conditioners PCS _{1 to} PCS _{10. i} ^lmt, weight w _i relating active power suppression, and, on the basis of such an output command value P ^C, it can be confirmed that different values are calculated. Further, as shown in each figure (a) ~ (e), in accordance with the updating of the suppression indicators pr, it can be confirmed that the individual target power P _i ^ref is updated. The power conditioners PCS _{1 to} PCS ₁₀ control the individual output power P _i ^out according to the individual target power P _i ^ref . Thus, as shown in (g) is each figure, it can be confirmed that by matching linking point power P (t) to the output command value P ^C. From the above, it can be said that the suppression index pr calculated by the central management device MC1 using the above equations (9) and (10) is an appropriate value.

From the results of the simulation 1-1 to the simulation 1-7, in the photovoltaic power generation system PVS1, the individual target power P is distributed in a distributed manner based on the suppression index pr received by each power conditioner PCS _i from the central management device MC1. _i ^ref is calculated. Therefore, the target 1-1 is achieved. Further, the interconnection point power P (t) is suppressed, it coincides with the output command value P ^C. Therefore, the above target 1-2 is achieved. The individual output power P _i ^out changes for each power conditioner PCS _i according to various conditions. That is, according to various conditions, the output suppression quantity is changed for each power conditioner PCS _i. Therefore, the above target 1-3 is achieved. From the above, it can be seen that the photovoltaic power generation system PVS1 has achieved the above three goals.

As described above, in the photovoltaic power generation system PVS1 according to the first embodiment, the centralized management device MC1 uses the output command value P ^C from the power company and the detected connection point power P (t) as described above ( The suppression index pr is calculated using Equation 9) and Equation (10) above, and is transmitted to each power conditioner PCS _i . Also, each power conditioner PCS _i calculates the individual target power P _i ^ref by solving the optimization problem of the above equation (8) in a distributed manner based on the received suppression index pr, and the individual output power the P _i ^out are controlled in a separate target power P _i ^ref. Thereby, the centralized management device MC1 performs only simple calculations shown in the above formulas (9) and (10). Therefore, in the photovoltaic power generation system PVS1, the processing load of the central management device MC1 can be reduced. Further, even when each power conditioner PCS _i calculates the individual target power P _i ^ref in a distributed manner based on the suppression index pr and controls the individual output power P _i ^out , the connection point power P (t ) Can be matched with the output command value P ^C from the electric power company. That is, the solar power generation system PVS1 can make the connection point power P (t) coincide with the target power.

Next, the solar power generation system PVS2 according to the second embodiment will be described. In addition, about the same or similar thing as the photovoltaic power generation system PVS1 which concerns on the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. FIG. 12 shows the overall configuration of the photovoltaic power generation system PVS2. As shown in FIG. 12, the photovoltaic power generation system PVS2 includes a plurality of solar cells SP _i (i = 1, 2,..., N; n is a positive integer), a plurality of power conditioners PCS _PVi , A plurality of storage batteries B _k (k = 1, 2,..., M; m is a positive integer), a plurality of power conditioners PCS _Bk , and a centralized management device MC2. The solar power generation system PVS2 is a grid-connected reverse power flow system.

In the solar power generation system PVS1 according to the first embodiment, the case where the solar power generation system PVS1 is configured by a plurality of power conditioners PCS _{i to} which the solar cells SP _i are connected has been described as an example. However, in the case of such a photovoltaic power generation system PVS1, the influence on the output due to weather fluctuation is large. Therefore, photovoltaic systems PVS2, in order to suppress the output variation due to the weather change, as compared with the solar power generation system PVS1, further comprising a power conditioner PCS _Bk connected to battery B _k.

Each of the plurality of power conditioners PCS _PVi is configured similarly to the power conditioner PCS _i of the first embodiment. That is, each power conditioner PCS _PVi converts the power (DC power) generated by the solar cell SP _i into AC power, and outputs the converted AC power to the power system A.

Each of the plurality of storage batteries B _k is a battery that can repeatedly store power by charging. The storage battery B _k is a secondary battery such as a lithium ion battery, a nickel metal hydride battery, a nickel cadmium battery, or a lead storage battery. A capacitor such as an electric double layer capacitor may be used. The storage battery B _k discharges the stored power and supplies DC power to the power conditioner PCS _Bk .

Each of the plurality of power conditioners PCS _Bk converts DC power input from the storage battery B _k into AC power and outputs the AC power. Furthermore, the power conditioner PCS _Bk is the AC power input from the electric power system A and each of the power conditioner PCS _PVi converted into DC power and supplies the battery B _k. That is, the storage battery _Bk is charged. Each power conditioner PCS _Bk is controlling the charging and discharging of the battery B _k. Thus, functions as a discharge circuit to discharge the charging circuit and the battery B _k to charge the battery B _k.

When the active power output from each power conditioner PCS _PVi is P _PVi ^out and the reactive power is Q _PVi ^out , the complex power of P _PVi ^out + jQ _PVi ^out is output from each power conditioner PCS _PVi . Also, assuming that the active power output from each power conditioner PCS _Bk is P _Bk ^out and the reactive power is Q _Bk ^out , the complex power of P _Bk ^out + jQ _Bk ^out is output from each power conditioner PCS _Bk . Therefore, a plurality of power conditioners PCS _PVi, the interconnection point between the PCS _Bk and power system ^{_{A, (Σ i P PVi out}} + Σ k P Bk out) + j (Σ i Q PVi out + Σ k Q Bk out) The complex power is output. That is, the interconnection point power P (t) is the sum of the output powers of the power conditioners PCS _PVi and PCS _Bk . In the present embodiment, the output control of reactive powers Q _PVi ^out and Q _Bk ^out mainly used for suppressing voltage fluctuation at the interconnection point is not particularly considered. That is, interconnection point power P (t), the effective power P _PVi ^out at interconnection points, and the sum of ^{_{P Bk out (Σ i P PVi}} out + Σ k P Bk out). Therefore, the individual output powers controlled by the power conditioners PCS _PVi and PCS _Bk are effective powers P _PVi ^out and P _Bk ^out , respectively. Therefore, the individual output power of each power conditioner PCS _PVi is P _PVi ^out, and the individual output power of each power conditioner PCS _Bk is P _Bk ^out .

The central management device MC2 centrally manages a plurality of power conditioners PCS _PVi and PCS _Bk . The central management device MC2 transmits and receives various types of information to and from the power conditioners PCS _PVi and PCS _Bk , for example, by wireless communication. Note that wired communication may be used instead of wireless communication.

In the photovoltaic power generation system PVS2 configured as described above, the central management device MC2 monitors the predetermined adjustment target power, and adjusts the adjustment target based on the adjustment target power and the target power that is the target value of the adjustment target power. An index for matching the power with the target power is calculated. And this is transmitted to each power conditioner PCS _PVi , PCS _Bk . Each power conditioner PCS _PVi (PCS _Bk ) receives the index from the centralized management device MC2, and based on the received index, the individual target power P that is the target value of the individual output power P _PVi ^out (P _Bk ^out ). _PVi ^ref (P _Bk ^ref ) is calculated. The individual output power P _PVi ^out (P _Bk ^out ) is controlled based on the calculated individual target power P _PVi ^ref (P _Bk ^ref ). The index is information for setting the adjustment target power as the target power, and is information for calculating the individual target power P _PVi ^out (P _Bk ^out ).

Also in the photovoltaic power generation system PVS2, suppression of output power is instructed from an electric power company. Therefore, in the photovoltaic power generation system PVS2 according to the present embodiment, the power conditioners PCS _PVi and PCS _Bk are controlled in a distributed manner using the above index, and the output power of the entire photovoltaic power generation system PVS2 is set to the output command value P. Match ^C. That is, the photovoltaic power generation system PVS2 also performs output suppression control. Specifically, in photovoltaic systems PVS2, the central control device MC2 monitors the interconnection point power P (t), based on the linking point power P (t) and the output command value P ^C, continuous It calculates an index for matching system point power P (t) to the output command value P ^C. And this is transmitted to each power conditioner PCS _PVi , PCS _Bk . In the output suppression control according to the present embodiment, an index transmitted to each power conditioner PCS _PVi is a suppression index pr _PV, and an index transmitted to each power conditioner PCS _Bk is a charge / discharge index pr _B. Thus, inhibition index pr _PV is information for linking point power P (t) to the output command value P ^C, which is information for calculating the individual target power P _PVi ^ref. Further, charge and discharge indicator pr _B is information for linking point power P (t) to the output command value P ^C, which is information for calculating the individual target power P _Bk ^ref. Furthermore, it is also information for determining how much the storage battery B _k is charged or discharged. Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref based on the suppression index pr _PV received from the central management device MC2. The individual output power P _PVi ^out is controlled based on the calculated individual target power P _PVi ^ref . Each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref based on the charge / discharge index pr _B received from the central management device MC2. Then, the individual output power P _Bk ^out is controlled based on the calculated individual target power P _Bk ^ref . Accordingly, it is made to coincide linking point power P (t) to the output command value P ^C.

FIG. 13 shows a functional configuration of a control system related to output suppression control of the photovoltaic power generation system PVS2 shown in FIG. In FIG. 13, the illustration of the solar cell SP _i and the storage battery B _k is omitted. As a control system related to the output suppression control, as shown in FIG. 13, each power conditioner PCS _PVi includes a reception unit 11, a target power calculation unit 12 ′, and an output control unit 13. Each power conditioner PCS _Bk includes a reception unit 31, a target power calculation unit 32, and an output control unit 33. The centralized management device MC2 includes a target power setting unit 21, an interconnection point power detection unit 22, an index calculation unit 23 ′, and a transmission unit 24 ′.

The target power calculation unit 12 ′ calculates the individual target power P _PVi ^ref of the own device (power conditioner PCS _PVi ) based on the suppression index pr _PV received by the reception unit 11. Specifically, the target power calculation unit 12 ′ calculates the individual target power P _PVi ^ref by solving the constrained optimization problem expressed by the following equation (19). Therefore, the target power calculation unit 12 ′ is different from the target power calculation unit 12 according to the first embodiment in the calculation formula of the optimization problem for calculating the individual target power P _PVi ^ref . In the equation (19), w _PVi represents a weight related to active power suppression of the power conditioner PCS _PVi , and is a design value. P _φi is a design value indicating a design parameter (hereinafter referred to as “priority parameter”) indicating whether or not to give priority to suppression of the individual output power P _PVi ^out of the power conditioner PCS _PVi . . The smaller the priority parameter P _.phi.i, to reduce the amount of charge of battery B _k, tends individual output power P _PVi ^out is suppressed. On the other hand, increasing the priority parameter P _.phi.i, to increase the amount of charge of battery B _k, difficult individual output power P _PVi ^out is suppressed. Therefore, the priority parameter P _.phi.i can be said to be a design parameter that indicates whether to prioritize charging of the battery B _k. In addition, this priority parameter P _.phi.i, the output limit according to the rated output of the power conditioner PCS _PVi separately, considered as pseudo output limits of the individual output power P _PVi ^out of the power conditioner PCS _PVi is set It is done. Therefore, it can be said that the priority parameter _Pφi is a pseudo effective output limit. The weight w _PVi and the priority parameter P _φi can be set by the user. Details of the following equation (19) will be described later.

The receiving unit 31 is configured in the same manner as the receiving unit 11 according to the first embodiment, and receives the charge / discharge indicator pr _B transmitted from the central management device MC2.

The target power calculation unit 32 calculates the individual target power P _Bk ^ref of the own device (power conditioner PCS _Bk ) based on the charge / discharge index pr _B received by the reception unit 31. Specifically, the target power calculation unit 32 calculates the individual target power P _Bk ^ref by solving the optimization problem expressed by the following equation (20). In the equation (20), P _Bk ^lmt represents the rated output (output limit) of each power conditioner PCS _Bk . w _Bk represents a weight related to the active power of the power conditioner PCS _Bk . The weight w _Bk can be set by the user. Α _k and β _k represent adjustment parameters that can be adjusted according to the remaining amount of the storage battery B _k . Details of the following equation (20) will be described later.

The output control unit 33 is configured similarly to the output control unit 13 according to the first embodiment. The output control unit 33 controls the discharging and charging of the storage battery B _{k to set} the individual output power P _Bk ^out to the individual target power P _Bk ^ref calculated by the target power calculation unit 32. Specifically, when the individual target power P _Bk ^ref calculated by the target power calculation unit 32 is a positive value, the power (DC power) stored in the storage battery B _k is converted into AC power and Supply. That is, the power conditioner PCS _Bk is caused to function as a discharge circuit. On the other hand, when the individual target power P _Bk ^ref is a negative value, at least part of the AC power output from the power conditioner PCS _PVi is converted into DC power and supplied to the storage battery B _k . That is, the power conditioner PCS _Bk is caused to function as a charging circuit.

The index calculation unit 23 ′ calculates an index for setting the interconnection point power P (t) as the target power. In the present embodiment, since the output command value P ^C is input as the target power, the index calculation unit 23 ′ uses the suppression index pr _PV for setting the interconnection point power P (t) to the output command value P ^C and A charge / discharge index pr _B is calculated. The index calculation unit 23 ′ calculates the suppression index pr _PV and the charge / discharge index pr _B based on the following formula (21) and the following formula (22), where λ is a Lagrange multiplier, ε is a gradient coefficient, and t is time. However, when the numerical value −1 indicating that there is no output suppression command from the power company is input as the output command value P ^C from the target power setting unit 21, the index calculation unit 23 ′ sets the Lagrange multiplier λ to “ 0 ”. That is, both the suppression index pr _PV and the charge / discharge index pr _B are calculated as “0”. Incidentally, the following in equation (21), individual output power P _PVi ^out, P _Bk ^out and the output command value P ^C is because a value that varies with respect to time t, respectively a separate output power P _PVi ^out (t) , P _Bk ^out (t) and the output command value are described as P ^C (t). Details of these formulas (21) and (22) will be described later.

The transmission unit 24 ′ transmits the suppression index pr _PV calculated by the index calculation unit 23 ′ to the power conditioner PCS _PVi, and transmits the charge / discharge index pr _B calculated by the index calculation unit 23 ′ to the power conditioner PCS _Bk . .

Next, in the output suppression control performed by the photovoltaic power generation system PVS2, the reason why the above equation (19) is used to calculate the individual target power P _PVi ^ref by the power conditioner PCS _PVi , the individual target power P by the power conditioner PCS _{Bk. The} reason why the above equation (20) is used for calculating _Bk ^ref and the reason why the above equation (21) and the above equation (22) are used for calculating the suppression index pr _PV and the charge / discharge index pr _B by the centralized management device MC2. Will be explained.

The photovoltaic power generation system PVS2 is configured to achieve the following five goals in the output suppression control. The first target (target 2-1) is “each power conditioner PCS _PVi , PCS _Bk calculates the individual target power in a distributed manner”. The second target (target 2-2) is “not to suppress the output power of the power conditioner PCS _PVi connected to the solar cell as much as possible”. The third target (target 2-3) is “the storage battery is charged when the connection point power is larger than the output command value (target power), and discharged when it is insufficient”. is there. The fourth target (target 2-4) is “to match the output power (interconnection point power) at the connection point of the photovoltaic power generation system PVS2 with the output command value (target power) from the power company”. is there. The fifth target (2-5) is “to allow the output suppression amount to be adjusted for each of the power conditioners PCS _PVi and PCS _Bk ”.

First, consider a constrained optimization problem when the central management device MC2 intensively obtains the individual target powers P _PVi ^ref and P _Bk ^ref . Then, the following equation (23) is obtained. Here, as described above, P _PVi ^ref and P _Bk ^ref represent the individual target powers of the respective power conditioners PCS _PVi and PCS _Bk , and P _PVi ^lmt and P _Bk ^lmt respectively represent the respective power conditioners PCS _PVi. , PCS _Bk rated output (output limit), and P _φi represents a priority parameter. Note that the individual target powers P _PVi ^ref and P _Bk ^ref which are the optimum solutions of the following equation (23) are (P _PVi ^ref ) ^* and (P _Bk ^ref ) ^* , respectively. In the following equation (23), equation (23a) represents the minimization of the output suppression amount of the individual output power P _PVi ^out of each power conditioner PCS _PVi and the output amount of the individual output power P _Bk ^out of each power conditioner PCS _Bk. (23b) is a constraint due to the rated output P _PVi ^lmt of each power conditioner PCS _PVi , (23c) is a constraint due to the rated output P _Bk ^lmt of each power conditioner PCS _Bk , (23d) the remaining constraints of the storage batteries B _k, (23e) expression to match interconnection point power P (t) to the output command value P ^C, it represents respectively.

This shows a case where the centralized management device MC2 obtains the individual target powers (P _PVi ^ref ) ^* and (P _Bk ^ref ) ^* from the above equation (23). Therefore, in the case of the above equation (23), each power conditioner PCS _PVi and PCS _Bk does not calculate the individual target powers (P _PVi ^ref ) ^* and (P _Bk ^ref ) ^* in a distributed manner. Not achieved.

Next, consider a constrained optimization problem when each power conditioner PCS _PVi obtains the individual target power P _PVi ^ref in a distributed manner. Then, the following equation (24) is obtained.

Similarly, consider a constrained optimization problem when each power conditioner PCS _Bk obtains the individual target power P _Bk ^ref in a distributed manner. Then, the following equation (25) is obtained.

However, the individual target power, which is the optimum solution of the above equation (24), is the individual target power P _PVi ^ref obtained by each power conditioner PCS _PVi in a distributed manner, but the above equation (23e) is not considered. Similarly, the individual target power that is the optimum solution of the above equation (25) is the individual target power P _Bk ^ref obtained by each power conditioner PCS _Bk in a distributed manner, but the above equation (23e) is not taken into consideration. . Therefore, the target 2-4 for matching the interconnection point power P (t) with the output command value P ^C from the power company cannot be achieved.

Then, consider achieving the target 2-4 by the next method. That is, each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref in a distributed manner based on the suppression index pr _PV received from the central management device MC2, and each power conditioner PCS _Bk is calculated by the central management device MC2. The individual target power P _Bk ^ref is calculated in a distributed manner based on the charging / discharging index pr _B received from. Thereby, the target 2-4 is achieved. The constrained optimization problem when each power conditioner PCS _PVi obtains the individual target power P _PVi ^ref in a distributed manner using the suppression index pr _PV can be expressed by the above equation (19). The individual target power P _PVi ^ref which is the optimum solution of the above equation (19) is assumed to be (P _PVi ^ref ) ^♭ . Similarly, the constrained optimization problem when each power conditioner PCS _Bk obtains the individual target power P _Bk ^ref in a distributed manner using the charge / discharge index pr _B can be expressed by the above equation (20). . The individual target power P _Bk ^ref that is the optimum solution of the above equation (20) is assumed to be (P _Bk ^ref ) ^♭ .

Here, the above (23) best solutions obtained by formula (P _PVi ^{ref) *,} the (19) optimal solution (P _PVi ^{ref) ♭} and match obtained by formula, and, by the equation (23) When the optimum solution (P _Bk ^ref ) ^* obtained and the optimum solution (P _Bk ^ref ) ^♭ obtained by the above equation (20) coincide with each other, the interconnection point power P (t) is output from the electric power company. it can be matched to the value P ^C. That is, even if each of the power conditioners PCS _PVi and PCS _Bk solves the optimization problem in a distributed manner, the target 2-4 can be achieved. Thus, focusing on the optimality of the ^{_{steady-state, (P PVi ref) * =}} (P PVi ref) ♭ become suppressed index pr _{PV, ^{and, (P Bk ref) * =}} (P Bk ref) ♭ become charged and discharged Consider the index pr _B. Therefore, the KKT conditions of the above equation (23), the above equation (19), and the above equation (20) are considered. Thus, the following expression (26) is obtained from the KKT condition of the above expression (23), the following expression (27) is obtained from the KKT condition of the above expression (19), and the following ( 28) is obtained. Μ and ν are predetermined Lagrange multipliers.

From these equation (26), equation (27), and equation (28), by setting pr _PV = pr _B = λ (the above equation (22)), (P _PVi ^ref ) ^* and (P It can be seen that _PVi ^ref ) ^♭ and (P _Bk ^ref ) ^* and (P _Bk ^ref ) ^一致 match. Thus, the central control device MC2 calculates the Lagrange multiplier lambda, the calculated Lagrange multiplier lambda as suppression indicator pr _PV, to present to each power conditioner PCS _PVi (transmission), the power conditioner PCS _PVi respectively, The individual target power (P _PVi ^ref ) ^♭ can be calculated from the above equation (19). Similarly, the central management device MC2 presents (transmits) the calculated Lagrangian multiplier λ to each power conditioner PCS _Bk as the charge / discharge index pr _B so that each power conditioner PCS _Bk has the above (20). The individual target power (P _Bk ^ref ) ^♭ can be calculated from the equation. Thus, even if each power conditioner PCS _PVi and PCS _{Bk obtains} the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, the connection point power P (t) and the output command from the power company The value P ^C can be matched. That is, the target 2-4 can be achieved.

Next, a method for calculating the Lagrange multiplier λ by the central management device MC2 will be described. In order to obtain the Lagrangian multiplier λ, first, h ¹ _{1, i} = −P _PVi ^ref , h ¹ _{2, i} = P _PVi ^ref −P _PVi ^lmt, and the inequality constraints of each power conditioner PCS _PVi are summarized as h ^1. _{x, i} ≦ 0 (x = 1, 2, i = 1,..., n). Similarly, h ² _{1, k} = −P _Bk ^lmt −P _Bk ^ref , h ² _{2, k} = P _Bk ^ref −P _Bk ^lmt , h ² _{3, k} = α _k −P _Bk ^ref , h ² _{4 , k} = P _Bk ^ref −β _k, and inequality constraints of each power conditioner PCS _Bk are summarized and h ² _{y, k} ≦ 0 (y = 1, 2, 3, 4, k = 1,..., m ). Then, consider the following equation (29) which is a dual problem of the above equation (23).

Wherein each power conditioner PCS _PVi, optimum solution obtained by ^{_{PCS Bk (P PVi ref) ♭}} , assuming that (P _Bk ^{ref) ♭} is determined, it becomes the following equation (30), the maximum for the Lagrange multiplier λ It becomes a form of a problem. When the gradient method is applied to the following equation (30), the following equation (31) is obtained. Note that ε represents a gradient coefficient, and τ represents a time variable.

In the above equation (31), (P _PVi ^ref ) ^♭ is replaced with the individual output power P _PVi ^out of the corresponding power conditioner PCS _PVi , and (P _Bk ^ref ) ^♭ is replaced with the individual output power P of the corresponding power conditioner PCS _{Bk. Replace} with _Bk ^out . Further, the centralized management device MC2 does not individually observe the individual output powers P _PVi ^out and P _Bk ^out of the power conditioners PCS _PVi and PCS _Bk , and the connection point power P (t) = Σ _i P _PVi ^out + Σ Observe _k P _Bk ^out . Moreover, to have a valid sequential output command value P ^C from the power company. Then, the above equation (21) is obtained. Thus, the central control device MC2, based on the interconnection point power P (t) and the output command value P ^C from the power company may calculate the Lagrange multiplier lambda. Then, based on the above equation (22), the calculated Lagrangian multiplier λ is used as the suppression index pr _PV and the charge / discharge index pr _B.

From the above, in this embodiment, each power conditioner PCS _PVi uses the optimization problem shown in the above equation (19) when calculating the individual target power P _PVi ^ref . Each power conditioner PCS _Bk uses the optimization problem shown in the above equation (20) when calculating the individual target power P _Bk ^ref . The centralized management device MC2 uses the above formula (21) and the above formula (22) when calculating the suppression index pr _PV and the charge / discharge index pr _B.

  Next, in the photovoltaic power generation system PVS2 configured as described above, it was verified by simulation that the above five goals were achieved and the system was operating properly.

In the simulation, 5 units of the power conditioner PCS _PVi the solar cell SP _i is connected; and _{(i = 1~5 PCS PV1 ~PCS PV5} ), 5 units of the power conditioner PCS _Bk storage battery B _k are connected ( k = 1 to 5; PCS _{B1 to} PCS _B5 ).

In this simulation, the model of the storage battery B _k is d / dt (x _k ) = − K _k P _Bk ^out , s _k = x _k . Here, s _k denotes the charged electrical energy of the storage battery B _k, K _K represents the characteristic of the battery B _k. Furthermore, the adjustment parameters α _k and β _k that can be adjusted according to the remaining amount of the storage battery B _k are set as shown in Table 1. In Table 1, SOC _k indicates the charging rate (State Of Charge) [%] of each storage battery B _Bk , the charging power [kWh] is S _k , and the maximum capacity [kWh] of the storage battery B _k is S _{As k} ^max , SOC _k = (S _k / S _k ^max ) × 100 is calculated.

Priority parameter of the power conditioner PCS _PVi which is a parameter related to the optimization problem (pseudo effective output limit) P _.phi.i was 1000 [kW]. In addition, the model of the power system A (interconnection point voltage) (see the above equation (18)) and the models of the power conditioners PCS _PVi and PCS _Bk (see FIGS. 3 and 4) are related to the first embodiment. The same as in the simulation.

  14-16 has shown the result when simulating on several conditions using the solar power generation system PVS2 of the model shown above.

Case 1, all five of the power conditioner PCS _PV1 ~PCS _PV5 the same conditions, a case where all five of the power conditioner PCS _B1 ~PCS _B5 are the same conditions was simulated. This simulation is referred to as simulation 2-1. In the simulation 2-1, all five of the power conditioner PCS _PV1 ~PCS _PV5 is rated output P _PVi ^lmt is 500 [kW], the weights w _PVi about active power suppression 1.0, the amount of power generated by solar cell SP _i It was assumed that P _i ^SP was 600 [kW]. In addition, it is assumed that the five power conditioners PCS _{B1 to} PCS _B5 all have a rated output P _PVi ^lmt of 500 [kW] and a weight w _PVi for effective power suppression of 1.0. The maximum capacities S ₁ ^{max to} S ₅ ^max of the storage batteries B _{1 to} B ₅ were all 500 [kWh]. The output command value P ^C from the electric power company is assumed to be no command when 0 ≦ t <60 [s] and 1500 [kW] when 60 ≦ t [s]. Note that, when “there is no command for the output command value P ^C ”, as described above, the numerical value −1 indicating that there is no command is used as the output command value P ^C. In addition, the slope coefficient ε is 0.05, the update of the suppression index pr _PV and the charge / discharge index pr _B performed by the central control device MC2, and the individual target powers P _PVi ^ref and P _Bk ^ref performed by the power conditioners PCS _PVi and PCS _Bk Each sampling time with the update of 1 was set to 1 [s]. In addition, all the power conditioners PCS _PVi and PCS _Bk are assumed to be operating at a power factor of 1 (reactive power target value = 0 [kvar]). FIG. 14 shows a simulation result in the simulation 2-1.

FIG. 14A shows the power generation amount P _i ^SP of the solar cell SP _i . FIG. 14B shows the individual target power P _PVi ^ref of each power conditioner PCS _PVi . FIG. 14C shows the individual output power P _PVi ^out of each power conditioner PCS _PVi . FIG. 14D shows the interconnection point power P (t) (solid line) and the output command value P ^C (broken line) from the power company. FIG. _14E shows the individual target power P _Bk ^ref of each power conditioner PCS _Bk . FIG. _14F shows the individual output power P _Bk ^out of each power conditioner PCS _Bk . FIG. 14G shows the suppression index pr _PV and the charge / discharge index pr _B calculated by the index calculation unit 23 ′.

The following can be confirmed from FIG. That is, as shown in FIG. 14 (b) and FIG. 14 (c), the even after the command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _PV1 ^ref ~P _PV5 ^ref It remains 500 [kW], and it can be confirmed that the individual output powers P _PV1 ^{out to} P _PV5 ^out are not suppressed. Further, as shown in FIG. 14 (e) and FIG. 14 (f), the individual output power P _B1 ^out ~P _B5 ^out of the power conditioner PCS _Bk is, transitions from 0 [kW] negative (minus) It can be confirmed. This represents the fact that the input power to the power conditioner PCS _Bk, with the power input to the power conditioner PCS _Bk, charging the battery B _k. Further, as shown in FIG. 14 (d), the interconnection point power P (t) can also be confirmed that it matches the output command value P ^C. Thus, solar systems PVS2, when the output command value P ^C from the power company is commanded not suppress individual output power P _PVi ^out of the power conditioner PCS _PVi, it is used to charge the battery B _k I can confirm that.

Case 2, the five power conditioner PCS _B1 ~PCS maximum capacity of the storage battery B _5, which is connected to one of the power conditioner PCS _B5 of _B5 S ₅ ^max other power conditioner PCS _B1 ~PCS _B4 a case different from that of the connected battery B ₁ ~B _4, and simulation. This simulation is referred to as simulation 2-2. In the simulation 2-2, the maximum capacity S ₅ ^max of the storage battery B ₅ connected to one power conditioner PCS _B5 was set to 3 [kWh]. Other conditions were the same as those in the simulation 2-1. FIG. 15 shows a simulation result in the simulation 2-2. In FIG. 15, FIGS. 15A to 15G correspond to FIGS. 14A to 14G in the simulation 2-1.

The following can be confirmed from FIG. That is, as shown in FIG. 15 (a) ~ (c) , similarly to the simulation 2-1, even after a command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _It can be confirmed that _PV1 ^{ref to} P _PV5 ^ref are not suppressed. Further, as shown in FIG. 15 (e) and FIG. 15 (f), negative (minus) from the individual output power P _B1 ^out ~P _B5 ^out of the power conditioner PCS _B1 ~PCS _B5 is, 0 [kW] It can be confirmed that there is a transition. Therefore, similarly to the simulation 2-1, each power conditioner PCS _B1 ~PCS _B5, using a power input, and to charge the battery B _k. Further, as shown in FIGS. 15 (e) and 15 (f), when 110 ≦ t [s], the individual output power P _B5 ^out of the power conditioner PCS _B5 becomes 0 (zero), and other power conditioners PCS _B1 individual output power P _B1 ^out ~P _B4 ^out of ～PCS _B4 is further decreased (the input power is increasing). This is because the maximum capacity S ₅ ^max of the storage battery B ₅ is 3 [kWh] and is lower than the other storage batteries B _{1 to} B ₄ , so that at t = 110 [s], the storage battery B ₅ is connected to the other storage batteries B ₁ to B. before the B ₄ represents that the charging is completed. Thus, since the charging of the battery B ₅ is completed, it stops the input power to the power conditioner PCS _B5, represents that it stops charging. Then, the power due to distribute conditioner PCS _B5 minute power which has been input to the other of the power conditioner PCS _B1 ~PCS _B4, other power conditioner PCS _B1 ~PCS _B4 individual output power P _B1 ^out to P _B4 ^out has further decreased (input power has increased). Furthermore, as shown in FIG. 15 (d), the with the charge stop the battery B _5, and temporarily linking point power P (t) becomes greater than the output command value P ^C. However, in the steady state, interconnection point power P (t) can also be confirmed that it matches the output command value P ^C. Thus, solar systems PVS2 can be said in consideration of the performance of each battery B _k, it is subjected to proper operation.

Case 3, the weight w _B5 is set to the other of the power conditioner PCS _B1 ~PCS _B4 relates active power is set to one of the power conditioner PCS _B5 of five power conditioner PCS _B1 ~PCS _B5 A different case was simulated. This simulation is referred to as simulation 2-3. In the simulation 2-3, the weight w _B5 related to the active power of the one power conditioner PCS _B5 is set to 2.0. That is, the charging amount is halved compared with those of the other power conditioners PCS _{B1 to} PCS _B4 . Other conditions were the same as those in the simulation 2-1. FIG. 16 shows a simulation result in the simulation 2-3. In addition, in FIG. 16, (a)-(g) is a figure corresponding to FIG.14 (a)-(g) in the said simulation 2-1.

The following can be confirmed from FIG. That is, as shown in FIGS. 16A to 16C, as in the case of the simulation 2-1, the individual target power P is obtained even after the output command value P ^C is commanded (60 ≦ t [s]). _It can be confirmed that _PV1 ^{ref to} P _PV5 ^ref are not suppressed. Further, from FIG. 15 (e) and FIG. 15 (f), the individual output powers P _B1 ^{out to} P _B5 ^{out of} the power conditioners PCS _{B1 to} PCS _B5 transition from 0 [kW] to negative (minus). I can confirm that. Therefore, similarly to the simulation 2-1, each power conditioner PCS _B1 ~PCS _B5, using a power input, and to charge the battery B _k. As shown in FIGS. 16E and _16F , the charge amount of the power conditioner PCS _B5 having different weight w _B5 related to the active power (input power to the power conditioner PCS _B5 ) is the other power. It can be confirmed that the conditioners are half of PCS _{B1 to} PCS _B4 . Then, as shown in FIG. 16D, it can also be confirmed that the connection point power P (t) matches the output command value P ^C in a steady state. Therefore, it can be said that the photovoltaic power generation system PVS2 is appropriately operating in consideration of the weight w _Bk related to the active power set in the power conditioner PCS _Bk .

In addition to the results shown in FIGS. 14 to 16, the following can be confirmed by comparing FIGS. That is, as shown in each figure (g), suppression indicators pr _PV and charge-discharge index pr _B is, in each power conditioner _{PCS PV1 ~PCS PV5, PCS B1 ~PCS} B5, power generation amount P of the solar cell SP _{i i} ^SP, the performance of the battery B _k, the rated output P _PVi ^lmt, P _Bk ^lmt, weights w _PVi about active power suppression, weight w _Bk regarding active power, and, based on such an output command value P ^C, different values are calculated Can be confirmed. As shown in (b) and (e) of each figure, the individual target powers P _PVi ^ref and P _Bk ^ref are updated in accordance with the update of the suppression index pr _PV and the charge / discharge index pr _B. I can confirm. Each power conditioner _{PCS PV1 ~PCS PV5, PCS B1 ~PCS} B5 , the individual target power P _PVi ^ref, depending on the P _Bk ^ref, and controls the individual output power P _PVi ^out, P _Bk ^out. Therefore, as shown in each figure (d), it can be confirmed that the interconnection point power P (t) coincides with the output command value P ^C. From the above, it can be said that the suppression index pr _PV and the charge / discharge index pr _B calculated by the central management device MC2 using the above formulas (21) and (22) are appropriate values.

From the results of the above simulations 2-1 to 2-3, in the photovoltaic power generation system PVS2, the individual target powers are distributed in a distributed manner based on the suppression index pr _PV received by each power conditioner PCS _PVi from the central management device MC2. P _PVi ^ref is calculated. Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref in a distributed manner based on the charge / discharge index pr _B received from the central management device MC2. Therefore, the target 2-1 is achieved. Each power conditioner PCS _PVi are individually output power P _PVi ^out not suppress as much as possible, the amount of interconnection point power P (t) exceeds the output command value P ^C, the power conditioner PCS enter to _Bk, it is available to charge the battery B _k. Therefore, the above goals 2-2 and 2-3 are achieved. Further, the interconnection point power P (t) matches the output command value P ^C. Therefore, the target 2-4 is achieved. The individual output powers P _PVi ^out and P _Bk ^out change for each power conditioner PCS _PVi and PCS _Bk according to various conditions. That is, the output suppression amount changes for each power conditioner PCS _PVi and PCS _Bk according to various conditions. Therefore, the target 2-5 is achieved. From the above, it can be seen that the photovoltaic power generation system PVS2 has achieved the above five goals.

As described above, in the photovoltaic power generation system PVS2 according to the second embodiment, the central control device MC2 is suppressed index pr from the output command value P ^C and detected interconnection point power P from the power company (t) _PV and charge / discharge index pr _B are calculated. Then, the suppression index pr _PV is transmitted to each power conditioner PCS _PVi , and the charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk . Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref by solving the optimization problem of the above equation (19) in a distributed manner based on the received suppression index pr _PV . Then, the individual output power P _PVi ^out is controlled to the individual target power P _PVi ^ref . Furthermore, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref by solving the optimization problem of the above equation (20) in a distributed manner based on the received charge / discharge index pr _B. The individual output power P _Bk ^out is controlled to the individual target power P _Bk ^ref . Thereby, the centralized management device MC2 performs only simple calculations shown in the above formula (21) and the above formula (22). Therefore, in the photovoltaic power generation system PVS2, the processing load of the central management device MC2 can be reduced. Further, each of the power conditioners PCS _PVi and PCS _Bk calculates the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner based on the suppression index pr _PV and the charge / discharge index pr _B , respectively, and the individual output powers P _PVi ^out , Even when P _Bk ^out is controlled, the connection point power P (t) can be matched with the output command value P ^C from the power company.

In the first embodiment, the weight w _i related to active power suppression is considered, and in the second embodiment, the case where the weight w _PVi related to active power suppression and the weight w _Bk related to active power are considered is described as an example. However, it is not limited to this. For example, in the first embodiment described above, the target 1-3 is set for each power conditioner PCS _i unless it is necessary to consider “allowing the output suppression amount to be adjusted for each power conditioner PCS _i ”. The weights w _i related to the effective power suppression may all be the same value (for example, “1”). Similarly, in the second embodiment, if it is not necessary to consider the target 2-5 “allowing the output suppression amount to be adjusted for each of the power conditioners PCS _PVi and PCS _Bk ”, the power conditioner PCS. _The weight w _PVi related to effective power suppression set for each _PVi and PCS _Bk and the weight w _Bk related to active power may all be set to the same value (for example, “1”).

In the second embodiment, the case where the target power calculation unit 12 ′ calculates the individual target power P _PVi ^ref using the priority parameter P _φi as in the above equation (19) has been described as an example. as noted above (8) in the first embodiment, it may be used the rated output P _PVi ^lmt. In this case, whether priority is given to the suppression of the individual output power P _PVi ^out or priority is given to the charge / discharge of the storage battery B _k (individual output power P _Bk ^out ), the weight w _PVi and the weight related to the active power Adjust with w _Bk .

In the second embodiment, the optimization problem solved by the target power calculation unit 12 ′ is not limited to the above equation (19). For example, instead of the above equation (19), the following equation (19 ′) may be used. The following equation (19 ′) is added to the output current constraint of each power conditioner PCS _PVi shown in the following equation (19c ′) as compared with the above equation (19). In the following (19 ') equation, Q _PVi the reactive power of the power conditioner PCS _PVi, S _PVi ^d is printable maximum apparent power of the power conditioner PCS _PVi, V ₀ is the interconnection at the time of design The point reference voltage, V _PVi , indicates the voltage at the connection point in each power conditioner PCS _PVi . In the following equation (19 ′), instead of the output current constraint of each power conditioner PCS _PVi shown in the following equation (19c ′), the rated capacity constraint of the power conditioner PCS _PVi shown in the following equation (19d ′) is used. It may be used.

In the second embodiment, the optimization problem solved by the target power calculation unit 32 is not limited to the above equation (20). For example, instead of the above equation (20), the following equation (20 ′) may be used. The following equation (20 ′) is added with a weight w _SOCk corresponding to the SOC of the storage battery B _k in the evaluation function shown in the following (20a ′) as compared with the above equation (20). This weight w _SOCk is calculated by the following equation (32). The In (32), A _SOC's w _SOCK offset, K _SOC is the weight w _SOCK gain, s is the weight w _SOCK ON / OFF switch (e.g., 1 When on, the off-0), SOC _k Indicates the SOC of the current storage battery B _k , and SOC _d indicates the reference SOC. Furthermore, the C rate constraint of the storage battery B _k shown in the following equation (20c ′) and the output current constraint of each power conditioner PCS _Bk shown in the following equation (20e ′) are added to the constraint conditions. The C rate is a relative ratio of the charging time or the time of the discharge current to the total capacitance of the storage battery B _k, obtained by the 1C when to charge or discharge the total capacitance of the storage battery B _k at 1 hour is there. In the present embodiment, the C rate on the charging side is the charging rate C _rate ^M , the C rate on the discharging side is the discharging rate C _rate ^P, and predetermined values (for example, both 0.3 C) are set in advance. . In the following equation (20 ′), P _SMk ^lmt is a rated charge output of the storage battery B _k obtained by −C _rate ^M × WH _S ^lmt (WH _S ^lmt is a rated output capacity of the storage battery B _k ), and P _SPk ^lmt is The discharge rated output of the storage battery B _k obtained by C _rate ^P × WH _S ^lmt , Q _Bk is the reactive power of each power conditioner PCS _Bk , S _Bk ^d is the maximum apparent power that can be output by each power conditioner PCS _Bk , V _Bk indicates the voltage at the interconnection point in each power conditioner PCS _Bk . Further, the rated charge output P _SMk ^lmt of the storage battery B _k takes into account the storage battery charge amount correction according to the SOC shown in the following equation (33), with the correction start SOC as SOC _C and the SOC charge limit threshold as cMAX. . The storage battery charge amount correction is performed as usual until the correction start SOC, and from the correction start SOC to the SOC upper limit, the output is corrected linearly so that the output becomes 0 at the SOC upper limit. Yes. Further, in the following equation (20 ′), instead of the output current constraint of each power conditioner PCS _Bk shown in the following (20e ′), the rated capacity constraint of each power conditioner PCS _Bk shown in the following (20f ′) equation. It may be used.

In the photovoltaic power generation system according to another embodiment described below, the target power calculation unit 12 ′ calculates the above-described formula (19) or (19 ′) formula when calculating the individual target power P _PVi ^ref. Any of these optimization problems may be used. Similarly, when calculating the individual target power P _Bk ^ref , the target power calculation unit 32 may use any optimization problem of the above equation (20) or the above equation (20 ′).

Next, the solar power generation system PVS3 according to the third embodiment will be described. In the following description, the same or similar parts as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and the description thereof is omitted. FIG. 17 shows the overall configuration of the photovoltaic power generation system PVS3. As shown in the figure, the photovoltaic power generation system PVS3 includes a plurality of solar cells SP _i , a plurality of power conditioners PCS _PVi , a plurality of storage batteries B _k , a plurality of power conditioners PCS _Bk , and a centralized management device. MC3 and power load L are configured. Therefore, it differs in the point further provided with the electric power load L compared with the solar power generation system PVS2 which concerns on the said 2nd Embodiment.

The power load L consumes the supplied power, and is, for example, a factory or a general household. The power load L is connected to the interconnection point, and power is supplied from the power system A, each power conditioner PCS _PVi , and each power conditioner PCS _Bk .

In such a solar power generation system PVS3, and power generation solar cell SP _i is power output from the power conditioner PCS _PVi (sum .SIGMA.P _PVi ^out of each individual output power P _PVi ^out), the charging of the battery B _k The surplus power that is consumed by the power load L but not consumed by these flows back to the power system A. Even when the surplus power is flowing backward in this way, it is necessary to prevent the output command value P ^C from the power company from being exceeded if an instruction to suppress output is given from the power company. Since this surplus power can be regarded as the connection point power P (t) detected by the connection point power detection unit 22, the solar power generation system PVS3 is similar to the second embodiment in that the suppression index pr _PV and the charge / discharge Output suppression control using the index pr _B is performed. That is, the connection point power P (t) is set to the target power (output command value P ^C ). Thus, so that the surplus power does not exceed the output command value P ^C.

FIG. 18 shows a functional configuration of a control system related to output suppression control of the photovoltaic power generation system PVS3 shown in FIG. In FIG. 18, illustration of the solar battery SP _i and the storage battery B _k is omitted. Only the first power conditioners PCS _PVi and PCS _Bk are shown. As shown in the figure, the configurations of the power conditioners PCS _PVi and PCS _{Bk according} to the third embodiment and the central management device MC3 are the same as those of the power conditioners PCS _PVi and PCS _{Bk according} to the second embodiment. The configuration is the same as that of the central management device MC2 (see FIG. 13).

According to the solar power generation system PVS3 according to the present embodiment, the central control device MC3, based on the output command value P ^C and linking point power P from the power company (t), suppression indicators pr _PV and charge-discharge index pr _B is calculated. At this time, the central management device MC3 calculates the suppression index pr _PV and the charge / discharge index pr _B using the above formula (21) and the above formula (22). Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref in a distributed manner based on the suppression index pr _PV . Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref in a distributed manner based on the charge / discharge index pr _B. As a result, the processing load of the central management device MC3 can be reduced. Furthermore, interconnection point power P (t), i.e., it is possible to control the surplus power to be backward flow to the power grid A to the output command value P ^C. Therefore, it is possible to prevent the surplus power to flow backward in the power system A from exceeding the output command value P ^C from the power company.

In the said 3rd Embodiment, although the case where the electric power load L was added was demonstrated to the photovoltaic power generation system PVS2 which concerns on 2nd Embodiment as an example, electric power is supplied to the photovoltaic power generation system PVS1 which concerns on 1st Embodiment. Even when the load L is added, output suppression control can be performed using the suppression index pr. Also in this case, the processing load of the central management device MC1 can be reduced while the interconnection point power P (t) is set to the target power (output command value P ^C ).

  Next, the solar power generation system PVS4 according to the fourth embodiment will be described. The overall configuration of the photovoltaic power generation system PVS4 is substantially the same as the photovoltaic power generation system PVS3 (see FIG. 17) according to the third embodiment.

In the third embodiment, the case where the individual output power P _PVi ^{out of} each power conditioner PCS _PVi (power generation amount P _i ^SP of the solar cell SP _i ) exceeds the power consumption of the power load L has been described. In the fourth embodiment, on the contrary, the sum ΣP _PVi ^out of the individual output power P _PVi ^out (power generation amount P _i ^SP of the solar cell SP _i ) of each power conditioner PCS _PVi is lower than the power consumption of the power load L. It shall be. That is, a part or all of the insufficient power that is insufficient for the power generation amount P _i ^SP of the solar cell SP _i is supplied from the power system A. The power shortage is the difference between the individual output power P _PVi ^out of total .SIGMA.P _PVi ^out and the power consumption.

  In such a photovoltaic power generation system PVS4, in order to supply insufficient power from the power grid A, it is necessary to purchase (purchase) power from an electric power company. Then, the electricity bill is paid to the power company for the purchased power. Electricity charges include basic charges and pay-as-you-go charges. The basic charge is determined by the maximum value (peak value), for example, by recording the amount of power used every 30 minutes by a power meter provided at the connection point. Specifically, the basic charge is high when the peak value of power usage is high, and the basic charge is low when the peak value of power usage is low.

Therefore, in the photovoltaic power generation system PVS4 according to the fourth embodiment, each of the power conditioners PCS _PVi and PCS _Bk is controlled in a distributed manner using the suppression index pr _PV and the charge / discharge index pr _B. Suppress the peak value of supplied power (purchased power). This is called “peak cut control”. The purchased power is the amount of power supplied from the power system A to the solar power generation system PVS4, that is, the power obtained by the solar power generation system PVS4 from the power system A (purchased). As described above, the connection point power P (t) has a positive value when it is output from the photovoltaic power generation system PVS4 to the power system A (in the case of reverse power flow). Therefore, when it inputs into the photovoltaic power generation system PVS4 from the electric power grid | system A, the connection point electric power P (t) becomes a negative value. In the case of peak cut control for controlling the purchased power, the target value is set to a negative value, and control is performed so that the interconnection power P (t) does not fall below the target value. Photovoltaic systems PVS4, in the peak-cut control, to control the individual output power P _PVi ^out of the power conditioner PCS _PVi, and outputs all the electric power generated by the solar cell SP _i. Further, the individual output power P _Bk ^out of each power conditioner PCS _Bk is controlled, and the power stored in the storage battery B _k is discharged as necessary. In this way, a part of the power consumption of the power load L is supplemented with the power generated by the solar battery SP _i and the power stored in the storage battery B _k , thereby suppressing the increase in the purchased power. .

FIG. 19 shows a functional configuration of a control system related to peak cut control of the photovoltaic power generation system PVS4. In FIG. 19, illustration of the solar battery SP _i and the storage battery B _k is omitted. Only the first power conditioners PCS _PVi and PCS _Bk are shown. The photovoltaic power generation system PVS4 includes a centralized management device MC4 as a control system for the peak cut control, instead of the centralized management device MC3, compared to the photovoltaic power generation system PVS3 according to the third embodiment. It is different.

In the centralized management device MC4, the target power setting unit 21 sets, as the target power, a peak cut target value P _cut having the upper limit value as a negative value based on the upper limit value of the purchased power. This peak cut target value P _cut is a target value of the interconnection point power P (t) and is a negative value. The peak cut target value P _cut can be freely specified by the user. The target power setting unit 21 outputs the set target power (peak cut target value P _cut ) to the index calculation unit 23 ′. Accordingly, in the present embodiment, as the target power, instead of the output command value P ^C, and using the peak cutting target value P _cut.

In the centralized management device MC4, the index calculation unit 23 ′ uses the interconnection point power P (t) and the peak cut target value P _cut input from the target power setting unit 21 to control the suppression index pr _PV and A charge / discharge index pr _B is calculated. That is, in the present embodiment, the index calculation unit 23 ′ calculates the suppression index pr _PV and the charge / discharge index pr _{B for} setting the interconnection point power P (t) to the peak cut target value P _cut . At this time, the index calculation unit 23 ′ calculates the Lagrange multiplier λ using the peak cut target value P _cut instead of the output command value P ^C (t) in the equation (21). Then, the calculated Lagrangian multiplier λ is calculated as the charge / discharge index pr _B by the above equation (22). For the suppression index pr _PV , a fixed value “0” is used so that all the electric power generated by the solar cell SP _i is output from each power conditioner PCS _PVi . Therefore, it can be said that the index calculation unit 23 ′ calculates only the charge / discharge index pr _B. The index calculation unit 23 ′ transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 24 ′. Further, the calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 24 ′.

In the photovoltaic power generation system PVS4 configured as described above, the central management device MC4 monitors the connection point power P (t) detected by the connection point power detection unit 22. Then, when the interconnection point power P (t) becomes equal to or less than the peak cut target value _Pcut , the index calculation unit 23 ′ suppresses the interconnection point power P (t) to be the peak cut target value _Pcut. An index pr _PV (= 0) and a charge / discharge index pr _B are calculated. Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref based on the optimization problem using the suppression index pr _PV calculated by the central management device MC4, and the individual output power P _PVi ^out is the individual target power. It is controlled to become P _PVi ^ref . Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref based on the optimization problem using the charge / discharge index pr _B calculated by the centralized management device MC4, and calculates the individual output power P _Bk ^out . Control to individual target power P _Bk ^ref . As a result, when the interconnection point power P (t) is equal to or less than the peak cut target value P _cut , all the power generated by the solar cell SP _i is output and the power stored in the storage battery B _k is discharged. Is done. As a result, the connection point power P (t) increases, and the connection point power P (t) becomes the peak cut target value P _cut . Therefore, to prevent the interconnection point power P (t) is equal to or less than the peak cut target value P _cut, photovoltaic systems PVS4 is suppressed the peak value.

Note that when the interconnection point power P (t) is equal to or less than the set peak cut target value P _cut , the centralized management device MC4 controls this to the peak cut target value P _cut . Therefore, depending on the detection interval of the interconnection point power P (t) and the calculation intervals of the suppression index pr _PV and the charge / discharge index pr _B , the peak cut target value P _cut is instantaneously reduced. Therefore, when setting the upper limit value of purchased power, a value smaller than the upper limit value desired by the user may be set. Thereby, since the peak cut target value P _cut is set to a value larger than the actual target value, even if the interconnection point power P (t) instantaneously decreases, the peak cut target value P _cut does not exceed the peak cut target value P _cut. Can be suppressed.

From the above, according to the solar power generation system PVS4 according to the present embodiment, as the target power of the interconnection point power P (t), when using a peak cut target value P _cut instead of the output command value P ^C Even so, the interconnection point power P (t) can be matched with the target power (peak cut target value P _cut ). Furthermore, each power conditioner PCS _PVi and PCS _Bk obtains the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, thereby reducing the processing load on the central management device MC4.

In the fourth embodiment, during the peak cut control, since the discharge of the storage battery B _k is given priority, the power stored in battery B _k decreases. Therefore, when filled with predetermined charging conditions, using a portion of the power supplied from the power system A, it may be to charge the battery B _k. Examples of such charging conditions include a case where the interconnection point power P (t) is larger than the peak cut target value P _cut by a threshold value or more. By doing in this way, storage battery _Bk can be charged in preparation for the next peak cut control.

In such charge control of the storage battery B _k , the presence / absence of charge and the charge speed may be changed for each predetermined time period. For example, the charging mode can be set for each predetermined time zone. Then, in accordance with the charging mode, it controls the charging of the battery B _k. Examples of such a charging mode include a no-charge mode, a normal charging mode, and a low-speed charging mode. The no charge mode is a mode in which charging is not performed. The normal charging mode is a mode for charging at a predetermined charging speed (normal speed). The low-speed charging mode is a mode for charging at a predetermined speed (low speed) slower than the normal speed. The charging mode is not limited to these. The user can set the charging mode by using the user interface of the centralized management device MC4, and a mode setting unit (not shown) sets the charging mode according to the user's operation instruction. The predetermined time period is a predetermined period in which one day is divided into a plurality of times. For example, when divided every hour, it can be set every 24 time periods and divided every 30 minutes. In this case, it can be set every 48 time zones. It may be divided into time zones such as morning, noon, evening, evening, and midnight. Further, a predetermined time zone may be provided not in units of days but in units of weeks.

Specifically, the central management device MC4 transmits the charging mode setting information set by the mode setting unit to each of the power conditioners PCS _Bk via the transmission unit 24 ′. Each power conditioner PCS _Bk received this via the receiving unit 31, the storage battery B shown above (20c ') equation using the charging rate C _rate ^M associated with the charging mode is set Change the C rate constraint (charge rated output P _SMk ^lmt ) of _k . For example, the charging rate C _rate ^M for the normal charging mode is set to 0.3, the charging rate C _rate ^M for the low speed charging mode is set to 0.1, and the charging rate C _rate ^M for the no charging mode is set to 0. . Each power conditioner PCS _Bk obtains the individual target power P _Bk ^ref based on the optimization problem shown in the above equation (20 ′), so that the storage battery B _k is charged according to the setting of the charging mode. And the charging speed can be changed. Note that the charging speed may be variable so that the storage battery _Bk is fully charged in the time zone in which the low-speed charging mode is continuously set. For example, when the “low-speed charging mode” is set continuously from midnight to 6:00 am, the charging speed is set so that the storage battery _Bk is fully charged over 6 hours. Specifically, the charging rate C _rate ^{M is set} to 1/6 (≈0.167). However, it is desirable not to exceed the normal speed. In this way, according to the charging mode, it is possible to change whether or charging rate of the charging of the appropriate battery B _k. Therefore, when the unit price of the pay-as-you-go charge (for purchasing electricity) varies depending on the time of day, for example, the amount of purchased power is increased during a period when the unit price of electricity is low, and the power is purchased during a period when the unit price of power is high. Electric power can be reduced.

In the fourth embodiment, the case where a plurality of power conditioners PCS _PVi to which the solar cells SP _i are connected is described as an example, but these may not be provided. That may be those composed of battery B _k are connected to a plurality of power conditioners PCS _Bk and power load L and the central control device MC4.

  Next, the photovoltaic power generation system PVS5 according to the fifth embodiment will be described. The overall configuration of the photovoltaic power generation system PVS5 is substantially the same as that of the photovoltaic power generation system PVS3 (see FIG. 17) according to the third embodiment, and illustration thereof is omitted. In the third embodiment, it was possible to reverse the surplus power, but in the fifth embodiment, reverse power flow is prohibited.

In the photovoltaic power generation system PVS5 in which reverse power flow is prohibited, it is necessary to provide the reverse power relay 51 at the connection point to the power system A. The reverse power relay 51 is a kind of relay. When the reverse power relay 51 detects that a reverse power flow has occurred in the power system A from the solar power generation system PVS5, the reverse power relay 51 disconnects the solar power generation system PVS5 from the power system A. For example, the reverse power relay 51 detects the connection point power P (t), and detects the occurrence of a reverse power flow based on the connection point power P (t). And when generation | occurrence | production of reverse power flow is detected, the photovoltaic power generation system PVS5 is disconnected from the electric power grid | system A by interrupting the circuit breaker which is not shown provided in the connection point. Once disconnected, it takes time because it is necessary to call a specialist to return. For example, the power consumption of the power load L decreases when the power load L is low due to, for example, a factory stoppage day. Therefore, when the weather is fine on the days when the factory is closed, the power generation amount P _i ^SP of the solar cell SP _i may exceed the power consumption of the power load L, and at this time, a reverse power flow occurs.

Therefore, in the photovoltaic power generation system PVS5 according to the fifth embodiment, the power conditioners PCS _PVi and PCS _Bk are controlled in a distributed manner using the suppression index pr _PV and the charge / discharge index pr _B to generate reverse power flow. Suppress. This is called “reverse power flow avoidance control”. In addition, when the connection point power P (t) is a positive value, a reverse power flow is generated. Therefore, in order to suppress the generation of the reverse power flow, the connection point power P (t) is a positive value. It is sufficient to maintain a negative value so as not to become. The solar power generation system PVS5 suppresses the individual output power P _PVi ^out of each power conditioner PCS _{PVi in} the reverse power flow avoidance control. Further, to charge the battery B _k controls the individual output power P _Bk ^out of the power conditioner PCS _Bk. In this way, power is always supplied from the power system A to the solar power generation system PVS5. Accordingly, the negative value is maintained so that the interconnection point power P (t) does not become a positive value. Thereby, generation | occurrence | production of a reverse power flow is suppressed.

FIG. 20 shows a functional configuration of a control system related to reverse power flow avoidance control of the photovoltaic power generation system PVS5. In FIG. 20, illustration of the solar battery SP _i and the storage battery B _k is omitted. Only the first power conditioners PCS _PVi and PCS _Bk are shown. As compared with the photovoltaic power generation system PVS3 according to the third embodiment, the photovoltaic power generation system PVS5 includes a centralized management device MC5 instead of the centralized management device MC3 as a control system for the reverse power flow avoidance control. It is different in point.

In the centralized management device MC5, the target power setting unit 21 sets a reverse power flow avoidance target value _PRPR for suppressing the occurrence of reverse power flow as the target power. This reverse power flow avoidance target value _PRPR is a target value of the interconnection point power P (t) and is a negative value. The reverse power flow avoidance target value _PRPR can be freely specified by the user. The target power setting unit 21 outputs the set target power (reverse power flow avoidance target value P _RPR ) to the index calculation unit 23 ′.

Further, in the centralized management device MC5, the index calculation unit 23 ′ uses the interconnection point power P (t) and the reverse power flow avoidance target value _PRPR input from the target power setting unit 21 to control the suppression index pr _PV. And a charge / discharge index pr _B is calculated. That is, in this embodiment, the index calculator 23 'calculates the suppression indicators pr _PV and charge-discharge indicator pr _B for interconnection point power P (t) to reverse flow around the target value P _RPR. Specifically, the index calculation unit 23 ′ calculates a Lagrange multiplier λ using the reverse power flow avoidance target value _PRPR instead of the output command value P ^C (t) in the equation (21). Then, the calculated Lagrangian multiplier λ is calculated as the suppression index pr _PV and the charge / discharge index pr _B by the above equation (22). The index calculation unit 23 ′ transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 24 ′. Further, the calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 24 ′.

In the photovoltaic power generation system PVS5 configured as described above, the central management device MC5 monitors the connection point power P (t) detected by the connection point power detection unit 22. When the interconnection point power P (t) becomes equal to or higher than the reverse power flow avoidance target value _PRPR , the index calculation unit 23 'sets the connection point power P (t) to the reverse power flow avoidance target value _PRPR. The suppression index pr _PV and the charge / discharge index pr _B are calculated. Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref based on the optimization problem using the suppression index pr _PV calculated by the central management device MC5, and sets the individual output power P _PVi ^out as the individual target power. Control to P _PVi ^ref . Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref based on the optimization problem using the charge / discharge index pr _B calculated by the centralized management device MC5, and calculates the individual output power P _Bk ^out . Control to individual target power P _Bk ^ref . Thus, the connection point power P (t) is controlled to the reverse power flow avoidance target value _PRPR to suppress the generation of the reverse power flow. That is, the reverse power relay 51 is prevented from operating due to the reverse power flow.

If the set value of the reverse power flow avoidance target value _PRPR is 0 (or close to 0), it depends on the detection interval of the connection point power P (t) and the calculation interval of the suppression index pr _PV and the charge / discharge index pr _B. When the connection point power P (t) increases instantaneously, the connection point power P (t) becomes a positive value and a reverse power flow may occur. For this reason, the set reverse power flow avoidance target value _PRPR may be set to a value smaller than 0 by a predetermined amount or less. Thereby, since reverse power flow avoidance target value _PRPR becomes smaller than 0, even if connection point electric power P (t) rises instantaneously, it can suppress exceeding 0. Therefore, it is possible to suppress the occurrence of reverse power flow.

From the above, according to the solar power generation system PVS5 according to the present embodiment, as the target power of the interconnection point power P (t), using a reverse power flow avoidance target value P _RPR instead of the output command value P ^C Even in this case, the interconnection power P (t) can be matched with the target power (reverse power flow avoidance target value P _RPR ). Furthermore, each power conditioner PCS _PVi , PCS _Bk obtains the individual target powers P _PVi ^ref , P _Bk ^ref in a distributed manner, thereby reducing the processing load on the central management device MC5.

In the fifth embodiment, during the reverse flow prevention control, since the charging of the battery B _k is the priority, the power is accumulated in the battery B _k. Therefore, when filled with a predetermined discharge condition may be to discharge the battery B _k. Examples of such discharge conditions include a case where the interconnection point power P (t) is smaller than the reverse power flow avoidance target value _PRPR by a threshold value or more. By doing in this way, the storage battery _Bk can be discharged in preparation for the next reverse power flow avoidance control.

In such discharge control of the storage battery B _k , whether or not to discharge may be changed for each predetermined time period. For example, the discharge mode can be set for each predetermined time period. And according to the said discharge mode, it is controlled whether the storage battery _Bk is discharged. Such discharge modes include, for example, a discharge mode and a discharge no mode. The discharge mode is a mode in which discharge is performed. The no discharge mode is a mode in which no discharge is performed. The discharge mode is not limited to these. The user can set the discharge mode by using the user interface of the central management device MC5, and a mode setting unit (not shown) sets the discharge mode according to the user's operation instruction. The predetermined time zone at this time may be the same as or different from the predetermined time zone in the peak cut control.

Specifically, the central management device MC5 transmits the discharge mode setting information set by the mode setting unit to each of the power conditioners PCS _Bk via the transmission unit 24 ′. Each power conditioner PCS _Bk received this via the receiving unit 31, the storage battery B shown above (20c ') equation using the discharge rate C _rate ^P associated with the discharge mode that is set Change the C rate constraint (discharge rated output P _SPk ^lmt ) of _k . For example, 0.3 is the discharge rate C _rate ^P to the discharge chromatic mode, the discharge rate C _rate ^P to the discharge-free mode is set to 0, respectively. Then, the power conditioner PCS _Bk obtains the individual target power P _Bk ^ref based on the optimization problem shown in the above equation (20 ′), and thereby discharges the storage battery B _k according to the setting of the discharge mode. Can be changed. By doing in this way, it can change suitably whether storage battery _Bk is discharged according to discharge mode. Therefore, the electric power can be accumulated without discharging the storage battery B _k as necessary.

In the said 5th Embodiment, although the reverse power relay 51 demonstrated the case where the solar power generation system PVS5 was disconnected from the electric power grid | system A, it is not limited to this. For example, the power conditioners PCS _PVi and PCS _Bk may be _disconnected from the power system A. That is, even if the power relay L is disconnected by the reverse power relay 51, the power load L may remain connected to the power system A. For example, the circuit breaker is installed at the connection line position BP1 shown in FIG. 20 or at the connection line position BP2 shown in FIG. 20 (in the vicinity of the output ends of the power conditioners PCS _PVi and PCS _Bk , respectively). Thus, the reverse power relay 51 can _disconnect the power conditioners PCS _PVi and PCS _Bk from the power system A while leaving the power load L.

In the fifth embodiment, the case where a plurality of power conditioners PCS _Bk to which the storage battery B _k is connected is described as an example. However, these may not be provided. That is, it may be configured by a plurality of power conditioners PCS _PVi , a power load L, and a central management device MC5 to which the solar cell SP _i is connected. In this case, when the photovoltaic power generation system PVS5 performs the reverse power flow avoidance control, the reverse power flow in which the connection point power P (t) is set only by suppressing the individual output power P _PVi ^out from the power conditioner PCS _PVi. The avoidance target value P _RPR is set.

  In the third to fifth embodiments, the solar power generation systems PVS3, PVS4, and PVS5 in which output suppression control, peak cut control, and reverse power flow avoidance control are individually implemented have been described. Combinations are also possible. In this case, it is only necessary to switch which control the centralized management apparatus performs as appropriate. For example, switching may be performed according to the user's operation, the situation (positive / negative of the connection point power P (t) (whether or not reverse flow is in progress), reverse flow is prohibited, or power of the power load L It may be automatically switched according to a consumption history or a working day.

Next, the solar power generation system PVS6 according to the sixth embodiment will be described. In the said 1st Embodiment thru | or 5th Embodiment, the connection point electric power P (t) which the connection point electric power detection part 22 detects was considered as the output electric power of the photovoltaic power generation systems PVS1-PVS5 whole. However, not only the connection point power P (t) but also the individual output power P _i ^out or the individual output powers P _PVi ^out and P _Bk ^out from each power conditioner PCS _i or each power conditioner PCS _PVi and PCS _Bk . It is also possible to calculate the sum (hereinafter referred to as “system total output”) and regard this as the output power of the entire photovoltaic power generation system. Therefore, the solar power generation system PVS6 performs control so that the total system output becomes the target power. Therefore, the total system output is used as the adjustment target power.

Figure 21 is, as shown in FIG. 21 shows an overall configuration of a solar power generation system PVS6, photovoltaic systems PVS6 the plurality of solar cells SP _i, a plurality of power conditioners PCS _PVi, the plurality A storage battery B _k , a plurality of power conditioners PCS _Bk , and a centralized management device MC6 are included.

The photovoltaic power generation system PVS6 according to the sixth embodiment does not detect the connection point power P (t), and sums all of the individual output powers P _PVi ^out and P _Bk ^out of the power conditioners PCS _PVi and PCS _Bk. (System total output P _total (t)) is calculated. Then, it is controlled so as to match the system total output P _total (t) to the output command value P ^C instructed by the power company as the output power of the entire solar power system PVS6. That is, photovoltaic systems PVS6 performs output suppression control using the total system output P _total (t) instead of interconnection point power P (t).

FIG. 22 shows a functional configuration of a control system related to output suppression control of the photovoltaic power generation system PVS6 shown in FIG. In FIG. 22, illustration of the solar battery SP _i and the storage battery B _k is omitted. Only the first power conditioners PCS _PVi and PCS _Bk are shown. The photovoltaic power generation system PVS6 is different in that a central management device MC6 is provided instead of the central management device MC2 according to the second embodiment as a control system for the output suppression control. The configurations of the power conditioners PCS _PVi and PCS _Bk are also different.

In the present embodiment, each power conditioner PCS _PVi further includes an output power detection unit 14 and a transmission unit 15, and each power conditioner PCS _Bk further includes an output power detection unit 34 and a transmission unit 35, respectively. I have. The central management device MC6 includes a receiving unit 61, a total output calculating unit 62, and an index calculating unit 63 instead of the interconnection point power detecting unit 22 and the index calculating unit 23 ′.

The output power detection unit 14 is provided in each power conditioner PCS _PVi and detects the individual output power P _PVi ^out of its own device. The output power detection unit 34 is provided in each power conditioner PCS _Bk and detects the individual output power P _Bk ^out of its own device.

The transmission unit 15 transmits the individual output power P _PVi ^out detected by the output power detection unit 14 to the central management device MC6. The transmission unit 35 transmits the individual output power P _Bk ^out detected by the output power detection unit 34 to the central management device MC6.

The receiving unit 61 receives the individual output powers P _PVi ^out and P _Bk ^out transmitted from the power conditioners PCS _PVi and PCS _Bk .

The total output calculation unit 62 calculates a system total output P _total (t) that is the sum of the individual output powers P _PVi ^out and P _Bk ^out received by the reception unit 61. In the present embodiment, the total output calculation unit 62 calculates the _total system output P _total (t) obtained by adding all the individual output powers P _PVi ^out and P _Bk ^out that are input.

The index calculation unit 63 calculates an index for setting the system total output P _total (t) calculated by the total output calculation unit 62 as the target power. In the present embodiment, since the output command value P ^C as the target power is inputted, index calculation unit 63, the system total output P _total (t) inhibition index for the output command value P ^C and pr _PV and charge A discharge index pr _B is calculated. At this time, the index calculation unit 63 calculates the Lagrange multiplier λ using the system total output P _total (t) instead of the interconnection point power P (t) in the above equation (21). Then, the calculated Lagrangian multiplier λ is calculated as the suppression index pr _PV and the charge / discharge index pr _B by the above equation (22). The calculated suppression index pr _PV is transmitted to each power conditioner PCS _PVi via the transmission unit 24 ′. Further, the calculated charging / discharging index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 24 ′.

According to the photovoltaic power generation system PVS6 according to the present embodiment, the system total output _Ptotal (t) is used as the adjustment target power instead of the interconnection power P (t) in the second embodiment. However, the system total output P _total (t) can be set to the target power (output command value P ^C ). Furthermore, since the power conditioners PCS _PVi and PCS _Bk obtain the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, the processing load on the central management device MC6 can be reduced.

In the above-described sixth embodiment, with respect to solar power generation system PVS2 according to the second embodiment, a case has been described for controlling the output command value P ^C total system output P _total (t) as an example, the first The same may be applied to the photovoltaic power generation system PVS1 according to the embodiment. That is, in the photovoltaic power generation system PVS1 according to the first embodiment, even when controlling system total output P _total (t) to the output command value P ^C in place of interconnection point power P (t), the suppression indicators pr It is possible to perform output suppression control. In this case as well, the processing load of the centralized management device can be reduced while setting the _total system output P _total (t) to the target power (output command value P ^C ).

Next, the photovoltaic power generation system PVS7 according to the seventh embodiment will be described. Note that the same or similar parts as those in the sixth embodiment are denoted by the same reference numerals, and the description thereof is omitted. FIG. 23 shows the overall configuration of the photovoltaic power generation system PVS7. As shown in the figure, the photovoltaic power generation system PVS7 includes a plurality of solar cells SP _i , a plurality of power conditioners PCS _PVi , a plurality of storage batteries B _k , a plurality of power conditioners PCS _Bk , and a centralized management device. It has MC7 and electric power load L, and is comprised. Therefore, it differs in the point further provided with the electric power load L compared with the solar power generation system PVS6 which concerns on the said 6th Embodiment.

FIG. 24 shows a functional configuration of a control system related to output suppression control of the photovoltaic power generation system PVS7 shown in FIG. In FIG. 24, illustration of the solar battery SP _i and the storage battery B _k is omitted. Only the first power conditioners PCS _PVi and PCS _Bk are shown. As shown in the figure, the configurations of the power conditioners PCS _PVi and PCS _{Bk according} to the seventh embodiment and the centralized management device MC7 are the same as those of the power conditioners PCS _PVi and PCS _{Bk according} to the sixth embodiment. The configuration is the same as that of the central management device MC6 (see FIG. 22).

In the photovoltaic power generation system PVS7 according to the present embodiment, similarly to the sixth embodiment, the output using the suppression index pr _PV and the charge / discharge index pr _B based on the calculated _total system output P _total (t). Suppression control can be performed. Therefore, similarly to the sixth embodiment, it is possible to reduce the processing load of the central management device MC7 while setting the system total output P _total (t) to the target power (output command value P ^C ).

In the said 7th Embodiment, although the case where the electric power load L was added with respect to the solar power generation system PVS6 which concerns on the said 6th Embodiment was demonstrated to the example, the electric power load L with respect to the solar power generation system PVS1. Add a, and, even in the solar power generation system that controls the output command value P ^C total system output P _total (t) instead of interconnection point power P (t), by using the suppression indicators pr, output Suppression control can be performed. Also in this case, the system total output P _total (t) can be set to the target power (output command value P ^C ), and the processing load of the centralized management device can be reduced.

Next, a solar power generation system PVS8 according to the eighth embodiment will be described. The overall configuration of the photovoltaic power generation system PVS8 is substantially the same as that of the photovoltaic power generation system PVS7 (see FIG. 23) according to the seventh embodiment. In the sixth and seventh embodiments, various target powers are set for the _total system output P _total (t). However, in this embodiment, a plurality of power conditioners are divided into a plurality of groups. The target power is set for each group. In the following description, a plurality of power conditioners PCS _PVi and PCS _Bk are _combined into a first power conditioner group G _PV that is a set of a plurality of power conditioners PCS _PVi and a plurality of power conditioners PCS _Bk . It will be described as an example a case where it is divided into two groups of the second power conditioner group G _B is.

The solar power generation system PVS8 according to the eighth embodiment sets a target power for each of the first power conditioner group G _PV and the second power conditioner group G _B, and sets the first power conditioner group G _PV. the total output power and the total output power of the second power conditioner group G _B in is controlled to respectively become the target power. This control is called “schedule control”. The total output power of the first power conditioner group G _PV is the sum ΣP _PVi ^out of the individual output powers P _PVi ^out of each power conditioner PCS _PVi , and is hereinafter referred to as the first group total output P _GPV . The total output power of the second power conditioner group G _B is the sum .SIGMA.P _Bk ^out of individual output power P _Bk ^out of the power conditioner PCS _Bk, hereinafter referred to as the second group the total output P _GB.

FIG. 25 shows a functional configuration of a control system related to schedule control of the photovoltaic power generation system PVS8. In FIG. 25, illustration of the solar battery SP _i and the storage battery B _k is omitted. Only the first power conditioners PCS _PVi and PCS _Bk are shown. The control system related to the schedule control is different from the solar power generation system PVS7 according to the seventh embodiment in the following points. That is, the central management device MC8 includes a total output calculation unit 62 ′ instead of the total output calculation unit 62, and an index calculation unit 63 ′ instead of the index calculation unit 63.

In the central control device MC8, target power setting unit 21, the second group target is the first group target value P _TPV and the target value of the second group the total output P _GB which is a target value of the first group the total output P _GPV The value P _TB is set as the target power. The first group target value P _TPV and the second group target value P _TB can be set for each predetermined time period. These target values can be freely specified by the user. The target power setting unit 21 outputs the set target power (the first group target value P _TPV and the second group target value P _TB ) to the index calculation unit 63 ′.

The total output calculation unit 62 ′ calculates the first group total output P _GPV and the second group total output P _GB , respectively. Specifically, the total output calculation unit 62 ′ calculates the first group total output P _GPV by adding the individual output power P _PVi ^out of the power conditioner PCS _PVi received by the reception unit 61. The total output calculation unit 62 'adds the individual output power P _Bk ^out of the power conditioner PCS _Bk the receiving unit 61 has received, it calculates the total output P _GB second group.

The index calculation unit 63 ′ sets a suppression index pr _PV for setting the first group total output P _GPV calculated by the total output calculation unit 62 ′ to the first group target value P _TPV input from the target power setting unit 21. calculate. At this time, the index calculation unit 63 ′ calculates the suppression index pr _PV using the following equation (34). In the following equation (34), λ _PV represents a Lagrange multiplier for a plurality of power conditioners PCS _PVi , and ε _PV represents a gradient coefficient for the plurality of power conditioners PCS _PVi . Further, since the first group total output P _GPV and the first group target value P _TPV are values that change with respect to time t, the first group total output is P _GPV (t), and the first group target value is P _TPV (t) is described. Therefore, the index calculation unit 63 ′ uses the first group total output P _GPV (t) instead of the interconnection point power P (t) in the above equation (9), instead of the output command value P ^C (t). A Lagrange multiplier λ _PV is calculated using the first group target value P _TPV (t). Then, the calculated Lagrangian multiplier λ _PV is set as the suppression index pr _PV . The index calculation unit 63 ′ transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 24 ′.

In addition, the index calculation unit 63 ′ is a charge / discharge index for setting the second group total output P _GB calculated by the total output calculation unit 62 ′ to the second group target value P _TB input from the target power setting unit 21. Calculate pr _B. At this time, the index calculation unit 63 ′ calculates the charge / discharge index pr _B using the following equation (35). In the following equation (35), λ _B represents a Lagrange multiplier for a plurality of power conditioners PCS _Bk , and ε _B represents a gradient coefficient for the plurality of power conditioners PCS _Bk . Further, since the second group total output P _GB and the second group target value P _TB are values that change with respect to time t, the second group total output is P _GB (t), and the second group target value is P _TB (t) is described. Therefore, the index calculation unit 63 ′ uses the second group total output P _GB (t) instead of the interconnection power P (t) in the above equation (9), instead of the output command value P ^C (t). A Lagrange multiplier λ _B is calculated using the second group target value P _TB (t). The calculated Lagrangian multiplier λ _B is used as the charge / discharge index pr _B. The index calculation unit 63 ′ transmits the calculated charge / discharge index pr _B to each power conditioner PCS _Bk via the transmission unit 24 ′.

In the photovoltaic power generation system PVS8 configured as described above, the central management device MC8 obtains the individual output power P _PVi ^out from each power conditioner PCS _PVi, and calculates the first group total output P _GPV . Then, the suppression index pr _PV is calculated using the above equation (34) so that the calculated first group total output P _GPV becomes the first group target value P _TPV . The calculated suppression index pr _PV is transmitted to each power conditioner PCS _PVi . Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref using the received suppression index pr _PV and controls the individual output power P _PVi ^{out to} become the individual target power P _PVi ^ref . Further, the central management device MC8 obtains the individual output power P _Bk ^out from the power conditioner PCS _Bk, and calculates the second group total output P _GB . Then, the charge / discharge index pr _B is calculated using the above equation (35) so that the calculated second group total output P _GB becomes the second group target value P _TB . The calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk . Each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref using the received charge / discharge index pr _B and controls the individual output power P _Bk ^{out to} be the individual target power P _Bk ^ref . Thus, the first group total output P _GPV becomes the first group target value P _TPV , and the second group total output P _GB becomes the second group target value P _TB .

From the above, according to the solar power generation system PVS8 according to this embodiment, and target power (first group target value P _TPV to the first power conditioner group G _PV and the second power for each conditioner group G _B No. The second group target value P _TB ) is set, the first group total output P _GPV is set to the first group target value P _TPV , and the second group total output P _GB is set to the second group target value P _TB. it can. Further, the power conditioners PCS _PVi and PCS _Bk calculate the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner based on the suppression index pr _PV and the charge / discharge index pr _B , respectively. Processing load can be reduced.

In the above-described eighth embodiment, if you set the target power (first group target value P _TPV and the second group target value P _TB) to the first power conditioner group each G _PV and second power conditioner group G _B However, only one of them may be used.

In the eighth embodiment, a plurality of power conditioners PCS _PVi and PCS _Bk are used as a first power conditioner group G _PV that is a set of a plurality of power conditioners PCS _PVi and a plurality of power conditioners PCS _Bk. it is a set of but a case in which divided into two groups with the second power conditioner group G _B is described as an example, but is not limited thereto. For example, the first power conditioner group G _PV further divided into a plurality of groups, may be set the target power for each the group. The same applies to the second power conditioner group G _B. In addition, one group may be grouped so that both one or more power conditioners PCS _PVi and one or more power conditioners PCS _Bk are included, and target power may be set for each group. . In this case, the suppression index pr _PV and the charge / discharge index pr _B may be calculated for each group using the formula (21) and the formula (22).

In the eighth embodiment, the case of dividing into a plurality of groups has been described. However, schedule control may be performed with a plurality of power conditioners PCS _PVi and PCS _Bk as one group without being divided into a plurality of groups. . That is, the user may freely set the target value of the system total output P _total (t) for each predetermined time period, and control so that the system total output P _total (t) matches the target value. In addition, when performing schedule control as one group in this way, the connection point power P (t) may be used instead of the system total output P _total (t). That is, in the photovoltaic power generation systems PVS1 to PVS5 according to the first embodiment to the fifth embodiment, the target value of the interconnection point power P (t) is freely set as the target power every predetermined time zone. The interconnection point power P (t) may be matched with the target value.

In the seventh embodiment and the eighth embodiment, the solar power generation systems PVS7 and PVS8 in which the output suppression control and the schedule control are individually implemented have been described, but it is also possible to combine them. In this case, it is only necessary to switch which control the centralized management apparatus performs as appropriate. For example, you may make it switch according to a user's operation, and a situation (whether the suppression instruction is received from the electric power company, or the 1st group target value _PTPV or the 2nd group target value _PTB is set) It is also possible to automatically switch according to the above.

In the seventh embodiment and the eighth embodiment, the central management devices MC7 and MC8 have a configuration in which the individual output powers P _PVi ^out and P _Bk ^out are obtained from the power conditioners PCS _PVi and PCS _Bk. Although described as an example, a configuration for obtaining the power consumption of the power load L from the power load L may be added. When the power consumption of the power load L is available in this way, the sum of the individual output powers P _PVi ^out and P _Bk ^out obtained from the power conditioners PCS _PVi and PCS _Bk and the power consumption obtained from the power load L is calculated. By calculating, the connection point power P (t) can be estimated. Therefore, even if the interconnection point power detection unit 22 is not provided, the output suppression control according to the third embodiment, the peak cut control according to the fourth embodiment, and the reverse power flow avoidance according to the fifth embodiment. Control can be performed.

In the third to fifth embodiments, the case where output suppression control, peak cut control, and reverse power flow avoidance control are performed based on the interconnection point power P (t) will be described as an example. In the embodiment and the eighth embodiment, examples of performing output suppression control and schedule control based on the _total system output P _total (t), the first group total output P _GPV and the second group total output P _GB are examples. However, the present invention is not limited to this. Both means for detecting the connection point power P (t) (connection point power detection unit 22) and means for obtaining the individual output powers P _PVi ^out and P _Bk ^out from the power conditioners PCS _PVi and PCS _Bk , respectively, are provided. In addition, output suppression control, peak cut control, reverse power flow avoidance control, and schedule control may be controlled in combination.

Next, a photovoltaic power generation system PVS9 according to the ninth embodiment will be described. In the solar power generation system PVS9, reverse power flow is prohibited. Thus, when reverse power flow is prohibited, it is necessary to install the reverse power relay 51 as described in the fifth embodiment. And in the said 5th Embodiment, in order to suppress that the said reverse power relay 51 operate | moves, reverse power flow avoidance control is performed. However, when the interconnection point power P (t) suddenly increases, a reverse power flow may occur. For example, the set value of the reverse power flow avoidance target value _PRPR is 0 (or close to 0), and the detection interval of the connection point power P (t), the calculation interval of the suppression index pr _PV, and the charge / discharge index pr _B Is long, the control by changing the suppression index pr _PV and the charge / discharge index pr _B cannot cope with a rapid increase in the interconnection point power P (t). As a result, the interconnection point power P (t) becomes a positive value, and a reverse power flow occurs. Thereby, the reverse power relay 51 detects a reverse power flow and disconnects the photovoltaic power generation system from the power system A. Therefore, in the fifth embodiment, a method for avoiding the occurrence of reverse power flow by setting the reverse power flow avoidance target value _{PRPR to} a value smaller than 0 by a predetermined amount or less has been shown. However, during the reverse power flow avoidance control, the interconnection point power P (t) is controlled so as to coincide with the reverse power flow avoidance target value _PRPR . Therefore, in this method, the connection point power P (t) is equal to or less than a value smaller than 0 by a predetermined amount (reverse power flow avoidance target value P _RPR ), and the purchased power increases accordingly. Therefore, the reverse power flow avoidance target value _PRPR should be as close to 0 as possible.

  Therefore, the photovoltaic power generation system PVS9 according to the ninth embodiment is a method different from the method shown in the fifth embodiment with respect to the sudden increase in the interconnection point power P (t) as described above. Is also avoided from being disconnected from the power system A.

FIG. 26 shows the overall configuration of the photovoltaic power generation system PVS9. As shown in the figure, the photovoltaic power generation system PVS9 includes a plurality of solar cells SP _i , a plurality of power conditioners PCS _PVi , a plurality of storage batteries B _k , a plurality of power conditioners PCS _Bk , and a centralized management device. MC 9, power load L, and auxiliary relay 52 are configured. Moreover, the solar power generation system PVS9 is connected to the power system A, and a reverse power relay 51 is installed at the connection point between the solar power generation system PVS9 and the power system A. Therefore, the reverse power relay 51 disconnects the photovoltaic power generation system PVS9 from the power system A when detecting the reverse power flow. Also in this embodiment, as in the fifth embodiment, the reverse power relay 51 _disconnects the power conditioners PCS _PVi and PCS _Bk from the power system A when a reverse power flow is detected. Also good. That is, even if the power relay L is disconnected by the reverse power relay 51, the power load L may remain connected to the power system A. Each solar cell SP _i and each power conditioner PCS _PVi correspond to the “solar power generation device” and “distributed power source” of the present invention. Further, each storage battery B _k and each power conditioner PCS _Bk correspond to the “power storage device” and “distributed power source” of the present invention. And what included the photovoltaic power generation system PVS9 and the reverse power relay 51 is equivalent to the "electric power system" of this invention.

The auxiliary relay 52 is a relay device that operates by detecting a reverse power flow. The auxiliary relay 52 has an electrical contact (not shown). The electrical contact operates by detecting the occurrence of a reverse power flow when the connection point power P (t) is equal to or greater than a threshold value. For example, 0 is set as the threshold value. It may be a value smaller than 0 by a predetermined amount (however, a value larger than the reverse power flow avoidance target value _PRPR ). When the electrical contact is operated, the auxiliary relay 52 transmits a contact signal indicating that the electrical contact has been operated to each of the power conditioners PCS _PVi and PCS _Bk and the central management device MC9. In this embodiment, the reverse power relay 51 detects the reverse power flow when the reverse power flow state continues for about 50 ms, whereas the auxiliary relay 52 (electrical contact) continues the reverse power flow state for about 10 ms. If a reverse power flow is detected. That is, the reverse power flow detection time of the auxiliary relay 52 is set shorter than the time during which the reverse power relay 51 detects the reverse power flow (reverse power flow detection time). Thereby, the auxiliary relay 52 can detect the reverse power flow earlier than the reverse power relay 51.

The photovoltaic power generation system PVS9 uses the auxiliary relay 52 installed at the connection point to avoid being disconnected from the power system A even when the connection point power P (t) is suddenly increased. . Specifically, when a reverse power flow occurs and the auxiliary relay 52 operates, the photovoltaic power generation system PVS9 notifies the power conditioners PCS _PVi , PCS _Bk and the centralized management device MC9. Then, the individual output powers P _PVi ^out and P _Bk ^out of the power conditioners PCS _PVi and PCS _Bk are forcibly reduced. Thereby, connection point electric power P (t) falls. Therefore, the reverse power flow is eliminated and the above disconnection is avoided. This control is called “disconnection avoidance control”.

FIG. 27 shows a functional configuration of a control system related to the disconnection avoidance control of the photovoltaic power generation system PVS9 shown in FIG. In FIG. 27, illustration of the solar battery SP _i and the storage battery B _k is omitted. Only the first power conditioners PCS _PVi and PCS _Bk are shown. The photovoltaic power generation system PVS9 includes a centralized management device MC9 instead of the centralized management device MC5, as compared with the photovoltaic power generation system PVS5 according to the fifth embodiment, in order to perform the disconnection avoidance control. Different. The central management device MC9 further includes a receiving unit 25 as compared with the central management device MC5, and includes an index calculation unit 23 ″ instead of the index calculation unit 23 ′. Each power conditioner PCS _PVi includes: A receiving unit 11 ′ is provided instead of the receiving unit 11, and a target power calculating unit 12 ″ is provided instead of the target power calculating unit 12 ′. Each power conditioner PCS _Bk includes a reception unit 31 ′ instead of the reception unit 31, and includes a target power calculation unit 32 ′ instead of the target power calculation unit 32.

  The receiving unit 25 receives a contact signal transmitted from the auxiliary relay 52. The receiving unit 25 outputs the received contact signal to the index calculating unit 23 ″. Note that the receiving unit 25 corresponds to the “contact signal receiving unit for centralized management device” of the present invention.

The index calculation unit 23 ″ calculates an index for setting the interconnection point power P (t) as the target power in the normal manner, similarly to the index calculation unit 23 ′. In the present embodiment, the index calculation unit 23 ″ is reversed as the target power. Since the power flow avoidance target value P _RPR is input, the index calculation unit 23 ″ uses the suppression index pr _PV and the charge / discharge index pr _B for setting the interconnection point power P (t) to the reverse power flow avoidance target value P _RPR. Is calculated. However, the index calculation unit 23 ″ stops calculating the suppression index pr _PV and the charge / discharge index pr _B when the contact signal is input from the reception unit 25. Then, the disengagement avoidance value set in advance is determined as the suppression index. Pr _PV and charge / discharge index pr _{B. The} disconnection avoidance value is a set value for avoiding disconnection by the reverse power relay 51. The _{disconnection} avoidance value is a value for each power conditioner PCS _PVi. The individual output power P _PVi ^out is suppressed, and each power conditioner PCS _Bk is set to charge the storage battery B _k, that is, the disconnection avoidance value is the connection point power P (t). Note that a specific set value of the disconnection avoidance value will be described later. Further, the index calculation unit 23 ″ uses the suppression index pr _PV and the charge / discharge index pr _B as the avoidance of disconnection. With value Et al., A predetermined time (e.g., 120 [s]) after a lapse resumes normal calculation process of suppression indicators pr _PV and charge-discharge indicator pr _B at. That is, the process returns to the reverse power flow avoidance control. At this time, the calculation of the suppression index pr _PV and the charge / discharge index pr _B is restarted with the initial values of the suppression index pr _PV and the charge / discharge index pr _B being both set as the disconnection avoidance values.

The receiving unit 11 ′ receives the suppression index pr _PV transmitted from the central management device MC9, and receives the contact signal transmitted from the auxiliary relay 52. The reception unit 11 ′ outputs the received suppression index pr _PV and the contact signal to the target power calculation unit 12 ″. The reception unit 11 ′ includes the “index reception unit” and the “distributed power source contact” of the present invention. This corresponds to “signal receiving means”.

In the normal state, the target power calculation unit 12 ″, like the target power calculation unit 12 ′, is based on the suppression index pr _PV received by the reception unit 11 ′, and the individual target power P of its own device (power conditioner PCS _PVi ). _PVi ^ref is calculated, however, when the contact power signal is input from the receiving unit 11 ′, the target power calculating unit 12 ″ does not use the suppression index pr _PV received by the receiving unit 11 ′, but a preset solution. The avoidance value is set as the suppression index pr _PV . That is, in the optimization problem shown in the above equation (19), the individual target power P _PVi ^ref is calculated using the solution avoidance value as the suppression index pr _PV . As described above, since the disconnection avoidance value is set so as to reduce the interconnection point power P (t), the calculated individual target power P _PVi ^ref becomes small. Therefore, the individual output power P _PVi ^out is also reduced. The disconnection avoidance value is the same as that set in the index calculation unit 23 ″. The target power calculation unit 12 ″ uses the disconnection avoidance value as the suppression index pr _PV , and then performs a predetermined time ( For example, when 60 [s]) has elapsed, the processing returns to the calculation processing of the individual target power P _PVi ^ref at the normal time. Note that the former is set shorter between the predetermined time in which the target power calculation unit 12 ″ uses the disconnection avoidance value and the predetermined time in which the index calculation unit 23 ″ uses the disconnection avoidance value.

The receiving unit 31 ′ receives the charge / discharge index pr _B transmitted from the centralized management device MC9, and also receives the contact signal transmitted from the auxiliary relay 52. The receiving unit 31 ′ outputs the received charge / discharge index pr _B and the contact signal to the target power calculating unit 32 ′. The receiving unit 31 ′ also corresponds to “index receiving means” and “distributed power contact signal receiving means” of the present invention.

In the normal state, the target power calculation unit 32 ′, like the target power calculation unit 32, based on the charge / discharge index pr _B received by the reception unit 31 ′, the individual target power P of its own device (power conditioner PCS _Bk ). _Bk ^ref is calculated. However, when the contact signal is input from the receiving unit 31 ′, the target power calculating unit 32 ′ charges / discharges a preset disconnection avoidance value instead of the charging / discharging index pr _B received by the receiving unit 31 ′. The index is pr _B. That is, in the optimization problem shown in the above equation (20), the individual target power P _Bk ^ref is calculated using the disconnection avoidance value as the charge / discharge index pr _B. As described above, since the disconnection avoidance value is set so as to reduce the interconnection point power P (t), the calculated individual target power P _Bk ^ref becomes small. Accordingly, the individual output power P _Bk ^out is also reduced. The disconnection avoidance value is the same as that set in the index calculation unit 23 ″. The target power calculation unit 32 ′ uses the disconnection avoidance value as the charge / discharge index pr _B for a predetermined time. When the time elapses (for example, 60 [s]), the process returns to the calculation processing of the individual target power P _Bk ^ref at the normal time. 32 'is the same as the above-mentioned predetermined time for using the discontinuity avoidance value.

Next, the _{disconnection} avoidance values set in the power conditioners PCS _PVi and PCS _Bk and the central management device MC9 will be described.

In the present embodiment, the weight w _PVi about effective suppression of power each power conditioner PCS _PVi ((19a) above formula refer) weight w _Bk regarding active power and the power conditioner PCS _Bk (above (20a) see formula) Is set as shown below.

Specifically, a value calculated by the following equation (37) is used as the weight w _PVi related to effective power suppression of each power conditioner PCS _PVi . In the following equation (37), pr _PV ^lmt indicates the suppression index limit. The suppression index limit pr _PV ^lmt is a suppression index when the individual output power P _PVi ^{out is set} to 0, that is, a suppression index when the individual output power P _PVi ^out is suppressed by 100%. P _PVi ^lmt is the rated output of each of the power conditioners PCS _PVi . In place of the rated output P _PVi ^lmt of each power conditioner PCS _PVi , a pseudo effective output limit P _φi may be used. That is, a value calculated by the following equation (37 ′) may be used.
w _PVi = pr _PV ^lmt / (2 × P _PVi ^lmt ) (37)
w _PVi = pr _PV ^lmt / (2 × P _φi ) (37 ′)

FIG. _28A shows the relationship between the suppression index pr _PV and the individual output power P _PVi ^out when the weight w _PVi related to effective power suppression is set using the above equation (37). In FIG. 28 (a), the solid line when the rated output P _PVi ^lmt power conditioner PCS _PVi of 500kW, broken lines when the rated output P _PVi ^lmt power conditioner PCS _PVi of 250 kW, dashed line rated output This ^{shows the case} where the power conditioner PCS _PVi with P _PVi ^lmt of 100 kW is shown. Further, the suppression index limit pr _PV ^lmt in the above equation (37) was ^set to 100.

As shown in FIG. 28 (a), the each suppression index pr _PV is 20 rises between 0 and 100 (inhibition index limit pr _PV ^lmt), when the rated output P _PVi ^lmt is 500kW 100 kW, the rated output P _PVi ^{When lmt} is 250 kW, 50 kW, and when the rated output P _PVi ^lmt is 100 kW, the power decreases by 20 kW. This would have reduced by 20% of the rated output P _PVi ^lmt of the power conditioner PCS _PVi. That is, the individual output power P _PVi ^out is suppressed at a ratio to the rated output P _PVi ^lmt of each power conditioner PCS _PVi . Therefore, even if the change amount of the same suppression index pr _PV is changed, the suppression amount of the individual output power P _PVi ^out changes according to the rated output P _PVi ^lmt of each power conditioner PCS _PVi . In each power conditioner PCS _PVi , the individual output power P _PVi ^out is 0 when the suppression index pr _PV is the suppression index limit pr _PV ^lmt . That is, 100% is suppressed. Furthermore, when the suppression index pr _PV is 0, the individual output power P _PVi ^out is the rated output P _PVi ^lmt . That is, the maximum power that can be output is output. As shown in FIG. ^28A , when the suppression index pr _PV is between 0 and the suppression index limit pr _PV ^lmt (100), the individual output power P _PVi ^{out of} each power conditioner PCS _PVi changes linearly. doing. Since each power conditioner PCS _PVi cannot output electric power that ^exceeds its rated output P _PVi ^lmt , it is a constant value (rated output P _PVi ^lmt ) when the suppression index pr _PV is a negative value.

Similarly, a value calculated by the following equation (38) is used as the weight w _Bk related to the active power of each power conditioner PCS _Bk . In the following equation (38), pr _B ^lmt indicates a charge / discharge index limit. The charging / discharging index limit pr _B ^lmt is a charging / discharging index when charging / discharging the storage battery B _k with the maximum output power, that is, charging / discharging when the individual output power P _Bk ^out is 100% of the rated output P _Bk ^lmt. It is a charging / discharging index. In addition, w _SOCk indicates a weight according to the SOC of the storage battery B _k , and P _Bk ^max indicates power that can be output to the maximum when various restrictions in the storage battery B _k are considered (hereinafter referred to as “constraint maximum output”). "). The constraint maximum output P _Bk ^max is set based on the battery B _k charger rated output P _SMk ^lmt, rated output P _Bk ^lmt discharge rated output P _SPk ^lmt and power conditioner PCS _Bk of the battery B _k . Specifically, the value obtained by inverting the sign of the charge rated output P _SMk ^lmt and the value of the discharge rated output P _SPk ^lmt are compared to determine the larger value. Then, the larger value is compared with the value of the rated output P _Bk ^lmt , and the smaller value is set as the constraint maximum output P _Bk ^max .
w _Bk = pr _B ^lmt / (2 × w _SOCk × P _Bk ^max ) (38)

FIG. 28B shows the relationship between the charge / discharge index pr _B and the individual output power P _Bk ^out when the weight w _Bk related to the active power is set using the equation (38). In FIG. 28 (b), the solid line when the rated output P _Bk ^lmt is power conditioner PCS _Bk of 500kW, dashed lines when the rated output P _Bk ^lmt is power conditioner PCS _Bk of 250 kW, dashed line rated output This ^{shows a case} where the power conditioner PCS _Bk has P _Bk ^lmt of 100 kW. Further, the charging / discharging index limit pr _B ^lmt in the equation (38) was ^set to 100.

As shown in FIG. ^28B , the charge / discharge index pr _B is increased by 20 from −100 (the charge / discharge index limit pr _B ^lmt is a negative value) to 100 (charge / discharge index limit pr _B ^lmt ). When the rated output P _Bk ^lmt is 500 kW, the output is reduced by 100 kW, when the rated output P _Bk ^lmt is 250 kW, 50 kW, and when the rated output P _Bk ^lmt is 100 kW, the power decreases by 20 kW. This means that the rated output P _Bk ^lmt of each power conditioner PCS _Bk is reduced by 20%. That is, the individual output power P _Bk ^out is controlled at a ratio to the rated output P _Bk ^lmt of each power conditioner PCS _Bk . Therefore, even if the change amount of the same charge / discharge index pr _B is changed, the charge / discharge amount of the storage battery B _k is changed according to the rated output P _Bk ^lmt of the power conditioner PCS _Bk . Also, each power conditioner PCS _Bk has the same value as the rated output P _Bk ^lmt when the charge / discharge index pr _B is a negative value of the charge / discharge index limit pr _B ^lmt (−pr _B ^lmt ). discharging the storage battery B _k at the individual output power P _Bk ^out. On the other hand, when the charge / discharge index pr _B is the charge / discharge index limit pr _B ^lmt , the storage battery B _k is charged with the individual output power P _Bk ^out having the same value as the rated output P _Bk ^lmt . That is, the storage battery _Bk is charged / discharged with electric power that can be output to the maximum. Further, when the charge / discharge index pr _B is 0, the individual output power P _Bk ^out is 0. As shown in FIG. _28B , the individual output power P _Bk ^out changes linearly.

In the present embodiment, the ^{disconnection} avoidance value is set based on the suppression index limit pr _PV ^lmt and the charge / discharge index limit pr _B ^lmt . Specifically, the suppression index limit pr _PV ^lmt and the charge / discharge index limit pr _B ^lmt are set to the same value X, and this value X is set as a ^{disconnection} avoidance value. For example, when the suppression index limit pr _PV ^lmt and the charge / discharge index limit pr _B ^lmt are both set to 100, the ^{disconnection} avoidance value is also set to 100. As a result, when the auxiliary relay 52 operates and a contact signal is transmitted, the output of each power conditioner PCS _PVi is suppressed by 100%, and each power conditioner PCS _Bk is 100 of its rated output P _Bk ^lmt . %, The storage battery B _k can be charged (see FIG. 28). That is, it is possible to reduce the interconnection point power P (t) by reducing the individual output powers P _PVi ^out and P _Bk ^out of the power conditioners PCS _PVi and PCS _Bk as much as possible.

In the photovoltaic power generation system PVS9 configured as described above, the reverse power flow avoidance target is used for the connection point power P (t) as in the fifth embodiment so that the connection power P (t) does not flow backward. Control to the value _PRPR . At this time, when the connection point power P (t) rapidly increases and the connection point power P (t) becomes 0 or more, the auxiliary relay 52 detects a reverse power flow. Then, the contact signal is transmitted to each of the power conditioners PCS _PVi and PCS _Bk and the central control device MC9. When each power conditioner PCS _PVi receives the contact signal, it calculates the individual target power P _PVi ^ref using the _{disconnection} avoidance value as the suppression index pr _PV for a predetermined time (for example, 60 [s]). Similarly, each power conditioner PCS _Bk , when receiving the contact signal, calculates the individual target power P _Bk ^ref using the disconnection avoidance value as the charge / discharge index pr _B for a predetermined time (for example, 60 [s]). Further, upon receiving the contact signal, the central management device MC9 stops calculating the suppression index pr _PV and the charge / discharge index pr _B , and uses the disconnection avoidance values as the suppression index pr _PV and the charge / discharge index pr _B for each power condition. Send to PCS _PVi and PCS _Bk . Thus, the individual output power P _Bk ^out of individual output power P _PVi ^out and the power conditioner PCS _Bk of the power conditioner PCS _PVi both reduced. Accordingly, the interconnection point power P (t) is reduced, and the reverse power flow can be eliminated.

In the present embodiment, each power conditioner PCS _Bk receives a contact signal and uses the _{disconnection} avoidance value as the charge / discharge index pr _B. However, the present invention is not limited to this. Specifically, the auxiliary relay 52, each power conditioner PCS _Bk, without transmitting the contact signal, the power conditioner PCS _Bk may be configured not to receive the contact signal. In this case, each power conditioner PCS _Bk always continues to calculate the individual target power P _Bk ^out using the charge / discharge index pr _B received from the central management device MC9. Or even if each power conditioner PCS _Bk receives the contact signal, the charge / discharge index pr _B received from the centralized management device MC9 is always used without using the disconnection avoidance value as the charge / discharge index pr _B. The calculation of the individual target power P _Bk ^out may be continued. Even in these cases, when the centralized management device MC9 receives the contact signal, the disconnection avoidance value is transmitted as the charge / discharge index pr _B , so that the individual output power P _Bk ^out of each power conditioner PCS _Bk is descend.

FIG. 29 shows simulation results when the disconnection avoidance control is not performed and when it is performed. That is, the result when simulating assuming the photovoltaic power generation system PVS5 according to the fifth embodiment and the photovoltaic power generation system PVS9 according to the ninth embodiment is shown. In the simulation, the reverse power relay 51 is not provided, and the reverse power flow is not disconnected even if a reverse power flow occurs. In the simulation, it is assumed that no contact signal is transmitted from the auxiliary relay 52 to each power conditioner PCS _Bk . That is, each power conditioner PCS _Bk does not receive the contact signal, and always calculates the individual target power P _Bk ^ref based on the charge / discharge index pr _B received from the central management device MC9. FIG. 29A shows a case where the disconnection avoidance control is not performed. FIG. 29B shows a case where the disconnection avoidance control is performed. FIG. 29 (c) is an enlarged view of a part of FIG. 29 (b). In FIG. 29 (a) and FIG. 29 (b), the variation in the amount of solar radiation is the same.

When the disconnection avoidance control is not performed (in the case of the photovoltaic power generation system PVS5), as shown in FIG. 29 (a), the reverse power flow avoidance control cannot catch up in the period T1 in which the solar radiation fluctuation is severe, and the interconnection point power P ( It can be seen that t) exceeds 0 kW. At this time, since the reverse power flow is generated, the reverse power relay 51 detects the reverse power flow and is disconnected from the power system A. On the other hand, when the disconnection avoidance control is performed (in the case of the photovoltaic power generation system PVS9), as shown in FIGS. 29B and 29C, the interconnection point power P (t) is 0 kW in the period T1. It can be seen that it does not exceed. This indicates that the photovoltaic power generation system PVS9 restricts the interconnection power P (t) from exceeding 0 kW by the disconnection avoidance control. Therefore, reverse power flow is not detected by the reverse power relay 51 and is not disconnected from the power system A. Moreover, in each figure, after period T1, it turns out that the connection point electric power P (t) corresponds with the reverse power flow avoidance target value _PRPR by reverse power flow avoidance control.

From the above, according to the photovoltaic power generation system PVS9 according to the present embodiment, even if a reverse power flow occurs, the auxiliary relay 52 detects and operates before the reverse power relay 51 detects the reverse power flow. it is, it is possible to both reduce the individual output power P _Bk ^out of individual output power P _PVi ^out and PCS _Bk of each power conditioner of the power conditioner PCS _PVi. Thereby, connection point electric power P (t) falls and a reverse power flow can be eliminated. Therefore, it is possible to avoid the photovoltaic power generation system PVS9 being disconnected from the power system A by the reverse power relay 51. Further, in the reverse power flow avoidance control, the reverse power flow avoidance target value _PRPR can be set to a value as close to 0 as possible, so that the purchased power can be reduced.

In the ninth embodiment, the case where the auxiliary relay 52 is provided has been described. However, when the processing time of the central management device MC9 is shorter than the reverse power flow detection time of the reverse power relay 51, the auxiliary relay 52 is not provided. May be. In this case, instead of providing the auxiliary relay 52, the central management device MC9 performs the following processing. That is, the index calculation unit 23 ″ sets the disconnection avoidance value as the suppression index pr _PV and the charge / discharge index pr when the connection point power P (t) input from the connection point power detection unit 22 exceeds the threshold. and _B. Note that this threshold value, the reverse flow set for the auxiliary relay 52 may be the same as the threshold value for detecting. Then, disconnection avoided as suppression indicator pr _PV (discharge indicator pr _B) value is sent to each power conditioner PCS _PVi (PCS _Bk), individually using each power conditioner PCS _PVi (PCS _Bk) suppression indicators received pr _PV (discharge indicator pr _B) (disconnection avoidance value) By performing the calculation process of the target power P _PVi ^ref (P _Bk ^ref ), the connection point power P (t) can be reduced, so that the reverse power flow is detected before the reverse power relay 51 detects the reverse power flow. Tidal current can be eliminated. Therefore, it is possible to avoid disconnection due to the reverse power relay 51. Note that the processing time of the central control device MC9 is, the detection time (detection interval) interconnection node power P (t), suppression indicators pr _PV and charge calculation time of the discharge indicator pr _B, and alternatively on the suppression indicators pr _PV and charge-discharge indicator pr transmission time _B (transmission interval). Therefore, by shortening them, shorten the processing time of the central control device MC9 can do.

In the ninth embodiment, the auxiliary relay 52 transmits the contact signal to each of the power conditioners PCS _PVi and PCS _Bk and the central control device MC9. However, the power conditioners PCS _PVi and PCS are described. You may make it transmit only to _Bk . That is, it is not necessary to transmit to the central management device MC9. In this case, the index calculation unit 23 ″ continues to calculate the suppression index pr _PV and the charge / discharge index pr _B based on the interconnection point power P (t) and the reverse power flow avoidance target value _PRPR , but each power condition PCS _PVi (PCS _Bk ) solves the optimization problem based on the received contact signal, not using the suppression index pr _PV (charge / discharge index pr _B ) received from the central control device MC9 but using the separation avoidance value. As a result, the connection point power P (t) is reduced, so that the connection point power P (t) can be reduced without transmitting the contact point signal to the central management device MC9. May be transmitted only to the centralized management device MC9 and not transmitted to each of the power conditioners PCS _PVi and PCS _Bk . In this case, the index calculation unit 23 ″ avoids disconnection based on the received contact signal. Inhibition index p And _PV, and the charge-discharge index pr _B. The suppression indicator disconnection avoidance value as pr _PV (discharge indicator pr _B) is transmitted to the power conditioner PCS _PVi (PCS _Bk), suppression index pr _PV of the power conditioner PCS _PVi (PCS _Bk) received The interconnection point power P (t) can be reduced by calculating the individual target power P _PVi ^ref (P _Bk ^ref ) using (charge / discharge index pr _B ) (disconnection avoidance value). Therefore, the connection point power P (t) can be reduced without transmitting a contact signal to each of the power conditioners PCS _PVi and PCS _Bk . However, when transmitting only to the central management device MC9, the processing time of the central management device MC9 needs to be shorter than the reverse power flow detection time of the reverse power relay 51 as described above. From the above, even in these cases, the reverse power flow can be eliminated before the reverse power flow is detected by the reverse power relay 51, so that the above disconnection can be avoided.

In the ninth embodiment, the case where the ^{disconnection} avoidance value is set based on the suppression index limit pr _PV ^lmt and the charge / discharge index limit pr _B ^lmt has been described, but the interconnection point power P (t) The value is not limited to this as long as the value decreases. For example, in the disconnection avoidance control, each power conditioner PCS _Bk may not output power to the power system A side. That is, since the individual output power P _Bk ^out may be set to a value of 0 or less, the _{disconnection} avoidance value for each power conditioner PCS _Bk may be a value of 0 or more. Further, it may be determined from the situation at that time, not set in advance. For example, a suppression index pr _PV and a charge / discharge index pr _B that reduce the current individual output powers P _PVi ^out and P _Bk ^out by a predetermined amount (for example, 50%) may be obtained and used as the disconnection avoidance value.

In the ninth embodiment, a case has been described in which reverse power flow occurs when the interconnection point power P (t) is controlled to the reverse power flow avoidance target value _PRPR by reverse power flow avoidance control. It is not limited. That is, the reverse power flow may occur even when the target power of the interconnection point power P (t) (or the total system output P _total (t)) is other than the reverse power flow avoidance target value _PRPR . For example, in the peak cut control shown in the fourth embodiment, when the interconnection point power P (t) is controlled to the peak cut target value P _cut , if the power load L decreases rapidly, each power condition In some cases, the total value of the individual output powers P _PVi ^out and P _Bk ^out of the PCS _PVi and PCS _Bk may exceed the power consumption of the power load L. In this case, reverse power flow occurs. If the reverse power flow is prohibited and the reverse power relay 51 is provided in the photovoltaic power generation system PVS4, the reverse power relay 51 is disconnected. Therefore, when reverse power flow is also prohibited in peak cut control, an auxiliary relay 52 may be added to the photovoltaic power generation system to perform peak cut control and disconnection avoidance control. During peak cut control, the suppression index pr _{PV is set} to “0” and all the electric power generated by the solar cell SP _i is output. Therefore, when the peak cut control is returned from the disconnection avoidance control, the suppression is performed. The index pr _PV changes rapidly (for example, changes instantaneously from 100 to 0). This change in drastic suppression indicator pr _PV, because the control of the individual output power P _PVi ^out of the power conditioner PCS _PVi may become unstable, slowly suppression index pr _PV from Kairetsu avoidance value ( It may be set to “0” (for example, over about 5 minutes). Similarly, also in the photovoltaic power generation system PVS8 shown in the eighth embodiment, when reverse power flow is prohibited, an auxiliary relay 52 is added to perform schedule control and disconnection avoidance control. May be. From the above, in the photovoltaic power generation system in which reverse power flow is prohibited, the auxiliary relay 52 may be added to perform disconnection avoidance control.

In the ninth embodiment, by making the reverse power flow detection time of the auxiliary relay 52 shorter than the reverse power flow detection time of the reverse power relay 51, the auxiliary relay 52 detects the reverse power flow earlier than the reverse power relay 51. Although the case has been described, the present invention is not limited to this. For example, the threshold value (threshold value determined to be in the reverse power flow state) set at the electrical contact of the auxiliary relay 52 may be smaller than the threshold value that determines that the reverse power relay 51 is in the reverse power flow state. . However, the threshold value set for the electrical contact of the auxiliary relay 52 is set to a value larger than the reverse power flow avoidance target value _PRPR . In this case, since the interconnection point power P (t) exceeds the threshold value of the auxiliary relay 52 before the threshold value of the reverse power relay 51, the auxiliary relay 52 may detect the reverse power flow earlier than the reverse power relay 51. it can.

In the ninth embodiment, the case where the power storage device (the storage battery B _k and the power conditioner PCS _Bk ) is provided has been described, but the disconnection avoidance control is applied even to a solar power generation system that does not include the power storage device. can do.

  In the said 1st Embodiment thru | or 9th Embodiment, although the case where the said grid connection system was a solar power generation system was demonstrated to the example, it is not restricted to this. The grid interconnection system may be another power generation system. Other power generation systems include, for example, a wind power generation system, a fuel cell power generation system, a rotary generator-type power generation system, and a virtual power generation system that manages the load on consumers by an aggregator that performs negawatt transactions. Conceivable. Note that the aggregator does not actually generate power because it regards the power saved by the negawatt transaction as generated power. Even in the case of these power generation systems, the centralized management device detects the connection point power or calculates the sum of the individual output powers as the adjustment target power, calculates the index, and transmits it to each power device. And the electric power apparatus of each electric power generation system calculates the individual target electric power of an own apparatus based on the optimization problem using the received parameter | index, and controls individual output electric power so that it may become the said individual target electric power. In the case of a photovoltaic power generation system, a wind power generation system, or a power generation system using a fuel cell, the power device is a power conditioner. In the case of a power generation system using a rotating machine type generator, the power device is a generator and a control device that controls the generator. Moreover, in the case of the power generation system by an aggregator, an electric power apparatus is a consumer's load and a control apparatus which controls this. In the power generation system using the aggregator, since the saved power is regarded as generated power, the power reduced from the normal power consumption of the consumer's load becomes the individual output power. The grid interconnection system may be a combination of the power generation system described above. For example, a configuration in which a rotating machine type generator is added to the photovoltaic power generation system, and the central control device transmits an index to each power conditioner and generator control device of the photovoltaic power generation system to control the overall output It is good.

  The power system according to the present disclosure is not limited to the above-described embodiment, and the specific configuration of each part can be variously modified without departing from the content described in the claims.

PVS1~PVS9 photovoltaic system A power system SP _i solar cell B _k accumulator PCS _i, PCS _PVi, PCS _Bk power conditioner G _PV first power conditioner group G _B second power conditioner group 11, 11 ', 31 , 31 ′ receiving unit 12, 12 ′, 12 ″, 32, 32 ′ target power calculation unit 13, 33 output control unit 14, 34 output power detection unit 15, 35 transmission unit MC1 to MC9 centralized management device 21 target power setting unit 22 interconnection point power detection unit 23, 23 ′, 23 ″ index calculation unit 24, 24 ′ transmission unit 25 reception unit 51 reverse power relay 52 auxiliary relay 61 reception unit 62, 62 ′ total output calculation unit 63, 63 ′ index Calculation part L Electricity load

Claims (6)

An electric power load, a distributed power source, and a centralized management device for managing the distributed power source, and a grid interconnection system linked to an electric power system;
When detecting a reverse power flow from the grid interconnection system to the power system, at least the reverse power relay that disconnects the distributed power source from the power system;
A power system comprising:
The centralized management device is:
Adjustment target power detection means for detecting adjustment target power;
Index calculation means for calculating an index for controlling individual output power of the distributed power source based on the adjustment target power and the target power so that the adjustment target power becomes target power;
Index transmitting means for transmitting the index to the distributed power source,
The distributed power source is
Index receiving means for receiving the index;
Target power calculation means for calculating individual target power of the distributed power source based on the optimization problem using the index;
Control means for controlling the individual output power of the distributed power source so as to be the individual target power,
The grid interconnection system reduces the individual output power by changing the index before a reverse power flow is detected by the reverse power relay,
A power system characterized by that. The grid interconnection system further includes an auxiliary relay different from the reverse power relay,
The auxiliary relay has an electrical contact that operates based on a connection point power at a connection point between the grid connection system and the power system, and when the electrical contact is operated, the electrical contact is Send a contact signal indicating that it has operated to the distributed power source,
The distributed power source is
It further comprises distributed power source contact signal receiving means for receiving the contact signal,
The target power calculation means uses, as the index, a disconnection avoidance value for reducing the individual output power when the distributed power contact signal receiving means receives the contact signal.
The power system according to claim 1. The target power calculation means resumes the calculation of the individual target power using the index received by the index receiving means after continuing the calculation of the individual target power using the disjunction avoidance value for a predetermined time.
The power system according to claim 2. The auxiliary relay further transmits the contact signal to the central control device,
The centralized management device is:
It further comprises contact signal receiving means for a centralized management device that receives the contact signal,
The index calculation means stops the calculation of the index when the contact signal receiving means for the centralized management device receives the contact signal, and the discontinuity avoidance value is calculated while the calculation of the index is stopped. As an indicator,
The electric power system of Claim 2 or Claim 3. The index calculation means restarts the calculation of the index when a predetermined time has elapsed since the calculation of the index was stopped;
The power system according to claim 4. The grid interconnection system has a plurality of the distributed power sources,
The plurality of distributed power sources include a solar power generation device and a power storage device,
The disconnection avoidance value for the solar power generation device is different from the disconnection avoidance value for the power storage device.
The power system according to any one of claims 2 to 5.