Power system stabilization device and method

Abstract

To provide an index capable of performing the same evaluation on stabilization effects due to electrical control of a synchronous generator and a renewable energy power source, and an electrical control algorithm using the same.SOLUTION: A power system stabilization device determines an electrical control target to implement stabilization control in the case of fault occurrence in a power system in accordance with stability in the case of assumed fault in a power system including a synchronous generator and a renewable energy power source. The power system stabilization device comprises: an acceleration synchronous generator determination section for determining an acceleration synchronous generator based on a transient stability calculation result in the case of assumed fault in the power system; an electrical control candidate determination section for determining electrical control candidates for the synchronous generator and renewable energy power source based on the transient stability calculation result; a sensitivity average value calculation section for calculating sensitivity of a speed reduction index of the acceleration synchronous generator with respect to the electrical control of an electrical control candidate and calculating an average value of sensitivity of the acceleration synchronous generator; an electrical control target selection section for selecting the electrical control candidate as the electrical control target in a descending order of average values until transient stability of the power system is stabilized; and an output section for outputting results of the respective sections.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power system stabilization device and method for maintaining the stability of a power system. [Background technology]

[0002] When a fault (fault) occurs in a power system due to a lightning strike or other cause, the output of some synchronous generators (SG) 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.

[0003] To address the above-mentioned problems, conventional power system stabilizers have maintained the transient stability of a power system 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 shut down in order to maintain transient stability in the event of a contingency fault in the power system, and then performs stabilization control to shut down those synchronous generators when the contingency fault actually occurs. This power system stabilizer aims to maintain transient stability by first shutting down the synchronous generators 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 be used to refer to both suppressing and stopping generator output.

[0004] On the other hand, in recent years, in order to reduce CO2 emissions, the introduction of renewable energy sources such as solar power generation and wind power generation has been actively promoted as an alternative to synchronous generators such as thermal power generation, and the proportion of synchronous generators in the power system is on a downward trend.However, as the proportion of synchronous generators decreases, the inertia and voltage maintenance capacity of the power system, which they previously played a role in, decreases, which could lead to a decline in transient stability.

[0005] Furthermore, a reduction in the number of 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. This could make it difficult for conventional power system stabilizers to maintain transient stability, or could increase the total amount of shearing required to maintain transient stability (increasing the cost required to restore from shearing).

[0006] To address the above-mentioned issues, adding renewable energy sources, which are expected to be introduced in increasing numbers in the future, to the list of candidates for power control will increase the possibility of maintaining transient stability and is expected to reduce the total amount of power control required for stabilization (reducing the costs required to recover from power control).

[0007] In this regard, Patent Document 1 is known as an invention relating 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, and describes the power system stabilization device as including: "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." [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2020-96472 [Non-patent literature]

[0009] [Non-Patent Document 1] 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 Next-Generation Grids," Journal of Electrical Engineering, Vol. 137, No. 6, pp. 434-445 (2017) Summary of the Invention [Problem to be solved by the invention]

[0010] Patent Document 1 describes a method in which, in a power system where a large number of renewable energy sources are connected and the number of operating synchronous generators is small, if a synchronous generator is powered down in the event of a fault or the like, the power system may become unstable. The method expresses the stabilizing effect of power control of renewable energy sources as sensitivity, and based on that sensitivity, selects renewable energy sources to be powered down in preference to synchronous generators, and selects synchronous generators to be powered down when power control of renewable energy sources alone is insufficient.

[0011] However, depending on the area where the failure occurs, it is possible that the proportion of renewable energy sources in the power system is small, or that there are few renewable energy sources that have a high stabilizing effect through shearing control.In such cases, the method of Patent Document 1, which selects renewable energy sources to be sheared in preference to synchronous generators, may result in problems such as an increase in the total amount of shearing required for stabilization (increased costs required to recover from shearing control), adverse effects on the system due to excessive shearing control, and an increase in the amount of calculation required to select shearing control devices.

[0012] Therefore, a method is required that can prioritize the synchronous generators or renewable energy sources to be controlled, regardless of the proportion of renewable energy sources in the power system, based on the stabilizing effect of the control.

[0013] In view of the above, the problem that the present 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 power sources, and a shedding control algorithm that uses the index. [Means for solving the problem]

[0014] In view of the above, the present invention provides "a power system stabilization device that determines a target for control of power transmission, for which stabilization control is to be performed when a fault occurs in the power system, according to stability in the event of an anticipated 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 an acceleration synchronous generator based on a calculation result of transient stability in the event of an anticipated fault in the power system; a control candidate determination unit that determines a synchronous generator and a renewable energy power source as a candidate for control based on the calculation result of transient stability; a sensitivity average value calculation unit that calculates the sensitivity of the deceleration index of the acceleration synchronous generator to the control of the candidate for control and calculates an average value of the sensitivity of the acceleration synchronous generator; a control target selection unit that selects candidates for control as a target for 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."

[0015] Furthermore, the present invention is described as "a power system stabilization method for determining a power system target for which stabilization control is to be performed when a fault occurs in the power system, depending on the stability in the event of an anticipated fault in the power system including synchronous generators and renewable energy power sources, the power system stabilization method comprising: an acceleration synchronous generator determination step for determining an acceleration synchronous generator based on the calculation result of the transient stability of the power system in the event of an anticipated fault in the power system; a control candidate determination step for determining a synchronous generator and a renewable energy power source as a control candidate based on the calculation result of the transient stability; a sensitivity average value calculation step for calculating the sensitivity of the deceleration index of the acceleration synchronous generator to the control of the control candidate and calculating the average value of the sensitivity of the acceleration synchronous generator; a control target selection step for selecting control candidates as a control target 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." [Effects of the Invention]

[0016] According to the present invention, the stabilization effects of shedding of synchronous generators and renewable energy power sources can be evaluated in the same way, and at least one of the synchronous generators or renewable energy power sources can be selected as the shedding control source in order of the stabilization effect. This improves transient stability regardless of the proportion of renewable energy power sources in the power system, and reduces the total amount of shedding required for stabilization (the cost required to recover from shedding). [Brief explanation of the drawings]

[0017] [Figure 1] 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. [Figure 2] 1 is a diagram showing an example of the hardware configuration of a power system stabilization device 1 according to a first embodiment. [Figure 3] FIG. 2 is a diagram showing programs held in a program database DB20. [Figure 4] FIG. 10 is a diagram showing an example of system configuration data D11. [Figure 5] FIG. 10 is a diagram showing an example of systematic measurement data D12. [Figure 6] FIG. 10 is a diagram showing an example of system model data D13. [Figure 7] FIG. 10 is a diagram showing an example of contingency data D14. [Figure 8] FIG. 10 is a diagram showing an example of threshold data D15. [Figure 9] FIG. 10 is a diagram showing an example of power control constraint data D16. [Figure 10] FIG. 10 is a diagram showing an example of sensitivity calculation setting data D17. [Figure 11] 1 is a diagram showing an overall flow of processing of a power system stabilizing device 1 according to a first embodiment. [Figure 12] FIG. 12 is a diagram showing detailed processing content of processing step S23 in FIG. 11. [Figure 13] FIG. 12 is a diagram showing detailed processing content of processing step S24 in FIG. 11. [Figure 14] 12 is a diagram showing a detailed flow of the process of detecting an isolated out-of-step synchronous generator in the process step S25 of FIG. 11. [Figure 15]A diagram showing an image of sensitivity calculation when a synchronous generator is controlled. [Figure 16] A diagram showing an image of sensitivity calculation when power is controlled from a renewable energy source. [Figure 17] FIG. 12 is a diagram showing an image of sensitivity average value calculation in processing step S26 of FIG. 11. [Figure 18] FIG. 12 is a diagram showing a detailed flow of the power control target selection process in processing step S27 of FIG. 11. [Figure 19] FIG. 15 is a diagram showing an image of updating the sensitivity average value in processing step S275 of FIG. 14. [Figure 20] FIG. 4 is a diagram showing an example of a result display on the display unit 4. [Figure 21] FIG. 4 is a diagram showing an example of a result display on the display unit 4. [Figure 22] FIG. 4 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. [Figure 23] FIG. 10 is a diagram showing a hardware configuration of a power system stabilizing device 1 according to a second embodiment. [Figure 24] FIG. 10 is a diagram showing an example of past sensitivity calculation result data D18 in the second embodiment. [Figure 25] FIG. 11 is a diagram showing a detailed flow of the power control target selection unit 27 in the third embodiment. [Figure 26] FIG. 11 is a diagram showing an image of updating an average sensitivity value in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present invention, the terms "stability" and "stability" are used interchangeably. [Example]

[0019] First, an example of the functional configuration of a power system stabilizing device 1 according to a first embodiment of the present invention will be described with reference to FIG.

[0020] The power system stabilization device 1 is composed of input data D1 held in advance by a power system operator or planner, a calculation unit 2 that determines stabilization control commands for the power system 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 outputs the contents of the input data D1 and the output data D2.

[0021] The control device 3 receives the control command determined by the calculation unit 2, and transmits a control command (power control command) to the generator when a contingency fault (contingency fault) occurs in the power system.

[0022] 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.

[0023] The calculation unit 2 is composed of an analysis cross section creation unit 21, a transient stability calculation unit 22, an acceleration synchronous generator determination unit 23, a power control candidate determination unit 24, an isolated out-of-step synchronous generator detection unit 25, a sensitivity average value calculation unit 26, and a power control target selection unit 27, and processes are performed in this order.

[0024] The database DB that stores the output data D2 is composed of an analysis cross section database DB21 that holds analysis cross section data D21 which is the result of the analysis cross section creation unit 21, a transient stability calculation result database DB22 that holds transient stability calculation result data D22 which is the result of the transient stability calculation unit 22, an acceleration synchronous generator determination result database DB23 that holds acceleration synchronous generator determination result data D23 which is the result of the acceleration synchronous generator determination unit 23, a power control candidate determination result database DB24 that holds power control candidate determination result data D24 which is the result of the power control candidate determination unit 24, 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.

[0025] Fig. 2 is a diagram showing an example of the hardware configuration of the power system stabilization device 1 of the embodiment 1. The upper part of Fig. 2 shows an example of the hardware configuration of the power system stabilization device 1, and the lower part shows an example of the configuration of the power system that is the control target.

[0026] The power system stabilizing device 1 includes various input databases DB11 to DB17, a program database DB20, various output databases DB21 to 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.

[0027] The group of programs held by the program database DB20 is shown in Figure 3. 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.

[0028] The display unit 4, which is an output unit, is configured by, for example, any one or more of a display device, a printer device, a projector device, an audio output device, etc. The display unit 4 displays any one or more of various input data D1 (D11 to D17) and various output data D2 (D21 to D28) on a screen. Examples of the screen to be displayed will be described later.

[0029] The input unit 5 is configured with, for example, one or more of a keyboard, a switch, a mouse, a touch panel, a voice input device, and the like.

[0030] The communication unit 6 exchanges data with the power system 100 via the communication network 200 .

[0031] 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 a program database DB20, input data D1, output data D2, and the like.

[0032] An example power system 100 shown in the lower part of Figure 2 is composed of generators 110a to 110c, such as synchronous generators and renewable energy power sources, nodes (buses) 120a to 120c and 121a to 121c, transformers 130a to 130c, branches (lines) 140a to 140c, etc.

[0033] The power system 100 also includes measuring devices 30a to 30b. The measuring devices 30a to 30b are linked to the power system stabilization device 1 via a communication network 200.

[0034] The measuring devices 30a to 30b acquire one or more of the following as system measurement data D12: the output of the generators 110a to 110c, the voltage values ​​at each of the nodes 120a to 120c and 121a to 121c, the values ​​of the active and reactive power flowing through the transformers 130a to 130c and branches 140a to 140c, and on / off information of circuit breakers at the nodes, transformers, branches, and phase modifying equipment, and transmit this data to the communication unit 6.

[0035] Furthermore, when a fault occurs in the power system 100, the measuring devices 30a to 30b detect information such as the location and nature of the fault and transmit the information to the control device 3 via the communication network 200.

[0036] 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. When a fault occurs in the power system 100, the control device 3 compares the fault information acquired from the measurement devices 30a to 30b with the power control target calculation result data D28, and transmits a control command to the generators 110a to 110c.

[0037] The measurement 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 the nodes 120a-120c and 121a-121c, the values ​​of the active power P and reactive power Q flowing through the transformers 130a-130c and branches 140a-140c, and SV (Super Vision) information on the on / off status of circuit breakers at the nodes, transformers, branches, and phase modifying equipment, and transmit it to the communication unit 13. Specifically, measurements are made using voltage transformers (VT), potential transformers (PT), current transformers (CT), etc.

[0038] The power system stabilizing device 10 can periodically acquire TM information and SV information from the measuring devices 30a to 30b via the communication network 300 and store the information in the power system measurement value DB.

[0039] Furthermore, some of the measuring devices 30a to 30b detect information such as the location and nature of a fault when a fault occurs in the power system 100, and transmit the information to the control device 3 via the communication network 200.

[0040] The control device 3 (slave station) receives the power control target calculation result table data D25 from the power system stabilizing device 10 via the communication network 200. When a fault occurs in the power system 100, the control device 3 compares the fault information acquired from the measuring devices 30a to 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 to 110c.

[0041] Here, the data D11 to D17 held in the various input databases DB11 to DB17 constituting the power system stabilizing device 1 will be described with reference to the drawings.

[0042] 4 shows an example of system configuration data D11 stored in the system configuration database DB11. The system configuration database DB11 stores information on the branches (lines) and synchronous generators that make up the power system, as well as information on loads, renewable energy power sources, transformers, phase modifying equipment, etc. The data that should be stored for these devices is, in the case of a branch, the transmission line number, the number of lines, the node numbers at both ends, resistance, reactance, etc., and, in the case of the same equipment, the synchronous generator number, interconnection node, the 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.

[0043] 5 shows an example of system measurement data D12 held in 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 of nodes 120a-120c and 121a-121c; values ​​of active power 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 stored in chronological order for each measurement location, linked to timestamp information indicating the date and time of measurement.

[0044] Fig. 6 shows an example of the 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 that are required for numerical analysis of power systems using computers or calculators, as well as information on constants used therein.

[0045] FIG. 7 shows an example of the contingency data D14 held in the contingency database DB14. The contingency database DB14 stores information relating to the location, state, and means of eliminating contingency faults in the power system.

[0046] 8 shows an example of threshold data D15 held in the threshold database DB15. In the illustrated example, the threshold database DB15 stores an internal phase difference angle threshold and an output change rate threshold as threshold data used for determination in the acceleration tendency determination unit 23 and the electrical control candidate determination unit 24.

[0047] 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 power sources, such as whether or not power control of generators is possible and, if power control is possible, the timing of power control.

[0048] 10 shows an example of the sensitivity calculation setting data D17 held in the sensitivity calculation setting database DB17. The sensitivity calculation setting database DB17 stores the sensitivity calculation time width T for each contingency fault type, the sensitivity average value calculation method, etc. as setting values ​​required for the sensitivity average value calculation unit 26 to calculate the sensitivity average value.

[0049] Next, the processing contents of the calculation unit 2 will be described with reference to Fig. 11. Fig. 11 shows the overall flow of processing of the power system stabilization device 1 in the first embodiment. The flow of the calculation processing will be described for each processing step.

[0050] First, in processing step S21, the analysis cross section creation program P1 is executed using the system configuration data D11, the system measurement data D12, and the system model data D13 to create analysis cross section data D21 of the power system 100 at the current time.

[0051] Next, in processing step S22a, the transient stability calculation program P2 is executed using the analysis cross-section data D21 and the assumed fault data D14 under the condition that no generators are powered down, and transient stability calculation result data D22 of the power system 100 is output.

[0052] 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, for example, the internal phase difference angle, frequency, and voltage of the synchronous generator as indicators. If it is stable ("YES" in S22b), this processing flow ends. If it is unstable ("NO" in S22b), the processing proceeds to processing step S23, which will be described later.

[0053] 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 an acceleration synchronous generator include, for example, a method of determining as an acceleration synchronous generator a synchronous generator whose speed deviation is always positive in the time range from after the occurrence of a fault to the transient stability calculation end time, and a method of determining as an acceleration synchronous generator a synchronous generator whose internal phase difference angle exceeds the threshold specified by the threshold data D15 at the transient stability calculation end time.

[0054] The detailed processing content of processing step S23 will be explained using Fig. 12. Fig. 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 including synchronous generators SG1, SG2, and SG3 as generators and renewable energy power sources RES1 and RES2. The left side of Fig. 12 also shows the time change in the speed deviation ω of synchronous generators SG1, SG2, and SG3 before and after the fault occurred.

[0055] In this example, the speed deviation ω of the synchronous generators SG1, SG2, and SG3 increases in the accelerating direction from the time the fault occurs until the time T1 immediately before shedding, when the speed before the fault occurs is used as the reference speed, and then begins to decrease after shedding is implemented. However, looking at the situation further after that, the synchronous generators SG1 and SG2, which are located close to the point of fault occurrence, show signs of increasing again and becoming unstable at the time T2 when the analysis is cut off, but the speed deviation ω of the synchronous generator SG3, which is located farther away, shows signs of becoming small and stabilizing.

[0056] 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, and ωi(t=T1) is the synchronous generator SG at time T1. i The speed deviation of the synchronous generator SG at time T2 is ωi(t=T2). iThe speed deviation is shown.

[0057]

number

[0058] Next, in processing step S24, the threshold data D15, the shearing control constraint data D16, and the transient stability calculation result data D22 are used to execute the shearing control candidate determination program P4, and the shearing control candidate determination result data D24 is output.

[0059] As a method for determining candidates for power supply control, for example, there is a method for determining synchronous generators and renewable energy power sources for which the value of formula (2) is below the threshold value specified by the threshold data D15 as candidates for power supply control. i represents the rate of change of the active power output of the synchronous generator or renewable energy source just before and after the occurrence of a contingency fault, and P i1 represents the active power output of the synchronous generator or renewable energy source just before the occurrence of a contingency fault, and P i2 represents the active power output of synchronous generators and renewable energy sources immediately after a contingency fault occurs. Also, G represents the set of all synchronous generators and renewable energy sources that can be dispatched.

[0060]

number

[0061] The formula for determining candidates for power control is not limited to formula (2). For example, the deviation or rate of change of the voltage of a synchronous generator or a renewable energy power source immediately before and after the occurrence of a contingency fault may be used as the formula for determination.

[0062] The detailed processing content of processing step S24 will be explained using Fig. 13. Fig. 13 is a diagram showing the concept of determining candidates for shedding control. The right side of this figure shows a power system in which a fault has occurred in the transmission line to which synchronous generator SG1 is connected, in a 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 Fig. 12. The left side of Fig. 12 also shows the time changes in the active power change rates of each of the synchronous generators SG1, SG2, and SG3 and the renewable energy power sources RES1 and RES2 before and after the fault occurred.

[0063] According to the rate of change in active power of each power source before and after the occurrence of a fault shown on the left side of Figure 13, the change in active power is displayed 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, namely, 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.

[0064] The purpose of the shedding 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 to reduce the amount of calculation. If there is no need to reduce the amount of calculation, processing step S24 may be omitted, and all generators that are indicated as being shedding-controllable in the shedding control constraint data D16 may be set as shedding candidate (targets for calculating the sensitivity average value).

[0065] 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.

[0066] A detailed flow of the process for detecting an isolated out-of-step synchronous generator in process step S25 is shown in Fig. 14. The detection procedure will be explained for each process step in Fig. 14.

[0067] First, in process step S251, the acceleration index of the generator determined to be an accelerating synchronous generator in process step S23 is calculated based on the transient stability calculation result data D22. Examples of the acceleration index include the internal phase difference angle at the time when the transient stability calculation ends and its increase from its initial value. Also, the acceleration / deceleration energy described in Non-Patent Document 1 may be calculated for each accelerating synchronous generator and used as the acceleration index.

[0068] Next, in process step S252, transient stability calculation is performed under the condition that only the synchronous generator having the largest acceleration index obtained in process step S251 is controlled.

[0069] Next, in processing step S253, it is determined whether or not the transient stability is achieved based on the transient stability calculation result data from processing step S252. If the transient stability is achieved (YES in S253), the process proceeds to processing step S254, which will be described later. If the transient stability is achieved (NO in S253), the process does not proceed to processing step S254, but rather the results of processing steps S251 to S253 are output as isolated step-out synchronous generator data D25, and this flow is terminated (processing proceeds to processing step S26).

[0070] Next, in processing step S254, the synchronous generator with the largest acceleration index is determined as the temporary controlled generator, and after excluding that synchronous generator from the sensitivity calculation candidates, 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.

[0071] Returning to FIG. 11, next, in processing step S26, transient stability is calculated under the condition that each of the shedding candidates determined in processing step S24 is shedding-controlled individually, the sensitivity of each acceleration synchronous generator to the shedding of each shedding candidate is determined by a 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 the 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 of calculating the average value will be described later.

[0072] Next, in processing step S27, the power control target selection program P7 is executed using the analysis cross-sectional data D21, threshold data D15, isolated out-of-step synchronous generator data D25, and sensitivity calculation result data D26, and sensitivity average value update data D27 and power control target calculation result data D28 are output.

[0073] The procedure of the processing steps S22a to S27 described above is performed for each contingency fault and is repeated until the calculations for all contingencies are completed. When the calculations for all contingencies are completed, the power control target calculation result data D28 is transmitted to the control device 3.

[0074] Here, the definition of the sensitivity calculated in processing step S26 will be explained. The sensitivity is expressed, for example, as in equation (3).

[0075]

number

[0076] However, in equation (3), SS ij(T) indicates the amount of change in deceleration energy (DE) of the jth (i≠j) accelerating synchronous generator in response to the shedding of the i-th synchronous generator or renewable energy power source. Here, 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 the grid fault is cleared. ΔDE ij(T) is 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, compared to the deceleration energy when it is not shedding. ΔP i、ave(T) is the average amount of shedding of the i-th synchronous generator or renewable energy generator during T milliseconds from the start of shedding of that generator. Note that G represents the set of all synchronous generators and renewable energy generators that can be shedding, and S represents the set of all accelerating synchronous generators.

[0077] 15 and 16 show calculation images of equation (3) in processing step S26. Fig. 15 shows an image of sensitivity calculation when a synchronous generator is controlled, and Fig. 16 shows an image of sensitivity calculation when a renewable energy power source is controlled. In each figure, (a) shows the denominator ΔP i、ave(T) (b) is the numerator ΔDE on the right side of equation (3). ij(T) This is an image of the calculation.

[0078] The sensitivity numerator shown in (b) of Figure 15 and (b) of Figure 16 is the difference in deceleration energy ΔDE within time T from time t = Ts between when the synchronous generator or renewable energy power source is controlled and when it is not controlled on the plane showing the active power Pi of the synchronous generator SGi against the internal phase difference angle δ of the synchronous generator SGi. ij(T) represents.

[0079] The sensitivity denominators shown in Figure 15(a) and Figure 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, power control of the synchronous generator or renewable energy power source is performed or not performed after time t = Ts.

[0080] The sensitivity definition formula (3) can be found for all synchronous generators and renewable energy power sources, so the stabilizing effect of shedding of synchronous generators and renewable energy power sources can be evaluated uniformly. Also, because the sensitivity is found for only accelerating synchronous generators, rather than for all synchronous generators, it is possible to efficiently find targets for shedding that are effective for stabilization, i.e., deceleration of accelerating synchronous generators.

[0081] The time span T for the sensitivity calculation is a value that is preset by the power system operator or planner in the sensitivity calculation setting data D17 via the 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.

[0082] An image of the sensitivity average value calculation in processing step S26 is shown in Figure 17. In the table shown, the vertical axis indicates the acceleration synchronous generator sensitivity, average value, ranking, and selection status, and the horizontal axis lists the synchronous generators SG1-SG3 to be controlled or the candidates for shedding of renewable energy sources RES1 and RES2.

[0083] As is clear from this table, when a common synchronous generator (e.g., SG1 to SG3 in FIG. 17) is included among the sensitivity calculation candidates (shunting 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 tripped. Conversely, for sensitivity calculation candidates other than the synchronous generator in question, the sensitivities of all acceleration synchronous generators can be calculated. Therefore, when the sensitivity calculation candidates are ranked in descending order of the total sensitivity of the acceleration synchronous generators, the total value of the acceleration synchronous generators that are also sensitivity calculation candidates tends to be small, so the ranking of the synchronous generator in question is likely to be low, which creates the problem that all sensitivity calculation candidates cannot be selected fairly.

[0084] In contrast to this, in the first embodiment of the present invention, the ranking of shedding control is based on the descending average values ​​of the sensitivities of the acceleration synchronous generators, rather than on the descending total values, thereby making it possible to eliminate the above-mentioned unfairness.

[0085] The types of averages used in calculating the sensitivity average value include the arithmetic average (arithmetic mean), weighted average, geometric mean (geometric mean), and harmonic mean. When using a weighted average, the sensitivity of each acceleration synchronous generator is weighted, for example, by the rated output of the acceleration synchronous generator, the internal phase difference angle at the time the transient stability calculation ends, 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 arbitrarily change the type via the 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.

[0086] If the sensitivity average calculation results in multiple shedding candidates with the same ranking, the power system operator or planner determines the priority of shedding among 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 lower numbers assigned to each generator, shedding candidates with lower potential costs due to shedding, or shedding candidates with less past shedding history. Allowing the operator or planner to set such priorities not only increases the operator or planner's flexibility in setting shedding conditions, but also enables the operator or planner to select shedding units that meet their objectives.

[0087] A detailed flow of the power control target selection process in processing step S27 is shown in Fig. 18. The power control target selection procedure will be explained for each processing step in Fig. 18.

[0088] First, in process step S271, the highest-ranked sensitivity calculation candidate (shearing control candidate) determined in process step S26 is selected. The number of selected units may be the single highest-ranked candidate for shedding control, or multiple highest-ranked candidates. When selecting multiple units, transient stability must be assessed to avoid selecting excessive shedding control units for stabilization. Examples of methods for assessing transient stability include selecting multiple shedding control candidates in descending order of average sensitivity within a range where the total shedding 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 shedding control unit selection in process step S271 is repeated until the transient stability calculation result in process step S273 (described later) becomes stable (i.e., the total shedding control amount exceeds the shedding 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.

[0089] Next, in processing step S272, if the total power control amount of the generators selected in processing step S271 is smaller than the power control amount of the temporary power control generators (temporary power control amount) 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 amount of the generators selected in processing step S271 is equal to or larger than the temporary power control amount ("NO" in S272), the subsequent processing steps S273 to S276 are omitted, 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 amount, so the process forcibly proceeds to "YES" at the branch in processing step S272.

[0090] Next, in process step S273, transient stability is calculated under the condition that the generator selected in process step S271 is controlled.

[0091] Next, in process step S274, it is determined whether or not the transient stability is achieved based on the transient stability calculation result of process step S273. If the transient stability is achieved (YES in S274), the process proceeds to process step S276, which will be described later. If the transient stability is achieved (NO in S274), the process proceeds to process step S275, which will be described later.

[0092] Next, in processing step S275, the column of the generator newly selected in processing step S271 is excluded from the sensitivity table of FIG. 17, and if there is an acceleration synchronous generator that has been decelerated due to the shedding of that generator, the row and column of that synchronous generator are excluded 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 the acceleration synchronous generator has decelerated, the acceleration synchronous generator is determined using the same method as in processing step S23 based on the transient stability calculation result in processing step S273. After updating, processing returns to processing step S271, and a new generator to be shedding is additionally selected based on the updated sensitivity table.

[0093] Figure 19 shows an image of updating the sensitivity average value in processing step S275. When the renewable energy power source RES1 is selected as the generator to be shedding 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 of the generator (renewable energy power source RES1) newly selected in processing step S271 is excluded, and the column and row of the accelerating synchronous generator (SG2) that has been decelerated by the shedding of the renewable energy power source RES1 are deleted, thereby updating the sensitivity average value and shedding ranking.

[0094] In Patent Document 1, stability calculation is performed every time a specified amount of renewable energy output reduction is added based on the sensitivity calculation result, and if it is not stable, 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 may become enormous.

[0095] 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 making it possible to maintain the accuracy of the selection of shearing control units while suppressing an increase in the amount of calculation.

[0096] Next, in process step S276, the combination of all generators selected until it is determined to be stable in process step S274 is determined as the shedding control combination with the minimum total shedding amount, and this process flow ends.

[0097] Next, in processing step S277, the temporary shear control machines determined in processing step S254 are determined as the shear control combination with the smallest total shear control amount, and this processing flow ends.

[0098] Here, the effect of the independent out-of-step synchronous generator detection unit 25 will be described.

[0099] Depending on the power flow cross section and the location and nature of the fault in the power system, there are cases where 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 means of minimizing the total amount of power that can be powered down.

[0100] However, in the above case, since the accelerated synchronous generator is only 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 target for shedding.

[0101] As a countermeasure to the above, before selecting a generator to be sheared using sensitivity in processing step S26 and thereafter, the presence or absence of an independently out-of-step synchronous generator is detected in processing step S25, and if detected, that synchronous generator is determined to be a generator to be temporarily sheared. As described above, the shearing control amount of the temporarily sheared generator (temporary shearing control amount) is compared in processing step S272 with the total shearing control amount of the generators to be sheared selected based on sensitivity, and if the temporary shearing control amount is smaller, the temporarily sheared generator is determined to be the final generator to be sheared in processing step S277, thereby preventing an independently out-of-step synchronous generator from being omitted from selection.

[0102] Next, an example of the result display on the display unit 4 will be described with reference to FIGS.

[0103] 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 and graph. In the "Search Settings" field in Figure 20, you set the time and contingency for the power flow cross section for which you want to display the results of the shedding machine selection. In the "Results" field in Figure 20, you display 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 waveforms of synchronous generators before and after the shedding machine selection. This allows power system operators and planners to easily check the shedding targets and their total shedding amount for each power flow cross section and contingency, the degree of stabilization effect, and other information.

[0104] In the display example of Figure 21, the shedding target calculation result data D28 is displayed in a power system diagram. This system diagram displays not only the contingency points but also the generators connected to the system, distinguishing between those to be shedding and those not to be shedding. In addition, acceleration synchronous generators and candidates for shedding may also be displayed on the system diagram. This has the advantage that power system operators and planners can easily grasp the positional relationship between contingency points, shedding targets, and acceleration synchronous generators. [Example]

[0105] In the second embodiment, the power control candidate determining unit 24 of the power system stabilizing device 1 determines a power control candidate for each contingent fault using the past sensitivity calculation result data D18 instead of using equation (2).

[0106] FIG. 22 shows an example of the functional configuration of the power system stabilizing device 1 according to the second embodiment, which differs from the first embodiment in that a past sensitivity calculation result database DB18 is added to the input data D1.

[0107] FIG. 23 shows the hardware configuration of the power system stabilizing device 1 according to the second embodiment, which differs from the first embodiment in that a past sensitivity calculation result database DB18 is added.

[0108] In the case of the second embodiment, 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 shedding control, for example, the sensitivity calculation candidates (candidates for shedding control) recorded in the past sensitivity calculation result data D18 can be directly inherited as candidates for shedding control, or only generators whose average sensitivity value is greater than the threshold value specified in the threshold data D15 can be determined to be candidates for shedding control, or only generators whose descending order of average sensitivity values ​​is within the rank specified in the threshold data D15 can be determined to be candidates for shedding control.

[0109] An example of past sensitivity calculation result data D18 is shown in Fig. 24. As shown in the table in Fig. 24, the sensitivity calculation result data for each shedding candidate for past dates and times is organized for each of contingency faults A, B, and C, and the shedding candidate determination unit 24 determines shedding candidates for each of contingency faults A, B, and C based on this table.

[0110] The first advantage of using Example 2 is that it is possible to expect an improvement in the accuracy of determining candidates for shedding compared to Example 1. When sensitivity calculation result data D26 output within the past several tens of seconds by the sensitivity average value calculation unit 26 is used as is as the past sensitivity calculation result data D18, if there is no significant difference between the power flow cross section within the past several tens of seconds and the current time, it is thought that there will be no significant difference in the generators that have a high stabilizing effect when shedding occurs for each contingent fault.

[0111] 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.

[0112] A second advantage of using the second embodiment is that it is possible to expect a reduction in the amount of calculation required for determining candidates for shedding and calculating the average sensitivity value compared to the first embodiment. When the past sensitivity calculation result data D18 is used as is to determine candidates for shedding, the calculation of equation (2) can be omitted. In addition, when determining candidates for shedding using the above-described method, the threshold data D15 can be set to narrow down the candidates for shedding to a smaller number than when determining candidates for shedding using equation (2), thereby reducing the number of times that the transient stability and sensitivity are calculated in the sensitivity average value calculation unit 26.

[0113] In addition to the above two advantages, the second embodiment also has the advantage that past calculation results by the power system stabilization device 1 can be effectively utilized. [Example]

[0114] The differences and advantages of the third embodiment from the first and second embodiments will be described with reference to FIGS. 25 and 26. FIG.

[0115] In the third embodiment, the power control target selection unit 27 of the power system stabilizing device 1 determines whether or not to recalculate the sensitivity depending on the reduced number of acceleration synchronous generators after the selection of the target generators to be controlled.

[0116] 25 shows a detailed flow of the power control target selection unit 27 in the third embodiment. The difference from the first and second embodiments is that processing steps S278 and S279 are added after processing step S275.

[0117] In processing step S278, if the number of acceleration synchronous generators to be reduced is less than the number specified by the 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 the threshold data D15 ("YES" in processing step S278), the process proceeds to processing step S279, which will be described later.

[0118] In processing step S279, transient stability is calculated under the conditions that all generators selected in processing step S271 are shedding and that the shedding candidates updated in processing step S275 are shedding individually, the sensitivity of the updated acceleration synchronous generators is determined, and the sensitivity average value and shedding order are updated. After reflecting the results, processing returns to processing step S271, and a new generator to be shedding is additionally selected based on the latest shedding order.

[0119] The flow from processing step S275 to processing step S279 will be explained using the sensitivity table shown in FIG. 26. If adding renewable energy power source RES2 to the list of power sources to be shedding 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 of the selected renewable energy power source RES2 and also excludes the row and column of synchronous generators SG1 and SG2 that have been decelerated (no longer acceleration synchronous generators) due to the shedding of renewable energy power source RES2. At this time, because the number of reduced acceleration synchronous generators is equal to or greater than the number (2) specified by threshold data D15, processing proceeds to processing step S279. In processing step S279, the sensitivities of the remaining sensitivity calculation candidates (synchronous generators SG3, synchronous generators SG4, and renewable energy power source RES1) are recalculated, and the sensitivity average value and ranking are updated based on the recalculation results.

[0120] By using the third embodiment, it is expected that the accuracy of shedding control selection will be improved. In a case where the number of acceleration synchronous generators is significantly reduced due to the addition of shedding machines, it is assumed 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 be degraded.

[0121] Therefore, only when the number of acceleration synchronous generators reduced after the selection of shedding targets is equal to or greater than a certain number, by recalculating the sensitivity in addition to updating the acceleration synchronous generators and shedding candidate generators, it is possible to expect an improvement in the accuracy of 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.

[0122] 25 shows that the processing content of 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.

[0123] 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. [Explanation of symbols]

[0124] 1:Power system stabilization device 2: Arithmetic section 3: Control device 4: Display section 5: Input section 6: Communications Department 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: Power control constraint data D17: Sensitivity calculation setting data D18: Past sensitivity calculation result data D21: Analysis cross-sectional data D22: Transient stability calculation result data D23: Acceleration synchronous generator judgment result data D24: Power control candidate evaluation result data D25: Individual step-out synchronous generator data D26: Sensitivity calculation result data D27: Sensitivity average value update data D28: Power control target calculation result data DB11: System configuration database DB12: System Measurement Database DB13: System model database DB14: Contingency Database DB15: Threshold database DB16: Power control constraint database DB17: Sensitivity calculation setting database DB18: Database of past sensitivity calculation results DB20: Program Database DB21: Analysis cross section database DB22: Transient stability calculation results database DB23: Acceleration synchronous generator judgment result database DB24: Database of power control candidate evaluation results DB25: Database of isolated out-of-step synchronous generators DB26: Sensitivity calculation results database DB27: Sensitivity average value update database DB28: Power control target calculation result database P1: Analysis cross section creation program P2: Transient stability calculation program P3: Acceleration synchronous generator judgment program P4: Power control candidate evaluation program P5: Program for detecting isolated out-of-step synchronous generators P6: Sensitivity average value calculation program P7: Power Control Target Selection Program 30a, 30b: Measuring device 100: Power system 110a to 110c: Synchronous generator or renewable energy power source 120a~120c, 121a~121c: Node (bus line) 130a~130c: Transformers 140a~140c: Branch (railway) 200: Communication Network

Claims

1. 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. 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.

3. 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.

4. 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.

5. 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.

6. 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 contingent fault in the power system using contingent fault data and analytical cross-section data as inputs.

7. 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.

8. 2. The power system stabilization device according to claim 1, The power system stabilization device 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.

9. 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 a control device.

10. 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 electrical control constraint data, the analysis cross-sectional data, the transient stability calculation results, and the acceleration synchronous generator judgment results.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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.

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