JP7822262B2 - Power system stabilization device and method - Google Patents

Description

The present invention relates to a power system stabilization device and method for maintaining the stability of a power system.

When a fault (fault) occurs in a power system due to a lightning strike or other cause, the output of some synchronous generators (SGs) may become unstable. If effective measures are not taken to prevent this instability, the number of unstable synchronous generators will increase over time, and this could ultimately lead to a major blackout.

In response to the above-mentioned problems, conventional power system stabilizers have maintained the transient stability of power systems by isolating unstable synchronous generators from the power system in the event of a fault, i.e., by limiting power supply (shunting). For example, the power system stabilizer described in Non-Patent Document 1 uses numerical simulations to calculate in advance which synchronous generators to suppress in order to maintain transient stability in the event of a contingency fault in the power system, and then performs stabilization control to suppress those synchronous generators when a contingency fault actually occurs. This power system stabilizer aims to maintain transient stability by first suppressing the synchronous generator with the largest internal phase difference angle in the event of a fault. Note that stabilization control does not only involve the above-mentioned shedding, but also includes methods of suppressing or stopping generator output; however, in the following, the term "shunting" will include both suppressing and stopping generator output.

On the other hand, in recent years, in order to reduce CO2 emissions, the introduction of renewable energy sources such as solar and wind power has been actively promoted as an alternative to synchronous generators such as thermal power plants, and the proportion of synchronous generators in power grids has been on a downward trend. However, as the proportion of synchronous generators decreases, the inertia and voltage maintenance capabilities of the power grid, which were previously carried out by synchronous generators, decrease, raising the risk of a decline in transient stability.

Furthermore, a reduction in synchronous generators means a reduction in the stabilization means in conventional power system stabilizers. Because renewable energy power sources do not have the internal phase difference angle that is an indicator for selecting generators to be sheared in conventional power system stabilizers, conventional power system stabilizers cannot select renewable energy power sources as targets for shearing. As a result, it may become difficult for conventional power system stabilizers to maintain transient stability, and there is a possibility that the total amount of shearing required to maintain transient stability may increase (increasing the cost required to restore from shearing).

In response to the above-mentioned issues, adding renewable energy sources, which are expected to be increasingly introduced in the future, to the list of candidates for power control will increase the likelihood of maintaining transient stability and reduce the total amount of power control required for stabilization (reducing the costs required to recover from power control).

In this regard, Patent Document 1 is known as an invention related to a power system stabilization device that includes renewable energy power sources as candidates for power control. Patent Document 1 aims to provide a power system stabilization device that can efficiently ensure the stability of the power system by selecting renewable energy power generation devices (renewable energy power sources) whose output will be reduced or stopped. It describes a power system stabilization device that includes: "a stability calculation unit 11 that calculates stability for a predicted target failure case; an acceleration tendency synchronous generator extraction unit 12 that extracts one or more synchronous generators 4 with an acceleration tendency; a sensitivity calculation unit 13 that calculates the deceleration sensitivity of the acceleration tendency synchronous generator 6 when the output of the renewable energy power generation device 6 is reduced by a first reduction amount P1; a renewable energy reduction amount addition unit 14 that determines a total output reduction amount P3 of the extracted renewable energy power generation devices 6 that is determined to have stable stability; and a reduction target determination unit 15 that determines the renewable energy power generation devices 6 whose output will be reduced."

Japanese Patent Application Laid-Open No. 2020-96472

Hiroshi Yoshida, Ryuji Tate, Koya Takafuji, Hironori Imaeda, Masaru Takeishi, Hiroyuki Taguchi, and Kenichiro Kusaba, "Development of an Integrated Online Power System Stabilization System (ISC) for Backbone Systems Adapted to Next-Generation Grids," Journal of Electrical Engineering B, Vol. 137, No. 6, pp. 434-445 (2017)

Patent Document 1 describes a method for expressing the stabilizing effect of controlling renewable energy sources in terms of sensitivity, and using that sensitivity to select renewable energy sources to be controlled in preference to synchronous generators, and selecting synchronous generators to be controlled when controlling renewable energy sources alone is insufficient, given that in a power system with a large number of connected renewable energy sources and a small number of operating synchronous generators, there is a possibility that the power system may become unstable if synchronous generators are controlled in the event of a fault or other such occurrence.

However, depending on the region where the failure occurs, it is possible that the proportion of renewable energy sources in the power grid is low, or that there are few renewable energy sources that have a high stabilizing effect through shedding control. In such cases, the method of Patent Document 1, which selects renewable energy sources to be shedding controlled in preference to synchronous generators, may result in problems such as an increase in the total amount of shedding required for stabilization (increased costs required to restore from shedding control), adverse effects on the grid due to excessive shedding control, and an increase in the amount of calculation required to select shedding control units.

Therefore, a method is needed that allows for the prioritization of synchronous generators or renewable energy sources to be controlled, regardless of the proportion of renewable energy sources in the power grid, based on which has the greatest stabilizing effect.

Based on the above, the problem that this invention aims to solve is to provide an index that can uniformly evaluate the stabilizing effect of shedding control on synchronous generators and renewable energy sources, and a shedding control algorithm that uses this index.

In light of the above, the present invention provides a power system stabilization device that determines targets for shedding control to be performed for stabilization control in the event of a fault in a power system, depending on the stability in the event of a contingent fault in the power system including synchronous generators and renewable energy power sources, the power system stabilization device comprising: an acceleration synchronous generator determination unit that determines acceleration synchronous generators based on the results of a transient stability calculation in the event of a contingent fault in the power system; a shedding candidate determination unit that determines shedding candidates for synchronous generators and renewable energy power sources based on the results of the transient stability calculation; a sensitivity average value calculation unit that calculates the sensitivity of the deceleration index of the acceleration synchronous generators to the shedding of the shedding candidates and calculates the average value of the acceleration synchronous generator sensitivities; a shedding candidate selection unit that selects shedding candidates as targets for shedding control in descending order of the average value until the transient stability of the power system is stabilized; and an output unit that outputs the results of each unit.

The present invention also provides a power system stabilization method for determining targets for shedding control to be performed for stabilization control in the event of a fault in a power system, depending on the stability in the event of a contingent fault in the power system including synchronous generators and renewable energy power sources, the method comprising: an acceleration synchronous generator determination step for determining acceleration synchronous generators based on the results of a transient stability calculation of the power system in the event of a contingent fault in the power system; a shedding candidate determination step for determining candidates for shedding of synchronous generators and renewable energy power sources based on the results of the transient stability calculation; a sensitivity average value calculation step for calculating the sensitivity of the deceleration index of the acceleration synchronous generators to the shedding of the shedding candidates and calculating the average value of the sensitivity of the acceleration synchronous generators; a shedding target selection step for selecting candidates for shedding control as targets for shedding control in descending order of the average value until the transient stability of the power system becomes stable; and an output step for outputting the results of each part.

This invention allows the stabilizing effect of shedding of synchronous generators and renewable energy power sources to be evaluated in the same way, and at least one of the synchronous generators or renewable energy power sources to be selected for shedding in order of the stabilizing effect. This improves transient stability regardless of the proportion of renewable energy sources in the power system, and reduces the total amount of shedding required for stabilization (the cost required to restore from shedding).

1 is a diagram showing an example of the functional configuration of a power system stabilizing device 1 according to a first embodiment of the present invention; 1 is a diagram showing an example of the hardware configuration of a power system stabilization device 1 according to a first embodiment; FIG. 2 is a diagram showing programs held in a program database DB20. FIG. 10 is a diagram showing an example of system configuration data D11. FIG. 10 is a diagram showing an example of systematic measurement data D12. FIG. 10 is a diagram showing an example of system model data D13. FIG. 10 is a diagram showing an example of contingency data D14. FIG. 10 is a diagram showing an example of threshold data D15. FIG. 10 is a diagram showing an example of power control constraint data D16. FIG. 10 is a diagram showing an example of sensitivity calculation setting data D17. FIG. 2 is a diagram showing an overall flow of processing of the power system stabilizing device 1 according to the first embodiment. FIG. 12 is a diagram showing detailed processing content of processing step S23 in FIG. 11 . FIG. 12 is a diagram showing detailed processing content of processing step S24 in FIG. 11; FIG. 12 is a diagram showing a detailed flow of the process of detecting an isolated out-of-step synchronous generator in processing step S25 of FIG. 11 . A diagram showing an image of sensitivity calculation when a synchronous generator is controlled. A diagram showing an image of calculating sensitivity when power is controlled from a renewable energy source. FIG. 12 is a diagram showing an image of sensitivity average value calculation in processing step S26 of FIG. 11. FIG. 12 is a diagram showing a detailed flow of the electrical control target selection process in processing step S27 of FIG. 11 . FIG. 15 is a diagram showing an image of updating the sensitivity average value in processing step S275 of FIG. 14. FIG. 4 is a diagram showing an example of a result display on the display unit 4. FIG. 4 is a diagram showing an example of a result display on the display unit 4. FIG. 10 is a diagram showing an example of the functional configuration of a power system stabilizing device 1 according to a second embodiment of the present invention. FIG. 10 is a diagram showing a hardware configuration of a power system stabilizing device 1 according to a second embodiment. FIG. 11 is a diagram showing an example of past sensitivity calculation result data D18 in the second embodiment. FIG. 11 is a diagram showing a detailed flow of the power control target selection unit 27 in the third embodiment. FIG. 11 is a diagram illustrating an image of updating an average sensitivity value in the third embodiment.

The following describes an embodiment of the present invention with reference to the accompanying drawings. Note that in this specification, "stability" and "stability" are used interchangeably.

First, an example of the functional configuration of a power system stabilization device 1 according to Example 1 of the present invention will be described using Figure 1.

The power system stabilization device 1 is composed of input data D1 held in advance by the power system operator or planner, a calculation unit 2 that determines power system stabilization control commands based on the input data D1, output data D2 that stores the calculation results of the calculation unit 2, and a display unit 4 that is an output unit that displays the contents of the input data D1 and output data D2.

The control device 3 receives the control commands determined by the calculation unit 2 and transmits control commands (power control commands) to the generator when a contingency fault (contingency failure) occurs in the power grid.

The database DB that stores the input data D1 is composed of a system configuration database DB11 that holds system configuration data D11, a system measurement database DB12 that holds system measurement data D12, a system model database DB13 that holds system model data D13, a contingency database DB14 that holds contingency data D14, a threshold database DB15 that holds threshold data D15, a shearing control constraint database DB16 that holds shearing control constraint data D16, and a sensitivity calculation setting database DB17 that holds sensitivity calculation setting data D17.

The calculation unit 2 is composed of an analysis section creation unit 21, a transient stability calculation unit 22, an acceleration synchronous generator determination unit 23, a shedding candidate determination unit 24, an isolated out-of-step synchronous generator detection unit 25, a sensitivity average value calculation unit 26, and a shedding target selection unit 27, and processes are performed in this order.

The databases DB that store the output data D2 are the analysis cross section database DB21, which holds the analysis cross section data D21 that is the result of the analysis cross section creation unit 21; the transient stability calculation result database DB22, which holds the transient stability calculation result data D22 that is the result of the transient stability calculation unit 22; the acceleration synchronous generator determination result database DB23, which holds the acceleration synchronous generator determination result data D23 that is the result of the acceleration synchronous generator determination unit 23; and the shedding candidate database DB24, which holds the shedding candidate determination result data D24 that is the result of the shedding candidate determination unit 24. It is composed of a judgment result database DB24, an isolated out-of-step synchronous generator database DB25 that holds isolated out-of-step synchronous generator data D25 which is the result of the isolated out-of-step synchronous generator detection unit 25, a sensitivity calculation result database DB26 that holds sensitivity calculation result data D26 which is the result of the sensitivity average value calculation unit 26, a sensitivity average value update database DB27 that holds sensitivity average value update data D27 which is the result of the power control target selection unit 27, and a power control target calculation result database DB28 that holds power control target calculation result data D28.

Figure 2 is a diagram showing an example of the hardware configuration of the power system stabilizer 1 of Example 1. The upper part of Figure 2 shows an example of the hardware configuration of the power system stabilizer 1, and the lower part shows an example of the configuration of the power system that is the object of its control.

The power system stabilization device 1 is composed of various input databases DB11-DB17, a program database DB20, various output databases DB21-DB28, a display unit 4, an input unit 5, a communication unit 6, a processor 7, a memory 8, and a bus line 9 connecting these.

Figure 3 shows the group of programs held by the program database DB20. The program database DB20 consists of an analysis section creation program P1, a transient stability calculation program P2, an acceleration synchronous generator determination program P3, a shedding candidate determination program P4, an isolated out-of-step synchronous generator detection program P5, a sensitivity average value calculation program P6, and a shedding target selection program P7.

The display unit 4, which serves as the output unit, is composed of, for example, one or more of a display device, printer device, projector device, audio output device, etc. The display unit 4 displays one or more of the various input data D1 (D11-D17) and the various output data D2 (D21-D28) on a screen. Examples of the screen to be displayed are described below.

The input unit 5 may be composed of one or more of the following: a keyboard, a switch, a mouse, a touch panel, a voice input device, etc.

The communication unit 6 exchanges data with the power system 100 via the communication network 200.

The processor 7 reads a program required for processing by the calculation unit 2 from the various programs constituting the program database DB20 and executes the calculation. The processor may be configured with one or more semiconductor chips, or may be configured with a computer or calculator.
The memory 8 is configured by a storage device such as a RAM (Random Access Memory), and stores programs read from the program database DB20, input data D1, output data D2, and the like.

The example power system 100 shown at the bottom of Figure 2 is composed of generators 110a-110c, such as synchronous generators and renewable energy power sources, nodes (busbars) 120a-120c and 121a-121c, transformers 130a-130c, and branches (lines) 140a-140c.

The power system 100 also includes measurement devices 30a-30b. The measurement devices 30a-30b communicate with the power system stabilization device 1 via the communication network 200.

The measuring devices 30a-30b acquire one or more of the following as system measurement data D12: the output of the generators 110a-110c, the voltage values at each node 120a-120c and 121a-121c, the values of the active and reactive power flowing through the transformers 130a-130c and branches 140a-140c, and on/off information for circuit breakers at nodes, transformers, branches, and phase modifying equipment, and transmit this data to the communication unit 6.

In addition, when a fault occurs in the power system 100, the measuring devices 30a-30b detect information such as the fault location and nature, and transmit this information to the control device 3 via the communication network 200.

The control device 3 receives the power control target calculation result data D28 from the power system stabilization device 1 via the communication network 200. Furthermore, when a fault occurs in the power system 100, the control device 3 compares the fault information acquired from the measurement devices 30a-30b with the power control target calculation result data D28 and transmits control commands to the generators 110a-110c.

The measuring devices 30a-30b acquire one or more of the following as system measurement data D14: TM (Telemeter) information such as the output P of the generators 110a-110c, the voltage values V at each node 120a-120c and 121a-121c, the active power P and reactive power Q values flowing through the transformers 130a-130c and branches 140a-140c, and SV (Super Vision) information on the on/off status of circuit breakers at nodes, transformers, branches, and phase modifying equipment, and transmit this information to the communication unit 13. Specifically, measurements are made using voltage transformers (VT), potential transformers (PT), current transformers (CT), etc.

The power system stabilization device 10 can periodically acquire TM information and SV information from the measurement devices 30a-30b via the communication network 300 and store it in the system measurement value DB.

In addition, some of the measuring devices 30a-30b detect information such as the location and nature of a fault when a fault occurs in the power system 100, and transmit this information to the control device 3 via the communication network 200.

The control device 3 (slave station) receives the power control target calculation result table data D25 from the power system stabilization device 10 via the communication network 200. Furthermore, when a fault occurs in the power system 100, the control device 3 compares the fault information acquired from the measurement devices 30a-30b with the power control target calculation result table data D25, and transmits a control command to the generator terminal station (transfer cutoff device) that cuts off the generators 110a-110c.

Here, we will explain the data D11 to D17 held in the various input databases DB11 to DB17 that make up the power system stabilization device 1 using drawings.

Figure 4 shows an example of system configuration data D11 stored in the system configuration database DB11. In addition to information about the branches (lines) and synchronous generators that make up the power system, the system configuration database DB11 also stores information about loads, renewable energy power sources, transformers, phase modifying equipment, etc. The data that should be stored for these devices includes, for branches, the transmission line number, number of lines, node numbers at both ends, resistance, reactance, etc., and for the same equipment, the synchronous generator number, interconnected node, number of parallel units, rated capacity, rated output, reactance, etc. In the cases of loads, renewable energy power sources, transformers, phase modifying equipment, etc., appropriate information will also be stored.

Figure 5 shows an example of system measurement data D12 held by the system measurement database DB12. The system measurement database DB12 stores one or more of the following information acquired via the communication network 200: the output of generators 110a-110c of the power system 100; voltage values at each node 120a-120c and 121a-121c; values of active and reactive power flowing through transformers 130a-130c and branches 140a-140c; and on/off information for circuit breakers at nodes, transformers, branches, and phase modifying equipment. This information is linked to timestamp information indicating the date and time of measurement for each measurement location and stored in chronological order.

Figure 6 shows an example of system model data D13 held in the system model database DB13. The system model database DB13 stores information such as model types related to synchronous generators, renewable energy power sources, and load models required for numerical analysis of power systems using computers and calculators, as well as information on the constants used therein.

FIG. 7 shows an example of the contingency data D14 held in the contingency database DB14.
The contingency fault database DB14 stores information relating to the location, state, and fault removal means of contingency faults in the power system.

Figure 8 shows an example of threshold data D15 held by threshold database DB15. In the illustrated example, threshold database DB15 stores an internal phase difference angle threshold and an output change rate threshold as threshold data used for judgment by acceleration tendency judgment unit 23 and electrical control candidate judgment unit 24.

Figure 9 shows an example of power control constraint data D16 held in the power control constraint database DB16. The power control constraint database DB16 stores information regarding generators and renewable energy sources, such as whether or not power can be controlled for generators and, if so, the timing of power control.

Figure 10 shows an example of sensitivity calculation setting data D17 held by the sensitivity calculation setting database DB17. The sensitivity calculation setting database DB17 stores setting values required for calculating the sensitivity average value by the sensitivity average value calculation unit 26, such as the sensitivity calculation time width T for each contingency fault type and the sensitivity average value calculation method.

Next, the processing content of the calculation unit 2 will be explained using Figure 11. Figure 11 shows the overall processing flow of the power system stabilization device 1 in Example 1. The flow of the calculation processing will be explained for each processing step.

First, in processing step S21, the analysis cross-section creation program P1 is executed using the system configuration data D11, system measurement data D12, and system model data D13 to create analysis cross-section data D21 for the power system 100 at the current time.

Next, in processing step S22a, the analysis cross-section data D21 and the contingent fault data D14 are used to execute the transient stability calculation program P2 under the condition that no generators are powered down, and transient stability calculation result data D22 for the power system 100 is output.

Next, in processing step S22b, it is determined whether the power system 100 is transiently stable or unstable based on the transient stability calculation result data D22. Stability is determined using indicators such as the internal phase difference angle, frequency, and voltage of the synchronous generator. If the power system is stable (YES in S22b), this processing flow ends. If the power system is unstable (NO in S22b), the processing proceeds to processing step S23, which will be described later.

Next, in processing step S23, the acceleration synchronous generator determination program P3 is executed using the threshold data D15 and the transient stability calculation result data D22, and acceleration synchronous generator determination result data D23 is output. Methods for determining whether an acceleration synchronous generator is an acceleration synchronous generator include, for example, a method in which a synchronous generator whose speed deviation is always positive in the time range from the occurrence of a fault to the end time of the transient stability calculation is determined to be an acceleration synchronous generator, and a method in which a synchronous generator whose internal phase difference angle exceeds the threshold specified by the threshold data D15 at the end time of the transient stability calculation is determined to be an acceleration synchronous generator.

The detailed processing content of processing step S23 will be explained using Figure 12. Figure 12 is a diagram showing the concept of accelerating synchronous generator determination. The right side of this figure shows an electric power system in which a fault has occurred in the transmission line to which synchronous generator SG1 is connected, in an electric power system that includes synchronous generators SG1, SG2, and SG3 as generators and renewable energy power sources RES1 and RES2. The left side of Figure 12 also shows the change over time in the speed deviation ω of synchronous generators SG1, SG2, and SG3 before and after the fault occurred.

In this example, the speed deviation ω of synchronous generators SG1, SG2, and SG3 increases in the accelerating direction from the time the failure occurs until time T1 immediately before shedding, when the speed before the failure occurs is used as the reference speed, and then begins to decrease once shedding is implemented. However, looking at the situation further after that, the speed deviation ω of synchronous generators SG1 and SG2, which are located close to the point of failure, increases again and shows signs of becoming unstable at time T2 when the analysis is stopped, but the speed deviation ω of synchronous generator SG3, which is located farther away, shows signs of becoming smaller and stabilizing.

For this reason, in the present invention, the synchronous generators SG1 and SG2 with an accelerating tendency are set as the synchronous generators SG for evaluating the shedding effect. The acceleration tendency of the synchronous generators SG is determined by equation (1) using the speed deviation ω of each synchronous generator SG when a grid fault occurs. In equation (1), T1 is the time immediately before shedding, T2 is the time when the analysis is stopped, ωi (t=T1) is the speed deviation of the synchronous generator _SGi at time T1, and ωi (t=T2) is the speed deviation of the synchronous generator _SGi at time T2.

Next, in processing step S24, the power control candidate determination program P4 is executed using the threshold data D15, power control constraint data D16, and transient stability calculation result data D22, and power control candidate determination result data D24 is output.

One method for determining candidates for shedding is to determine, for example, synchronous generators and renewable energy power sources for which the value of equation (2) is below the threshold specified in threshold data D15 as candidates for shedding. Here, ΔP _i in equation (1) represents the rate of change in the active power output of the synchronous generator or renewable energy power source immediately before and after the occurrence of a contingency fault, P _i1 represents the active power output of the synchronous generator or renewable energy power source immediately before the occurrence of a contingency fault, and P _i2 represents the active power output of the synchronous generator or renewable energy power source immediately after the occurrence of a contingency fault. Furthermore, G represents the set of all synchronous generators and renewable energy power sources that can be shedding-controlled.

Note that the formula for determining candidates for power control is not limited to formula (2). For example, the deviation or rate of change in the voltage of a synchronous generator or renewable energy power source immediately before and after a contingency fault occurs may also be used as the formula for determination.

The detailed processing content of processing step S24 will be explained using Figure 13. Figure 13 is a diagram showing the concept of determining candidates for power control. The right side of this figure shows an electric power system in which a fault has occurred in the transmission line to which synchronous generator SG1 is connected, in an electric power system that includes synchronous generators SG1, SG2, and SG3 and renewable energy power sources RES1 and RES2 as generators, just like the right side of Figure 12. The left side of Figure 12 also shows the time changes in the active power change rate of each power source, i.e., the synchronous generators SG1, SG2, and SG3 and the renewable energy power sources RES1 and RES2, before and after the fault occurred.

The active power change rate of each power source before and after the fault occurs, shown on the left side of Figure 13, shows the change in active power as a percentage based on the active power before the fault occurred. According to this, generators that show a change of more than the threshold value of 30% from the fault period from the occurrence of the fault to its removal are considered candidates for shedding, including synchronous generators SG1 and SG2 and renewable energy power sources RES1 and RES2, while synchronous generator SG3, which shows a change of less than 30%, is not considered a candidate for shedding.

The purpose of the power control candidate determination process in processing step S24 is to narrow down the targets for calculating the sensitivity average value in the sensitivity average value calculation process in processing step S26, which will be described later, and reduce the amount of calculation. If there is no need to reduce the amount of calculation, processing step S24 can be omitted, and all generators indicated as being capable of power control in the power control constraint data D16 can be considered as power control candidates (targets for calculating the sensitivity average value).

Next, in processing step S25, the isolated out-of-step synchronous generator detection program P5 is executed using the power control constraint data D16, the analysis cross-section data D21, the transient stability calculation result data D22, and the acceleration synchronous generator determination result data D23, and the isolated out-of-step synchronous generator data D25 is output.

Figure 14 shows a detailed flow of the process for detecting an isolated out-of-step synchronous generator in processing step S25. The detection procedure will be explained for each processing step in Figure 14.

First, in processing step S251, the acceleration index of the generator determined to be an accelerating synchronous generator in processing step S23 is calculated based on the transient stability calculation result data D22. Examples of acceleration indexes include the internal phase difference angle at the time the transient stability calculation ends and its increase from its initial value. Furthermore, the acceleration/deceleration energy described in Non-Patent Document 1 may be calculated for each accelerating synchronous generator and used as the acceleration index.

Next, in processing step S252, a transient stability calculation is performed under the condition that only the synchronous generator with the largest acceleration index determined in processing step S251 is controlled.

Next, in processing step S253, it is determined whether or not the system is transiently stable based on the transient stability calculation result data from processing step S252. If the system is stable (YES in S253), the process proceeds to processing step S254, which will be described later. If the system is unstable (NO in S253), the process does not proceed to processing step S254, but instead outputs the results of processing steps S251 to S253 as isolated step-out synchronous generator data D25, and this flow ends (proceeds to processing step S26).

Next, in processing step S254, the synchronous generator with the largest acceleration index is determined as the temporary controlled generator, and that synchronous generator is excluded from the sensitivity calculation candidates. After that, the results of processing steps S251 to S254 are output as isolated out-of-step synchronous generator data D25, this flow ends, and processing proceeds to processing step S26.

Returning to FIG. 11, in processing step S26, transient stability is calculated under the condition that each of the shedding candidates determined in processing step S24 is shedding individually, the sensitivity of each acceleration synchronous generator to the shedding of each shedding candidate is determined using the method described below, and the average sensitivity value of all acceleration synchronous generators is calculated for each shedding candidate. The shedding candidates are then ranked in descending order of average sensitivity value. Data related to the sensitivity calculation results and rankings are output as sensitivity calculation result data D26. The definition of sensitivity and the method for calculating the average value will be described later.

Next, in processing step S27, the analysis cross-section data D21, threshold data D15, isolated out-of-step synchronous generator data D25, and sensitivity calculation result data D26 are used to execute the shear control target selection program P7, and output sensitivity average value update data D27 and shear control target calculation result data D28.

The processing steps S22a to S27 described above are performed for each contingency fault and are repeated until calculations for all contingencies are completed. Once calculations for all contingencies are completed, the electrical control target calculation result data D28 is sent to the control device 3.

Here, we will explain the definition of the sensitivity calculated in processing step S26. The sensitivity is expressed, for example, as in equation (3).

In equation (3), SS _{ij (T)} represents the change in deceleration energy (DE) of the jth (i≠j) accelerating synchronous generator in response to the shedding of the ith synchronous generator or renewable energy power source. The deceleration energy of the accelerating synchronous generator is an index similar to the deceleration energy described in Non-Patent Document 1, and indicates the degree of deceleration of the synchronous generator after grid fault clearance. _{ΔDE ij (T)} represents the deviation of the deceleration energy of the jth (i≠j) accelerating synchronous generator during T milliseconds from the start of shedding when the ith synchronous generator or renewable energy power source is shedding-controlled, compared to the deceleration energy when the ith synchronous generator or renewable energy power source is not shedding-controlled. _{ΔP i,ave (T)} represents the average shedding amount of the ith synchronous generator or renewable energy power source during T milliseconds from the start of shedding. Note that G represents the set of all synchronous generators and renewable energy power sources that can be shedding-controlled, and S represents the set of all accelerating synchronous generators.

15 and 16 show calculation images of equation (3) in processing step S26. Fig. 15 is an image of calculating the sensitivity when a synchronous generator is controlled, and Fig. 16 is an image of calculating the sensitivity when a renewable energy power source is controlled. In each figure, (a) is an image of calculating the denominator ΔP _i,ave(T) on the right side of equation (3), and (b) is an image of calculating the numerator ΔDE _ij(T) on the right side of equation (3).

The sensitivity numerators shown in (b) of Figure 15 and (b) of Figure 16 represent the difference ΔDE ij (T) in deceleration energy within time T from time t = Ts between when power control of the synchronous generator or renewable energy power source is performed and when it is not performed on a plane that shows the active power Pi of the synchronous generator SGi versus the internal phase difference angle δ of the synchronous generator _SGi .

The sensitivity denominators shown in Figures 15(a) and 16(a) show the time-series changes when a fault occurs during steady-state operation of a synchronous generator or renewable energy power source, and after the fault is cleared, control of the synchronous generator or renewable energy power source is performed or not performed after time t = Ts.

The sensitivity definition formula (3) can be found for all synchronous generators and renewable energy power sources, so the stabilizing effect of shedding on synchronous generators and renewable energy power sources can be evaluated uniformly. Furthermore, because the sensitivity is found for only accelerating synchronous generators, rather than all synchronous generators, it is possible to efficiently find targets for shedding that are effective for stabilization, i.e., deceleration of accelerating synchronous generators.

The time width T for the sensitivity calculation is a value preset by the power system operator or planner in the sensitivity calculation setting data D17 via input unit 5. The larger T is, the more the transient characteristics of the power system can be reflected in the sensitivity calculation, which may improve the accuracy of shedding control selection, but the amount of calculation increases. Operators and planners can adjust the accuracy of shedding control selection and the amount of calculation as desired, taking into account the characteristics of T described above.

Figure 17 shows an example of the sensitivity average value calculation in processing step S26. In the table shown, the vertical axis shows acceleration synchronous generator sensitivity, average value, ranking, and selection status, while the horizontal axis lists the synchronous generators SG1-SG3 that are subject to shedding or the candidates for shedding of renewable energy sources RES1 and RES2.

As is clear from this table, if a common synchronous generator (e.g., SG1-SG3 in Figure 17) is included among the sensitivity calculation candidates (shearing candidates) and the acceleration synchronous generators, the sensitivity of that synchronous generator cannot be calculated according to the definition of equation (3). In other words, it is impossible to measure the sensitivity of synchronous generator SG1 when it is sheared. Conversely, for sensitivity calculation candidates other than the synchronous generator in question, the sensitivity of all acceleration synchronous generators can be calculated. Therefore, when sensitivity calculation candidates are ranked in descending order of the total sensitivity of the acceleration synchronous generators, synchronous generators that are both acceleration synchronous generators and sensitivity calculation candidates tend to have small total values, so the ranking of those synchronous generators is likely to be low, and this creates the problem of not being able to select all sensitivity calculation candidates fairly.

In contrast, in Example 1 of the present invention, the ranking of shedding is determined based on descending average values of the sensitivity of the acceleration synchronous generators, rather than descending total values, thereby eliminating the above-mentioned unfairness.

Types of averages used in sensitivity average value calculations include the arithmetic mean (arithmetic mean), weighted mean, geometric mean (geometric mean), and harmonic mean. When using a weighted mean, the sensitivity of each accelerated synchronous generator is weighted, for example, by the rated output of the accelerated synchronous generator, the internal phase difference angle at the end time of the transient stability calculation, or the increase in value relative to the initial value. The type of average is preset in the sensitivity calculation setting data D17, and power system operators and planners can change the type as desired via input unit 5. This allows operators and planners to use a more appropriate type of average depending on the state and faults of the power system, which also leads to improved accuracy in shedding selection.

If, as a result of calculating the average sensitivity values, there are multiple shedding candidates with the same ranking, the power system operator or planner will determine the priority of shedding for the shedding candidates with the same ranking according to rules preset in the shedding constraint data D16. Examples of rules include prioritizing shedding candidates with smaller numbers assigned to each generator, shedding candidates with smaller potential costs due to shedding, or shedding candidates with less past shedding history. Setting such priorities not only gives operators and planners greater freedom in their settings, but also allows them to select shedding machines that meet their objectives.

Figure 18 shows a detailed flow of the power control target selection process in processing step S27. The power control target selection procedure will be explained for each processing step in Figure 18.

First, in processing step S271, the highest-ranked sensitivity calculation candidate (shearing control candidate) determined in processing step S26 is selected. The number of selected units may be the single highest-ranked shearing control candidate, or multiple highest-ranked units. When selecting multiple units, transient stability must be assessed to avoid selecting excessive shearing control units for stabilization. Examples of methods include selecting multiple shearing control candidates in descending order of average sensitivity within a range where the total shearing control amount is equal to or less than the value specified in threshold data D15, or referencing the speed deviation of the accelerating synchronous generator from the last transient stability calculation result and selecting multiple units if the maximum value of the speed deviation is greater than the value specified in threshold data D15. The shearing control unit selection in processing step S271 is repeated until the transient stability calculation results in processing step S273, described below, become stable (the total shearing control amount exceeds the shearing control amount required for stabilization). Therefore, allowing multiple units to be selected at once shortens the number of repeated calculations in this flow and reduces the amount of calculation required.

Next, in processing step S272, if the total power control capacity of the generators selected in processing step S271 is smaller than the power control capacity of the temporary power control generators (temporary power control capacity) determined in processing step S254 ("YES" in S272), the process proceeds to processing step S273, which will be described later. On the other hand, if the total power control capacity of the generators selected in processing step S271 is equal to or greater than the temporary power control capacity ("NO" in S272), the subsequent processing steps S273 to S276 are skipped and the process proceeds to processing step S277, which will be described later. Note that if processing step S254 has not been executed ("NO" in processing step S253), there is no temporary power control capacity, so the process forcibly proceeds to "YES" at the branch in processing step S272.

Next, in processing step S273, transient stability is calculated under conditions for controlling the generator selected in processing step S271.

Next, in processing step S274, it is determined whether or not the system is transiently stable based on the transient stability calculation results from processing step S273. If the system is stable (YES in S274), the system proceeds to processing step S276, which will be described later. If the system is unstable (NO in S274), the system proceeds to processing step S275, which will be described later.

Next, in processing step S275, the column of the generator newly selected in processing step S271 is removed from the sensitivity table of FIG. 17, and if there is an accelerated synchronous generator that has been decelerated due to the shedding of that generator, the row and column of that synchronous generator are removed from the ranking table of FIG. 17, thereby updating the average sensitivity value of the shedding candidates. Note that the sensitivity itself is not updated (recalculated), and the sensitivity value calculated in processing step S26 continues to be used. Furthermore, when checking whether an accelerated synchronous generator has decelerated, the accelerated synchronous generator is determined using the transient stability calculation results of processing step S273 in the same manner as processing step S23. After updating, processing returns to processing step S271, and a new generator to be shedding is additionally selected based on the updated sensitivity table.

Figure 19 shows an example of how the sensitivity average value is updated in processing step S275. When renewable energy power source RES1 is selected as the generator to be sheared in processing step S271 based on the ranking in Figure 19(a), the sensitivity table is updated in the subsequent processing step S275 as shown in Figure 17(b). In Figure 19(b), as described above, the column for the generator (renewable energy power source RES1) newly selected in processing step S271 is excluded, and the column and row for the accelerating synchronous generator (SG2) that was decelerated due to the shearing of renewable energy power source RES1 are deleted, thereby updating the sensitivity average value and shearing ranking.

In Patent Document 1, a stability calculation is performed each time a specified amount of renewable energy output reduction is added based on the sensitivity calculation results, and if stability is not achieved, the sensitivity and acceleration tendency of the synchronous generator are recalculated. Therefore, if a large amount of output reduction is required for stabilization, the amount of calculation can become enormous.

In contrast, in Example 1 of the present invention, even if the transient stability calculation indicates instability, the sensitivity itself is not recalculated, and the average sensitivity value is updated using the method described above, thereby minimizing the increase in the amount of calculations and maintaining the accuracy of the shedding control unit selection.

Next, in processing step S276, the combination of all generators selected up until stability is determined in processing step S274 is determined to be the power control combination with the minimum total power control amount, and this processing flow ends.

Next, in processing step S277, the temporary power control units determined in processing step S254 are determined as the power control combination with the smallest total power control amount, and this processing flow ends.

Here, we will explain the effect of the isolated out-of-step synchronous generator detection unit 25.

Depending on the power system's power flow cross section and the location and nature of the fault, there are cases in which a synchronous generator will lose step alone during a fault, and stabilization can be achieved by simply powering down that single generator. In such cases, powering down the single out-of-step synchronous generator may be a way to minimize the total amount of power needed to be powered down.

However, in the above case, since the only accelerating synchronous generator is the isolated out-of-step synchronous generator, the sensitivity due to shedding of the isolated out-of-step synchronous generator cannot be calculated due to the definition of equation (3). In other words, the isolated out-of-step synchronous generator cannot be selected as the generator to be shedding controlled.

As a countermeasure to the above, before selecting an isolated out-of-step synchronous generator using sensitivity in processing step S26 and subsequent steps, the presence or absence of an isolated out-of-step synchronous generator is detected in processing step S25, and if detected, that synchronous generator is selected as the generator to be temporarily controlled. As mentioned above, the power control amount of the temporarily controlled generator (temporary power control amount) is compared in processing step S272 with the total power control amount of the generators selected based on sensitivity, and if the temporary power control amount is smaller, the temporarily controlled generator is selected as the final generator to be controlled in processing step S277, thereby preventing the overlooking of the selection of an isolated out-of-step synchronous generator.

Next, an example of the results displayed by the display unit 4 will be explained using Figures 20 and 21.

In the display example in Figure 20, the sensitivity average value update data D27 and the shedding target calculation result data D28 are displayed in the form of a table or graph. In the "Search Settings" field in Figure 20, you set the time and expected fault for the power flow cross section for which you want to display the results of shedding machine selection. The "Results" field in Figure 20 displays the shedding combination, total shedding amount, and updated data for the sensitivity table, as well as showing the transient stabilization effect of shedding using the internal phase difference angle waveform of the synchronous generator before and after the shedding machine selection. This allows power system operators and planners to easily check the shedding targets, total shedding amount, and degree of stabilization effect for each power flow cross section and expected fault.

In the display example of Figure 21, the shedding target calculation result data D28 is displayed in a power system diagram. In addition to the anticipated fault locations, this system diagram also displays generators connected to the system, distinguishing between those that are subject to shedding and those that are not. In addition, acceleration synchronous generators and candidates for shedding may also be shown on the system diagram. This has the advantage that power system operators and planners can easily grasp the relative positions of anticipated faults, shedding targets, and acceleration synchronous generators.

In Example 2, instead of using equation (2), the power control candidate determination unit 24 of the power system stabilization device 1 uses past sensitivity calculation result data D18 to determine power control candidates for each contingent fault.

Figure 22 shows an example of the functional configuration of a power system stabilization device 1 according to Example 2. The difference from Example 1 is that a database DB18 of past sensitivity calculation results has been added to the input data D1.

Figure 23 shows the hardware configuration of a power system stabilization device 1 according to Example 2. The difference from Example 1 is that a database DB18 of past sensitivity calculation results has been added.

In the case of Example 2, the past sensitivity calculation result data D18 can be, for example, the sensitivity calculation result data D26 previously output by the sensitivity average value calculation unit 26. As a method for determining candidates for power control, for example, the sensitivity calculation candidates (power control candidates) recorded in the past sensitivity calculation result data D18 can be directly inherited as power control candidates, or only generators whose sensitivity average value is greater than the threshold value specified in the threshold data D15 can be determined to be power control candidates, or only generators whose descending order of sensitivity average value is within the rank specified in the threshold data D15 can be determined to be power control candidates.

Figure 24 shows an example of past sensitivity calculation result data D18. As shown in the table in Figure 24, the sensitivity calculation result data for each power control candidate for past dates and times is organized by contingency A, B, and C, and the power control candidate determination unit 24 determines power control candidates for each contingency A, B, and C based on this table.

The first advantage of using Example 2 is that it is expected to improve the accuracy of determining candidates for shedding compared to Example 1. If, for example, the sensitivity calculation result data D26 output within the past few tens of seconds by the sensitivity average calculation unit 26 is used as is as the past sensitivity calculation result data D18, then if there is no significant difference between the power flow cross section within the past few tens of seconds and the current time, it is thought that there will be no significant difference in the generators that will have a high stabilizing effect when shedding occurs for each contingency fault.

On the other hand, because equation (2) is an index based only on data before and after the occurrence of a contingency fault, it does not take into account the state of the power system up until the timing of shedding, as does sensitivity. Therefore, by using past sensitivity calculation result data D18, it is expected that the accuracy of determining shedding candidate candidates will be improved compared to when equation (2) is used to determine shedding candidate candidates.

A second advantage of using Example 2 is that it is expected that the amount of calculation required for determining power control candidates and calculating sensitivity average values can be reduced compared to Example 1. If past sensitivity calculation result data D18 is used as is to determine power control candidates, the calculation of equation (2) can be omitted. In addition, when determining power control candidates using the above method, the threshold data D15 can be set to narrow down the number of power control candidates to a smaller number than when determining power control candidates using equation (2), thereby reducing the number of times transient stability and sensitivity are calculated in the sensitivity average value calculation unit 26.

In addition to the two points above, Example 2 also has the advantage of being able to effectively utilize past calculation results from the power system stabilization device 1.

The differences and advantages of Example 3 compared to Examples 1 and 2 will be explained using Figures 25 and 26.

In Example 3, the power system stabilizer 1's power control target selection unit 27 determines whether to recalculate the sensitivity depending on the reduction in the number of acceleration synchronous generators after selecting the target generators for power control.

Figure 25 shows a detailed flow of the power control target selection unit 27 in Example 3. The difference from Examples 1 and 2 is that processing steps S278 and S279 are added after processing step S275.

In processing step S278, if the number of acceleration synchronous generators to be reduced is less than the number specified by threshold data D15 ("NO" in processing step S278), the process proceeds to processing step S271. On the other hand, if the number of acceleration synchronous generators to be reduced is equal to or greater than the number specified by threshold data D15 ("YES" in processing step S278), the process proceeds to processing step S279, which will be described later.

In processing step S279, all generators selected in processing step S271 are sheared, and transient stability is calculated under the conditions that each of the shearing candidates updated in processing step S275 is sheared individually, the sensitivity of the updated acceleration synchronous generator is determined, and the average sensitivity value and shearing order are updated. After reflecting the results, processing returns to processing step S271, and a new generator is additionally selected for shearing based on the latest shearing order.

The flow from processing step S275 to processing step S279 will be explained using the sensitivity table shown in Figure 26. If adding renewable energy power source RES2 to the list of power sources to be controlled based on the sensitivity table (a) before the sensitivity average value was updated does not result in stabilization, processing step S278 first excludes the column for the selected renewable energy power source RES2, and also excludes the row and column for synchronous generators SG1 and SG2 that have been decelerated (no longer acceleration synchronous generators) due to the control of renewable energy power source RES2. At this time, since the number of reduced acceleration synchronous generators is equal to or greater than the number (2) specified in threshold data D15, processing proceeds to processing step S279. In processing step S279, the sensitivity is recalculated for the remaining sensitivity calculation candidates (synchronous generators SG3, synchronous generators SG4, and renewable energy power source RES1), and the sensitivity average value and ranking are updated based on the recalculation results.

By using Example 3, it is expected that the accuracy of shedding control selection will be improved. In cases where the number of acceleration synchronous generators is significantly reduced due to the addition of shedding machines, it is expected that the power flow conditions will have changed significantly from the initial power flow cross section used in the transient stability calculation by the sensitivity average value calculation unit 26. Therefore, if the sensitivity calculated by the sensitivity average value calculation unit 26 is continued to be used, the accuracy of shedding control selection may deteriorate.

Therefore, by recalculating the sensitivity in addition to updating the acceleration synchronous generators and shedding candidate generators only if the number of acceleration synchronous generators reduced after shedding target selection is equal to or greater than a certain number, it is possible to expect improved accuracy in shedding selection compared to Examples 1 and 2. However, since recalculating the sensitivity increases the amount of calculation, it is desirable to implement Example 3 within the constraints of the amount of calculation.

Note that Figure 25 shows that the processing content of processing step S278 is to determine whether or not to recalculate the sensitivity based on the reduced number of acceleration synchronous generators, but the determination method is not limited to this. For example, it may be determined whether or not to recalculate the sensitivity based on the total capacity of the reduced acceleration synchronous generators.

The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. Furthermore, part or all of the above-described configurations, functions, processing units, etc. may be realized in hardware, for example by designing them as integrated circuits.

1: Power system stabilization device 2: Calculation unit 3: Control device 4: Display unit 5: Input unit 6: Communication unit 7: Processor 8: Memory 9: Bus line D1: Input data D2: Output data D11: System configuration data D12: System measurement data D13: System model data D14: Contingency data D15: Threshold data D16: Shedding constraint data D17: Sensitivity calculation setting data D18: Past sensitivity calculation result data D21: Analysis cross section data D22: Transient stability calculation result data D23: Acceleration synchronous generator determination result data D24: Shedding candidate determination result data D25: Isolated step-out synchronous generator data D26: Sensitivity calculation result data D27: Sensitivity average value update data D28: Shedding target calculation result data DB11: System configuration database DB12: System measurement database DB13: System model database DB14: Contingency database DB15: Threshold database DB16: Shedding constraint database DB17: Sensitivity meter Calculation setting database DB18: Past sensitivity calculation result database DB20: Program database DB21: Analysis cross section database DB22: Transient stability calculation result database DB23: Acceleration synchronous generator determination result database DB24: Shedding candidate determination result database DB25: Isolated step-out synchronous generator database DB26: Sensitivity calculation result database DB27: Sensitivity average value update database DB28: Shedding target calculation result database P1: Analysis cross section creation program P2: Transient stability calculation program P3: Acceleration synchronous generator determination program P4: Shedding candidate determination program P5: Isolated step-out synchronous generator detection program P6: Sensitivity average value calculation program P7: Shedding target selection program 30a, 30b: Measurement device 100: Power system 110a to 110c: Synchronous generator or renewable energy power source 120a to 120c, 121a to 121c: Node (bus)
130a to 130c: Transformers 140a to 140c: Branches (lines)
200: Communication network

Claims (15)

A power system stabilization device that determines a power control target for performing stabilization control when a failure occurs in a power system according to stability at the time of an assumed failure in a power system including a synchronous generator and a renewable energy power source,
a control candidate determination unit that determines a control candidate of the synchronous generator and a renewable energy power source based on the transient stability calculation result; a sensitivity average value calculation unit that calculates the sensitivity of a deceleration index of the acceleration synchronous generator to the control of the control candidate and calculates an average value of the sensitivity of the acceleration synchronous generator; a control target selection unit that selects the control candidates as a control target in descending order of the average value until the transient stability of the power system is stabilized; and an output unit that outputs the results of each unit. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the control target selection unit selects one or more control targets from the control candidate targets in descending order of the average value until the transient stability in the power system at the time of the anticipated fault stabilizes, and each time selects one or more control targets from the control candidate targets in descending order of the average value, performs a transient stability calculation under the condition that all of the control targets selected up to that point are controlled, and if the transient stability is not stable, updates the average value by updating the acceleration synchronous generator and the control candidate targets based on the result of the transient stability calculation without recalculating the sensitivity. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the sensitivity is a change in deceleration energy of an accelerating synchronous generator in response to electrical control of a synchronous generator or a renewable energy power source. 2. The power system stabilization device according to claim 1,
the acceleration synchronous generator determination unit receives threshold data and the transient stability calculation result as inputs, determines whether the synchronous generator is an acceleration synchronous generator based on an internal phase difference angle or a speed deviation of the synchronous generator, and outputs the result as an acceleration synchronous generator determination result. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the power control candidate determination unit receives threshold data, the transient stability calculation result, and the power control constraint data as inputs, determines a power control candidate based on the active power output deviation or voltage deviation of the synchronous generator or renewable energy power source immediately before and after a contingency fault occurs in the power system, and outputs the result as a power control candidate determination result. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the transient stability calculation result is created by a transient stability calculation unit that calculates transient stability at the time of a contingency fault in the power system using contingency fault data and analytical cross-section data as inputs. 7. The power system stabilization device according to claim 6,
The power system stabilization device is characterized in that the analysis cross section data is output by an analysis cross section creation unit that creates an analysis cross section of the power system using system configuration data, system measurement data, and system model data as inputs. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the sensitivity average value calculation unit receives as inputs the shedding constraint data, the sensitivity calculation setting data, the analysis cross-section data, the determination result of the acceleration synchronous generator, and the determination result of the shedding candidate, and outputs a sensitivity calculation result. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the power control target selection unit receives analysis cross-sectional data, isolated out-of-step synchronous generator data, and the sensitivity calculation results as inputs, outputs sensitivity average value update data and power control target calculation results, and transmits the power control target calculation results to the control device. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the isolated out-of-step synchronous generator data is created by an isolated out-of-step synchronous generator detection unit that detects an isolated out-of-step synchronous generator in the event of a postulated fault using as inputs the power control constraint data, the analysis cross-sectional data, the transient stability calculation results, and the acceleration synchronous generator judgment results. 2. The power system stabilization device according to claim 1,
The power system stabilization device, wherein the average value is determined by one or more of an arithmetic average, a weighted average, a geometric average, and a harmonic average of the sensitivities of the acceleration synchronous generators. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the power control candidate determination unit determines power control candidates based on sensitivity calculation results previously output by the sensitivity average value calculation unit, and outputs the result as a power control candidate determination result. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the power control target selection unit selects one or more power control targets from the power control candidates in descending order of average value until the transient stability of the power system stabilizes, and each time selects one or more power control targets from the power control candidates in descending order of average value, performs a transient stability calculation under the condition that all of the power control targets selected up to that point are controlled, and if the selected targets are not stable, updates the acceleration synchronous generators based on the results of the transient stability calculation, and if one or more of the reduced number or reduced capacity of the acceleration synchronous generators due to the update is equal to or greater than a threshold value specified in threshold data, recalculates the sensitivity, thereby updating the average value. 2. The power system stabilization device according to claim 1,
The power system stabilization device is characterized in that the output unit displays at least one of system configuration data, system measurement data, system model data, contingency data, threshold data, shedding constraint data, sensitivity calculation setting data, analysis cross-section data, transient stability calculation results, acceleration synchronous generator determination results, shedding candidate determination results, isolated out-of-step synchronous generator data, sensitivity calculation results, sensitivity average value update data, and shedding target calculation results. A power system stabilization method for determining a power control target for performing stabilization control when a fault occurs in a power system according to stability at the time of a contingency fault in a power system including a synchronous generator and a renewable energy power source,
a power system stabilization method comprising: an acceleration synchronous generator determination step of determining an acceleration synchronous generator based on a calculation result of the transient stability of the power system at the time of the contingent fault in the power system; a control candidate determination step of determining control candidates of synchronous generators and renewable energy power sources based on the transient stability calculation result; a sensitivity average value calculation step of calculating the sensitivity of the deceleration index of the acceleration synchronous generator to the control of the control candidate and calculating an average value of the sensitivity of the acceleration synchronous generator; a control target selection step of selecting the control candidates as targets for control in descending order of the average value until the transient stability of the power system becomes stable; and an output step of outputting the results of each part.