Power system stabilization device, computer program for power system stabilization device and power system stabilization method

Abstract

To provide a power system stabilization device which further reliably stabilizes a power system, a computer program for a power system stabilization device and a power system stabilization method.SOLUTION: In a power system, a power system stabilization device comprises a normal condition control selection section 12 which selects control corresponding to an estimated failure based on a normal condition for making a regenerative energy power source parallel off in accordance with a dynamic characteristic model of the regenerative energy power source, a severe condition stability confirmation section 14 which confirms stability of the power system under a severe condition, and a severe condition addition control selection section 15 which selects addition control for an addition based on the stability which is confirmed by the severe condition stability confirmation section. At least one of the control on the normal condition which is selected by the normal condition control selection section 12, the control on the severe condition which is selected by the severe condition stability conformation section 14 and control including the addition control which is selected by the severe condition addition control selection section 15 in the control on the normal condition or the control on the severe condition is instructed to a terminal device which is disposed in the power system via a communication line 80.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present embodiment relates to a power system stabilization device, a computer program for the power system stabilization device, and a power system stabilization method that create control information for disconnecting a power source from a power system and stabilizing the power system. [Background technology]

[0002] 2. Description of the Related Art In order to ensure the stability of a power system, a power system stabilizer is known that controls a plurality of generators that supply power to the power system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-182199 [Patent Document 2] Japanese Patent Publication No. 2022-38125 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the introduction of renewable energy sources (hereinafter sometimes referred to as "renewable energy sources") into power systems has been expanding. The main power source in conventional power systems has been synchronous generators. Renewable energy sources have different dynamic characteristics than synchronous generators. For this reason, power systems connected to renewable energy sources may be controlled differently from power systems connected to power sources consisting of synchronous generators.

[0005] For example, when a renewable energy power source is operated in an isolated mode in a power grid, it is preferable that the renewable energy power source be quickly disconnected from the power grid. Also, when the voltage or frequency in the power grid fluctuates beyond a specified threshold, it is preferable that the output of the renewable energy power source be restricted or that the renewable energy power source be disconnected in order to protect the equipment.

[0006] Power system stabilizers are installed for the purpose of stabilizing the power system. Power system stabilizers anticipate possible system faults and create corresponding control tables. Pre-calculation type power system stabilizers run simulations of stability in the event of anticipated faults at regular intervals (e.g., 30 seconds) based on the state of the power system before the fault occurs, and create control tables.

[0007] A control table is created for each anticipated fault. In the control table, a generator that will be the target of control to stabilize the power system in response to the anticipated fault is selected in advance. Control to stabilize the power system means disconnecting the target generator from the power system. Disconnecting a generator from the power system is called power supply limitation or power control. The control table is sent to a control terminal device connected to the generator, and if an accident actually occurs in the power system, control corresponding to the fault is selected from the control table and power control is executed.

[0008] In a power system where the proportion of power supplied by renewable energy sources has increased, the disconnection of renewable energy sources affects the stability of the system. In order to more reliably stabilize the power system, it is preferable for the power system stabilization device to more accurately simulate the dynamic characteristics of the disconnection and output suppression of renewable energy sources.

[0009] Renewable energy sources are scattered throughout the power grid. In some cases, renewable energy sources are also connected to lower-level grids. In a simulation for stabilizing the power grid, it would be extremely cumbersome to individually and in detail model all of the renewable energy sources scattered throughout the power grid, including the lower-level grids. For this reason, a grid model that aggregates multiple renewable energy sources is created as a simple lower-level grid model, and a simulation is performed.

[0010] However, it has been difficult to perform accurate simulations that include dynamic characteristics using a grid model that aggregates multiple renewable energy sources. In the above simulations, calculations are performed assuming that the aggregated multiple renewable energy sources have representative dynamic characteristics collectively. This has led to a discrepancy between the results of the simulation and the behavior of the dynamic characteristics of renewable energy sources in an actual power grid, making it difficult to accurately calculate the control amount required for stabilization.

[0011] The present embodiment aims to provide a power system stabilization device, a computer program for a power system stabilization device, and a power system stabilization method that can more reliably stabilize a power system by performing a simulation that more closely corresponds to an actual power system that includes both synchronous generators and renewable energy power sources. [Means for solving the problem]

[0012] The power system stabilization device of this embodiment has the following features. (1) A normal condition control selection unit is provided for selecting control corresponding to an anticipated failure based on normal conditions for disconnecting the renewable energy power source in accordance with a dynamic characteristic model of the renewable energy power source in a power system in which a synchronous generator and a renewable energy power source are arranged. (2) A severe condition stability confirmation unit is provided which selects a severe condition that impairs stability more than the normal condition selected by the normal condition control selection unit, and confirms the stability of the power system under the severe condition. (3) A severe condition additional control selection unit is provided which, when it is determined that the power system is unstable based on the stability confirmed by the severe condition stability confirmation unit, selects an additional control to be added to the control under the normal conditions selected by the normal condition control selection unit. (4) Instruct the power system to perform at least one of the control under the normal conditions selected by the normal condition control selection unit, the control under the severe conditions selected by the severe condition stability confirmation unit, and the control under the normal conditions or the control under the severe conditions including the additional control selected by the severe condition additional control selection unit. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing a configuration of a system using a power system stabilization device 1 according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing a configuration of a power system stabilization device 1 according to a first embodiment. [Figure 3] FIG. 1 is a diagram showing a program flow of a power system stabilizing device 1 according to a first embodiment. [Figure 4] FIG. 1 is a diagram showing an example of contingent fault data of the power system stabilizing device 1 according to the first embodiment; [Figure 5] FIG. 1 is a diagram showing an example of first-stage control information D12 of the power system stabilizing device 1 according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing an example of severe condition data D14 of the power system stabilizing device 1 according to the first embodiment. [Figure 7] FIG. 10 is a diagram showing an example of harsh condition additional control information D15 of the power system stabilization device 1 according to the first embodiment. [Figure 8] FIG. 10 is a diagram showing an example of first-stage control information D12 including additional control of the power system stabilizing device 1 according to the first embodiment. [Figure 9] FIG. 1 is a diagram showing an example of a control table of the power system stabilizing device 1 according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] [1. First embodiment] [1-1.Configuration] [1-1-1. Overall structure] 1 is an overall diagram showing the configuration of a system using a power system stabilizing device 1 according to a first embodiment. In this embodiment, when there are multiple devices or components with the same configuration, they will be described using the same number, and when describing each individual device or component with the same configuration, they will be distinguished by adding a hyphen to the common number.

[0015] The power system 90 is made up of a power system 91 and a power system 92. As an example, the power system 91 includes a synchronous generator 2 and a renewable energy power source 3. Electricity generated by the synchronous generator 2 and the renewable energy power source 3 of the power system 91 is supplied to the power system 92. A renewable energy power source may be referred to as a renewable energy power source. The power system 91 may have any number of synchronous generators 2 and renewable energy power sources 3.

[0016] The synchronous generator 2-1 is connected to the power grid 92 via a transformer 6-1, a circuit breaker 5-1, a transmission line 4-2, and a transmission line 4-1. Similarly, the synchronous generator 2-2 is connected to the power grid 92 via a transformer 6-2, a circuit breaker 5-2, a transmission line 4-2, and a transmission line 4-1, and the synchronous generator 2-3 is connected to the power grid 92 via a transformer 6-3, a circuit breaker 5-3, a transmission line 4-2, and a transmission line 4-1.

[0017] The synchronous generators 2-1, 2-2, and 2-3 are constituted by power generation devices such as nuclear, hydroelectric, and thermal power plants. The transformers 6-1, 6-2, and 6-3 convert the voltage of the power output from the synchronous generators 2-1, 2-2, and 2-3, respectively, into a predetermined voltage.

[0018] The circuit breakers 5-1, 5-2, and 5-3 are configured by switches that cut off power, and cut off the power output from the synchronous generators 2-1, 2-2, and 2-3, respectively. The circuit breakers 5-1, 5-2, and 5-3 are connected to a terminal device 50, which will be described later, by communication lines. The opening and closing of the circuit breakers 5-1, 5-2, and 5-3 is controlled by the terminal device 50. When the circuit breakers 5-1, 5-2, and 5-3 are opened, the synchronous generators 2-1, 2-2, and 2-3 are disconnected from the power grid 90, respectively.

[0019] The renewable energy power source 3 is connected to the power grid 92 via a transformer 6-4, a circuit breaker 5-4, a transmission line 4-3, and a transmission line 4-1. The renewable energy power source 3 is composed of a power generation device such as a solar or wind power generator. The transformer 6-4 converts the voltage of the power output from the renewable energy power source 3 into a predetermined voltage.

[0020] The circuit breaker 5-4 is connected to a terminal device 50 (described later) via a communication line. The opening and closing of the circuit breaker 5-4 is controlled by the terminal device 50. When the circuit breaker 5-4 is opened, the renewable energy power source 3 is disconnected from the power grid 90.

[0021] The information collection devices 7-1, 7-2, 7-3, 7-4, 7-5, 7-6, and 7-7 are composed of detection devices that detect state quantities such as frequency, voltage, current, phase, active power, and reactive power. The information collection devices 7-1, 7-2, and 7-3 are installed in the synchronous generators 2-1, 2-2, and 2-3, respectively. The information collection devices 7-1, 7-2, and 7-3 detect state quantities such as frequency, voltage, current, phase, active power, and reactive power of the synchronous generators 2-1, 2-2, and 2-3, respectively, and transmit the state quantities to the power system stabilization device 1 via a communication line 80, which will be described later.

[0022] The information collection device 7-4 is installed in the renewable energy power source 3. The information collection device 7-4 detects state quantities of the renewable energy power source 3, such as frequency, voltage, current, phase, active power, and reactive power, and transmits the detected state quantities to the power system stabilization device 1 via the communication line 80.

[0023] The information collection devices 7-5, 7-6, and 7-7 are installed on the power transmission lines 4-1, 4-2, and 4-3. The information collection devices 7-5, 7-6, and 7-7 detect state quantities, such as frequency, voltage, current, phase, active power, and reactive power, of the power transmission lines 4-1, 4-2, and 4-3, respectively, and transmit the state quantities to the power system stabilization device 1 via the communication line 80.

[0024] The fault detection device 8 is configured by a detection device that detects faults due to abnormal voltage, ground fault current, etc. The fault detection device 8 detects faults in the power system 92 and the power generation system configured by the synchronous generators 2-1, 2-2, 2-3, and renewable energy power source 3, and transmits the detected faults to the power system stabilization device 1 via the communication line 80.

[0025] The communication line 80 is configured by a communication line such as a dedicated line, a public line such as the Internet, a telephone line, etc. Communication is performed between the power system stabilizing device 1, the terminal device 50, and the information collecting device 7 via the communication line 80.

[0026] The terminal device 50 is configured by a control device having a communication function. The terminal device 50 is connected to the circuit breakers 5-1, 5-2, 5-3, and 5-4. The terminal device 50 is also connected to the power system stabilization device 1 via a communication line 80. The terminal device 50 receives a control table from the power system stabilization device 1 and trips the circuit breakers 5-1, 5-2, 5-3, and 5-4 based on the received control table.

[0027] [1-1-2. Configuration of Power System Stabilizer 1] FIG. 2 shows the configuration of a power system stabilizing device 1 according to the first embodiment. The power system stabilizing device 1 is a device that creates a control table for stabilizing a power system 90. The power system stabilizing device 1 is a device configured by a computer or the like. The power system stabilizing device 1 is connected to a terminal device 50 arranged in the power system 90 via a communication line 80. The power system stabilizing device 1 is also connected to an information collecting device 7 and a fault detecting device 8 via the communication line 80.

[0028] The power system stabilizing device 1 creates control tables for stabilizing the power system 90. The power system stabilizing device 1 creates a first-stage control table T1 for control corresponding to anticipated failures and a post-correction control table T2 for control corresponding to failures that have actually occurred.

[0029] The synchronous generator 2 or the renewable energy power source 3 that is the object of control based on the first-stage control table T1 or the post-correction control table T2 is disconnected from the power grid 90, and the power grid 90 is stabilized.

[0030] The power system stabilization device 1 is composed of a system information collection unit 11, a normal condition control selection unit 12, a stability calculation unit 13, a severe condition stability confirmation unit 14, a severe condition additional control selection unit 15, a post-correction control candidate selection unit 16, a control table creation unit 17, and a control information transmission unit 18.

[0031] The above-mentioned components constituting the power system stabilization device 1 may be configured by a calculation unit in a computer or a software module. Furthermore, the above-mentioned components constituting the power system stabilization device 1 may be configured by separate devices or may be configured as an integrated unit.

[0032] The power system information collection unit 11 is a receiving module or receiving device that receives information about the power system 90. The power system information collection unit 11 includes a transmitting and receiving circuit. The power system information collection unit 11 is connected to the information collection device 7 and the fault detection device 8 arranged in the power system 90 via a communication line 80. The power system information collection unit 11 is also connected to the normal condition control selection unit 12.

[0033] The system information collection unit 11 receives data relating to the state quantities of the synchronous generators 2, renewable energy power sources 3, and each bus in the power system 90 from the information collection device 7 or the fault detection device 8. The system information collection unit 11 transmits the received data as system information D11 to the normal condition control selection unit 12. The system information D11 includes, for example, TM data relating to voltage, current, phase, active power, and reactive power, and SV data relating to generator start / stop and the operational status of the transmission line.

[0034] The normal condition control selection unit 12 is a calculation module or calculation device that generates first-stage control information D12 and renewable energy power supply information D10. The normal condition control selection unit 12 is connected to the grid information collection unit 11, the stability calculation unit 13, and the severe condition stability confirmation unit 14.

[0035] The normal condition control selection unit 12 creates first-stage control information D12 and renewable energy power source information D10 based on the state quantities of the power grid 90 related to the grid information D11 received from the grid information collection unit 11. The first-stage control information D12 is information related to control required for stabilization for each anticipated failure based on normal conditions. The renewable energy power source information D10 is information indicating renewable energy power sources 3 whose parallel-out improves the stability of the power grid 90 and renewable energy power sources 3 whose stability does not improve.

[0036] The normal conditions refer to the state quantities of the power system 90 that disconnect the renewable energy power source 3 in accordance with the dynamic characteristic model of the renewable energy power source 3. The system information D11 includes the dynamic characteristic model of the renewable energy power source 3. The normal condition control selection unit 12 creates system data D13 based on the state quantities of the power system 90 related to the system information D11.

[0037] The normal condition control selection unit 12 causes the stability calculation unit 13 to calculate the stability of the power system 90 in which a contingency fault case has occurred using the system data D13, and receives the stability calculation result F01, which is the calculation result. The normal condition control selection unit 12 creates first-stage control information D12 based on the stability calculation result F01. The normal condition control selection unit 12 transmits the created first-stage control information D12 to the severe condition stability confirmation unit 14.

[0038] Furthermore, the normal condition control selection unit 12 determines whether the stability of the power grid 90 will improve by disconnecting each renewable energy power source 3, based on the behavior of the dynamic characteristic model of the stability calculation result F01. The normal condition control selection unit 12 determines which renewable energy power sources 3 will improve the stability of the power grid 90 when disconnected, and which renewable energy power sources 3 will not improve the stability, and creates renewable energy power source information D10. The normal condition control selection unit 12 transmits the created renewable energy power source information D10 to the severe condition stability confirmation unit 14.

[0039] The stability calculation unit 13 is a calculation module or calculation device that calculates the stability of the power system 90. The stability calculation unit 13 is connected to the normal condition control selection unit 12, the severe condition stability confirmation unit 14, the severe condition additional control selection unit 15, and the ex-post correction control candidate selection unit 16.

[0040] The stability calculation unit 13 receives the system data D13 and the contingent fault cases from the normal condition control selection unit 12 and calculates the stability. The stability calculation unit 13 performs stability calculations related to power flow calculation and transient stability, and sets the calculated stability as a stability calculation result F01. The stability calculation unit 13 transmits the stability calculation result F01 to the normal condition control selection unit 12.

[0041] The stability calculation unit 13 receives the system data D13 and the severe conditions from the severe condition stability checking unit 14 and calculates the stability. The stability calculation unit 13 performs stability calculations related to power flow calculation and transient stability, and sets the calculated stability as the stability calculation result F02. The stability calculation unit 13 transmits the stability calculation result F02 to the severe condition stability checking unit 14.

[0042] The stability calculation unit 13 receives the system data D13, information on the severe conditions and additional controls from the severe condition additional control selection unit 15, and calculates the stability. The stability calculation unit 13 performs stability calculations related to power flow calculation and transient stability, and sets the calculated stability as the stability calculation result F03. The stability calculation unit 13 transmits the stability calculation result F03 to the severe condition additional control selection unit 15.

[0043] The stability calculation unit 13 receives the harsh condition addition control information D15, and information regarding the timing of executing the post-correction control and the time required to execute the post-correction control from the post-correction control candidate selection unit 16, and calculates the stability. The stability calculation unit 13 performs stability calculations related to power flow calculation and transient stability, and sets the calculated stability as the stability calculation result F04. The stability calculation unit 13 transmits the stability calculation result F04 to the post-correction control candidate selection unit 16.

[0044] The harsh condition stability confirmation unit 14 is a calculation module or calculation device that creates harsh condition data D14. The harsh condition stability confirmation unit 14 is connected to the normal condition control selection unit 12, the stability calculation unit 13, and the harsh condition additional control selection unit 15. The harsh condition stability confirmation unit 14 creates the harsh condition data D14 based on the renewable energy power supply information D10 received from the normal condition control selection unit 12.

[0045] The severe condition data D14 is information about a renewable energy power source 3 that is disconnected according to the dynamic characteristic model under normal conditions, and that will cause a loss of stability if not disconnected. Conditions that cause a loss of stability more than normal conditions are called severe conditions.

[0046] The severe condition stability checking unit 14 creates severe conditions under which stability is stricter than that under normal conditions, based on the renewable energy power supply information D10 received from the normal condition control selecting unit 12.

[0047] The severe condition stability checking unit 14 causes the stability calculation unit 13 to calculate the stability when control under normal conditions is performed on the power system 90 to which severe conditions have been applied, and receives the stability calculation result F02, which is the calculation result. Based on the stability related to the stability calculation result F02, the severe condition stability checking unit 14 checks whether the power system 90 can be stabilized by control under normal conditions related to the first-stage control information D12.

[0048] The harsh condition stability checking unit 14 sets the created harsh conditions as harsh condition data D 14. The harsh condition stability checking unit 14 transmits the harsh condition data D 14 to the harsh condition additional control selecting unit 15.

[0049] The harsh condition additional control selection unit 15 is a calculation module or calculation device that creates harsh condition additional control information D15. The harsh condition additional control selection unit 15 is connected to the stability calculation unit 13, the harsh condition stability confirmation unit 14, the post-correction control candidate selection unit 16, and the control table creation unit 17.

[0050] The harsh condition additional control selection unit 15 generates harsh condition additional control information D15 by performing stability calculations based on the harsh condition data D14 received from the harsh condition stability confirmation unit 14. The harsh condition additional control information D15 is information regarding additional control when it is determined that the power system 90 is unstable under control related to the first-stage control information D12.

[0051] The harsh condition additional control selection unit 15 selects additional control when the harsh conditions according to the harsh condition data D14 are applied to the system data D13 and the harsh condition stability confirmation unit 14 determines that the power system 90 cannot be stabilized by control under normal conditions according to the first stage control information D12.

[0052] The severe condition additional control selection unit 15 causes the stability calculation unit 13 to calculate the stability when additional control is applied to the power system 90 to which the severe condition is applied, and receives the stability calculation result F03 which is the calculation result.

[0053] The severe condition additional control selection unit 15 creates information on additional control based on the stability calculation result F03 and sets it as severe condition additional control information D15. The severe condition additional control selection unit 15 transmits the severe condition additional control information D15 to the ex-post correction control candidate selection unit 16.

[0054] The post-correction control candidate selector 16 is a calculation module or calculation device that generates the first-stage control information D12 or the post-correction control information D16. The post-correction control candidate selector 16 is connected to the stability calculation unit 13, the severe condition additional control selector 15, and the control table creator 17.

[0055] The post-correction control candidate selector 16 generates first-stage control information D12 or post-correction control information D16 by stability calculation based on control under normal conditions related to the first-stage control information D12 and the severe condition data D14 and severe condition additional control information D15 received from the severe condition additional control selector 15. The first-stage control information D12 is information related to control for stabilizing the power system 90 when a predicted failure occurs. The post-correction control information D16 is information related to control for stabilizing the power system 90 after a failure actually occurs.

[0056] When the severe condition additional control selection unit 15 determines that additional control is necessary, the post-correction control candidate selection unit 16 determines whether the additional control should be included in the first stage control or the post-correction control.

[0057] The first stage control is a control anticipated in advance in the event that an anticipated fault occurs in the power grid 90. When a fault occurs, the first stage control is executed on the synchronous generator 2 or the renewable energy power source 3 in order to stabilize the power grid 90. The first stage control is executed after a fault occurs in the power grid 90 and before the state quantities of the power grid 90 are measured.

[0058] The post-correction control is control calculated based on the state quantities of the power grid 90 after a fault actually occurs. When a fault occurs, in order to stabilize the power grid 90, the post-correction control is executed on the synchronous generator 2 or the renewable energy power source 3. The post-correction control is executed after the first-stage control and after the state quantities of the power grid 90 are measured.

[0059] The post-correction control candidate selection unit 16 has the stability calculation unit 13 calculate the stability when the harsh condition addition control information D15 and the post-correction temporal information are applied to the power system 90, and receives the stability calculation result F04, which is the calculation result.

[0060] When the post-correction control candidate selector 16 determines that the power system 90 is unstable based on the stability calculation result F04, it generates first-stage control information D12 by including the additional control in the first-stage control.

[0061] When the post-correction control candidate selector 16 determines that the power system 90 is stable based on the stability calculation result F04, it creates post-correction control information D16 by including the additional control in the post-correction control.

[0062] The post-correction control candidate selector 16 transmits the first-stage control information D12 and the post-correction control information D16 to the control table creator 17.

[0063] The control table creation unit 17 is a calculation module or calculation device that creates the first-stage control table T1 and the post-correction control table T2. The control table creation unit 17 is connected to the harsh condition additional control selection unit 15, the post-correction control candidate selection unit 16, and the control information transmission unit 18.

[0064] The control table creation unit 17 creates a first-stage control table T1 and a post-correction control table T2 based on the first-stage control information D12 and the post-correction control information D16 received from the post-correction control candidate selection unit 16. The control table creation unit 17 transmits the created first-stage control table T1 and post-correction control table T2 to the control information transmission unit 18.

[0065] The control information transmitter 18 is a transmission module or a transmission device that transmits the first-stage control table T1 and the post-correction control table T2. The control information transmitter 18 includes a transmission / reception circuit. The control information transmitter 18 is connected to a terminal device 50 disposed in the power system 90 via a communication line 80. The control information transmitter 18 is also connected to the control table creation unit 17.

[0066] The control information transmission unit 18 transmits the first-stage control table T1 and the post-correction control table T2 received from the control table creation unit 17 to the terminal device 50. The terminal device 50 receives the first-stage control table T1 and the post-correction control table T2 and controls the synchronous generator 2 or the renewable energy power source 3.

[0067] The above is the configuration of the power system stabilization device 1 according to this embodiment.

[0068] [1-2. Effect] Next, an outline of the operation of the power system stabilization device 1 of this embodiment will be described with reference to FIGS.

[0069] The power system stabilization device 1 creates control tables for stabilizing the power system 90. The power system stabilization device 1 creates a first-stage control table T1 for control corresponding to anticipated failures and a post-correction control table T2 for control corresponding to failures that have actually occurred. Based on the first-stage control table T1 or the post-correction control table T2, the synchronous generator 2 or renewable energy power source 3 to be controlled is disconnected from the power system 90, and the power system 90 is stabilized.

[0070] The normal condition control selection unit 12 of the power system stabilization device 1 selects control corresponding to an expected failure based on the normal conditions for disconnecting the renewable energy power source 3 in accordance with a dynamic characteristic model of the renewable energy power source 3 in the power system 90 in which the synchronous generator 2 and the renewable energy power source 3 are arranged.

[0071] The normal condition control selection unit 12 determines, among the renewable energy power sources 3 arranged in the power system 90, those whose stability improves when disconnected as supply-side renewable energy power sources 3, and those whose stability does not improve when disconnected as demand-side renewable energy power sources 3.

[0072] The normal condition control selection unit 12 selects, as targets for control, the synchronous generator 2 and the renewable energy power source 3 to which the terminal device 50 that receives instructions from the power system stabilization device 1 and controls the output is connected.

[0073] The harsh condition stability confirmation unit 14 selects harsh conditions under which stability would be impaired if the renewable energy power source 3 is not disconnected from the normal conditions selected by the normal condition control selection unit 12 according to the dynamic characteristic model, and confirms the stability of the power system 90 under control under harsh conditions.

[0074] The harsh condition stability confirmation unit 14 selects, as the harsh condition, at least one of the conditions under which the renewable energy power source 3 designated as the supply side is not disconnected and the conditions under which the renewable energy power source 3 designated as the demand side is disconnected by the normal condition control selection unit 12.

[0075] When it is determined that the power system 90 is unstable based on the stability confirmed by the harsh condition stability confirmation unit 14, the harsh condition additional control selection unit 15 selects additional control to be added to the control under normal conditions selected by the normal condition control selection unit 12.

[0076] The post-correction control candidate selection unit 16 includes the additional control selected by the severe condition additional control selection unit 15 in the control under normal conditions selected by the normal condition control selection unit 12. Under severe conditions, the stability is confirmed when the additional control is performed for the estimated time of the post-correction control, not for the estimated time of the first stage control.

[0077] The post-correction control candidate selector 16 determines whether the additional control selected by the severe condition additional control selector 15 should be included in the first-stage control or the post-correction control. The first-stage control is control that is executed after a fault occurs in the power system 90 and before the state quantities of the power system 90 are measured. The post-correction control is control that is executed after the first-stage control and after the state quantities of the power system 90 are measured.

[0078] If the post-correction control candidate selection unit 16 determines that the power system 90 is unstable due to control including the additional control selected by the severe condition additional control selection unit 15 during the expected time of the post-correction control, the post-correction control candidate selection unit 16 includes the additional control in the first stage control that is executed after a fault has occurred in the power system 90 and before the state quantity of the power system 90 is measured.

[0079] If the post-correction control candidate selection unit 16 determines that the power system 90 is stable through control including the additional control selected by the severe condition additional control selection unit 15 during the expected time of the post-correction control, the post-correction control candidate selection unit 16 includes the additional control in the post-correction control that is executed after the first stage control and after measuring the state quantities of the power system 90.

[0080] The post-correction control candidate selection unit 16 selects the synchronous generator 2 to be the control target of the post-correction control based on at least one index of the peak of the internal phase difference angle, the increase in the internal phase difference angle, the peak of the angular velocity, and the increase in the angular velocity of the synchronous generator 2 arranged in the power system 90, which is related to the stability of the power system 90 on which the first stage control has been executed, in addition to the synchronous generator 2 to be the control target of the additional control selected by the severe condition additional control selection unit 15.

[0081] The control table creation unit 17 creates a control table for the first stage control and the post-correction control created by the post-correction control candidate selection unit 16 based on the control under normal conditions selected by the normal condition control selection unit 12 and the additional control under severe conditions selected by the severe condition additional control selection unit 15.

[0082] The control information transmitter 18 transmits the control table created by the control table creator 17 and issues control instructions to the power system 90. The control table creator 17 creates two control tables: a first-stage control table T1 and a post-correction control table T2.

[0083] The first-stage control table T1 records control for stabilizing the power system 90 when an anticipated failure occurs. The post-correction control table T2 records control for stabilizing the power system 90 after an actual failure occurs. The first-stage control table T1 and the post-correction control table T2 are created before an actual failure occurs.

[0084] The first-stage control table T1 and the post-correction control table T2 are created for each failure. The control using the post-correction control table T2 is executed when it is predicted that control using the first-stage control table T1 will result in unstable control. The power system stabilizing device 1 transmits the first-stage control table T1 and the post-correction control table T2 to the terminal device 50.

[0085] In the first-stage control table T1 and the post-correction control table T2, the synchronous generator 2 or the renewable energy power source 3 to be controlled to stabilize the power grid 90 in response to an expected failure is selected in advance. The circuit breaker 5 is tripped by the terminal device 50 based on the first-stage control table T1 or the post-correction control table T2. As a result, the synchronous generator 2 or the renewable energy power source 3 to be controlled is disconnected from the power grid 90, and the power grid 90 is stabilized.

[0086] Control to stabilize the power grid 90 is control to disconnect the target synchronous generator 2 or renewable energy power source 3 from the power grid 90. Disconnecting the synchronous generator 2 or renewable energy power source 3 from the power grid 90 is called power supply limitation or power control. The first-stage control table T1 or the post-correction control table T2 is transmitted to a terminal device 50 that controls the shutoff of the synchronous generator 2 or renewable energy power source 3. When an accident actually occurs in the power grid 90, the terminal device 50 selects control corresponding to the failure based on the first-stage control table T1 or the post-correction control table T2, and power control is executed.

[0087] The normal condition control selection unit 12 determines whether the renewable energy power source 3 is located on the supply side or the demand side in the power system 90 in which a predicted failure has occurred or in the power system 90 in which a failure has actually occurred.

[0088] A power source located in a position where the transient stability of the power system 90 is improved by being disconnected from the power system 90 is determined to be a power source located on the supply side. The supply side refers to a subsystem located on the side that sends out electric power in the power system 90. A supply-side subsystem is a subsystem that has a generator that becomes unstable in the event of a fault or has a large voltage phase expansion.

[0089] A power source located at a position where the transient stability of the power system 90 would deteriorate if it were to be disconnected from the power system 90 is determined to be a power source located on the demand side. The demand side refers to a subsystem located on the side that receives power in the power system 90. A demand-side subsystem is a subsystem in which the voltage phase expansion is small when a fault occurs.

[0090] The transient stability of the power grid 90 improves when the synchronous generator 2 or the renewable energy power source 3 located on the supply side is disconnected or its output is reduced. On the other hand, the transient stability of the power grid 90 deteriorates when the synchronous generator 2 or the renewable energy power source 3 located on the demand side is disconnected or its output is reduced.

[0091] The power system stabilizing device 1 determines whether the renewable energy power source 3 will be located on the supply side or the demand side in the power system 90 in the event of an accident, and creates a first-stage control table T1 and a post-correction control table T2. The power system stabilizing device 1 transmits the created first-stage control table T1 and post-correction control table T2 to the terminal device 50.

[0092] The details of the operation of the power system stabilization device 1 are as follows.

[0093] The system information collection unit 11 receives data relating to the state quantities of the synchronous generators 2, renewable energy power sources 3, and each bus in the power system 90 from the information collection device 7 or the fault detection device 8. The system information collection unit 11 transmits the received data as system information D11 to the normal condition control selection unit 12. The system information D11 includes, for example, TM data relating to voltage, current, phase, active power, and reactive power, and SV data relating to generator start / stop and the operational status of the transmission line.

[0094] The normal condition control selection unit 12 calculates stability based on the state quantities of the power system 90 related to the system information D11 received from the system information collection unit 11, and creates first-stage control information D12 and renewable energy power source information D10. The first-stage control information D12 is information related to control required for stabilization for each anticipated failure based on normal conditions. The renewable energy power source information D10 is information related to the renewable energy power source 3 on the supply side and the renewable energy power source 3 on the demand side.

[0095] The stability is calculated by the stability calculation performed by the stability calculation unit 13. The normal conditions are conditions under which the renewable energy power source 3 is disconnected in accordance with the dynamic characteristic model of the renewable energy power source 3.

[0096] The normal condition control selection unit 12 creates system data D13 based on the state quantities of the power system 90 related to the system information D11 received from the system information collection unit 11. The system data D13 is data used to perform power flow calculations and stability calculations. The normal condition control selection unit 12 estimates the state of the power system 90 based on the system information D11 received from the system information collection unit 11, and creates the system data D13. The created system data D13 includes a dynamic characteristic model of the renewable energy power source 3, and this data may be referred to as normal conditions.

[0097] The normal condition control selection unit 12 selects one contingency case to be used for stability calculation from contingency data stored in an external database (not shown). The contingency data is data in which contingency failures are accumulated and stored. The contingency case is individual information related to the mode of a contingency failure stored in the contingency data.

[0098] An example of contingency data is shown in Fig. 4. In Fig. 4, the power transmission lines La and Lb in the "fault location" column are the power transmission lines 4 installed in the power system 90.

[0099] The "Fault Mode" column in Figure 4 shows the mode of the fault at the location where it occurred. For example, in the description "3φ4LG," "3φ" indicates that a fault occurred in three phases of at least one of the three-phase, two-circuit transmission lines. Also, in the description "3φ4LG," "4LG" indicates that a ground fault occurred in wire four of the three-phase, two-circuit transmission line. Similarly, the description "3φ6LG" indicates that a fault occurred in three phases of the three-phase, two-circuit transmission line, and a ground fault occurred in wire six.

[0100] The normal condition control selection unit 12 transmits the system data D13 and the contingency fault cases to the stability calculation unit 13. The stability calculation unit 13 performs stability calculations based on the received system data D13 and the contingency fault cases. The stability calculation unit 13 calculates stability by power flow calculation and transient stability calculation, and sets the calculated stability as the stability calculation result F01.

[0101] The normal condition control selection unit 12 receives the stability calculation result F01 from the stability calculation unit 13. Based on the stability related to the stability calculation result F01, the normal condition control selection unit 12 selects a renewable energy power source 3 or a synchronous generator 2 to be subject to stabilization control for each expected failure under normal conditions, and generates first-stage control information D12. The normal condition control selection unit 12 transmits the generated first-stage control information D12 to the severe condition stability confirmation unit 14. FIG. 5 shows an example of the first-stage control information D12. As an example, the first-stage control information D12 shown in FIG. 5 specifies the generator Ga as the control target. The generator Ga may be one of the synchronous generators 2 or the renewable energy power source 3. Furthermore, the targets selected by the first-stage control information D12 may be multiple synchronous generators 2 or renewable energy power sources 3, or a combination thereof.

[0102] The normal condition control selection unit 12 determines whether stability will be improved by disconnecting each renewable energy power source 3 from the power grid 90, based on the behavior of the dynamic characteristic model of the stability calculation result F01. The normal condition control selection unit 12 stores the renewable energy power source 3 whose stability will be improved by disconnecting it as a supply-side renewable energy power source 3, and stores the renewable energy power source 3 whose stability will not be improved by disconnecting it as a demand-side renewable energy power source 3.

[0103] The determination of whether the stability improves by paralleling off the renewable energy power source 3 may be made based on the stability calculation result F01, or may be made by other calculations. The normal condition control selection unit 12 sets information on the supply-side renewable energy power source 3 and the demand-side renewable energy power source 3 as renewable energy power source information D10. The renewable energy power source information D10 includes information on either the supply-side renewable energy power source 3 or the demand-side renewable energy power source 3, or both.

[0104] The normal condition control selection unit 12 creates renewable energy power source information D10 as information about the supply-side renewable energy power source 3 and the demand-side renewable energy power source 3. The normal condition control selection unit 12 transmits the created renewable energy power source information D10 to the severe condition stability confirmation unit 14.

[0105] The normal condition control selection unit 12 may add a renewable energy power source 3 that is decoupled based on dynamic characteristics to improve the stability of the power grid 90 and is controlled by the terminal device 50 to the control targets related to the first-stage control information D12.

[0106] Even if the renewable energy power source 3 controlled by the terminal device 50 is determined to be disconnected in the simulation but is not actually disconnected, the power grid 90 can be stabilized by controlling the target renewable energy power source 3. By controlling the target renewable energy power source 3, the state of the renewable energy power source 3 in the simulation can be brought closer to the disconnected state. In other words, the deviation between the simulation and the actual state of the power grid 90 can be reduced.

[0107] Furthermore, for a renewable energy power source 3 that is slowly disconnected after a fault occurs, the first-stage control may change whether or not it is disconnected. In this case, even if the renewable energy power source 3 is controlled by the terminal device 50 in the simulation, it may not be included as a control target in the control related to the first-stage control information D12.

[0108] The harsh condition stability confirmation unit 14 creates harsh condition data D14 based on the renewable energy power source information D10 received from the normal condition control selection unit 12. The harsh condition data D14 is information on conditions under which stability is further impaired by changing whether or not a renewable energy power source 3 that is determined to be a supply-side or demand-side renewable energy power source 3 in the renewable energy power source information D10 is disconnected. Conditions under which stability is further impaired are called harsh conditions.

[0109] Typically, renewable energy power sources 3 are scattered across the power system 90. The stability calculation by the stability calculation unit 13 is performed through a simulation in which the renewable energy power sources 3 scattered across the power system 90 are divided into multiple groups.

[0110] Although it is assumed that a renewable energy power source 3 will be disconnected in the simulation, there may be cases where it does not disconnect in the actual power grid 90. In the simulation, the renewable energy power sources 3 in the power distribution grid are aggregated and modeled as one, so for example, a renewable energy power source 3 that generates solar power and is installed in an ordinary home may behave differently in the simulation and may not be disconnected.

[0111] Although it was assumed that the renewable energy source 3 would be disconnected in the simulation, if there is a renewable energy source 3 that is not disconnected in the actual power grid 90, the control calculated by the simulation may not be sufficient to stabilize the power grid 90.

[0112] In order to eliminate the lack of control amount in the control of the power system 90 when a failure occurs, it is preferable to calculate the control amount under severe conditions where the stability of the power system 90 becomes more severe.

[0113] The harsh condition stability confirmation unit 14 creates harsh conditions that result in stricter stability based on information about the supply-side renewable energy power source 3 or the demand-side renewable energy power source 3 related to the renewable energy power source information D10 received from the normal condition control selection unit 12.

[0114] The harsh conditions are information for controlling not to disconnect a supply-side renewable energy power source 3 that is set to be disconnected in the renewable energy power source information D10, or information for controlling to disconnect a demand-side renewable energy power source 3 that is set not to be disconnected. FIG. 6 shows an example of the harsh condition data D14. As an example, the harsh condition in the harsh condition data D14 shown in FIG. 6 is to control not to disconnect the renewable energy power sources Rb and Rc. The renewable energy power sources Rb and Rc are selected from the renewable energy power sources 3.

[0115] The severe condition stability confirmation unit 14 applies the severe conditions to the system data D13 created by the normal condition control selection unit 12, and confirms whether the power system 90 can be stabilized by control under normal conditions according to the first-stage control information D12. The confirmation of whether the power system 90 can be stabilized is performed by stability calculation.

[0116] The harsh condition stability checking unit 14 transmits the system data D13 and the created harsh conditions to the stability calculation unit 13. The stability calculation unit 13 performs stability calculations based on the received system data D13 and the harsh conditions. The stability calculation unit 13 calculates stability by power flow calculation and transient stability calculation, and sets the calculated stability as the stability calculation result F02.

[0117] The severe condition stability checking unit 14 receives the stability calculation result F02 from the stability calculation unit 13. Based on the stability related to the stability calculation result F02, the severe condition stability checking unit 14 checks whether the power system 90 can be stabilized by control under normal conditions related to the first-stage control information D12.

[0118] The harsh condition stability checking unit 14 sets the created harsh conditions as harsh condition data D 14. The harsh condition stability checking unit 14 transmits the harsh condition data D 14 to the harsh condition additional control selecting unit 15.

[0119] The severe conditions are realized by either or both of control that does not disconnect the supply-side renewable energy power source 3 and control that disconnects the demand-side renewable energy power source 3. When the transient stability becomes unstable, the voltage phase difference between both end nodes of one of the transmission lines of the power system 90 increases.

[0120] When the supply-side renewable energy power source 3 is disconnected, the power flow through the transmission line, where the voltage phase difference between the nodes at both ends has increased, decreases. This reduces the phase difference between both ends of the transmission line, improving stability. Furthermore, when the supply-side renewable energy power source 3 is disconnected, the acceleration of surrounding generators is suppressed. This has the same effect as power control. In other words, by changing the settings so that the supply-side renewable energy power source 3 that should be disconnected does not disconnect, stability decreases further, resulting in harsh conditions.

[0121] When the renewable energy power source 3 on the demand side is disconnected, the power flow in the transmission line increases as the voltage phase difference between the nodes at both ends increases. This increases the phase difference between the two ends of the transmission line, further reducing stability and creating harsh conditions. Since the impact on stability caused by the disconnection of the renewable energy power source 3 on the demand side is smaller than that of the renewable energy power source 3 on the supply side, the disconnection of the renewable energy power source 3 on the supply side may be changed to set harsh conditions.

[0122] The harsh condition additional control selection unit 15 generates harsh condition additional control information D15 by performing stability calculations based on the harsh condition data D14 received from the harsh condition stability confirmation unit 14. The harsh condition additional control information D15 is information regarding additional control when it is determined that the power system 90 is unstable under control related to the first-stage control information D12.

[0123] The harsh condition additional control selection unit 15 selects additional control when the harsh condition stability confirmation unit 14 determines that the power system 90 cannot be stabilized by control under normal conditions based on the first stage control information D12, in which the harsh conditions based on the harsh condition data D14 are applied to the system data D13.

[0124] The severe condition additional control selection unit 15 transmits the system data D13 and information on the severe conditions and additional control to the stability calculation unit 13. The stability calculation unit 13 performs stability calculation based on the system data D13 and information on the severe conditions and additional control. The stability calculation unit 13 calculates stability by power flow calculation and transient stability calculation, and sets the calculated stability as the stability calculation result F03. The severe condition additional control selection unit 15 receives the stability calculation result F03 from the stability calculation unit 13.

[0125] The harsh condition additional control selection unit 15 sets information regarding additional control as harsh condition additional control information D15. The harsh condition additional control selection unit 15 transmits the harsh condition additional control information D15 to the post-correction control candidate selection unit 16. FIG. 7 shows an example of the harsh condition additional control information D15. As an example, the harsh condition additional control information D15 shown in FIG. 7 specifies generators Gb, Gc, and Gd as targets for control when the transmission line La fails. The generators Gb, Gc, and Gd are selected from the synchronous generator 2 or the renewable energy power source 3.

[0126] The post-correction control candidate selector 16 generates first-stage control information D12 or post-correction control information D16 by stability calculation based on control under normal conditions according to the first-stage control information D12, and the severe condition data D14 and severe condition additional control information D15 received from the severe condition additional control selector 15. The first-stage control information D12 is information related to control for stabilizing the power system 90 when a predicted failure occurs. The post-correction control information D16 is information related to control for stabilizing the power system 90 based on state quantities observed after an actual failure occurs.

[0127] When the severe condition additional control selection unit 15 determines that additional control is necessary, the post-correction control candidate selection unit 16 determines whether the synchronous generator 2 in the additional control should be included in the first stage control or the post-correction control.

[0128] The first stage control is a control anticipated in advance for the synchronous generator 2 or the renewable energy power source 3 in order to stabilize the power system 90 in the event that an anticipated fault occurs in the power system 90. The first stage control is executed after a fault occurs in the power system 90 and before the state quantities of the power system 90 are measured.

[0129] The post-correction control is control of the synchronous generator 2 for stabilizing the power system 90, calculated based on system information D11 indicating the state of the power system 90 after a fault actually occurs in the power system 90. The post-correction control is executed after the first-stage control and after the state quantities of the power system 90 are measured.

[0130] If the post-correction control candidate selection unit 16 determines that the power system 90 is unstable based on the stability calculation, it selects any number of synchronous generators 2 required for stabilization in the case of a contingent fault as targets for power control and sets them as candidates for post-correction control.

[0131] The post-correction control is executed at a later timing than the first-stage control. If the first-stage control cannot stabilize the power grid 90 due to a malfunction not included in the expected failure, such as a change in the state of the power grid 90, the post-correction control executes additional control to stabilize the power grid 90.

[0132] The post-correction control candidate selector 16 transmits to the stability calculation unit 13 the control under normal conditions and the severe condition additional control information D15 related to the first-stage control information D12, as well as information regarding the timing of executing the post-correction control and the time required to execute the post-correction control. The stability calculation unit 13 performs stability calculations based on the severe condition additional control information D15 and the information regarding the timing of executing the post-correction control and the time required to execute the post-correction control. The stability calculation unit 13 calculates stability by power flow calculation and transient stability calculation, and sets the calculated stability as the stability calculation result F04. The post-correction control candidate selector 16 receives the stability calculation result F04 from the stability calculation unit 13.

[0133] The post-correction control candidate selector 16 determines whether the power system 90 is stable based on the stability calculation result F04. If it is determined that the power system 90 is unstable based on the stability calculation result F04, the post-correction control candidate selector 16 includes additional control in the first-stage control to stabilize the power system 90. The post-correction control candidate selector 16 includes the additional control in the first-stage control and creates first-stage control information D12. FIG. 8 shows an example of first-stage control information D12 including the additional control. As an example, the first-stage control information D12 shown in FIG. 8 targets generators Ga, Gb, Gc, and Gd for additional control of the transmission line La. The generators Ga, Gb, Gc, and Gd are selected from the synchronous generator 2 or the renewable energy power source 3.

[0134] If it is determined that the power system 90 is stable, the post-correction control candidate selection unit 16 includes additional control in the post-correction control to suppress excessive control of the power system 90. The post-correction control candidate selection unit 16 includes the additional control in the post-correction control and creates post-correction control information D16.

[0135] The post-correction control candidate selector 16 transmits the first-stage control information D12 or the post-correction control information D16 to the control table creator 17.

[0136] The post-correction control candidate selector 16 may add, to the post-correction control information D16, synchronous generators 2 other than the synchronous generators 2 that are the targets of additional control and that are selected by the severe condition additional control selector 15.

[0137] For example, if the harsh condition stability confirmation unit 14 determines that the power system 90 is unstable, the harsh condition additional control selection unit 15 does not select a synchronous generator 2 to be subjected to additional control. Therefore, additional control is not included in the ex-post correction control, and the ex-post correction control information D16 is not created. By selecting a synchronous generator 2 to be subjected to additional control based on a determination different from that of the harsh condition additional control selection unit 15, it is possible to execute control according to the ex-post correction control information D16 even when various faults occur in the power system 90.

[0138] Furthermore, in the control related to the post-correction control information D16, when power control of a plurality of synchronous generators 2 is required, there is a possibility that the control amount will be insufficient if only the power control of the synchronous generator 2 that is the target of additional control is performed. Therefore, in addition to the synchronous generator 2 that is the target of additional control selected by the severe condition additional control selection unit 15, a synchronous generator 2 that is the target of further control may be selected.

[0139] Based on the stability calculation result when the first stage control is executed, the synchronous generators 2 to be the targets of the control according to the ex-post-correction control information D16 may be further selected based on one or more of the peak of the internal phase difference angle, the increase amount of the internal phase difference angle, the peak of the angular velocity, and the increase amount of the angular velocity of the synchronous generator 2. For example, any number of synchronous generators 2 may be selected in descending order of the peak of the internal phase difference angle of the generators, and may be added to the targets of the control according to the ex-post-correction control information D16.

[0140] The control table creation unit 17 creates a first-stage control table T1 and a post-correction control table T2 based on the first-stage control information D12 and the post-correction control information D16 received from the post-correction control candidate selection unit 16. The first-stage control table T1 is a table that records control of the power system 90 related to the first-stage control. The first-stage control table T1 may include additional control. The post-correction control table T2 is a table that records control of the power system 90 related to the post-correction control. The post-correction control table T2 may include additional control.

[0141] The control table creation unit 17 associates the target failure cases with the control contents based on the first-stage control information D12 and the post-correction control information D16 received from the post-correction control candidate selection unit 16, and creates a first-stage control table T1 and a post-correction control table T2, respectively. FIG. 9 shows an example of the control table. The generators Ga, Gb, Gc, and Gd in FIG. 9 are selected from the synchronous generator 2 or the renewable energy power source 3. The control table creation unit 17 transmits the created first-stage control table T1 and post-correction control table T2 to the control information transmission unit 18.

[0142] The control information transmission unit 18 transmits the first-stage control table T1 and the post-correction control table T2 received from the control table creation unit 17 to the terminal device 50. The terminal device 50 receives the first-stage control table T1 and the post-correction control table T2 and controls the synchronous generator 2 or the renewable energy power source 3.

[0143] The above operation is realized by a computer program shown in Fig. 3. The computer program shown in Fig. 3 is built into the power system stabilizing device 1. The program is repeatedly executed at a fixed cycle, for example, every 30 seconds.

[0144] (Step S01: Creating system data D13) The operation in step S01 is executed by the normal condition control selection unit 12. The normal condition control selection unit 12 receives system information D11 from the system information collection unit 11. The system information D11 is data relating to the state quantities of the synchronous generator 2, the renewable energy power source 3, and each bus in the power system 90. The system information D11 includes, for example, TM data relating to voltage, current, phase, active power, and reactive power, and SV data relating to generator start / stop and the operational state of the transmission line.

[0145] The normal condition control selection unit 12 creates system data D13 based on state quantities related to the current system state of the power system 90, based on system information D11 received from the system information collection unit 11. The system data D13 is data used to perform power flow calculations and stability calculations.

[0146] (Step S02: Selection of assumed failure cases) The operation in step S02 is executed by the normal condition control selection unit 12. The normal condition control selection unit 12 selects one contingency case to be used for stability calculation from contingency data stored in an external database (not shown). Figure 4 shows an example of contingency data.

[0147] (Step S03: Selection of renewable energy power source to be subject to first-stage control) The operation in step S03 is executed by the normal condition control selection unit 12 and the stability calculation unit 13. The normal condition control selection unit 12 transmits system data D13, which is the power flow cross section data created in step S01, and the contingency fault cases selected in step S02 to the stability calculation unit 13. The stability calculation unit 13 calculates stability based on the received system data D13 and the contingency fault cases, and sets the calculated stability as the stability calculation result F01.

[0148] The normal condition control selection unit 12 determines whether the power grid 90 is stable or unstable based on the stability related to the stability calculation result F01. If it determines that the power grid 90 is unstable, the normal condition control selection unit 12 selects the synchronous generator 2 and the renewable energy power source 3 to be targets of first-stage control that stabilizes the contingency fault case selected in step S02. The normal condition control selection unit 12 creates first-stage control information D12, including the synchronous generator 2 and the renewable energy power source 3 to be targets of the selected first-stage control. Figure 5 shows an example of the first-stage control information D12.

[0149] The selection of the synchronous generators 2 to be subjected to first-stage control may be performed, for example, by a step-out ranking method in which the generators are selected in the order in which their internal phase difference angles exceed a certain threshold (e.g., 360 degrees) based on the stability of the stability calculation result F01, and generators to be subjected to shedding are added one by one until the power grid 90 becomes stable. When selecting generators that include renewable energy power sources 3, a method may be used in which, for example, a P-δ curve representing the relationship between the active power output and the internal phase difference angle of an unstable generator is used to add generators one by one based on the amount of deceleration energy when the synchronous generators 2 and renewable energy power sources 3 are shedding. The selection of the synchronous generators 2 and renewable energy power sources 3 to be subjected to first-stage control is not limited to the above calculation. The synchronous generators 2 and renewable energy power sources 3 to be subjected to shedding may also be selected using other calculations.

[0150] (Step S04: Determine whether the renewable energy power source has been disconnected) The operation in step S04 is executed by the normal condition control selection unit 12. In a state in which the control selected in step S03 is being executed, the normal condition control selection unit 12 determines whether any renewable energy power source 3 has been disconnected based on the dynamic characteristics. If it is determined that the renewable energy power source 3 has been disconnected based on the dynamic characteristics model (YES in step S04), the program proceeds to step S05. If it is not determined that the renewable energy power source 3 has been disconnected (NO in step S04), the program proceeds to step S09.

[0151] Typically, renewable energy power sources 3 are scattered across the power system 90. The stability calculation by the stability calculation unit 13 is performed through a simulation in which the renewable energy power sources 3 scattered across the power system 90 are divided into multiple groups.

[0152] In the actual power system 90, although it is assumed that the renewable energy power source 3 is disconnected in the simulation, there may be cases where the renewable energy power source 3 is not disconnected in the actual power system 90. For this reason, in step S04, it is determined whether the renewable energy power source 3 is disconnected.

[0153] (Step S05: Determine whether disconnection improves stability) The operation in step S05 is executed by the normal condition control selection unit 12. When it is determined in step S04 that the renewable energy power source 3 has been disconnected, the normal condition control selection unit 12 determines whether the stability of the power grid 90 will improve by disconnecting the selected renewable energy power source 3.

[0154] The determination of whether stability will improve may be made based on the stability calculated by the stability calculation result F01, or may be made by other calculations. If it is determined that parallel-out will improve stability (YES in step S05), the program proceeds to step S06. If it is not determined that parallel-out will improve stability (NO in step S05), the program proceeds to step S09.

[0155] (Step S06: Creating renewable energy power source information D10) The operation in step S06 is executed by the normal condition control selection unit 12. If it is determined in step S05 that the stability will improve by parallel-out, the normal condition control selection unit 12 stores the renewable energy power source 3 whose stability is determined to improve by parallel-out as a renewable energy power source 3 located on the supply side. The normal condition control selection unit 12 creates renewable energy power source information D10 related to information on the renewable energy power source 3 on the supply side and the renewable energy power source 3 on the demand side.

[0156] (Step S07: Determine whether renewable energy sources can be controlled) The operation in step S07 is executed by the normal condition control selection unit 12. The normal condition control selection unit 12 determines whether or not it is possible to control the renewable energy power source 3 whose stability is determined to improve by parallel-off. The determination of whether or not it is possible to control the renewable energy power source 3 is made based on, for example, whether or not a terminal device 50 that performs control is installed in the renewable energy power source 3.

[0157] Renewable energy power sources 3 such as solar power generation systems installed in ordinary homes do not have terminal devices 50 installed. Because of the large impact on the power grid 90, renewable energy power sources 3 such as large-scale wind power plants often have terminal devices 50 installed. Information on whether a terminal device 50 that performs power control is installed in a renewable energy power source 3 is stored in an external database (not shown). Based on the information on whether a terminal device 50 that performs power control is installed in a renewable energy power source 3, which is stored in an external database (not shown), the normal condition control selection unit 12 determines whether it is possible to perform power control on a renewable energy power source 3 that is determined to have its stability improved by parallel-off.

[0158] If it is determined that the renewable energy power source 3 can be controlled (YES in step S07), the program proceeds to step S08. If it is determined that the renewable energy power source 3 cannot be controlled (NO in step S07), the program proceeds to step S09.

[0159] (Step S08: Controlling the supply-side renewable energy source to be disconnected) The operation in step S08 is executed by the normal condition control selection unit 12. If it is determined in step S07 that the renewable energy power source 3 can be controlled, the normal condition control selection unit 12 adds the renewable energy power source 3, whose stability is determined to be improved by parallel-off, to the first-stage control information D12 created in step S03 as a control target.

[0160] (Step S09: Determine whether all renewable energy sources have been evaluated) The operation in step S09 is executed by the normal condition control selection unit 12. The normal condition control selection unit 12 determines whether all renewable energy power sources 3 in the power system 90 have been evaluated. If it is determined that all renewable energy power sources 3 have been evaluated (YES in step S09), the program proceeds to step S10. If it is determined that all renewable energy power sources 3 have not been evaluated (NO in step S09), the normal condition control selection unit 12 selects an unevaluated renewable energy power source 3, and the program proceeds to step S04.

[0161] (Step S10: Creating severe condition data D14) The operation in step S10 is performed by the harsh condition stability confirmation unit 14. The harsh condition stability confirmation unit 14 creates harsh condition data D14 based on the renewable energy power supply information D10. The harsh condition stability confirmation unit 14 receives the renewable energy power supply information D10 created in step S06 and sets harsh conditions.

[0162] The harsh condition stability confirmation unit 14 selects a renewable energy power source 3 located on the supply side based on the renewable energy power source information D10. The harsh condition stability confirmation unit 14 creates data for the case where the selected renewable energy power source 3 is not disconnected from the power grid 90 as harsh condition data D14. Fig. 6 shows an example of the harsh condition data D14.

[0163] (Step S11: Evaluating the stability of the power system reflecting severe conditions) The operation in step S10 is executed by the harsh condition stability checking unit 14 and the stability calculation unit 13. The harsh condition stability checking unit 14 transmits to the stability calculation unit 13 the harsh condition data D14 created in step S10, the first-stage control information D12 created in step S03, or the first-stage control information D12 corrected in step S08.

[0164] The stability calculation unit 13 calculates the stability based on the received severe condition data D14 and first-stage control information D12, and sets the calculated stability as the stability calculation result F02. The severe condition stability confirmation unit 14 receives the stability calculation result F02 calculated by the stability calculation unit 13.

[0165] (Step S12: Determine whether the power system is stable under the severe conditions) The operation of step S12 is executed by the harsh condition stability checking unit 14. Based on the stability calculation result F02, the harsh condition stability checking unit 14 determines whether the power system 90 is stable due to control according to the first-stage control information D12, which reflects the harsh conditions according to the harsh condition data D14. If it is determined that the power system 90 is stable (YES in step S12), the program proceeds to step S18. If it is not determined that the power system 90 is stable (NO in step S12), the program proceeds to step S13.

[0166] (Step S13: Creating additional severe condition control information D15) The operation in step S13 is executed by the harsh condition additional control selection unit 15. If it is not determined in step S12 that the power system 90 is stable, the harsh condition additional control selection unit 15 selects additional control under harsh conditions and creates harsh condition additional control information D15. The harsh condition additional control selection unit 15 selects additional control that stabilizes the harsh conditions for the control amount based on the first-stage control information D12 created in step S03 or the first-stage control information D12 modified in step S08.

[0167] The severe condition additional control selection unit 15 selects the additional control based on the stability according to the stability calculation result F03 calculated by the stability calculation unit 13. The selection of the synchronous generators 2 to be subjected to the additional control may be performed, for example, based on the stability according to the stability calculation result F03, in the order in which the internal phase difference angle of the generators exceeds a certain threshold value (for example, 360 degrees), using a step-out ranking method or the like, in which the generators to be subjected to the shedding control are selected one by one until the power grid 90 becomes stable.

[0168] When selecting a renewable energy power source 3, a method may be used in which the synchronous generator 2 and the renewable energy power source 3 are added one by one based on the magnitude of deceleration energy when the generator 2 and the renewable energy power source 3 are electrically controlled, using, for example, a P-δ curve that represents the relationship between the active power output of the unstable generator and the internal phase difference angle. The severe condition additional control selection unit 15 selects additional control based on the severe conditions and creates severe condition additional control information D15. Fig. 7 shows an example of the severe condition additional control information D15.

[0169] (Step S14: Calculation of stability by additional control) The operation in step S14 is executed by the post-correction control candidate selection unit 16 and the stability calculation unit 13. The post-correction control candidate selection unit 16 calculates the stability of the power system 90 when the synchronous generator 2 selected in the harsh condition additional control information D15 is controlled for the expected time of post-correction control, based on the first-stage control information D12 created in step S03 or the control amount based on the first-stage control information D12 corrected in step S08, the harsh condition data D14 created in step S10, and the harsh condition additional control information D15 created in step S13.

[0170] The post-correction control candidate selector 16 transmits the first-stage control information D12, the harsh condition additional control information D15, and information regarding the timing of executing the post-correction control and the time required to execute the post-correction control to the stability calculation unit 13. The stability calculation unit 13 calculates stability based on the first-stage control information D12, the harsh condition additional control information D15, and the information regarding the timing of executing the post-correction control and the time required to execute the post-correction control, and sets the calculated stability as a stability calculation result F04. The post-correction control candidate selector 16 receives the stability calculation result F04 calculated by the stability calculation unit 13.

[0171] The time required to execute the post-correction control is calculated as the sum of the calculation time for the post-correction control, the generator power control delay time, the data communication processing time of each device, etc. The time for which the post-correction control is executed is, for example, the time for which the first stage control is executed + 200 ms.

[0172] (Step S15: Determine whether the power system is stable after the post-correction is reflected) The operation of step S15 is executed by the post-correction control candidate selection unit 16. The post-correction control candidate selection unit 16 determines, based on the stability calculation result F04, whether the power system 90 is stable due to the control according to the severe condition additional control information D15 that reflects the post-correction control. If it is determined that the power system 90 is stable (YES in step S15), the program proceeds to step S16. If it is not determined that the power system 90 is stable (NO in step S15), the program proceeds to step S17.

[0173] (Step S16: Creating post-correction control information D16 including additional control) The operation in step S16 is executed by the post-correction control candidate selection unit 16. If it is determined in step S15 that the power system 90 is stable, the post-correction control candidate selection unit 16 selects the synchronous generator 2 to be the target of additional control as a candidate for the control target of post-correction control, and creates post-correction control information D16.

[0174] Even if the synchronous generator 2 that is the target of the additional control is controlled at a timing later than the first-stage control, the power grid 90 is stabilized. After the first-stage control is implemented, the stability due to the additional control is determined based on the actual state of the power grid 90, and the additional control is then implemented, thereby preventing excessive control of the power grid 90.

[0175] (Step S17: Creating first-stage control information D12 including additional control) The operation in step S17 is executed by the post-correction control candidate selection unit 16. If it is not determined in step S15 that the power system 90 is stable, the post-correction control candidate selection unit 16 selects the synchronous generator 2 to be the target of additional control as a candidate for the first-stage control, and creates first-stage control information D12. Fig. 8 shows an example of the first-stage control information D12 including the additional control.

[0176] If the synchronous generator 2 to be the target of additional control is selected as a candidate for control of post-correction control and the post-correction control information D16 is created, the additional control will not be executed in the first-stage control, and as a result, the power system 90 may not be stabilized. By including the synchronous generator 2 to be the target of additional control in the first-stage control information D12, the power system 90 can be more reliably stabilized.

[0177] (Step S18: Selection of candidate control targets for post-correction control) The operation in step S18 is executed by the post-correction control candidate selection unit 16. The post-correction control candidate selection unit 16 selects synchronous generators 2 as candidates for control targets of the post-correction control until the number of synchronous generators 2 reaches an arbitrary number, and adds the selected synchronous generators 2 to the post-correction control information D16.

[0178] The arbitrary number is the number required to stabilize the power system 90 by post-correction control. For example, if the arbitrary number is set to three and one synchronous generator 2 has already been selected in step S16, the remaining two synchronous generators 2 are selected as candidates for control targets of post-correction control.

[0179] For example, based on the stability calculated by the stability calculations executed in steps S03, S08, and S11, the synchronous generators 2 to be candidates for the control target of the post-correction control may be selected in descending order of the magnitude of one or more of the following indices: the peak of the internal phase difference angle of the generator, the increase in the internal phase difference angle, the peak of the angular velocity, and the increase in the angular velocity.

[0180] Furthermore, the post-correction control candidate selection unit 16 may assign priorities regarding shedding control to the synchronous generators 2 that are candidates for the control target of the post-correction control. For example, a higher priority regarding shedding control may be assigned to the synchronous generators 2 selected in step S16 than to the synchronous generators 2 selected in step S18. For example, the synchronous generators 2 selected in step S18 may be assigned higher priorities regarding shedding control in the order in which they were selected.

[0181] (Step S19: Determine whether all contingency cases have been evaluated) The operation of step S19 is executed by the post-correction control candidate selection unit 16. The post-correction control candidate selection unit 16 determines whether all contingency cases have been evaluated. If it is determined that all contingency cases have been evaluated (YES in step S19), the program proceeds to step S20. If it is not determined that all contingency cases have been evaluated (NO in step S19), the program proceeds to step S02.

[0182] (Step S20: Creating a control table) The operation in step S20 is executed by the control table creation unit 17. If it is determined in step S19 that all contingent fault cases have been evaluated, the control table creation unit 17 creates a first-stage control table T1 and a post-correction control table T2.

[0183] The control table creation unit 17 associates the target failure cases with the control contents based on the first-stage control information D12 created in step S16 or step S17, and creates a first-stage control table T1. The control table creation unit 17 associates the target failure cases with the control contents based on the post-correction control information D16 created in step S17 and step S18, and creates a post-correction control table T2. Figure 9 shows an example of a control table.

[0184] The control table creating unit 17 transmits the created first-stage control table T1 and post-correction control table T2 to the control information transmitting unit 18, and the program ends.

[0185] The above is the operation of the power system stabilizing device 1 according to this embodiment.

[0186] [1-3.Effects] (1) According to this embodiment, the power system stabilization device 1 includes a normal condition control selection unit 12 that selects control to stabilize the power system corresponding to an expected failure based on normal conditions for disconnecting the renewable energy power source 3 in accordance with a dynamic characteristic model of the renewable energy power source 3 of the power system 90 in which the synchronous generator 2 and the renewable energy power source 3 are arranged, a harsh condition stability confirmation unit 14 that confirms the stability of the power system 90 under harsh conditions in which stability is impaired more than under normal conditions, and ... the stability confirmed by the harsh condition stability confirmation unit 14 when it is determined that the power system 90 is unstable. and a severe condition additional control selection unit 15 that selects additional control to be added to the control under normal conditions selected by the normal condition control selection unit 12, and instructs the power system 90 to perform at least one of the control under normal conditions selected by the normal condition control selection unit 12 and the control under normal conditions including the additional control selected by the severe condition additional control selection unit 15.This makes it possible to perform a simulation that more closely corresponds to the actual power system 90 that includes both the synchronous generator 2 and the renewable energy power source 3, and to provide a power system stabilization device that can more reliably stabilize the power system.

[0187] Typically, renewable energy power sources 3 are scattered throughout the power system 90. It is complicated to grasp all of the renewable energy power sources 3 scattered throughout the power system 90. For this reason, the stability calculation by the stability calculation unit 13 is performed through a simulation in which the renewable energy power sources 3 scattered throughout the power system 90 are divided into multiple groups.

[0188] However, in an actual power system 90, there may be a renewable energy power source 3 that is assumed to be disconnected in the simulation but is not disconnected in the actual power system 90. In the simulation, the renewable energy power sources 3 in the power distribution system are aggregated and modeled as one, so for example, a renewable energy power source 3 that generates solar power and is installed in an ordinary home may behave differently in the simulation and may not be disconnected.

[0189] Although it was assumed that the renewable energy source 3 would be disconnected in the simulation, if there is a renewable energy source 3 that is not disconnected in the actual power grid 90, the control calculated by the simulation may not be sufficient to stabilize the power grid 90.

[0190] The power system stabilization device 1 uses the severe condition additional control selection unit 15 to select control under severe conditions that impair stability rather than control under normal conditions, thereby eliminating the shortage of control amount and more reliably stabilizing the power system 90.

[0191] Furthermore, when the power system stabilization device 1 determines that the power system 90 is unstable based on the stability of the control under severe conditions, the severe condition additional control selection unit 15 selects additional control to be added to the control under normal conditions, thereby eliminating the shortage of control amount and more reliably stabilizing the power system 90.

[0192] (2) According to this embodiment, the normal condition control selection unit 12 of the power system stabilization device 1 determines, among the renewable energy power sources 3 arranged in the power system 90, the renewable energy power sources 3 whose stability improves when they are disconnected as the supply-side renewable energy power sources 3, and the renewable energy power sources 3 whose stability does not improve when they are disconnected as the demand-side renewable energy power sources 3. The harsh condition stability confirmation unit 14 selects, as the harsh condition, at least one of the settings by the normal condition control selection unit 12 where the renewable energy power sources 3 determined to be the supply side are not disconnected and the renewable energy power sources 3 determined to be the demand side are disconnected. This eliminates the risk of insufficient control amount and makes it possible to more reliably stabilize the power system 90.

[0193] Although it is assumed that a renewable energy source 3 will be disconnected in the simulation, even if there is a renewable energy source 3 that is not disconnected in the actual power system 90, the normal condition control selection unit 12 appropriately selects the renewable energy source 3 that is subject to harsh conditions, thereby eliminating the risk of insufficient control amount and more reliably stabilizing the power system 90.

[0194] (3) According to this embodiment, the power system stabilization device 1 has a post-correction control candidate selection unit 16 that determines whether the additional control selected by the severe condition additional control selection unit 15 should be included in the first-stage control that is executed after a fault has occurred in the power system 90 and before the state quantities of the power system 90 are measured, or in the post-correction control that is executed after the first-stage control and after the state quantities of the power system 90 are measured. If the post-correction control candidate selection unit 16 determines that the power system 90 is unstable due to the control related to the additional control during the expected time of the post-correction control, it includes the additional control in the first-stage control, and if it determines that the power system 90 is stable, it includes the additional control in the post-correction control. Therefore, it is possible to avoid an unnecessary increase in the control amount related to the first-stage control and suppress excessive control.

[0195] (4) According to this embodiment, the post-correction control candidate selector 16 of the power system stabilization device 1 selects the synchronous generator 2 to be the control target of the post-correction control based on at least one index of the peak of the internal phase difference angle, the increase in the internal phase difference angle, the peak of the angular velocity, and the increase in the angular velocity of the synchronous generator 2 arranged in the power system 90, which are related to the stability of the power system 90 for which the first-stage control has been executed, in addition to the synchronous generator 2 to be the control target of the additional control selected by the severe condition additional control selector 15. Therefore, the synchronous generator 2 to be the control target of the post-correction control can be more appropriately selected, which can resolve the shortage of the control amount, and the power system 90 can be more reliably stabilized.

[0196] (5) According to this embodiment, the normal condition control selection unit 12 of the power system stabilization device 1 selects, as the target of control under normal conditions, a renewable energy power source 3 that receives instructions from the power system stabilization device 1 and controls its output, or a renewable energy power source 3 to which a terminal device 50 that receives instructions and controls its output is connected. Therefore, the renewable energy power source 3 that is the target of control under normal conditions can be more appropriately selected, and the shortage of control amount can be resolved, thereby more reliably stabilizing the power system 90.

[0197] 2. Other Embodiments Although embodiments including modifications have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. The following is an example.

[0198] (1) In the above embodiment, the power system stabilizing device 1 generates the first-stage control information D12 and the post-correction control information D16 and outputs a control table. The power system stabilizing device 1 may generate the first-stage control information D12 and output a control table without generating the post-correction control information D16. In the program, the processes of steps S14, S15, S16, S17, and S18 executed by the post-correction control candidate selecting unit 16 may be skipped.

[0199] As a result, the first-stage control table T1 corresponding to the first-stage control information D12 is created, and the power system 90 can be controlled quickly.

[0200] (2) In the above embodiment, the harsh condition stability confirmation unit 14 creates the harsh condition data D14 based on the renewable energy power source information D10 by controlling the supply-side renewable energy power source 3 not to be disconnected. However, the harsh condition data D14 is not limited to the above control. For example, the harsh condition data D14 may be the data by controlling the demand-side renewable energy power source 3 to be disconnected.

[0201] Furthermore, the harsh condition data D14 may be a combination of control not to disconnect the supply-side renewable energy power source 3 and control to disconnect the demand-side renewable energy power source 3. Furthermore, the harsh condition data D14 may not be control not to disconnect all of the supply-side renewable energy power sources 3, but may be control not to disconnect some of the supply-side renewable energy power sources 3. The harsh condition data D14 may be control to adjust the amount of disconnection to create harsh conditions.

[0202] This creates a first-stage control table T1 or a post-correction control table T2 in which the control amount due to parallel-off corresponds to the first-stage control information D12 selected more finely, allowing for more accurate control of the power system 90. [Explanation of symbols]

[0203] 1...Power system stabilization device 11. System Information Collection Department 12. Normal condition control selection section 13...Stability calculation section 14. Harsh condition stability confirmation section 15. Severe Condition Additional Control Selection Section 16. Post-correction control candidate selection section 17. Control table creation section 18. Control information transmission unit 2, 2-1, 2-2, 2-3...Synchronous generator 3. Renewable energy sources 4, 4-1, 4-2, 4-3... Transmission lines 5, 5-1, 5-2, 5-3, 5-4... Circuit breaker 6, 6-1, 6-2, 6-3, 6-4... Transformer 7, 7-1, 7-2, 7-3, 7-4, 7-5, 7-6, 7-7... Information gathering device 8. Fault detection device 50 Terminal device 80...Communication line 90, 91, 92...Power system

Claims

1. a normal condition control selection unit that selects control corresponding to an expected failure based on normal conditions for disconnecting the renewable energy power source according to a dynamic characteristic model of the renewable energy power source in a power system in which a synchronous generator and a renewable energy power source are arranged; a severe condition stability confirmation unit that selects a severe condition that impairs stability more than the normal condition selected by the normal condition control selection unit, and confirms the stability of the power system under the severe condition; a severe condition additional control selection unit that, when it is determined that the power system is unstable under control under normal conditions based on the stability confirmed by the severe condition stability confirmation unit, selects an additional control to be added to the control under normal conditions selected by the normal condition control selection unit, instructing the power system to perform at least one of the control under the normal conditions selected by the normal condition control selection unit, the control under the severe conditions selected by the severe condition stability confirmation unit, and the control under the normal conditions or the control under the severe conditions including the additional control selected by the severe condition additional control selection unit; Power system stabilizer.

2. the normal condition control selection unit determines, among the renewable energy power sources arranged in the power grid, the renewable energy power source whose stability is improved by being disconnected as the supply-side renewable energy power source, and determines the renewable energy power source whose stability is not improved by being disconnected as the demand-side renewable energy power source; The severe condition stability confirmation unit selects, as the severe condition, at least one of a setting in which the renewable energy power source set as the supply side is not disconnected and a setting in which the renewable energy power source set as the demand side is disconnected by the normal condition control selection unit. The power system stabilization device according to claim 1 .

3. The additional control selected by the severe condition additional control selection unit, a post-correction control candidate selection unit that determines whether the candidate is included in a first-stage control that is executed after a fault has occurred in the power system and before a state quantity of the power system is measured, or a post-correction control that is executed after the first-stage control and after a state quantity of the power system is measured, The post-correction control candidate selection unit performs the following by controlling the additional control during the estimated time of the post-correction control: When it is determined that the power system is unstable, the first stage control includes the additional control; If it is determined that the power system is stable, the post-correction control includes the additional control. The power system stabilization device according to claim 1 .

4. the post-correction control candidate selection unit selects the renewable energy power source to be a control target of the post-correction control based on at least one index of the peak of an internal phase difference angle, an increase in an internal phase difference angle, a peak of an angular velocity, and an increase in an angular velocity of the synchronous generator arranged in the power system, which index is related to the stability of the power system after the first stage control is executed, in addition to the synchronous generator to be a control target of the additional control selected by the severe condition additional control selection unit; The power system stabilizer according to claim 3.

5. The normal condition control selection unit selects the renewable energy power source that receives the instruction and controls the output, or the renewable energy power source to which a terminal device that receives the instruction and controls the output is connected, as a target for control under the normal condition. The power system stabilization device according to claim 1 .

6. On the computer, a normal condition control selection step of selecting control corresponding to an expected failure based on normal conditions for disconnecting the renewable energy power source according to a dynamic characteristic model of the renewable energy power source in a power system in which a synchronous generator and a renewable energy power source are arranged; a severe condition stability confirmation step of selecting a severe condition that impairs stability more than the normal condition selected in the normal condition control selection step, and confirming the stability of the power system under the severe condition; a severe condition additional control selection step of selecting an additional control to be added to the control under the normal condition selected in the normal condition control selection step when it is determined that the power system is unstable under the control under the normal condition based on the stability confirmed in the severe condition stability confirmation step; instructing the power system to perform at least one of the control under the normal conditions selected in the normal condition control selection step, the control under the severe conditions selected in the severe condition stability confirmation step, and the control under the normal conditions or the control under the severe conditions including the additional control selected in the severe condition additional control selection step; Computer program for power system stabilizers.

7. A normal condition control selection procedure for selecting a control corresponding to an expected failure based on a normal condition for disconnecting the renewable energy power source according to a dynamic characteristic model of the renewable energy power source in a power system in which a synchronous generator and a renewable energy power source are arranged; a severe condition stability confirmation procedure for selecting a severe condition that impairs stability more than the normal condition selected by the normal condition control selection procedure, and confirming the stability of the power system under the severe condition; a severe condition additional control selection step of selecting an additional control to be added to the control under the normal condition selected by the normal condition control selection step when it is determined that the power system is unstable under the control under the normal condition based on the stability confirmed by the severe condition stability confirmation step, instructing the power system to perform at least one of the control under the normal conditions selected by the normal condition control selection procedure, the control under the severe conditions selected by the severe condition stability confirmation procedure, and the control under the normal conditions or the control under the severe conditions including the additional control selected by the severe condition additional control selection procedure; Power system stabilization method.

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