HK1220551B - Voltage monitoring control device and voltage control device - Google Patents

Description

Voltage monitoring control device and voltage control device

Technical Field

The present invention relates to a voltage monitoring and controlling device and a voltage controlling device.

Background

The power distribution system generally comprises a high-voltage system (generally 6600V) and a low-voltage system (for example, 100V to 200V), and the power receiving end of a general user is connected with the low-voltage system. The utility company is under an obligation to maintain the voltage at the power receiving end of a general consumer within an appropriate range (for example, to maintain the voltage at 95V to 107V when receiving a 100V power supply). For this reason, power companies attempt to maintain the Voltage at the power receiving terminal of general users by adjusting the Control amount (e.g., operating a tap) of a Voltage Control device (e.g., an LRT (Load Ratio Control Transformer: Transformer of a tap changer with Load) or an SVR (Step Voltage Regulator: Step Voltage Regulator), etc.) connected to a high Voltage system. In addition, hereinafter, unless otherwise specified, the power distribution system refers to the high voltage system.

Conventionally, as for voltage control of a power distribution system, it is common to use a local voltage control device which is provided integrally with or simultaneously with a transformer-type voltage control device such as an LRT or an SVR and performs voltage control in an autonomous distributed manner based on measurement information (voltage and power flow) in the vicinity of a location where the voltage control device is provided. In addition to the transformer-type voltage control devices, reactive Power control-type voltage control devices such as phase-modulating devices (such as phase advance capacitors and shunt reactors), SVC (Static Var Compensator), PCS (Power Conditioning System) with a reactive Power adjusting function, and the like, which have a function of automatically switching between operation and non-operation, are known as voltage control devices, and local voltage control devices corresponding to these voltage control devices are put to practical use. Here, the PCS is, for example, a power conditioner for solar power generation, and connects a solar power generation device or a battery to a power distribution system.

These local voltage control devices are configured on the premise that: the load distribution of the distribution system varies equally, that is, the voltage at each point of the distribution system varies in the same direction over time. However, in recent years, due to diversification of the way of using electric power, popularization of distributed power sources by solar power generation and the like, load distribution of a power distribution system tends to fluctuate widely and unevenly over time, and therefore it is difficult to maintain an appropriate voltage by voltage control of a conventional power distribution system.

Therefore, instead of the autonomous distributed voltage control method, a centralized control method (centralized control method) for the voltage of the power distribution system is proposed in which the voltage of the power distribution system is controlled in a manner to be integrated in the entire system. Specifically, the following scheme is proposed: measurement information (voltage and power flow) at a plurality of points in a power distribution system is collected in a centralized voltage control apparatus using a dedicated network, the centralized voltage control apparatus determines a control amount (reactive power and the like) of each voltage control device based on the measurement information, and the centralized voltage control apparatus automatically remotely commands the control amount to each voltage control device (for example, see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 9-322404

Disclosure of Invention

Technical problem to be solved by the invention

However, in recent years, the interconnection of distributed power supplies based on solar power generation and low-voltage systems has been increasing every year, and for example, the following is assumed: the amount of solar power generation greatly changes due to a rapid change in the amount of sunlight caused by the flow of clouds in a sunny day, and therefore the resulting voltage change of the power distribution system is not negligible. In the concentrated voltage control apparatus, measurement information of voltage and power flow at each point of the power distribution system is collected, and optimal control is distributed to each voltage control device.

(1) If the measurement monitoring period is lengthened (for example, several tens of minutes), it is not possible to follow a sudden voltage change when the solar power generation amount rapidly changes due to a flow of cloud and the solar power generation amount greatly changes.

(2) Conversely, if the measurement monitoring period is shortened (for example, by several minutes or less), the communication load for measurement monitoring increases, and therefore, the equipment investment for the communication network becomes very large.

In addition, in a reactive power control type voltage control device such as an SVC, voltage control is performed with a value instructed by a collective voltage control device as a target value, and control is performed so as to remove voltage fluctuations in a short period. When the voltage variation in a short cycle is large, the reactive power control type voltage control device has the following problems: since the reactive power of the upper limit or the lower limit (maximum reactive power output) is continuously output (approaches to the upper and lower limits), the rapid voltage variation cannot be completely removed.

The present invention has been made in view of the above problems, and an object of the present invention is to maintain a voltage in accordance with a voltage variation of a power distribution system without increasing a communication load, and to prevent a reactive power control type voltage control device from approaching an upper limit value and a lower limit value.

Technical scheme for solving technical problem

In order to solve the above problems and achieve the object, the present invention includes: a transmission/reception unit that performs communication with a plurality of local voltage control devices, respectively, via a communication network, the plurality of local voltage control devices adjusting control amounts of a plurality of voltage control devices that are connected to a distribution line of a high-voltage system and that control a voltage of the distribution line, at a 2 nd cycle shorter than the 1 st cycle, based on command values updated at every 1 st cycle; an commandable range updating unit that determines a commandable range, which is a range of reactive power commandable to the local voltage control device that controls the reactive power control device, based on a control result transmitted from the local voltage control device that controls the reactive power control device and received via the transmission/reception unit, the control result being a boundary value time at which the reactive power generated by the voltage control device becomes a boundary value of a control range within a determined time or a boundary value time ratio obtained by dividing the boundary value time by the determined time; and a reactive power determining unit that determines a reactive power command value for the reactive power regulation type voltage control device, updates the reactive power command value for each of the 1 st cycle based on the commandable range for each of the local voltage control devices, and transmits the reactive power command value to each of the local voltage control devices that control the reactive power regulation type voltage control device via the transmission/reception unit.

Effects of the invention

According to the present invention, the following effects can be obtained: the voltage control device can keep the voltage by following the voltage variation of the power distribution system without increasing the communication load, and can prevent the upper and lower limit values of the reactive power control type voltage control device from approaching.

Drawings

Fig. 1 is a diagram showing an example of a configuration of a power distribution system voltage control system according to an embodiment of the present invention.

Fig. 2 is a diagram showing an example of the internal configuration of the concentrated voltage control device.

Fig. 3 is a diagram showing a concept of voltage control in the SVC that operates to suppress voltage variation in a short cycle.

Fig. 4 is a diagram showing an example of a case where the short-cycle voltage fluctuation is small and the SVC does not output the maximum reactive power in the power distribution system voltage control system of the embodiment.

Fig. 5 is a diagram showing an example of a case where the maximum reactive power output is continuously output in the voltage control of the SVC.

Fig. 6 is a flowchart for explaining the operation of the embodiment.

Fig. 7 is a flowchart for explaining the processing of step S104 in fig. 6 in detail.

Fig. 8 is a diagram showing an example of the measurement time of the boundary value time and the transmission time of the command value.

Detailed Description

Hereinafter, embodiments of a voltage monitoring control device and a voltage control device according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiment.

Provided is an implementation mode.

Fig. 1 is a diagram showing an example of a configuration of a power distribution system voltage control system according to an embodiment of the present invention. In fig. 1, the voltage control device 1 is, for example, an LRT (Load ratio control Transformer) as a distribution Transformer installed in a substation. The voltage control device 1 is connected to a local voltage control means 11, which local voltage control means 11 controls the voltage control device 1. The local voltage control means (voltage control means) 11 can be provided integrally with the voltage control device 1, for example, or simultaneously with the voltage control device 1. The local voltage control device 11 controls the voltage control apparatus 1 by adjusting the control amount of the voltage control apparatus 1, specifically, controls the voltage control apparatus 5 by adjusting the tap position. Further, the local voltage control device 11 has a communication function and is connected to the communication network 7.

A bus 2 is connected to the secondary side of the voltage control device 1. Two distribution lines 4-1, 4-2 are connected in parallel to the bus bar 2, for example. The distribution lines 4-1, 4-2 are those of a high voltage system (voltage level 6600V).

One end of the distribution line 4-1 is connected to the bus bar 2 via a breaker 3-1. A plurality of parts on the distribution line 4-1 are provided with voltage/current measuring devices 10 for measuring the voltage and current of the distribution line 4-1. That is, the voltage/current measuring device 10 is connected to the distribution line 4-1, measures the voltage and the current at the connection point thereof, and outputs the measured value as measurement information. The voltage power flow measuring device 10 has a communication function and is connected to the communication network 7. The voltage/power flow measurement device 10 periodically transmits measurement information to the central voltage control device 8, for example, via the communication network 7. The concentrated voltage control device 8 determines a target voltage distribution and an operation state of each voltage control device forming the target voltage distribution for the target system range, and supplies a command value to each voltage control device. The centralized voltage control device 8 may be installed in a place where the subject system is controlled, a control station, or the like.

Further, a Voltage control device 5, which is an SVR (Step Voltage Regulator) for compensating for a Voltage drop, is connected to the distribution line 4-1. The voltage control device 5 is connected to a local voltage control means 15 which controls the voltage control device 5. The local voltage control means 15 can be provided, for example, integrally with the voltage control device 5 or simultaneously with the voltage control device 6. The local voltage control device 15 controls the voltage control apparatus 5 by adjusting the control amount of the voltage control apparatus 5, specifically, controls the voltage control apparatus 5 by adjusting the tap position. Further, the local voltage control device 15 has a communication function and is connected to the communication network 7.

Further, a voltage control device 6, which is a Static Var Compensator (SVC), is connected to the power distribution line 4-1. The voltage control device 6 is connected to a local voltage control means 16 which controls the voltage control device 6. The local voltage control means 16 can be provided, for example, integrally with the voltage control device 6 or simultaneously with the voltage control device 6. The local voltage control device 16 controls the voltage control apparatus 6 by adjusting the control amount of the voltage control apparatus 6, and specifically, controls the voltage control apparatus 6 by adjusting the reactive power output. Further, the local voltage control device 16 has a communication function and is connected to the communication network 7.

One end of the distribution line 4-2 is connected to the bus bar 2 via a breaker 3-2. The distribution line 4-2 is provided with a voltage/current measuring device 10 for measuring the voltage and current of the distribution line 4-2 at a plurality of locations, as in the case of the distribution line 4-1.

The distribution lines 4-1 and 4-2 are high-voltage distribution lines, and although not shown, the distribution lines 4-1 and 4-2 are connected to low-voltage distribution lines constituting a low-voltage system (having a voltage level of, for example, 100V to 200V) via transformers, respectively. The low-voltage distribution line is connected with a load and is also connected with a dispersed power supply such as a solar power generation device. That is, in the present embodiment, the low-voltage system and the distributed power supply are interconnected. However, this embodiment is also applicable to a case where the low-voltage system does not include the distributed power supply. In addition, an example in which a solar power generator is used as a distributed power source will be described below. Voltage control of the power distribution system refers to voltage control of the high voltage system. The power distribution system is configured to include: the system comprises voltage control equipment 1, 5 and 6, local voltage control devices 11, 15 and 16, a bus 2, circuit breakers 3-1 and 3-2, distribution lines 4-1 and 4-2 and a voltage power flow measuring device 10.

In the illustrated example, the number of distribution lines connected to the bus bar 2 is, for example, two, but the present invention is not limited to this example. Further, the number of the voltage control devices to be provided is not limited to the illustrated example. The voltage control device may be provided with, for example, ShR Shunt reactors (Shunt Reactor: ShR), PCS (Power Conditioning System: Power regulators) with a reactive Power adjusting function, and the like, in addition to the LRT, SVR, SVC, and the like illustrated in fig. 1, depending on the configuration.

The centralized voltage control device (voltage monitoring control device) 8 is connected to the local voltage control devices 11, 15, and 16 and the plurality of voltage/power flow measurement devices 10 via the communication network 7. The communication network 7 is, for example, a dedicated network and is provided for monitoring and controlling the power distribution system. The central voltage control device 8 determines a target command value to be controlled by each local voltage control device in, for example, a central control period (for example, 1 hour period) based on, for example, measurement information transmitted from the voltage/current measurement device 10, and individually issues a command to each local voltage control device via the communication network 7. The centralized voltage control device 8 issues command values, that is, commands an upper voltage limit value and a lower voltage limit value (hereinafter, also referred to as an upper voltage limit value and a lower voltage limit value) of a predetermined voltage range, to local voltage control devices (the local voltage control device 11 and the local voltage control device 15 in the example of fig. 1) that control voltage control apparatuses (the voltage control apparatus 1 and the voltage control apparatus 5 in the example of fig. 1) of the transformer type. A value of reactive power to be output without voltage variation is instructed as an instruction value to a local voltage control device (local voltage control device 16 in the example of fig. 1) that controls a voltage control device (voltage control device 6 in the example of fig. 1) of a reactive power adjustment type. The central voltage control device 8 acquires control result information from the local voltage control device 16 that controls the reactive power adjustment type voltage control apparatus, and updates a range of reactive power (commandable range), i.e., a commandable range, that can be commanded to the local voltage control device 16 based on the control result information.

Each local voltage control device that controls the transformer-type voltage control device controls the voltage control device to be controlled so as to maintain the voltage between the upper and lower voltage limit values based on the command of the upper and lower voltage limit values from the centralized voltage control device 8. Each local voltage control device updates and sets the upper voltage limit and the lower voltage limit each time a command for the upper and lower voltage limits is received from the central voltage control device 8. For example, the local voltage control device 11 adjusts the control amount (the change amount of the tap position) of the voltage control device 1 so that the secondary-side voltage of the voltage control device 1 falls within the voltage upper and lower limit values (within the control target voltage range) in the local control period (2 nd period) shorter than the centralized control period (1 st period) during the centralized control period to which the voltage upper and lower limit values are applied, based on the voltage upper and lower limit values instructed from the centralized voltage control device 8.

Each local voltage control device that controls the reactive power adjustment type voltage control apparatus outputs the reactive power instructed by the collective voltage control device 8. The voltage control device of the reactive power adjustment type generates reactive power that is instructed without voltage variation, and acts to remove voltage variation of a short period (for example, a period of several seconds to several tens of seconds).

Fig. 2 is a diagram showing an example of the internal configuration of the concentrated voltage control device 8. As shown in fig. 2, the centralized voltage control device 8 includes: the control unit 20, the storage unit 28 connected to the control unit 20, and the transmission/reception unit 27 communicates with the control unit 20, the storage unit 28, and the local voltage control devices connected to the communication network 7.

The control unit 20 includes, in its functional structure: a load power generation amount prediction unit 21, a load power generation amount prediction value correction unit 22, a commandable range update unit 23, an optimum voltage distribution determination unit 24, a voltage upper and lower limit value determination unit 25, and a reactive power determination unit 26. The load power generation amount prediction unit 21 predicts the load/power generation amount distribution of the power distribution system in the future such as the next day, for example, every concentrated control period (for example, a period of 1 hour). The load/power generation amount corresponds to the amount obtained by subtracting the power generation amount from the pure load. The load/power generation amount indicates the load amount when the load/power generation amount is a positive value, and becomes the power generation amount when the load/power generation amount is a negative value. In addition, details regarding a method of predicting the load/power generation amount distribution will be set forth below. The load power generation amount predicted value correction unit 22 corrects the predicted value of the load power generation amount distribution in the period of the concentrated control period based on the comparison result between the actual value of the load power generation amount distribution in the period of the previous concentrated control period and the predicted value thereof in the period. Here, the actual value of the load/power generation amount distribution is calculated based on the measurement information (voltage and power flow).

The commandable range updating section 23 updates the commandable range of the reactive power adjustment type voltage control device (voltage control device 6) based on the control result information. Specifically, the transmission/reception unit 27 receives the control result information from the local voltage control device 16 and transmits the control result information to the commandable range updating unit 23, and the commandable range updating unit 23 updates the commandable range based on the control result information and the like. Updates regarding the commandable range are set forth below.

The optimal voltage distribution determination unit 24 performs power flow calculation based on the predicted value of the load/power generation amount distribution after correction, and determines the optimal voltage distribution and the optimal control amount of each voltage control device in the period of the concentrated control period by searching for an optimal solution in which the value of the evaluation function for evaluating the voltage distribution of the power distribution system is optimal, taking into account the commandable range of the reactive power adjustment type voltage control device. The optimum voltage distribution is a voltage distribution at each point of the system that satisfies the constraint condition and optimizes the evaluation function. The optimal control amount is a control amount that is instructed to each voltage control device to realize an optimal voltage distribution.

The voltage upper and lower limit determination unit 25 determines the voltage upper and lower limits, which are the upper and lower limits of the control target voltage range of each local voltage control device during the centralized control period, based on the determined optimum voltage distribution, and instructs each local voltage control device via the communication network 7 about the voltage upper and lower limits. The details of the process of determining the upper and lower voltage limit values performed by the upper and lower voltage limit value determination section 25 will be described below, and briefly summarized below.

First, the voltage upper and lower limit value determining unit 25 acquires information on the voltage control responsibility range allocated in advance to each local voltage control device from the storage unit 28. Here, the voltage control responsibility range is a range (or section) on the distribution line 4-1 or 4-2, and is a range in which voltage control in the range is handled by the local voltage control device assigned to the range or the voltage control device connected thereto.

In the reactive power control type voltage control device, when a transformer type voltage control device exists on a power supply side (a side where a distribution transformer exists, an upstream side) of the voltage control device, a range to a load side (a downstream side) of the transformer type voltage control device and a range to the load side of the voltage control device are set as a voltage control responsibility range, and when another voltage control device exists on the load side, the voltage control device is included in the voltage control responsibility range to the power supply side of the other voltage control device. For example, although the load side of the transformer is set as the voltage control duty range in the transformer type voltage control device, when another voltage control device exists on the load side, the voltage control duty range is set to the power supply side of the other voltage control device. In addition, the setting method of the voltage control duty range is not limited to the above example.

In addition, an appropriate voltage range is set in advance for each voltage control duty range. The proper voltage range is the proper voltage range that the high voltage system should maintain. The optimum voltage requirement of the voltage control device falls within an appropriate voltage range of the voltage control duty. The difference between the optimum voltage and the lower limit value of the appropriate voltage is referred to as a lower voltage limit margin, and the difference between the upper limit value of the appropriate voltage and the optimum voltage is referred to as an upper voltage limit margin.

In a local voltage control device for controlling a transformer-type voltage control device, a voltage upper and lower limit value determination unit 25 determines the voltage upper and lower limit values based on the optimum voltage and the dead zone width obtained by the optimum voltage distribution determination unit 24. The voltage upper limit value is a value obtained by adding half of the dead zone width to the optimum voltage, and the voltage lower limit value is a value obtained by subtracting half of the dead zone width from the optimum voltage.

The reactive power determination unit 26 determines a reactive power command value to command the local voltage control device that controls the reactive power adjustment type voltage control device, based on the optimal control amount of the reactive power adjustment type voltage control device calculated by the optimal voltage distribution determination unit 24.

The central voltage control device 8 may be configured as a server having a storage device such as a CPU, a memory, and a hard disk, and a communication function. The control unit 20 is realized by a CPU, and performs control processing in accordance with a control program stored in a memory. The storage unit 28 collectively represents a memory, a storage device, and the like. The transmission/reception unit 27 has a communication function. The centralized voltage control device 8 may be provided in a substation, for example.

Here, voltage control in the reactive power adjustment type voltage control device will be described. Fig. 3 is a diagram showing a concept of voltage control in the SVC that operates to suppress voltage variation in a short cycle. Here, although an SVC is described as an example of a reactive power control type voltage control device, the same applies to reactive power control type voltage control devices other than the SVC. Fig. 3 shows an example of voltage control of an SVC that operates without receiving a command from an external device such as the central voltage control device 8. In fig. 3, the horizontal axis represents time, and the vertical axis represents voltage.

There are a plurality of methods of controlling the voltage using the SVC, but the following control method is assumed in the example of fig. 3. First, voltage measurement value 101 at the installation site of the SVC and moving average 102 (moving average 102 in fig. 3 above) of voltage measurement value 101 over a certain time (for example, about 60 seconds) are calculated. The difference between the two, i.e. "voltage measurement 101-moving average 102", is then calculated. This difference is referred to as a voltage short-cycle variation value. In the voltage control by the SVC, the reactive power output from the SVC is controlled so as to cancel out the voltage short-period fluctuation. In addition, reactive power is defined as: the value is negative when the reactive power is transmitted from the SVC to the power distribution system, and the value is positive when the reactive power is absorbed from the power distribution system. The voltage can be increased by generating negative power in the SVC, that is, by supplying reactive power to the power distribution system. The voltage can be reduced by causing the SVC to generate positive power, i.e., to absorb reactive power from the power distribution system. In addition, if the system configuration is not changed, the voltage fluctuation has a proportional relationship with respect to the reactive power generated by the SVC.

A brief control method is as described above, but the above control method is feedback control, and in reality, a desired control result cannot be obtained by simple proportional control because of a control delay. Therefore, PID (Proportional Integral Derivative) control is often used in practice. PID control is a conventional technique, and is a control method in which a differential control and an integral control are added to the above-described control method, i.e., proportional control. By adopting PID control, the influence of control delay can be reduced as compared with proportional control, and accumulation of control errors can be prevented.

When the SVC independently performs the operation of suppressing the voltage fluctuation in the short cycle without receiving a command from the centralized voltage control device, the reactive power generated by the SVC is zero in a state where the current voltage detected by the SVC is the same as the moving average voltage, that is, in a state where the voltage fluctuation in the short cycle is not detected. In the present invention, reactive power to be generated in a state where the SVC does not detect a voltage variation of a short period is supplied as a command value from the centralized voltage control device to the local voltage control device that controls the SVC. When the voltage fluctuation occurs uniformly in the rising and falling states, the average value of the difference between the command value and the reactive power generated by the SVC to suppress the voltage fluctuation in the short cycle becomes substantially zero for a sufficiently long time. Thus, the SVC generates the commanded reactive power on average.

Since the SVC generates the commanded reactive power on an average basis, the centralized monitoring and control device can realize a more ideal voltage distribution. For example, in a power distribution system in which a large-scale solar power generator is connected to a terminal of a power distribution line, when the amount of power generated by the solar power generator is large in a clear day, the voltage of the power distribution line tends to increase. By generating reactive power determined and commanded in accordance with the amount of power generation predicted by the solar power generator, the SVC located near the solar power generator can reduce the voltage of the distribution line and maintain an appropriate voltage.

Fig. 4 is a diagram showing an example of a case where the SVC does not output the maximum reactive power because the short-cycle voltage variation is small in the distribution system voltage control system according to the embodiment. In the present embodiment, as described above, the command value 103 of the reactive power generated by the SVC is received from the concentrated voltage control device 8, and the command value 103 is operated as the control target value. The SVC outputs the commanded reactive power in a state where no voltage variation is detected, and copes with it so that the voltage does not change abruptly. Specifically, PID control is performed using the "voltage measurement value-moving average value" as an input, and the resultant is added to the command value of the reactive power to output the reactive power. When the state where the "voltage measurement value-moving average value" is zero continues, the output of the PID control is zero, and therefore, the commanded reactive power is output. When the voltage fluctuation occurs uniformly in the rise and fall, the SVC generates the commanded reactive power uniformly because the time average of the PID-controlled output is zero for a sufficiently long time.

When command value 103 is a positive value, the time during which reactive power 104 generated by the SVC is a positive value tends to be longer than the time during which the reactive power is a negative value. In the example of fig. 4, since the voltage fluctuation in the short cycle is small, the voltage fluctuation in the short cycle can be appropriately suppressed without exceeding the controllable upper limit value (maximum reactive power output on the positive side) of the SVC.

Fig. 5 is a diagram showing an example of continuously outputting the maximum reactive power in the voltage control of the SVC. In the example of fig. 5, when the control device 8 operates in response to the command value 103 for reactive power received from the central voltage control device, the following state occurs: the short-period fluctuation of the voltage rise is large, and the reactive power 104 generated by the SVC continues for a controllable upper limit (maximum reactive power output on the positive side) (approaches the upper limit). If such a state occurs, the SVC cannot suppress short-cycle fluctuations in voltage, and the voltage rises. Even when the short-cycle variation of the voltage drop is large, the time to reach the lower limit (maximum negative reactive power output) continues (approaches the lower limit).

For example, when an instruction to absorb 80kVar of reactive power from the distribution system is issued to an SVC having a capacity of 100kVar, if the voltage is to be increased rapidly, the SVC can increase only the amount of generated reactive power of the remaining 20 kVar. When the voltage rises above a voltage variation that can be suppressed by generating 20kVar of reactive power, the amount of reactive power generated by the SVC temporarily approaches the maximum 100kVar, and the voltage suppression capability is lost. This 20kVar is referred to as a reactive power generation margin of the SVC.

In the present embodiment, in order to prevent the reactive power generated by the SVC from approaching the boundary value (upper limit value or lower limit value), the local controller that controls the SVC transmits the boundary value time, which is the time during which the reactive power 104 of the voltage measurement value 101 continues to be the boundary value, or the boundary value time ratio obtained by dividing the boundary value time by the fixed time T0, to the concentrated voltage controller 8 as the control result of the SVC. The collective voltage control device 8 changes the commandable range of the SVC based on the control result. The commandable range is a value indicating a range of reactive power that can be commanded to the SVC, and is considered to be part of the limiting condition when the optimal voltage distribution determination unit 24 calculates the optimal voltage distribution. By changing the commandable range to be considered when calculating the optimum voltage distribution based on the control result, it is possible to make it difficult for the upper limit value or the lower limit value to approach.

Next, a method of obtaining the boundary value time, which is a control result of the SVC, will be described. Various calculation methods can be considered for the SVC control result, but three examples, example 1 to example 3, will be described here. In addition, the calculation method of the SVC control result is not limited to the following three examples.

In example 1, the total sum (T1 + T2 in the example of fig. 5) of the time (the time to be the upper limit value in the example of fig. 5) to be the boundary value (the upper limit value or the lower limit value) on the same sign side as the command value side from the concentrated voltage control device 8 within a certain time (T0 in the example of fig. 5) is taken as the SVC control result. That is, when the command value from the central voltage control device 8 is on the positive side, the sum of the boundary value times that become the upper limit value within a certain time period is used as the control result, and when the command value from the central voltage control device 8 is on the negative side, the sum of the boundary value times that become the lower limit value is used as the control result. T0 may be set to be different times during the day and late at night.

In example 2, a time to be the upper limit value (upper limit value boundary time) and a time to be the lower limit value (lower limit value boundary time) within a certain period of time are obtained, and these two times are used as the SVC control result.

In example 3, the time that becomes a boundary value (upper limit value or lower limit value) within a certain period of time is obtained without distinguishing the upper limit value from the lower limit value, and the total time is used as the SVC control result. That is, the time obtained by adding the upper limit boundary value time and the lower limit boundary value time becomes the SVC control result.

The commandable range updating unit 23 of the central voltage control device 8 updates the commandable range of the SVC based on the control result, and various updating methods are conceivable. For example, when the SVC control results are notified in examples 1 and 2, a method (method a) of changing the width of the usable reactive power on the side close to the center value from the center value, a method (method B) of changing the width on the upper side and the lower side from the center value at the same time, and the like may be employed. When the upper and lower sides are changed simultaneously, the upper and lower sides may be changed symmetrically or asymmetrically. In the case of the method a, the width of the usable reactive power on the same side as the instruction value is changed. In the case where the SVC control result is notified by example 3, since the upper side and the lower side are not distinguished, the width of usable reactive power is changed by the above-described method B.

For example, when the approach of time equal to or longer than the 1 st threshold (for example, 10%) occurs within a certain period of time, the commandable range, that is, the width of reactive power that can be used when the optimal voltage distribution is obtained (for example, α ═ 10)%, when the boundary value time within the certain period of time is equal to or shorter than the 2 nd threshold (for example, 1%) set to be smaller than the 1 st threshold, the width of reactive power that can be used (for example, one side in method a and both sides in method B) is enlarged β (for example, β ═ 5)%. the 2 nd threshold may be 0%. when the width of usable reactive power is enlarged, the change (α > 2) may be made once as compared with the case of enlargement, and the change may be made to reduce the width once as compared with the case of enlargement, the change may be made to reduce the usable reactive power by a step by step, the fixed value after the enlargement, or the limit value of time is increased by a fixed ratio, or the commandable range may be determined according to the optional change of the limit value when the limit value of time becomes equal to the limit, for example, the limit value becomes equal to the limit value range, or the limit value becomes larger.

Next, the operation of the present embodiment will be described with reference to fig. 6. Fig. 6 is a flowchart for explaining the operation of the present embodiment.

First, the voltage/current measuring device 10 periodically measures the voltage and current at each installation point, and stores the voltage and current data. The voltage/power flow measurement device 10 transmits the average value of the voltage and power flow data measured separately, for example, over ten minutes, to the centralized voltage control device 8 via the communication network 7. The central voltage control device 8 can obtain the load/power generation amount of each point of the power distribution system by obtaining the difference of the power flow average values between adjacent measurement points after receiving the average values of the voltage and the power flow data within ten minutes by the transmission/reception unit 27, and store the data in the storage unit 28 as load power generation amount data. Here, the load/power generation amount (load power generation amount data) corresponds to, for example, an amount obtained by subtracting the power generation amount from the pure load, and can take a positive value or a negative value according to the balance between the load amount and the power generation amount. The load power generation amount data is periodically stored and made into a database.

Next, as shown in fig. 6, the load power generation amount prediction unit 21 predicts the load/power generation amount distribution of the distribution system, for example, the next day per hour, based on the load power generation amount data of each point of the distribution system stored in the storage unit 28 (step S101).

Specifically, for example, in order to predict the load and the power generation amount, the load power generation amount prediction unit 21 first uses only the load power generation amount data in the clear time zone, removes the theoretical power generation amount from the data (calculated from the solar power generation rated capacity, the solar panel installation angle, the latitude, the date, the predicted temperature, and the power generation efficiency), and calculates the actual load amount, which is the pure load amount.

Next, the load power generation amount prediction unit 21 collects actual load amounts for a plurality of days, obtains the correlation between the load amounts and the temperatures for the same day of the week (divided into working day and resting day) and the same time zone, and predicts the load amounts at each point of the power distribution system every hour the day after the day based on the correlation and the predicted temperature the day after the day. The load power generation amount prediction unit 21 subtracts the expected power generation amount from the expected load amount to generate load power generation amount data of each point of the distribution system per hour on the next day.

In the present embodiment, for example, the load/power generation amount distribution per hour on the next day is predicted every day, but the present invention is not limited to this, and for example, the load/power generation amount distribution at every predetermined period in the future may be predicted. The 1 hour or fixed period corresponds to the above-described centralized control cycle. The load/power generation amount is predicted, for example, as a value per hour, whereas the measured values of the voltage and the power flow are not an average value for one hour, but an average value within, for example, ten minutes. This is because, when the correlation between the load amount and the air temperature is obtained on the same day of the week (divided into the working day and the rest day) and in the same time zone, the accuracy of the correlation is improved by increasing the number of measurement data, which contributes to grasping the change in the load amount within one hour. This can be used to grasp a time zone in which the load fluctuation is large in setting the control boundary of each voltage control device in S301 of fig. 7 to be described later. The measured values of voltage and power flow may also be set as average values over an hour, for example.

Next, the load power generation amount predicted value correction unit 22 corrects the predicted value of the load/power generation amount of the power distribution system for one hour in the future (step S102). Specifically, the load/power generation amount predicted value correction unit 22 compares the actual value (calculated based on the actual measured value) with the predicted value of the average value of the load/power generation amounts at the points of the power distribution system in the past hour to obtain the ratio thereof, and multiplies the ratio by the predicted value of the load/power generation amount in the next hour to thereby correct the predicted value of the load/power generation amount at the points of the power distribution system in the next hour. This can improve the accuracy of the predicted value.

Next, the commandable range updating unit 23 updates the commandable range for each of the reactive power adjustment type voltage control devices in the above-described manner based on the actual operation information (control result information) from each of the local voltage control devices that control the reactive power adjustment type voltage control devices (step S103).

Next, the optimum voltage distribution determining unit 24 determines the optimum voltage distribution of the power distribution system for one hour in the future based on the corrected load/power generation amount predicted values of the points of the power distribution system for one hour in the future generated in step S102 (step S104). Details of this process are set forth below using fig. 6. Although the process of correcting the predicted value of the load/power generation amount in step S102 is omitted, the optimum voltage distribution determination unit 24 may determine the optimum voltage distribution of the power distribution system for one hour in the future based on the predicted values of the load/power generation amount at the points of the power distribution system for one hour in the future generated in step S101. In S101, the load power generation amount prediction unit 21 predicts the load power generation amount distribution for one hour in the future based on the measurement information transmitted from the voltage power flow measurement device 10, but the present invention is not limited to this, and for example, a database relating to the load power generation amount data may be stored in the storage unit 28 in advance, and the load power generation amount prediction unit 21 may predict the load power generation amount distribution by referring to this database. In this case, the voltage/current measuring device 10 may not be provided, and the process of S102 may be omitted.

Next, the voltage upper and lower limit value determination unit 25 calculates the voltage upper limit value and the voltage lower limit value of each local voltage control device for one hour in the future based on the optimal voltage distribution of the power distribution system (step S105).

Next, the voltage upper and lower limit value determining unit 25 instructs the voltage upper limit value and the voltage lower limit value to each local voltage control device that controls the transformer-type voltage control device, and the reactive power determining unit 26 instructs the reactive power instruction value that is output on average to each local voltage control device that controls the reactive power adjusting-type voltage control device (steps S106 and S107).

Each local voltage control device that controls the transformer-type voltage control device adjusts the control amount of each voltage control device to be controlled based on the command of the upper and lower voltage limit values from the centralized voltage control device 8. Specifically, each local voltage control device adjusts the control amount of the voltage control device as necessary to maintain the voltage between the upper and lower voltage limits in a local control period of a short period shorter than the centralized control period (one hour). Each local voltage control device updates and sets the upper voltage limit value and the lower voltage limit value each time a command for the upper and lower voltage limit values is received from the centralized voltage control device 8 in the centralized control period.

Each local voltage control device that controls the reactive power adjustment type voltage control apparatus performs control using the reactive power instructed as described above as a control target value, and transmits the boundary value time of the voltage as control result information to the centralized voltage control device 8.

Next, the processing of step S104 in fig. 6 will be described in detail. Fig. 7 is a flowchart for explaining the process of step S104 in fig. 6 in detail, and shows a flow for calculating an optimum voltage distribution for one hour in the future of the power distribution system.

First, the optimum voltage distribution determining unit 24 sets control boundaries of the voltage control devices (upper and lower tap limits, which are upper and lower limits of controllable tap positions in the case of the transformer-type voltage control device, and an commandable range of reactive power in the case of the reactive power control-type voltage control device) in order to secure a margin for local control of the voltage control devices (step S301). In this case, the optimum voltage distribution determining unit 24 increases the margin of the local control in consideration of the directivity of the fluctuation such as the rising or falling tendency for the time zone in which a large voltage fluctuation is expected, that is, the time zone in which the load fluctuation is large (for example, the morning, around noon break, the lighting time zone, and the like) and the time zone in which the power generation fluctuation is large (for example, the daytime in which the theoretical power generation amount is large). In this case, the commandable range in the case of the reactive power control type voltage control device is used by narrowing the commandable range by a method determined according to the situation of the time zone based on the value updated by the commandable range updating unit 23.

Next, the optimum voltage distribution determination unit 24 initially sets the control amount of each voltage control device (step S302). At this time, the optimum voltage distribution determining unit 24 sets the tap position to a calculated value at the time of optimum voltage distribution calculation one hour before, for example, in the case of the transformer-type voltage control device (here, a neutral value in the case where there is no last calculated value), and sets the reactive power output to, for example, zero (no output) in the case of the reactive power control-type voltage control device.

Next, the optimum voltage distribution determining unit 24 calculates the voltage at each point of the power distribution system by performing power flow calculation using the set control amount (tap position, reactive power) of each voltage control equipment based on the prediction of the load/power generation amount distribution at each point of the power distribution system (step S303).

Next, the optimum voltage distribution determining unit 24 evaluates the power distribution system based on the result of the power flow calculation (step S304). Specifically, the optimum voltage distribution determination unit 24 evaluates the value of an evaluation function (objective function) set for the evaluation items of the power distribution system, thereby evaluating the power distribution system. Here, the first priority evaluation item is an out-of-limit (off) amount by which the voltage deviates from the appropriate voltage range (the appropriate voltage upper limit value and the appropriate voltage lower limit value) at each point of the distribution system. That is, the optimal voltage profile is first determined to minimize the sum of the out-of-limit (drop-out) amounts by which the voltage drops out of the appropriate voltage range at various points in the power distribution system.

The second priority evaluation item is, for example, a voltage margin (a margin to an appropriate voltage upper or lower limit value) at each point of the power distribution system. If the voltage margin at each point of the distribution system is small, a slight voltage variation may cause the voltage to deviate from the appropriate voltage range, and the voltage control device may frequently operate. Therefore, the larger the sum of the voltage margins, the higher the evaluation. When an evaluation function that is evaluated as optimal when the minimum value is obtained is used, the voltage margin is evaluated using a voltage margin reduction amount defined as follows. The calculation is performed in such a manner that the voltage margin reduction amount becomes zero when the voltage margin is sufficiently large, and the voltage margin reduction amount is larger as the voltage margin is smaller.

When the voltage margin reduction amount is equal to a threshold value, the voltage margin is less than the threshold value

When the voltage margin reduction amount is equal to or larger than the threshold when the voltage margin is 0

The threshold is suitably determined to be around 20% of the width of the suitable voltage range.

The sum is obtained by taking the maximum value of the appropriate upper voltage limit side and the appropriate lower voltage limit side at each point in the voltage control responsibility for each transformer (except for the transformer for stepping down to the low-voltage system).

The third-priority evaluation item may be set as a total amount of change in the control amount of the voltage control apparatus with respect to its initial setting value. Here, in the case of a voltage control device of a reactive power control type, the amount of change in the control amount of the voltage control device from its initial set value is the reactive power output amount, and in the case of a voltage control device of a transformer type, the amount of change in the control amount of the voltage control device from its initial set value is the difference in the tap position from the initial set tap position. By reducing the sum of the amounts of change, the number of times of actions of the voltage control device can be reduced.

The fourth priority evaluation item may be a transmission loss (active power loss + reactive power loss) of the entire power distribution system. The smaller the power transmission loss, the higher the evaluation. In addition, the transmission loss is a significant evaluation item in the case where there is a considerable margin between the upper and lower voltage limits of each point of the distribution system, because the transmission loss is a major portion of the active power loss and the loss is smaller as the voltage increases, but the voltage margin (upper limit value side) at each point of the distribution system of the second priority is correspondingly smaller.

The evaluation function may be set for the evaluation item of the first priority, or may be set for two or more items of the first priority to the fourth priority. In this case, the evaluation functions may be the overall evaluation function obtained by weighting and summing the evaluation functions. Further, the evaluation function may include a high-level priority item according to the power distribution system. The evaluation function may be configured to evaluate to be optimal (high evaluation) when the minimum value is obtained, for example.

For example, when an evaluation function is set based on all the evaluation items of the first priority to the fourth priority, the evaluation function may be determined as shown in the following expression (1). Wp, W1, W2, W3, and W4 are weighting coefficients.

Evaluation function value

The sum of the upper and lower limits of voltage at points in the distribution system multiplied by Wp

+ at each point within the voltage control responsibility of each transformer

Maximum value of upper limit side voltage margin reduction amount × W1

+ at each point within the voltage control responsibility of each transformer

Maximum value of lower limit side voltage margin reduction amount × W1

+ amount of change of target voltage of transformer x W2 from last command

+ absolute value of reactive power command xW 3

+ power transmission loss xW 4 … (1)

Next, the optimum voltage distribution determining unit 24 determines whether or not the predetermined number of searches has been performed (step S305), and if the predetermined number of searches has been performed (yes at step S305), the process is terminated, and if the predetermined number of searches has not been performed (no at step S305), the process proceeds to step S306.

Next, in step S306, the optimum voltage distribution determining unit 24 sets and changes the control amount of each voltage control device so as to improve the evaluation to the maximum extent, for example, by changing the control amount of each voltage control device by one unit (for example, increasing/decreasing the tap by one step, increasing/decreasing the reactive power by a rated value, for example, 5%) and then performing the voltage calculation (the same as in step S303) and the evaluation of the distribution system (the same as in step S304), and comparing the result with the evaluation result obtained for all the voltage control devices (step S306). As the optimization algorithm, for example, a method disclosed in japanese patent laid-open No. 2010-250599 and the like can be used. In addition, with respect to a voltage control device capable of continuously changing a control amount such as reactive power control of an SVC, the same effect can also be obtained by calculating an optimum control amount by a quadratic programming method which is one of continuous system optimization methods. After step S306 is performed, the process returns to step S305.

As described above, after the predetermined number of searches, the optimum voltage distribution determination unit 24 can determine the optimum voltage distribution and the optimum control amount of each voltage control device for one hour in the future of the power distribution system by setting the value of the evaluation function to the optimum solution that is the optimum.

Next, the processing of step S105 in fig. 6 will be described in detail. First, in the transformer-type voltage control device, for example, a voltage control duty range is set so that the voltage upper and lower limits are determined based on a minimum value (lm _ min) of a voltage lower limit margin, which is an absolute value of a difference between an optimum voltage and a lower limit value V _ min of an appropriate voltage, and a minimum value (um _ min) of a voltage upper limit margin, which is an absolute value of a difference between an optimum voltage and an upper limit value V _ max of an appropriate voltage, within the voltage control duty range.

Specifically, in the case where a transformer-type voltage control device exists on the power supply side (upstream side) of the voltage control device, the range to the load side (downstream side) of the transformer-type voltage control device and the range to the load side of the voltage control device are set as the voltage control responsibility range, and in the case where another voltage control device exists on the load side, the range to the power supply side of the other voltage control device is also included in the voltage control responsibility range.

For example, the voltage control responsibility of the local voltage control device 11 ranges from the load side of the voltage control apparatus 1 to the voltage control apparatus 5, and includes a low-voltage system (not shown in fig. 1) connected to the distribution line 4-1. The minimum value of the voltage lower limit margin, which is the absolute value of the difference between the optimum voltage and the lower limit value V _ min of the appropriate voltage in the voltage control duty range of the local voltage control device 11, is lm _ min, and the minimum value of the voltage upper limit margin, which is the absolute value of the difference between the optimum voltage and the upper limit value V _ max of the appropriate voltage, is um _ min. At this time, the voltage upper and lower limit value determining unit 25 sets a value obtained by adding um _ min to the value of the optimum voltage of the voltage control device 1 as the voltage upper limit value of the control target voltage range, and sets a value obtained by subtracting lm _ min from the value of the optimum voltage of the voltage control device 1 as the voltage lower limit value of the control target voltage range.

Thus, since the voltage control device 11 is determined in consideration of not only the upper and lower voltage margin near the installation location of the voltage control device 1 but also the upper and lower voltage margin at each point within the voltage control responsibility range, it is possible to maintain an appropriate voltage within a wide voltage control responsibility range, although the local voltage control device itself locally controls the voltage control device 1 within the control target voltage range.

Next, the measurement of the boundary value time and the transmission timing of the command value will be described. Fig. 8 is a diagram showing an example of the measurement of the boundary value time and the transmission timing of the command value. Here, there is a centralized control period (for example, one hour) between the commands, and when the local control device that controls the reactive power adjustment type voltage control apparatus receives the command, the local control device starts the control based on the command and starts the measurement (accumulation) of the boundary value time. During a period of T0 (for example, 50 minutes) shorter than the centralized control period, the integration of the boundary value time is performed, and the integration result (the sum of the boundary value times) is transmitted to the centralized voltage control device 8 as control result information. The concentrated voltage control device 8 obtains an optimum voltage distribution reflecting the control result information, and transmits a new command. It is preferable to set the timing (for example, 10 minutes) in which the difference between the centralized control period and T0 is obtained, so that transmission/reception of control result information, calculation of the optimum voltage distribution, transmission/reception processing of commands, and the like can be performed.

As described above, in the present embodiment, the concentrated voltage control device 8 obtains the optimum voltage distribution within a predetermined time (during the concentrated control period) in the future. Next, for the transformer type voltage control device, the upper and lower voltage limit values for commanding each local voltage control device are determined taking into account the upper and lower voltage limit margins at each point within the voltage control responsibility of each local voltage control device based on the relationship between the optimum voltage distribution and the appropriate voltage range, and for the reactive power regulation type voltage control device, the upper and lower voltage limit values are determined based on the optimum voltage and the dead zone width. The collective voltage control device 8 acquires a boundary value time at which the upper and lower limits of the reactive power regulation type voltage control equipment are reached, and updates the commandable range to be considered for calculation of the optimum voltage distribution based on the boundary value time. Thus, the central voltage control device 8 gives the commands of the voltage upper and lower limit values or the generated reactive power only to the local voltage control devices, and the local voltage control devices independently perform local control in accordance with the commands from the central voltage control device 8, and are distributed so as to be controlled collectively by the central voltage control device 8 and controlled locally by the local voltage control devices.

Thus, since the control itself of the voltage control device is performed by the local voltage control device on a device-by-device basis, it is possible to track the voltage fluctuation of the power distribution system due to a factor that makes prediction difficult, for example, due to a change in the amount of solar power generation, and to maintain the voltage. That is, it is not necessary to wait for communication with the centralized voltage control device 8 for a sudden voltage variation, and it is possible to cope with this by only the local voltage control device, and it is possible to perform a timely voltage control.

In the present embodiment, since the communication between the centralized voltage control device 8 and each local voltage control device is performed in the centralized control period, which is one hour, for example, the communication frequency is reduced and the communication load is not increased as compared with the case where a voltage command is transmitted in the local control period.

Further, the boundary value time in which the upper and lower limits of the reactive power regulation type voltage control device approach can be reduced, and it is possible to cope with a sudden change in voltage even when the short-cycle variation in voltage is large.

Thus, according to the present embodiment, even if the communication load is not increased, the voltage can be maintained by tracking the voltage fluctuation of the distribution system due to a factor that makes prediction difficult, such as a change in the amount of solar power generation. In the concentrated voltage control apparatus, the method of determining the upper and lower voltage limit values of the transformer-type voltage control device may be determined by a method other than the present embodiment. In this case, the above-described problems can be solved by assigning the centralized voltage control device to perform centralized control and the local voltage control devices to perform local control. However, as in the present embodiment, the central voltage control device determines the upper and lower voltage limit values, thereby improving the reliability of voltage control of the power distribution system.

In the present embodiment, the load/power generation amount prediction and the command for the upper and lower voltage limit values of the local voltage control device are performed every hour, for example, but the present invention is not limited to this, and may be performed every several tens of minutes (for example, 30 minutes) to several hours, or at a time interval equal to or longer than this. The transmission of the command for the upper and lower voltage limit values to the local voltage control device may be performed only when the upper and lower voltage limit values change significantly. Thereby, the communication load can be further reduced.

In addition, the present invention can be applied to a case where a local voltage control device which cannot receive a voltage upper/lower limit command from a centralized voltage control device in a centralized control cycle due to a communication failure or the like is present, and the local voltage control device includes: the upper and lower voltage limit values for the multiple time slot amount (for example, the amount of the day of the next day) are transmitted from the centralized voltage control device to the local voltage control device in advance, and are stored in the local voltage control device in advance. In this case, even when a communication of a certain local voltage control device is abnormal, the local voltage control device can operate based on the stored upper and lower voltage limit values, and the concentrated voltage control device can estimate the operation of the local voltage control device. In this case, the process of correcting the predicted value of the load/power generation amount in step S102 in fig. 6 is omitted.

Industrial applicability of the invention

As described above, the voltage monitoring and control device and the voltage control device according to the present invention are suitable for a system that controls the voltage of a power distribution system.

Description of the reference symbols

1. 5, 6 voltage control equipment, 2 bus, 3-1, 3-2 circuit breakers, 4-1, 4-2 distribution lines, 7 communication networks, 8 centralized voltage control devices, 10 voltage power flow measuring devices, 11, 15, 16 local voltage control devices, 20 control parts, 21 load power generation amount prediction parts, 22 load power generation amount prediction value correction parts, 23 commandable range update parts, 24 optimal voltage distribution determination parts, 25 voltage upper and lower limit value determination parts, 26 reactive power determination parts, 27 transmitting and receiving parts and 28 storage parts.

Claims (19)

1. A voltage monitoring control apparatus, comprising:

a transmission/reception unit that performs communication with a plurality of local voltage control devices via a communication network, the plurality of local voltage control devices adjusting control amounts of a plurality of voltage control devices that are connected to a distribution line of a high-voltage system and that control a voltage of the distribution line, at a 2 nd cycle shorter than the 1 st cycle, based on command values updated at every 1 st cycle;

an commandable range updating unit that determines a commandable range, which is a range of reactive power commandable to the local voltage control device that controls the reactive power adjustment type voltage control device, based on a control result transmitted from the local voltage control device that controls the reactive power adjustment type voltage control device and received via the transmitting/receiving unit, the control result being a boundary value time at which reactive power generated by the voltage control device becomes a boundary value within a determined time or a boundary value time ratio obtained by dividing the boundary value time by the determined time, the boundary value being at least one of an upper limit value that is a positive side maximum reactive power output and a lower limit value that is a negative side maximum reactive power output of the voltage control device; and

and a reactive power determination unit that determines a reactive power command value for the reactive power adjustment type voltage control device, updates the reactive power command value for each of the local voltage control devices at the 1 st cycle based on the commandable range, and transmits the reactive power command value to each of the local voltage control devices that control the reactive power adjustment type voltage control device via the transmission/reception unit.

2. The voltage monitoring and control apparatus of claim 1,

the commandable range updating section decreases the commandable range when the control result is larger than a 1 st threshold value.

3. The voltage monitoring and control apparatus of claim 2,

the commandable range updating unit increases the commandable range when the control result is less than a 2 nd threshold value smaller than the 1 st threshold value.

4. The voltage monitoring control apparatus of claim 3,

the commandable range updating unit makes an absolute value of a change amount of the commandable range at a time of increasing the commandable range smaller than an absolute value of a change amount of the commandable range at a time of decreasing the commandable range.

5. The voltage monitoring and control apparatus according to any one of claims 1 to 4,

the control result is obtained in consideration of the boundary value on the side of the reactive power command value having the same sign as the reactive power generated by the reactive power adjustment type voltage control device.

6. The voltage monitoring and control apparatus according to any one of claims 1 to 4,

the control result is obtained without distinguishing whether the acquired boundary value is the upper limit value or the lower limit value.

7. The voltage monitoring and control apparatus according to any one of claims 1 to 4,

the control result is a value obtained separately for each of the upper limit value and the lower limit value.

8. The voltage monitoring and control apparatus of claim 5,

the commandable range updating unit updates the commandable range of the reactive power adjustment type voltage control device on the side of the same sign as the command value supplied to the voltage control device.

9. The voltage monitoring and control apparatus of claim 6,

the commandable range updating unit updates the commandable range of the reactive power adjustment type voltage control device on the side of the same sign as the command value supplied to the voltage control device.

10. The voltage monitoring and control apparatus of claim 7,

the commandable range updating unit updates the commandable range of the reactive power adjustment type voltage control device on the side of the same sign as the command value supplied to the voltage control device.

11. The voltage monitoring and control apparatus of claim 5,

the commandable range updating unit updates the upper limit side and the lower limit side of the commandable range.

12. The voltage monitoring and control apparatus of claim 6,

the commandable range updating unit updates the upper limit side and the lower limit side of the commandable range.

13. The voltage monitoring and control apparatus of claim 7,

the commandable range updating unit updates the upper limit side and the lower limit side of the commandable range.

14. The voltage monitoring and control apparatus according to any one of claims 1 to 4,

the 1 st cycle is several tens of minutes to several hours, and the determined time is less than or equal to the 1 st cycle.

15. A voltage control apparatus, comprising:

a control result transmitting unit that transmits, to the voltage monitoring control device via the communication network, a control result that is a boundary value time at which reactive power generated by a reactive power adjustment type voltage control device that performs control becomes a boundary value within a determined time or a boundary value time ratio obtained by dividing the boundary value time by the determined time, the boundary value being at least one of an upper limit value that is a positive side maximum reactive power output and a lower limit value that is a negative side maximum reactive power output of the voltage control device; and

and a control unit that adjusts a control amount of the reactive power adjustment type voltage control device using, as a control target value, reactive power received from the voltage monitoring control device at every 1 st cycle and determined by the voltage monitoring control device based on the control result.

16. The voltage control apparatus of claim 15,

the control result is obtained for the boundary value on the side of the same sign as the reactive power received from the voltage monitoring control device with respect to the reactive power generated by the reactive power adjustment type voltage control device.

17. The voltage control apparatus of claim 15,

the control result is obtained without distinguishing whether the acquired boundary value is the upper limit value or the lower limit value.

18. The voltage control apparatus of claim 15,

the control result is a value obtained separately for each of the upper limit value and the lower limit value.

19. A voltage monitoring control apparatus, comprising:

a transmission/reception unit that performs communication with a plurality of local voltage control devices via a communication network, the plurality of local voltage control devices adjusting control amounts of a plurality of voltage control devices that are connected to a distribution line of a high-voltage system and that control a voltage of the distribution line, at a 2 nd cycle shorter than the 1 st cycle, based on command values updated at every 1 st cycle;

an commandable range updating unit that determines a commandable range, which is a range of reactive power commandable to be commanded to the local voltage control device that controls the reactive power adjustment type voltage control device, based on a control result transmitted from the local voltage control device that controls the reactive power adjustment type voltage control device and received via the transmitting/receiving unit, the control result being a boundary value time that is a time at which the reactive power generated by the voltage control device is approaching an upper limit value or a lower limit value within a determined time or a boundary value time ratio obtained by dividing the boundary value time by the determined time; and

and a reactive power determination unit that determines a reactive power command value for the reactive power adjustment type voltage control device, updates the reactive power command value for each of the local voltage control devices at the 1 st cycle based on the commandable range, and transmits the reactive power command value to each of the local voltage control devices that control the reactive power adjustment type voltage control device via the transmission/reception unit.