JP2018038132A - Power stabilization system using power storage device and controller - Google Patents

Description

  The present invention relates to a power stabilization system and a control device using a power storage device that suppresses power fluctuations in a power system.

Frequency fluctuations occur when the balance between generated power and consumed power is lost in the power system. For this reason, the output increase / decrease adjustment of the generator is carried out so as to balance the power consumption and the generated power which change every moment by various frequency control according to the fluctuation cycle of the load. For minute fluctuations of several minutes or less, the number of revolutions of the generator is controlled in a governor-free manner (GF: Governor-Free
It responds instantaneously by operation, and copes with short cycle fluctuations of several minutes to several tens of minutes by controlling the generator output by load frequency control (LFC) of the power feeding system. Furthermore, for long-period fluctuations of several tens of minutes or more, it is possible to perform output distribution in consideration of economics of the generator by economic load distribution control (EDC).

  On the other hand, the interconnection of variable power sources using renewable energy such as solar power generation and wind power generation to the power system has been increasing in recent years. There has been a concern that frequency adjustment capability by governor-free control or load frequency control applied to a synchronous generator group of an electric power system may be insufficient due to the introduction of a large amount of renewable energy. Conventionally, it has been possible to apply power fluctuation mitigation control that compensates for minute fluctuation components or short-period fluctuation components of power generation equipment output by installing power storage devices composed of storage batteries or flywheels at solar power plants or wind power plants. It has been proposed (see, for example, Patent Document 1).

  The power stabilization system described in Patent Document 1 generates power generated by a variable power source in order to reduce the influence on the system frequency when a variable power source such as a solar power plant or a wind power plant is connected to the power system. The power is combined with the charge / discharge power of the power storage device and smoothed. In such a power stabilization system, when the stored power amount of the power storage device reaches the upper limit or the lower limit, further power compensation cannot be performed. Therefore, in addition to charge / discharge control for stabilizing power fluctuations, an appropriate storage can be performed. Correction control for ensuring the amount of electric power is performed.

JP 2007-318883 A

  However, for fluctuation components of variable power sources such as solar power generation and wind power generation whose output fluctuates depending on weather conditions etc., short period fluctuations that are output fluctuation components up to several tens of minutes and tens of minutes to several hours Are mixed with long-period fluctuations, which are output fluctuation components. In particular, suppression of long-period fluctuation with a long fluctuation cycle places a heavy burden on charge / discharge control of the power storage device, and if the capacity of the power storage device is reduced for economic reasons, long-period fluctuation is sufficiently suppressed. There is a problem that it becomes impossible.

  The present invention has been made in view of such points, and a power stabilization system and a control device using a power storage device that can sufficiently suppress long-period fluctuations without increasing the capacity of the power storage device. Is one of the purposes.

  A power stabilization system according to an aspect of the present invention includes a power storage device that performs charging and discharging, and power conversion that mutually converts input and output of power due to charging and discharging of the power storage device between a power system and the power storage device. Using a power storage device comprising: a control device, and a control device that controls a conversion operation of the power converter and smoothes a combined output of the variable power source and the power storage device linked to the power system A stabilizing system, wherein the control device outputs the combined output with respect to the long-period fluctuation among the long-period fluctuation and the short-period fluctuation included in the long-period fluctuation included in the output of the fluctuation power source or the synthesis output. A long period limiter that keeps the rate of change within a predetermined range, and includes an upper limit and / or a lower limit of the long period limiter that is controlled to a level that prohibits a decrease and / or increase in the combined output.

  ADVANTAGE OF THE INVENTION According to this invention, the power stabilization system and control apparatus using the power storage device which can fully suppress a long period fluctuation | variation can be provided, without increasing the capacity | capacitance of a power storage device.

It is a conceptual diagram which shows the structural example of the electric power stabilization system which is 1st Embodiment. It is a functional block diagram of the stored electric power target calculating part in 1st Embodiment. FIG. 3A is a schematic diagram of the output fluctuation waveform of the power plant combined output using the third function, and FIG. 3B is a schematic diagram of the output fluctuation waveform of the power plant combined output using the first function. It is a figure for demonstrating the 1st, 2nd and 3rd function in 1st Embodiment. FIG. 5A is a diagram showing the relationship between the upper limit and lower limit of the second limiter and the output change rate during the decrease prohibition period, FIG. 5B is a diagram showing the relationship between the upper limit and lower limit of the second limiter and the output change rate during the increase prohibition period, and FIG. These are the figures which show the relationship between the upper limit and lower limit of a 2nd limiter, and an output change rate in an increase / decrease prohibition period. It is a figure which shows the correspondence of an operation time slot | zone, an output change rate, and a 2nd limiter coefficient. FIG. 7A is a diagram showing the transition of the charge amount of the power storage device and the stored power target value, FIG. 7B is a diagram illustrating the change of the output change rate and the upper and lower limits of the limiter circuit, and FIG. 7C is the output of the wind power generator and the combined output It is a figure which shows the fluctuation | variation of the output of a power storage device.

  Hereinafter, the power stabilization system using the power storage device according to the first embodiment will be described in detail with reference to the drawings.

  FIG. 1 is a conceptual diagram illustrating a configuration example of the power stabilization system according to the first embodiment. A power stabilization system 10 illustrated in FIG. 1 includes a power storage device 11, a power converter 12, and a control device 13, and is connected to a power system 15 via a transformer 14. In the following description, it is assumed that the power stabilization system 10 performs output fluctuation compensation of a variable power source using renewable energy. In FIG. 1, a wind power generator 16 that is an example of a variable power source is connected to a power system 15 via a transformer 17. In addition, if it is the fluctuation | variation power supply linked | linked with the electric power grid | system, not only the wind power generator 16 but solar power generation etc. may be sufficient, for example, and it is not limited to renewable energy.

  The power storage device 11 is, for example, a flywheel, a secondary battery, or a capacitor. The power converter 12 is connected to the power system 15 based on the power converter output command value PO from the control device 13 (here, the direction in which the power is discharged from the power storage device 11 is “positive”). The power PS is exchanged with the device 11. When the power storage device 11 is a flywheel, the AC power on the flywheel side and the AC power on the power system 15 side are converted in both directions. When the power storage device 11 is a secondary battery or a capacitor, the DC power on the secondary battery or capacitor side and the AC power on the power system 15 side are converted bidirectionally.

  The control device 13 includes an active power detection unit 21, a stored power amount detection unit 22, a stored power target value calculation unit 23, a compensation power correction calculation unit 24, a smoothing filter 25, a limiter circuit 26, a power converter control unit 27, and the like. Have Although not shown, the control device 13 includes a CPU and a memory (storage device such as a hard disk), and various correction calculation processing, compensation power calculation processing, control processing of the power converter 12, and the like described below. May be realized by hardware, or may be realized by the CPU reading and executing a predetermined application program stored in the storage device. Further, when realized by hardware, it may be controlled using a digital circuit such as a programmable controller, or may be realized by an analog control circuit such as an operational amplifier.

  The active power detection unit 21 detects the active power PG of the wind power generator 21 serving as the output of the variable power source based on the voltage and current value at the output terminal of the wind power generator 16. The stored power amount detection unit 22 detects or calculates the stored power amount ES of the power storage device 11 directly or indirectly. For example, when the power storage device 11 is configured with a flywheel, the rotational speed of the flywheel is detected. Further, when the power storage device 11 is configured by either a secondary battery or a capacitor, the terminal voltage and / or the terminal current is detected, and the stored power amount ES is calculated based on the detection result.

  The stored power target value calculation unit 23 corresponds to the active power PG of the wind power generator 16, or the combined output (the combined output of the wind power generator 16 and the power storage device 11 (power converter 12)), or the combined output target value. The stored power target value of the power storage device 11 is calculated. The stored power target calculation unit 23 is set with a plurality of functions that output different stored power target values in response to the input of the active power PG, the combined output, or the combined output target value. For example, the first function, which is a function that promotes charging of the power storage device 11 in a time zone prepared for long-period fluctuation, and the power storage device 11 in another time zone prepared for long-period fluctuation. Of the second function, which is a function that promotes discharge, and the third function corresponding to a time zone other than the time zone prepared for long-period fluctuation, at least the third function, the first function, and / or It has two functions. In this embodiment, as an example, three types of functions (first function, second function, and third function) that output different stored power target values for active power PG are set, and active power A stored power target value corresponding to PG is calculated. The first function and the second function are an increasing function corresponding to a time zone prepared for long-period fluctuation (hereinafter, referred to as a long-period fluctuation control preparation time zone), and the third function is a long period It is an increasing function corresponding to a time zone other than the fluctuation control preparation time zone. The first function is a function for generating a stored power target value that promotes charging of the power storage device 11 or suppresses discharge in a time zone prepared for long-period fluctuation. The second function is a function that generates a stored power target value that promotes the discharge of the power storage device 11 or suppresses the charging in a time zone that is prepared for a long-period variation. FIG. 2 is a functional block diagram illustrating a configuration example of the stored power target value calculation unit 23. The stored power target value calculation unit 23 is a switch that selects three function calculation units 31, 32, and 33 and outputs (ECa, ECb, and ECc) of the function calculation units 31, 32, and 33 according to time zones. 34, a clock 35 for giving time information to the switch 34, and a stored power for calculating a corrected stored power amount ES ′ by subtracting the current stored power amount ES from the stored power target value (EC) output from the switch 34. A quantity correction unit 36. Note that the number of function calculation units is not limited to three, but the number of functions to be switched according to the time zone or other requirements can be prepared.

  When the corrected stored power amount ES ′ is within a predetermined range (EH to Emax) from the stored power amount upper limit value Emax, the compensated power correction calculation unit 24 discharges from the power storage device 11, that is, a positive compensated power correction. When the signal PC is output and the corrected stored power amount ES ′ is within a predetermined range (Emin to EL) from the stored power amount lower limit Emin of the power storage device 11, the charging direction of the power storage device 11, that is, minus A compensation power correction signal PC is output. The compensation power correction calculation unit 24 starts outputting the compensation power correction signal PCm as the compensation power correction signal PC when the correction storage power amount ES ′ falls below the storage power amount lower limit threshold EL. The compensation power correction signal PCm is a negative signal. In order to add the compensation power correction signal PC to the active power measurement value PG in the subsequent stage, the compensation power correction signal PCm is shifted in a direction to charge the power storage device 11 by the compensation power correction signal PCm. Become. When the corrected stored power amount ES ′ exceeds the stored power amount upper limit threshold EH, the output of the compensated power correction signal PCp is started as the compensated power correction signal PC. The compensation power correction signal PCp is a positive signal. In order to add the compensation power correction signal PC to the active power measurement value PG at a later stage, the compensation power correction signal PCp is shifted in the direction of discharging from the power storage device 11 by the compensation power correction signal PCp. Become. When the corrected stored power amount ES ′ subsequently falls below the stored power amount upper limit threshold value EH, or when the corrected stored power amount ES ′ exceeds the stored power amount lower limit threshold value EL, the compensation power correction signal The output of PCp is stopped and the compensation power correction signal PC becomes zero. In the configuration example shown in FIG. 1, the compensation power correction signal PC is added to the active power PG before the smoothing filter 25, but may be added after the smoothing filter 25.

  The smoothing filter 25 is a filter that removes a high-frequency component from the active power PG that is the output of the wind power generator 16 and smoothes it. In FIG. 1, the smoothing filter 25 is configured by a first-order lag filter, but other methods may be applied to configure the smoothing filter. For example, a method using a moving average filter, a method of recombining in combination with a high-pass filter, or the like can be applied.

  The limiter circuit 26 includes a first limiter 41 that constitutes a short-period limiter that operates so as to keep the rate of change of the combined output within a predetermined range with respect to short-period fluctuation, and the combined output of the combined output with respect to long-period fluctuation. And a second limiter 42 that constitutes a long-period limiter that operates to keep the change rate within a predetermined width. The limiter circuit 26 may have either a configuration for controlling the output of the wind power generator 16 that is a variable power source as an input or a configuration for controlling the combined output as an input. In the present embodiment, a configuration for controlling the output of the wind power generator 16 as an input will be described. The fluctuation component of the output of the wind power generator 16 or the combined output of the wind power generator 16 and the power storage device 11 includes a long-period fluctuation and a short-period fluctuation superimposed on the long-period fluctuation. The long-period fluctuation included in the output or combined output of the wind power generator 16 is, for example, an output fluctuation component of several tens of minutes to several hours, and the short-period fluctuation is an output fluctuation component of several tens of minutes. However, if there is a relationship in which short-period fluctuations are superimposed on long-period fluctuations, the fluctuation periods of long-period fluctuations and short-period fluctuations are not particularly limited. Analysis results (periodic characteristics) of the long-period fluctuations superimposed on the long-period fluctuations and the long-period fluctuations actually included in the output or combined output of the wind power generator 16, the management method by the power company, and the power company What is necessary is just to determine the assumption period of the long-term fluctuation | variation and the short-term fluctuation | variation which should be suppressed according to any one or arbitrary combinations of requirement specification and other conditions. For example, it is assumed that the long-period fluctuation is 10 minutes to 5 hours and the short-period fluctuation is 10 seconds to 5 minutes (pattern 1). Alternatively, it is assumed that the long period fluctuation is 30 minutes to 10 hours and the short period fluctuation is 1 minute to 20 minutes. Further, the fluctuation cycle of the long-period fluctuation and the short-period fluctuation need not be constant. The first limiter 41 and the second limiter 42 sample-hold the combined output target value or the combined output for sample times Δt1 and Δt2 for evaluating the short-period fluctuation and the long-period fluctuation of the combined output. In the present embodiment, the configuration in which the composite output target value is sampled and held is described. However, the present invention can also be applied to a configuration in which the composite output value is sampled and held. The first limiter 41 is given the previous combined output target value PA (S) from the first sample hold circuit 43 that samples and holds the combined output target value of the previous period Δt1 corresponding to the short period fluctuation. The sample hold period Δt1 is set to a sample time (for example, 10 seconds) suitable for evaluating short-period fluctuation. Note that the sample time for evaluating short-period fluctuations only needs to be shorter than the period of the fluctuation component to be suppressed, and is appropriately set in units of seconds or minutes, for example. The second limiter 42 is given the previous combined output target value PA (L) from the second sample hold circuit 44 that samples and holds the previous combined output target value for the period Δt2 corresponding to the long-period fluctuation. The sample hold period Δt2 is a sample time (for example, 10 minutes) suitable for evaluating long-period fluctuation. Note that the sample time for evaluating long-period fluctuations only needs to be shorter than the period of the fluctuation component to be suppressed, and is appropriately set, for example, in minutes or tens of minutes. Further, the sample hold periods Δt1 and Δt2 can be set to the same time. The first limiter 41 sets a value (= PA (S) + A1Δt1) obtained by adding a multiplication value obtained by multiplying the upper limit coefficient A1 by the sample hold time Δt1 to the combined output target value PA (S) before Δt1 to the upper limit level. Then, a value (= PA (S) + B1Δt1) obtained by multiplying the previous composite output target value PA (S) by the lower limit coefficient B1 multiplied by the sample hold time Δt1 is set as the lower limit level. With the coefficients A1 and B1, the change rate of the combined output corresponding to the short period fluctuation can be kept within a predetermined range. The second limiter 42 sets a value (= PA (L) + A2Δt2) obtained by adding a multiplication value obtained by multiplying the upper limit coefficient A2 by the sample hold time to the combined output target value PA (L) before Δt2 by the upper limit level. Then, a value (= PA (L) + B2Δt2) obtained by multiplying the previous combined output target value PA (L) and the lower limit coefficient B2 by the sample hold period is set as the lower limit level. With the coefficients A2 and B2, the change rate of the combined output corresponding to the long-period fluctuation can be kept within a predetermined range.

  The control device 13 prohibits the combined output at the connection point between the wind power generator 16 and the power stabilization system 10 from changing in the direction opposite to the increase / decrease in the power demand during a time period when the power demand greatly increases or decreases. The tendency for power demand to increase above a predetermined rate of change will be referred to as “significant increase”. A “decrease prohibited period” is set in which the combined output (combined output change rate) is prohibited from changing in a decreasing direction opposite to the power demand with respect to a time period in which the power demand increases significantly. In addition, the tendency for power demand to decrease by more than a predetermined rate of change will be referred to as “significant decrease”. It is set to an “inhibition increase period” in which the combined output (combined output change rate) is prohibited from changing in an increasing direction opposite to the power demand with respect to a time period in which the output is greatly decreased. In addition, the tendency for the power demand to increase and decrease beyond a predetermined rate of change will be referred to as “significant change”. The time zone during which the increase / decrease changes significantly is set to an “increase / decrease prohibition period” that prohibits the change in the combined output (the combined output change rate) in the decreasing direction and the increasing direction. The time zone set for “Decrease Prohibition Period”, “Increase Prohibition Period”, and “Increase / Decrease Prohibition Period” are not only fixed schedules (for example, fixed at 7: 00 to 10: 00), but also from power companies It may be determined according to an external command, or may be determined according to a demand prediction result. In addition, it is good also as a system determined suitably according to various specifications and a request | requirement.

  The second limiter 42 is set to a lower limit that prevents the current combined output from falling below the previous combined output during the combined output decrease prohibition period, and the current combined output from the previous combined output during the combined output increase prohibited period. It is set to an upper limit that cannot be exceeded. Note that the second limiter 42 may set only one of a lower limit and an upper limit. In this example, the coefficient B2 for calculating the lower limit of the second limiter 42 is controlled to 0 during the decrease prohibition period. As a result, the lower limit of the combined output is limited to a lower limit level that is not lower than the previous combined output in the second limiter 42, so that the combined output target value is maintained at the combined output immediately before the decrease inhibition period. In addition, the coefficient A2 for calculating the upper limit of the second limiter 42 is controlled to 0 during the increase prohibition period. As a result, the upper limit of the composite output in the second limiter 42 is limited to an upper limit level that does not exceed the current composite output from the previous composite output, so that the composite output target value is maintained at the composite output immediately before the increase prohibition period. The Further, during the increase / decrease prohibition period, the coefficient A2 for calculating the upper limit of the second limiter 42 and the coefficient B2 for calculating the lower limit are controlled to zero. Thereby, since the upper limit and the lower limit of the combined output are limited in the second limiter 42, the combined output target value is maintained at the combined output immediately before the increase / decrease prohibition period.

  The power converter control unit 27 generates a power converter output command value PO according to the magnitude of the corrected compensation power ΔPG that is the difference between the combined output target value output from the limiter circuit 26 and the active power PG, and the power The power converter 12 is controlled based on the converter output command value PO, and the power storage device 11 is charged and discharged with the power PS.

The operation of the power stabilization system according to the first embodiment configured as described above will be described.
First, the operation by the function calculation units 31, 32, 33 of the stored power target value calculation unit 23 will be specifically described.
FIG. 3A and FIG. 3B are diagrams schematically showing output fluctuation waveforms of the combined power plant output at the connection point of the wind power generator 16 (fluctuating power source) and the power stabilization system 10. FIG. 3A shows the long-term fluctuation control preparation in the power stabilization system according to the first embodiment without using the first function corresponding to the long-period fluctuation control preparation time zone. It shows the output fluctuation when only the third function corresponding to the time zone other than the time zone is used. FIG. 3B shows output fluctuation when the stored power target value calculation unit 23 uses the first function in the long-period fluctuation control preparation time zone in the power stabilization system according to the first embodiment.

  As shown in FIG. 3A, the output waveform of the wind power generator 16 includes a short-period fluctuation component superimposed on the long-period fluctuation. As a basic control, the control device 13 excludes the short-period fluctuation component of the output waveform and maintains the smoothed waveform, so that the power storage device 11 for the component whose output waveform is larger than the smoothed waveform. The power is absorbed by absorbing the power, and the power storage device 11 is discharged to discharge the component whose output waveform is smaller than the smoothed waveform. As a result, the power plant combined output is maintained in a smoothed waveform.

  By the way, in order to control long-period fluctuations with a small-capacity power storage device, the stored power of the power storage device is increased or corrected before the time period in which long-period fluctuation control is required. It is necessary to. Therefore, in the present embodiment, as shown in FIG. 3B, the long-period fluctuation control preparation time before the long-period fluctuation control execution time period in which the increase in power demand is predicted in the long-period fluctuation control execution time period. In the band, the stored power of the power storage device 11 is corrected to be higher. In addition, although not shown, the power storage device 11 is in the long-period fluctuation control preparation time zone before the long-cycle fluctuation control execution time zone in which the decrease in power demand is predicted in the long-cycle fluctuation control execution time zone. The stored power is corrected to a low level. In order not to sacrifice the control for short period fluctuations, the stored power target value EC of the power storage device 11 is determined by an increasing function using the active power PG of the wind power generator 16 as an input.

  FIG. 4 is a schematic diagram of an increase function set in the function calculation units 31, 32, 33 of the stored power target value calculation unit 23. The function calculation unit 31 is set with a first function for generating a stored power target value that corrects (accelerates charging) the stored power of the power storage device 11. The function calculation unit 32 is set with a second function that generates a stored power target value that corrects the stored power of the power storage device 11 to be lower (accelerates discharge). The function calculation unit 33 generates a stored power target value suitable for a time zone other than the long-period fluctuation control preparation time zone, which is an intermediate correction between the first function and the second function of the stored power of the power storage device 11. A third function is set. Note that the slope of the increase function is arbitrary. As shown in FIG. 4, the first function (F1) for generating a stored power target value that promotes charging by changing the slope with reference to the third function may be used, or storage that promotes discharging. It is good also as a 2nd function (F2) which produces | generates an electric power target value. The function in FIG. 4 is expressed as a linear function, but the increase function may be a quadratic function. The first function may be an area above the third function, or the second function may be an area below the third function.

  In the present embodiment, the switch 34 selects any one of the function calculation units 31, 32, 33 based on time information given from the clock 35. The stored power target value ECa output by the function calculation unit 31 is selected in the “long-cycle fluctuation control preparation time zone” before the long-cycle fluctuation execution time zone in which an increase in power demand is predicted. The function calculation unit 31 is set with a first function that generates a stored power target value that corrects (accelerates charging) the stored power of the power storage device 11. As a result, in the “long-cycle variation control preparation time zone” illustrated in FIG. 3B, the stored power target value ECa that facilitates charging is generated as compared with FIG. 3A (third function). Compensation power is calculated based on a corrected storage power amount ES ′ that is a deviation between the storage power target value ECa and the current storage power amount ES. The compensation power correction calculation unit 24 converts the compensation power correction signal PC corresponding to the compensation power to correct the active power PG, and the power storage device 11 is given an output command value PO that promotes charging. As a result, the stored power of the power storage device is corrected to be higher in the long-cycle fluctuation control preparation time zone before the long-cycle fluctuation control execution time zone in which an increase in power demand is predicted. In this way, at the time when the long-period fluctuation control execution time zone in which the increase in power demand is predicted is ensured while the remaining capacity of the short-cycle fluctuation relaxation control is ensured in the long-cycle fluctuation control preparation time zone, the power storage device 11. Since the amount of stored power is large, it is possible to perform more discharge in the long-period fluctuation control execution time zone.

  On the other hand, the stored power target value ECb output by the function calculation unit 32 is selected in the “long-cycle fluctuation control preparation time zone” before the long-cycle fluctuation execution time zone in which a decrease in power demand is predicted. Since the function calculation unit 32 is set with a second function for generating a stored power target value that corrects the stored power of the power storage device 11 to be low (acceleration of discharge), a long cycle in which a decrease in power demand is predicted The stored power of the power storage device is corrected to be lower in the long-cycle fluctuation control preparation time zone before the fluctuation control execution time zone. In this way, at the time when the long-period fluctuation control execution time zone in which a decrease in power demand is predicted by continuing to secure the reserve capacity of the short-cycle fluctuation relaxation control in the long-cycle fluctuation control preparation time zone, the power storage device Since the power storage amount of 11 is small, more charging can be performed in the long period variation control execution time zone.

  Next, in the first embodiment, the combined output at the connection point of the wind power generator 16 and the power stabilization system 10 changes in the direction opposite to the increase / decrease direction of the power demand during the time period when the power demand increases or decreases. The operation for prohibiting this will be specifically described.

  FIG. 5A is a diagram showing the relationship between the upper limit (long cycle upper limit value) and lower limit (long cycle lower limit value) set in the second limiter 42 serving as a long cycle limiter and the output change rate. In the example shown in the figure, time T11 to time T12 correspond to a time zone in which power demand increases (a time zone in which a decrease in the combined output is restricted), and is set as a reduction prohibition period. The first limiter 41 controls the coefficients A1 and B1 so that the output change rate of the combined output is within ± 1% from the previous value (before Δt1), and the second limiter 42 controls the decrease prohibition period (and increase / decrease). Except for the prohibition period), the case where the coefficients A2 and B2 are controlled so that the output change rate is within ± 2% from the previous value (before Δt2) is illustrated. The lower limit (long cycle lower limit value) of the second limiter 42 is calculated such that the coefficient B2 is calculated so that the output change rate of the combined output becomes 0 in the decrease prohibition period (and increase / decrease prohibition period) (the combined output is the previous value). The upper limit (long cycle upper limit value) of the second limiter 42 is within + 2% from the previous value (before Δt2) even in the decrease prohibition period (and increase / decrease prohibition period). Thus, the coefficient A2 is controlled. Specifically, the value obtained by multiplying the previous value PA (L) before Δt2 sampled and held by the second sample hold circuit 44 and the current coefficient B2 by the sample hold period Δt2 (= PA (L ) + B2Δt2) is set to the lower limit (long cycle lower limit value), but the decrease prohibition period (and increase / decrease prohibition period) is forcibly set to the coefficient B2 = 0. As a result, as shown in FIG. 5A, the lower limit (long period lower limit) of the second limiter 42 is fixed to the previous value in the decrease prohibition period (and increase / decrease prohibition period), so that the combined output is Δt2 before Control is performed so as not to become smaller than the previous value PA (L).

  FIG. 5B is a diagram showing the relationship between the upper limit (long cycle upper limit value) and lower limit (long cycle lower limit value) set in the second limiter 42 and the output change rate during the increase prohibition period. In the example shown in the figure, the time T21 to the time T22 correspond to a time zone in which the power demand decreases (a time zone in which the increase in the combined output is restricted) and is set as an increase prohibition period. The first limiter 41 calculates the coefficients A1 and B1 so that the output change rate falls within ± 1% from the previous value (before Δt1), and the second limiter 42 calculates the increase prohibition period (and the increase / decrease prohibition period). Other than the above, the case where the coefficients A2 and B2 are controlled so that the output change rate is within ± 2% from the previous value (before Δt2) is illustrated. The upper limit (long cycle upper limit value) of the second limiter 42 is calculated such that, in the increase prohibition period (and increase / decrease prohibition period), the coefficient A2 is calculated so that the rate of change of the composite output becomes 0 (the composite output is set to the previous value). The coefficient B2 is controlled so that the lower limit (long cycle lower limit value) of the second limiter 42 is within -2% from the previous value (before Δt2) even in the increase prohibition period. Specifically, the value obtained by multiplying the previous value PA (L) before Δt2 sampled and held by the second sample hold circuit 44 and the current coefficient A2 by the sample hold period Δt2 (= PA (L ) + A2Δt2) is set to the upper limit (long period upper limit value), but the increase prohibition period (and increase / decrease prohibition period) is forcibly set to the coefficient A2 = 0. As a result, as shown in FIG. 5B, the increase prohibition period (and increase / decrease prohibition period) is fixed at the upper limit (long period upper limit value) of the second limiter 42 at the previous value. Control is performed so as not to be larger than the previous value PA (L).

  FIG. 5C is a diagram showing the relationship between the upper limit (long cycle upper limit value) and lower limit (long cycle lower limit value) set in the second limiter 42 and the output change rate. In the example shown in FIG. However, it corresponds to a time zone in which the power demand greatly fluctuates up and down (increase and decrease) (a time zone in which both reduction and increase of the combined output are regulated) and is set as an increase / decrease prohibition period. The second limiter 42 exemplifies a case where the coefficients A2 and B2 are controlled so that the output change rate is within ± 2% from the previous value (before Δt2) except during the increase / decrease prohibition period. The lower limit (long cycle lower limit value) and upper limit (long cycle upper limit value) of the second limiter 42 are controlled in combination with FIGS. 5A and 5B. That is, in the increase / decrease prohibition period, the lower limit (long cycle lower limit value) of the second limiter 42 is fixed to the previous value, so that the combined output is controlled not to be smaller than the previous value PA (L) before Δt2. In addition, since the upper limit (long period upper limit value) of the second limiter 42 is fixed to the previous value, the combined output is controlled so as not to become larger than the previous value PA (L) before Δt2.

  The first limiter 41 is given the previous combined output target value PA (S) from the first sample hold circuit 43, and the coefficient A1 so that the output change rate is within ± 1% from the previous value (before Δt1). , B1 is controlled.

  Next, with reference to FIG.6 and FIG.7, the simulation result of the operation content by the electric power stabilization system of 1st Embodiment is demonstrated. FIG. 6 shows the correspondence between each operation time zone set in the simulation, the output change rate, and the coefficients A2 and B2. The period from 7:00 to 10:00 is set as a decrease prohibition period, and the period from 11:30 to 13:30 is set as an increase / decrease prohibition period. The period from 16:00 to 19:00 is set again as a decrease prohibition period, and the period from 20:00 to 23:00 is set as an increase prohibition period. In the second limiter 42 corresponding to the long period fluctuation, the coefficients A2 and B2 are controlled so that the output change rate other than the prohibition period is within ± 2%.

  7A shows the transition of the charge amount ES and the stored power target value EC of the power storage device 11, and FIG. 7B shows the output change rate of the combined output, the changes in the upper limit and lower limit of the first limiter 41 (one-dot chain line), and the second limiter. 7C is a diagram showing changes in the upper limit and the lower limit of 42 (solid line), and FIG. 7C shows fluctuations in the output PG (dotted line), the combined output (thick line) of the wind power generator 16, and the output PS (thin line) of the power storage device 11. FIG. In this example, in accordance with the increase or decrease in power demand, a decrease prohibition period (7:00 to 10:00, 16:00 to 19:00), an increase prohibition period (20:00 to 23:00), An increase / decrease prohibition period (11:30 to 13:30) is set.

  As shown in FIG. 7A, the stored power target value EC is set to a high value in the long-cycle fluctuation control preparation time zone set a predetermined time before the start time (7:00) of the long-cycle fluctuation control execution time zone. It is controlled to become. Thereby, in the long period fluctuation control preparation time zone, the stored power target value ECa output from the function calculation unit 31 is selected, and the stored power of the power storage device 11 is corrected to be higher based on the first function (charging promotion). A stored power target value is generated. As a result, at the time when the long-period fluctuation control execution time zone in which the increase in power demand is predicted is started while continuing to secure the reserve capacity of the short-cycle fluctuation relaxation control in the long-cycle fluctuation control preparation time zone, The amount of power stored in the power storage device 11 is increased, and more discharge can be performed in the long-period variation control execution time zone.

  As shown in FIG. 7B, the upper limit of the second limiter 42 (long period upper limit) so that the combined output change rate is within ± 2% in the time zone other than the decrease prohibition period, the increase / decrease prohibition period, and the increase prohibition period. And the lower limit (long cycle lower limit) is set. In the decrease prohibition period (7:00 to 10:00, 16:00 to 19:00) and the increase / decrease prohibition period (11:30 to 13:30), the lower limit (long) of the second limiter 42 is set. Cycle lower limit) is set to the composite output change rate = 0. In the second limiter 42, the decrease prohibition period and the increase / decrease prohibition period are forcibly set to the coefficient B2 = 0, and the lower limit (long period lower limit value) of the second limiter 42 is fixed to the previous value, so that The output is controlled so as not to become smaller than the previous value PA (L) before Δt2. As a result, it is possible to prevent the combined output at the interconnection point between the wind power generator 16 and the power system 15 from changing in the direction opposite to the increase direction of the power demand during a time period when the power demand increases.

  Further, in the increase prohibition period (20:00 to 23:00) and increase / decrease prohibition period (11:30 to 13:30), the upper limit (long period upper limit) of the second limiter 42 is the combined output change rate = It is set to 0. In the second limiter 42, the increase prohibition period and the increase / decrease prohibition period are forcibly set to the coefficient A2 = 0, and the upper limit (long period upper limit value) of the second limiter 42 is fixed to the previous value, so that The output is controlled so as not to become larger than the previous value PA (L) before Δt2. As a result, it is possible to prevent the combined output at the interconnection point between the wind power generator 16 and the power storage device 11 from changing in the direction opposite to the decreasing direction of the power demand during the time period when the power demand decreases.

  As shown in FIG. 7C, in the reduction prohibition period, the lower limit of the second limiter 42 is regulated so that the output change rate is 0, so that the combined output is flat or the combined output increases. Yes. Further, in the increase period, the upper limit of the second limiter 42 is regulated so that the output change rate becomes 0, so that the combined output is flat or the combined output is decreasing. In the increase / decrease prohibition period, the upper limit and the lower limit of the second limiter 42 are regulated so that the output change rate is zero, and thus the combined output is flat. As a result, in the decrease prohibition period, the increase period, and the increase / decrease prohibition period, the output change rate is controlled without being influenced by the output PG of the wind power generator 16. Therefore, in these periods, the power demand increases and decreases in the opposite direction. It is possible to prevent the composite output from fluctuating.

  In the first embodiment, the control device 13 may be provided with the second limiter 42 serving as a long-period limiter as long as it obtains an effect of sufficiently suppressing long-period fluctuation. The first limiter 41 serving as a period limiter is not essential for suppressing the long period fluctuation.

  Moreover, in the said 1st Embodiment, although it was set as the structure which switches the stored electric power target value calculating part 23 by time information, it is good also as a structure which switches the compensation electric power correction calculating part 24 by time information. The compensation power correction calculation unit 24 is a decreasing function having the corrected stored power amount ES ′ as an input and the compensation power correction signal PC as an output, and switches a plurality of types of decreasing functions according to time information.

  In the first embodiment, the storage power target value calculation unit 23 and the compensation power correction calculation unit 24 have been described as functions having no dynamic characteristics, but integral terms such as PI control, PD control, and I control, and differential A function having a term or a function having frequency characteristics such as a first-order lag system or a second-order lag system may be a function obtained by multiplying or adding a function having no dynamic characteristics.

  In the first embodiment, the input of the stored power target value calculation unit 23 is the active power PG of the wind power generator 16, but it is an example of an index for grasping the power generation amount of the power plant to which the present invention is applied. Yes, it may be a measured value or predicted value of the active power of the power generation facility, or a measured value, predicted value, or control target value of the combined output of the power plant.

DESCRIPTION OF SYMBOLS 10 Power stabilization system 11 Power storage apparatus 12 Power converter 13 Control apparatus 15 Power system 16 Wind generator 21 Active power detection part 22 Stored electric energy detection part 23 Storage power target value calculation part 24 Compensation power correction calculation part 25 Smoothing Filter 26 Limiter circuit 27 Power converter control unit 31, 32, 33 Function calculation unit 34 Switch 35 Clock 36 Stored power amount correction unit 41 First limiter 42 Second limiter 43 First sample hold circuit 44 Second sample hold circuit 44

Claims (7)

A power storage device that performs charging / discharging, a power converter that mutually converts power input / output by charging / discharging of the power storage device between a power system and the power storage device, and a control operation of the power converter And a control device that smoothes the combined output of the variable power source and the power storage device connected to the power system, and a power stabilization system using the power storage device.
The control device is configured to set a rate of change of the combined output with respect to a long-period fluctuation among a long-period fluctuation and a long-period fluctuation included in the output of the variable power supply or the composite output by a predetermined width. Power using the power storage device, characterized in that it includes a time period in which an upper limit and / or a lower limit of the long period limiter is controlled to a level that prohibits a decrease and / or increase in the combined output Stabilization system.   The long cycle limiter sets a lower limit that prevents the current combined output from being lower than the previous combined output during the decrease period of the combined output, and / or the current combined output during the increase prohibited period of the combined output. The power stabilization system using the power storage device according to claim 1, wherein an upper limit that does not exceed a previous combined output is set.   The long-period limiter is characterized in that a time period in which an increase in power demand is predicted is set in the decrease prohibition period, and a time period in which a decrease in power demand is predicted is set in the increase prohibition period. A power stabilization system using the power storage device according to Item 2.   The control device includes a sample hold circuit that samples and holds a combined output target value for smoothing the combined output, or the combined output for a sample time Δt for evaluating a long-period variation of the combined output. A value obtained by adding a multiplication value obtained by multiplying the sampled output Δt by a coefficient A that holds the change rate of the combined output within a predetermined range to the held combined output target value or the sampled and held combined output value is the upper limit of the long period limiter. A value obtained by adding a multiplication value obtained by multiplying a sample time Δt by a sample time Δt to a given sampled and held synthesized output target value or a sampled and held synthesized output value by a coefficient B that fits the rate of change of the synthesized output within a predetermined range is the long period The specific time period given as the lower limit of the limiter and prohibiting the decrease and / or increase of the combined output is the coefficient A and Or the power stabilizing system using a power storage device according to claim 2 or claim 3, characterized in that the coefficient B to 0. The control device includes a storage power target calculation unit that calculates a storage power target value of the power storage device according to the active power of the variable power source, or the combined output, or a combined output target value,
The storage power target calculation unit is set with a plurality of functions that output different storage power target values in response to the active power of the variable power supply, or the combined output, or the input of the combined output target value. A power stabilization system using the power storage device according to any one of claims 1 to 4.   The stored power target calculation unit is a first function that is a function that promotes charging of the power storage device in a time zone that is prepared for long-period fluctuation, and another time zone that is prepared for long-period fluctuation. In the second function, which is a function for promoting the discharge of the power storage device, and at least a third function and a third function corresponding to a time zone other than a time zone prepared for long-period fluctuations 6. The power stabilization using the power storage device according to claim 5, wherein the power storage device has a function of 1 and / or a second function, and a function used for calculating the stored power target value is changed according to a time zone. system. In the power stabilization system using the power storage device, the power system is controlled by controlling a power converter that mutually converts power input / output by charging / discharging of the power storage device between the power system and the power storage device. A control device for smoothing the combined output of the variable power supply and the power storage device connected to the power supply,
A long-period limiter that keeps the rate of change of the combined output within a predetermined range with respect to the long-period fluctuation among the long-period fluctuation and the short-period fluctuation superimposed on the long-period fluctuation included in the output of the fluctuation power source or the synthetic output And a time period in which the upper limit and / or lower limit of the long-period limiter is controlled to a level that prohibits the decrease and / or increase of the combined output.

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