WO2019207935A1

WO2019207935A1 - Power system control system and power system control method

Info

Publication number: WO2019207935A1
Application number: PCT/JP2019/006927
Authority: WO
Inventors: 亮坪田; 渡辺　雅浩; 小海　裕; 喜仁木下
Original assignee: 株式会社日立製作所
Priority date: 2018-04-27
Filing date: 2019-02-22
Publication date: 2019-10-31
Also published as: JP2019193539A

Abstract

A power system generates power, as a power supply, on the basis of renewable energy and is provided with a plurality of fluctuating power supplies, the outputs of which fluctuate depending on the state of the renewable energy. This power system control system integrates the probability distribution of the output fluctuation of each of the plurality of fluctuating power supplies and creates, on the basis of the integrated probability distribution, a control plan for controlling the output of each of the plurality of fluctuating power supplies so as to be able to maintain the stability of a power system to an assumed failure in the power system.

Description

Power system control system and power system control method

The present invention relates to a system and method for controlling a power system, and more particularly to a system that enables control for protecting a power system including a power source that generates power using renewable energy from a failure.

 Synchronous machines may accelerate and step out due to lightning strikes and accidents occurring in the power system, resulting in instability of the power system. Therefore, there is a power system stabilization technique for maintaining the stability of the power system even if there is a failure or accident in the power system.

This stabilization technology models the power system and uses this model to analyze the power system. In order to prevent out-of-step based on the analysis result, the stabilization technology creates a control plan for controlling the output of the generator, for example, before a failure occurs in the power system. When it is detected that a problem has occurred, a control plan is automatically implemented to prevent the power system from becoming unstable. For example, Patent Document 1 discloses a power system stabilization device that updates a power system model based on measured values of a power system and periodically updates a control plan. Patent Document 1 discloses that this power system stabilizing device includes a power source such as wind power generation or solar power generation as a control target.

Japanese Patent Laying-Open No. 2015-130777

Since power sources for solar power generation, wind power generation, etc. are constantly affected by the weather and weather, the stabilization device creates a control plan for the output of the power source using renewable energy based on the measured values of the power system. However, the output of the power supply changes until it is executed. Accordingly, an object of the present invention is to provide a power system control system that can obtain a power system stabilization effect as expected by a control plan even with a power source based on renewable energy.

In order to achieve the above object, the present invention provides a power system control system that maintains the stability of the power system by controlling the output of the power supply of the power system. The power system control system includes a plurality of variable power sources that generate power based on renewable energy and whose output varies depending on the state of the renewable energy. The power system control system includes a memory and a controller that executes a program recorded in the memory. The controller integrates the probability distribution of the fluctuations of the outputs of the plurality of variable power supplies, and based on the integrated probability distribution so that the stability of the power system can be maintained from a failure assumed in the power system. Then, a control plan for controlling the output of each of the plurality of variable power supplies is created.

According to the present invention, it is possible to realize an electric power system control system that can obtain the effect of stabilizing the electric power system as expected by the control plan even if the power source is based on renewable energy.

It is a block diagram of the hardware structural example which applied the power system control system to the power system. It is an example of a structure of the assumption failure database of an electric power system control system. It is an example of a structure of the output fluctuation database of an electric power system control system. It is a flowchart which shows operation | movement of an electric power system control system. It is a flowchart which shows the detail of the process which calculates the controllable amount with respect to a variable power supply. It is a graph which shows the probability distribution of the fluctuation | variation of the output of a fluctuation | variation power supply.

Next, an embodiment of the present invention will be described. FIG. 1 shows an example of a hardware block configuration in which the power system control system is applied to the power system 1. The power system control system includes a computing device 100 and a power supply control device 200, and the computing device 100 and the power supply control device 200 are connected to each other via a communication network 900. The power system 1 is connected to the communication network 900.

The arithmetic device 100 creates control information of the power system 1, and the power control device 200 controls the power source of the power system, in particular, the variable power source based on the control information. The fluctuating power source is a power source that generates power based on renewable energy such as wind power generation or solar power generation, and whose output fluctuates depending on environmental conditions such as weather and weather.

The arithmetic device 100 creates model data of the power system 1 at predetermined intervals, and is assumed to be a failure that can occur in the power system 1, hereinafter referred to as an assumed failure, but uses a model for each of a plurality of assumed failures. Analysis, and create stabilization measures. Based on the created stabilization measure, the power supply control device 200 executes a power system stabilization measure such as disconnecting, stopping, or limiting the output of the generator and / or the variable power supply. “Failure” may be understood as a term that includes accidents, malfunctions, failures, and the like.

The power system 1 includes a generator 4, a transformer 9, one or a plurality of measuring devices 10, and a plurality of variable power sources 23 (23 a, 23 b, 23 c). It is connected. A plurality of nodes (buses) 3 are connected to the branch 2. Reference numeral 7 denotes a relay. Since each of the plurality of variable power supplies and the relay of each of the plurality of variable power supplies are connected to the communication network 900, each of the plurality of variable power supplies is disconnected from the power system by the power supply control device 200, or , Can be stopped, or output can be limited. The same applies to the generator 4. The node is connected to a large power source such as a thermal power generator, a hydroelectric power generator or a nuclear power generator. The branch may be connected to another power source capable of controlling the output, such as a secondary battery or a fuel cell.

The measurement device 10 transmits measurement data to the communication module 106 of the arithmetic device 100 and the communication module 206 of the power supply control device 200 via the communication network 900. The measurement data may include a unique number for identifying the data and a time stamp. The measuring device 10 may be VT, PT, or CT that measures at least one of node voltage, branch current, power factor, active power, and reactive power. The measuring device 10 may exist in a bus or a power transmission line in addition to the power system 1.

The computing device 100 has a configuration in which a controller (CPU) 102, a memory 103, an input module 104 such as a keyboard and a mouse, an output module 105, a communication module 106, and a plurality of databases are connected to a bus line 101. The plurality of databases includes a program database 130, a system model database 131, and a contingency database 132. The program database 130 includes an analysis model creation program, a stability analysis program, and a control amount calculation program. The controller 102 reads these programs into the memory 103 and executes them. The contents of these programs will be described later.

The display module 105 may be, for example, a display, a printer, or an audio output device. The input module 104 may be, for example, a keyboard switch, a pointing device such as a mouse, a touch panel, or a voice instruction device. The communication module 106 includes a circuit for connecting to the communication network 900 and a communication protocol.

The controller 102 reads a predetermined program from the program database 130 and executes it. The controller 102 may be configured as one or a plurality of semiconductor chips, or may be configured as a computer device such as a calculation server. The memory 103 stores a computer program read from the program database 130, data and calculation results necessary for calculation by the controller 102, image data, and the like.

The system model database 131 includes the configuration of the power system, line impedance, ground capacitance, active power, reactive power, voltage, voltage phase angle, current, power factor, data necessary for state estimation (such as threshold value of bat data), The generator data, data necessary for power flow calculation, and data necessary for transient calculation are stored. The administrator of the arithmetic device 100 may input these information into the system model database by the input module 104.

The contingency database 132 includes data of one or a plurality of contingencies. An assumed failure is a group of events that occur in the power system. For example, a one-line ground fault in a transmission line, energization interruption (opening) of a transmission line due to activation of a protection relay or a system stabilization relay, disconnection of a power plant, Or the load is dropped. As shown in FIG. 2, each of the plurality of contingency failures includes a table 2000 including an event occurrence time, an event occurrence location, and an aspect.

The power supply control device 200 has a configuration in which a controller (CPU) 202, a memory 203, a communication module 206, and a plurality of databases are connected to a bus line 201. The plurality of databases includes a program database 230 and an output fluctuation database 231.

The program database 230 stores a controllable amount calculation program and a control amount distribution program. The controller 202 reads these programs into the memory 203 and executes them. The contents of these programs will be described later.

The output fluctuation database 231 has information related to output fluctuation of the variable power supply controlled by the power supply control device 200. For example, as shown in FIG. 3, the output fluctuation database 231 includes information on probability distributions for power supply output fluctuations for each of a plurality of variable power supplies. The controller 202 of the power supply control device 200 constantly monitors the variable power supply 23a, the variable power supply 23b, and the variable power supply 23c, collects the history of output of the variable power supply that varies depending on the weather and weather as measurement data, and calculates the amount of change. Calculate, add statistical processing to this, and record in the output fluctuation database 231. Since the output of the generator 4 does not change due to weather or weather, the power supply control device 200 may not record the output fluctuation of the generator in the output fluctuation database 231.

Next, an example of the operation of the power system control system (power system stabilization processing) will be described. FIG. 4 is a flowchart thereof. The arithmetic device 100 executes an analysis model creation process S1, a stability determination process S2, and a control plan creation process S3. The power supply control device 200 executes a controllable amount calculation process S4 and a control amount distribution S5.

The controller 102 of the arithmetic device 100 and the controller 202 of the power supply control device 200 start the flowchart of FIG. 4 every predetermined time. The communication module 106 of the arithmetic device 100 receives the power system measurement data D1 from the measurement device 10 via the communication network. The controller 102 executes the analysis model creation program (analysis model creation processing S1), fetches the aforementioned system data from the system model database 131, and creates the analysis model data D2 by state estimation or the like based on the measurement data D1. To do.

To determine the stability of the power system, electrical quantities such as voltage magnitude, voltage phase, active power, and reactive power are required for all buses and transmission lines at a specific time. The state estimation is a technique for estimating various electrical quantities at a specific time with respect to measurement time discrepancies and measurement errors included in measurement data, for example, “Lars Holten, Anders Gjelsvlk, Sverre Adam, F. F. Wu , And Wen-Hs Iung E. Liu, “Comparison of Different Methods for State Estimation”, IEEE Transaction on Power Systems, Vol. 3, pp. 1798-1806, 1988 ”.

The controller 102, based on the analysis model creation program, the electrical quantities obtained by the state estimation described above, the electrical characteristic data of the equipment included in the system model database 131, and the generator included in the system model database 131 The analysis model data D2 is created by combining the dynamic characteristic data of the control system. The analysis model data is a data group for analyzing the stability of the power system. The controller 102 records the analysis model data in the memory 103.

Next, the controller 102 executes a stability analysis program to determine the stability of the power system (stability determination processing S2). The controller 102 reads the analysis model data from the memory 103, reads a plurality of contingency data from the contingency database 132, analyzes whether the operation can be performed while maintaining the current state of the power system after each contingency, and assumes Determine whether the power system is stable or unstable at the time of failure.

The controller 102 determines whether or not the operation of the power system can be maintained, for example, by calculating the behavior of the power system after the assumed failure by transient calculation. As the transient calculation, for example, Yasuji Sekine “Power System Transient Analysis” pp. 377-392 is known. When the controller 102 determines that the behavior of the power system after the failure obtained by the transient calculation is, for example, that the voltage keeps decreasing or the operating angle of the generator exceeds a predetermined threshold due to the acceleration of the generator. The power system becomes unstable and it is determined that the operation of the power system cannot be maintained.

The controller 102 sequentially reads out the assumed failure data from the assumed failure database 132 and determines whether or not the power system is stable. When the controller 102 determines that the power system is unstable based on the read-out assumed failure data, the controller 102 executes a control amount calculation program to control the control amount, for example, the generator 4, And / or a control plan for setting the output limit amount of the

variable power sources

23a, 23b, and 23c is created (control plan creation process S3).

The controller 102 refers to the controllable amount D3 in the control plan creation process S3. The controllable amount is a range, width, or upper limit in which the power supply can limit its output. The limit amount of the control plan is set within the range of the controllable amount. The control plan may be determined by a method described in JP-A-2015-130777. Since the output of the generator 4 is not affected by weather or weather, the controllable amount of the generator 4 may be the current output of the generator. That is, the controller 102 can limit the output of the generator with the current output of the generator as the upper limit.

On the other hand, since the outputs of the

variable power supplies

23a, 23b, and 23c fluctuate due to the influence of weather and weather, the controllable amount D3 of the variable power supply becomes an output after fluctuating due to the influence of weather and weather. The controller 202 of the power supply control device 200 calculates the controllable amount of the variable power supply based on the current output of the variable power supply and the output fluctuation database 23 (controllable amount calculation process S4). By the way, the controllable amount calculated by integrating the outputs of the plurality of variable power sources is larger than the value obtained by calculating the controllable amount for each of the plurality of variable power sources and summing the controllable amounts. In other words, the latter has a greater contribution to the stabilization of the power system with respect to the assumed failure. Details of this will be described later. The controller 202 of the power supply control device 200 calculates the controllable amount of the generator 4 and the controllable amounts of the

variable power sources

23 a, 23 b, and 23 c and records them in the memory 203.

When the controller 102 determines that the power system is not stable in the stability determination process S2, the controller 102 provides the controllable amount of the generator 4 and the controllable amounts of the

variable power sources

23a, 23b, and 23c from the power supply control device 200. In response to this, a control plan for how much the output is increased or decreased with respect to the assumed failure taken in from the assumed failure database 131 is created (control plan creation process S4), and this is recorded in a predetermined area of the memory 103. In the predetermined area of the memory 103, a plurality of contingencies and control plans for the contingencies may be recorded in the form of a table, for example. The controller 102 updates the table every time the flowchart of FIG. 4 is executed. Therefore, the table has the latest control plan.

When the process of S3 is completed, the controller 102 returns to the power system stability determination process S2, and applies the power system stability process S2 for the next assumed failure. If the controller 102 determines in this process that the power system is stable, the controller 102 proceeds to the process of S6, and has the verification of the stability of the power system been performed for all the assumed faults registered in the assumed fault database? Determine whether or not.

When the controller 102 affirms S6, it refers to the memory 103 and determines whether or not a control plan is stored for at least one contingency failure. If this is affirmed, the controller 102 transmits the control plan for each contingency to the power supply control device 200 as control plan data D4 for all contingencies, and ends the flowchart. When the controller 102 determines that there is no control plan for all the assumed failures, the controller 102 ends the flowchart without transmitting to the power supply control device 200.

On the other hand, the controller 202 of the power supply control device 200 stores the control plan data D4 received from the memory 203 and the arithmetic device 100. Furthermore, the controller 202 receives the measurement value and the activation signal of the protection relay as the measurement data D1, and determines whether or not a failure has occurred in the power system by determining whether or not the measurement data D1 is within the normal value range. Is determined (S7). When the controller 202 determines that the measured value is within the specified range, the controller 202 ends the flowchart assuming that there is no failure in the power system.

On the other hand, when the controller 202 determines that a failure has occurred in the power system, the measurement data D1 is compared with a plurality of assumed failures. The controller 202 may acquire the information of the contingency database 132 through the communication network 900 using the communication module 206. When the controller 202 determines that the measurement data D1 does not correspond to any conceivable failure, the flowchart ends. At this time, the controller 202 may execute a predetermined measure in order to stabilize the power system.

Next, when the controller 202 determines that the measurement data D1 corresponds to at least one assumed failure among a plurality of assumed failures, the controller 202 refers to the memory 203 and determines whether a control plan is set for the assumed failure. To do. If the determination is negative, the controller 202 ends the flowchart. At this time, the controller 202 may execute a predetermined measure in order to stabilize the power system.

On the other hand, when the controller 202 affirms this determination and confirms that the control plan is set for the failure that has occurred in the power system, the controller 202 executes the control amount distribution program, and first, based on the control plan data D4. Thus, the output limit amount for stabilizing the power system is distributed to the generator 4 and / or the

variable power sources

23a, 23b, and 23c (control amount distribution processing S5).

Even if the controller 202 determines that a failure occurring in the power system corresponds to the assumed failure, if the control plan is not set for this assumed failure, the flowchart is terminated and a predetermined value is used to stabilize the power system. Countermeasures may be implemented. It is preferable that the allocation is performed without any bias to the generator 4 and / or the

variable power sources

23a, 23b, and 23c. For example, the limit amount may be apportioned according to the power generation output.

For example, when the output reduction of 60 MW is requested for the entire variable power supply, and the outputs of the variable power supply 23a, the variable power supply 23b, and the variable power supply 23c are 50 MW, 130 MW, and 120 MW, respectively, the controller 202 What is necessary is just to allocate the output decrease of 10 MW to 23a, the output decrease of 26 MW to the variable power source 23b, and the output decrease of 24 MW to the variable power source 23c.

Note that the controller 202 has been described that the allocation described above is determined according to the output of the variable power supply. However, the power supply control device 200 holds a history of past distributions, and a plurality of variable power supplies. The accumulated allocation amount may be made equal. The controller 202 transmits the distributed control amount to the generator 4 and the

variable power sources

23a, 23b, and 23c, and ends the flowchart. The generator 4 and the

variable power sources

23a, 23b, and 23c limit or increase the output according to the transmitted control amount.

Next, the process of calculating the controllable amount for the

variable power sources

23a, 23b, 23c (S4 in FIG. 4) will be described in detail. FIG. 5 is a flowchart of this, and the controller 202 refers to the output fluctuation database 231 based on the controllable amount calculation program, and acquires the statistical information of the output fluctuations of the

variable power supplies

23a, 23b, and 23c ( S500).

FIG. 6 shows that the probability distribution of fluctuation from the current output is a normal distribution for each of the

variable power supplies

23a, 23b, and 23c. The controller 202 obtains the average value and variance of the normal distribution for each variable power source, and based on these, the probability distribution of the output fluctuation of the integrated output obtained by integrating the outputs of the

variable power sources

23a, 23b, and 23c is normal. According to the distribution (FIG. 6: 600), the average value and the variance are calculated (S502). Fluctuation power 23a, fluctuation power 23b, and an in average probability distribution of the output fluctuation of the fluctuation power 23c respectively dispersed, μa, μb, μc, σa 2, σb 2, When .sigma.c ^2, the output of the three variations Power The normal distribution (FIG. 6: 600) of the integrated model in which the probability distribution of fluctuation is integrated is expressed by the following Equation 1.

The average of the integrated model is “μa + μb + μc”, and the variance is “(σ _a ² + σ _b ² + σ _c ² ) ^1/2 ”. The difference between the variance (σ _a + σ _b + σ _c ) in the probability distribution of each of the variable power source 23a, the variable power source 23b, and the variable power source 23c and the variance in the probability distribution of the integrated model is expressed by the following equation 2. become.

The presence of this difference indicates that the probability of large fluctuations in the output is reduced in the integrated model, and the controllable amount for a plurality of variable power supplies can be increased by the integrated model. That is, the controller 202 obtains the controllable amount based on the output of the integrated model rather than obtaining the controllable amount based on the outputs of the variable power source 23a, the variable power source 23b, and the variable power source 23c. Many can be set.

In order to calculate the controllable amount of the integrated model, the controller 202 needs to estimate the amount by which the output of the integrated model fluctuates before the next calculation timing. Therefore, the controller 202 sets a threshold value (α) (S504), and assumes that there is an output variation within the range of the threshold value, and based on the current output of the integrated model (sum of outputs of a plurality of variable power supplies). Subtracting the fluctuation of the output is the controllable amount of the integrated model.

The threshold value may be, for example, the total value (602 in FIG. 6) of the probability distribution at the lower end of the probability distribution of the integrated power supply model. For example, if this threshold is set to 2.5%, the value obtained by subtracting this from the current output is the controllable amount of the integrated model. (S506). The controller 202 of the power supply control device 200 may transmit this controllable amount to the arithmetic device 100 via the communication network 900 so that the arithmetic device 100 can create a control plan.

The threshold value is not limited to the aforementioned value (2.5%). The threshold value may be appropriately selected according to the characteristics of the variable power source, the performance of the power system, the weather, the characteristics of the weather, and the like. According to the above description, the fluctuation field probability distribution of the output of the fluctuation power source follows the normal distribution, but the present invention is not limited to this. The number of variable power supplies is not limited to three, but may be two or more. The arithmetic device 100 may display the controllable amount and the output of the variable power source on the display module 105. The arithmetic device 100 may determine whether or not the calculated controllable amount is within a normal value range, and may remove the uncontrollable control amount. An administrator may do this using the input module 104.

When the weather changes between when the power system control system creates a control plan and when the power system actually fails and when this control plan is implemented, the output of the variable power source will fluctuate. In this case, even if the control plan is applied to the power system, the stability of the power system cannot be maintained as expected. However, according to the above-described embodiment, the power system control system creates a control plan in anticipation of fluctuations in the output of the variable power source. Therefore, the weather changes between the creation of the control plan and the execution of the control plan. However, the stability of the power system can be maintained as expected. The power system control system described above calculates the controllable amount by predicting the output variation based on the probability distribution of the model that integrates the outputs of the multiple variable power supplies. It can be made larger than the controllable amount calculated by predicting the fluctuation of the output of each of the plurality of variable power supplies based on the probability distribution of each power supply.

In the above-described embodiment, a power supply control device may exist for each of a plurality of power supplies. In addition, the controllable amount calculation process S4 and the control amount distribution process S5 have been described as being performed by the power supply control device 200, but either one may be executed by the arithmetic device 100, or both may be executed by the arithmetic device 100. May be. Furthermore, the arithmetic device 100 and the power supply control device 200 may be a single device. Moreover, the power system control system may create a plurality of control plans for the contingency failure. Furthermore, the power system control system may use the storage of the output of the variable power source in the storage battery as a limited amount for the variable power source or as a substitute for a part thereof.

In the above-described embodiment, setting the controllable amount for a plurality of variable power sources is performed by generating a model in which the plurality of variable power sources are integrated in one step (one stage). It may be possible to set a unified model from a plurality of variable power sources by a plurality of steps. For example, a unified model of a plurality of variable power supplies (

variable power supplies

23a and 23b) may be set, and then a model in which another variable power supply (23c) is added to the variable power supply of this unified model may be generated.

Still further, before allocating the control amount to each variable power supply to the power supply control device 200, a determination module for determining whether or not the power supply system can be stabilized against an assumed failure, and if this cannot be stabilized, control is performed. A control amount correction module for changing the amount may be provided. The control amount when the system regenerates model data at each predetermined timing and generates a control amount for the variable power supply differs from the control amount that the power supply control device 200 distributes to each of the plurality of variable power supplies. This is because the degree of stabilization may deteriorate. The embodiment described above is not intended to limit the present invention, and the embodiment may be changed as appropriate.

1: Power system 2: Transmission line 3: Bus line 4: Power supply 7: Circuit breaker (relay)
9: Transformer 10: Measuring instrument 100: Arithmetic device 101: Communication bus line 102: Controller 103: Memory 104: Input module 105: Display module 106: Communication module 130: Program database 131: System model database 132: Assumed failure database 200 : Power supply control device 201: Communication bus line 202: Controller 203: Memory 206: Communication unit 230: Program database 231: Output fluctuation database 900: Communication network

Claims

A power system control system that maintains the stability of the power system by controlling the output of the power supply of the power system,
The power system, as the power source, includes a plurality of variable power sources that generate power based on renewable energy and whose output varies depending on the state of the renewable energy,
The power system control system includes a memory and a controller that executes a program recorded in the memory,
The controller is
Integrating the probability distribution of fluctuations in the output of each of the plurality of variable power sources;
Create a control plan for controlling the output of each of the plurality of variable power sources based on the integrated probability distribution so that the stability of the power system can be maintained from a failure assumed in the power system.
Power system control system.
The memory stores configuration information of the power system,
The controller is
Reading the configuration information from the memory;
Capture measurement data of the power system,
Based on the measurement data and the configuration information, create a model for analyzing the stability of the power system,
Calculating the control plan based on the model;
The power system control system according to claim 1.
The memory stores possible failure scenarios for the power system;
The controller is
Read the failure scenario from the memory;
Based on the integrated probability distribution, a controllable amount capable of limiting the output for the plurality of variable power sources is calculated,
Creating the control proposal based on the model, the failure scenario, and the controllable amount;
The power system control system according to claim 2.
The control plan includes a limit amount of output for the plurality of variable power sources,
The controller is
When the assumed failure occurs in the power system, the limit amount is allocated to the plurality of variable power sources, and the allocated limit amount is allocated to each of the plurality of variable power sources.
The power system control system according to claim 3.
The controller is
Setting the limit amount within the controllable amount range;
The power system control system according to claim 4.
The controller is
Distributing the limit amount to the plurality of variable power sources based on the current output of each of the plurality of variable power sources;
The power system control system according to claim 4.
The memory stores output fluctuation history information for each of the plurality of fluctuation power supplies.
The power system control system according to claim 1.
The probability distribution is a normal distribution of fluctuation amounts of outputs of the plurality of variable power sources.
The power system control system according to claim 1.
The controllable amount calculated for the plurality of variable power sources based on the integrated probability distribution is larger than the controllable amount calculated based on the probability distribution of each of the plurality of variable power sources.
The power system control system according to claim 3.
A power system control method for maintaining the stability of the power system by controlling the output of the power source of the power system by the power system control system,
The power system, as the power source, includes a plurality of variable power sources that generate power based on renewable energy and whose output varies depending on the state of the renewable energy,
The power system control system is:
Integrating the probability distribution of fluctuations in the output of each of the plurality of variable power supplies
Create a control plan for controlling each output of the plurality of variable power sources based on the integrated probability distribution so that the stability of the power system can be maintained from a failure assumed in the power system,
Power system control method.