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

Abstract

The present invention provides a power system stabilization device, a power system stabilization system, a computer program for a power system stabilization device, and a power system stabilization method that create control information that suppresses excessive control and maintains power system stability more appropriately, even when multiple faults occur at different times following multiple faults that occurred in close proximity in a power system. [Solution] The power system stabilization device 1 has a calculation unit 10 that selects a common control target for pre-progression accidents, which are accidents resulting from the failure to repair at least one accident among a group of simultaneous accidents that occurred within a predetermined time period, and post-progression accidents, which are accidents that occurred following a pre-progression accident, based on a system model D102 that shows the state of the power system 91 that supplies power, and assumed accident information D202 that shows accidents that are expected to occur in the power system 91.

Description

Technical Field

[0001] This embodiment relates to a power system stabilization device, a power system stabilization system, a computer program for a power system stabilization device, and a power system stabilization method that create control information for maintaining the stability of a power system in order to stably supply power even when an accident occurs in the power system.

Background Art

[0002] In order to maintain the stability of a power system, a power system stabilization device that controls the power system is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an accident such as lightning strike occurs in a power system, the generators in the power system may be unable to maintain synchronous operation and become out of step. If the out-of-step of the generator is left unattended, other generators will also become out of step in a chain reaction, and the stability of the power system cannot be maintained. As a result, there is a possibility of causing a blackout, which is a large-scale power outage.

[0005] Most of the conventional power system stabilization devices are designed to handle accidents up to N-2, where two facilities in the power system are lost simultaneously. In recent years, in order to cope with the assumed large-scale power outages, further improvement in the resilience of the power system has been demanded.

[0006] In power systems, multiple faults may occur within a short period of time. Furthermore, multiple faults may occur at different times following a series of faults that occurred within a short period of time. For example, multiple faults occurring within a short period of time may be followed by multiple faults at different times due to reclosing failures. In conventional technology, when multiple faults occurred within a short period of time in a power system, followed by faults at different times, control information was created independently for each fault to maintain the stability of the power system.

[0007] However, a problem arose when control information was created independently for each accident, and when control was applied to multiple accidents that occurred in close proximity followed by multiple accidents that occurred at different times, unnecessary control was sometimes implemented, resulting in over-control. Furthermore, when creating appropriate control information to avoid over-control for multiple accidents that occurred in close proximity followed by multiple accidents that occurred at different times, the calculation process took a long time, resulting in a longer calculation cycle and making it difficult to perform appropriate control.

[0008] The objective of this embodiment is to provide a power system stabilization device, a power system stabilization system, a computer program for a power system stabilization device, and a power system stabilization method that create control information that suppresses excessive control and maintains the stability of the power system more appropriately, even when multiple faults occur at different times following multiple faults that occurred in close proximity in the power system. [Means for solving the problem]

[0009] The power system stabilization device of this embodiment has the following features. (1) The calculation unit selects a control target based on a system model that shows the state of the power system that supplies power, and assumed accident information that shows accidents that are expected to occur in the power system. (2) The calculation unit selects a control target common to the pre-progression accident, which is an accident resulting from the repair failure of at least one of the multiple simultaneous accidents that occurred within a predetermined time period among the assumed accidents shown in the assumed accident information, and the post-progression accident, which is an accident that occurred following the pre-progression accident. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the configuration of the power grid stabilization system 100 according to the first embodiment. [Figure 2] This diagram shows the program flow of the power grid stabilization device 1 according to the first embodiment. [Figure 3] A diagram illustrating an example of a progressing accident in a simultaneous fault across multiple power transmission routes. [Figure 4] A diagram illustrating examples of accident patterns occurring during the advancement of power transmission routes. [Figure 5] This diagram shows an example of selecting a control target in cases of over-control using conventional technology. [Figure 6] This figure shows the control priority sequence table D203 of the power system stabilization device 1 according to the first embodiment. [Figure 7] This figure shows an example of selecting a control target by the power system stabilization device 1 according to the first embodiment. [Figure 8] This figure shows the configuration of the power grid stabilization system 100 according to the second embodiment. [Figure 9] This diagram shows the program flow of the power grid stabilizer 1 according to the second embodiment. [Figure 10] This figure shows an example of selecting a control target by the power system stabilization device 1 according to the second embodiment. [Figure 11] This figure shows the configuration of the power grid stabilization system 100 according to the third embodiment. [Figure 12] This diagram shows the program flow of the stability calculation unit 105 of the power system stabilization device 1 according to the third embodiment. [Figure 13] This diagram shows the program flow of the specific control content replacement unit 112 of the power system stabilization device 1 according to the third embodiment. [Figure 14] Figure showing the control combination priority table D204 of the power system stabilizer 1 according to the third embodiment [Figure 15] Figure showing a selection example of a control target by the power system stabilizer 1 according to the third embodiment [Figure 16] Figure showing an example of another configuration of the power system stabilization system 100

Embodiments for Carrying Out the Invention

[0011] [1. First Embodiment] [1-1. Configuration] [1-1-1. Configuration of the power system stabilization system 100] FIG. 1 is a diagram showing the configuration of a power system stabilization system 100 and a power system stabilizer 1 according to the first embodiment.

[0012] The power system stabilization system 100 includes a power system stabilizer 1, a startup terminal device 5, a central control device 6, and a control terminal device 7. The power system stabilization system 100 is connected to a power system 91 and a circuit breaker 93. A plurality of generators are connected to the power system 91 as generators 92. The circuit breaker 93 is arranged for each of the plurality of generators 92. The output power of the generator 92 is cut off by the circuit breaker 93. The circuit breaker 93 may be one that cuts off the transmission line of the power system 91.

[0013] The power system stabilization system 100 periodically receives system information D101 from the power system 91 and selects a control target based on the state of the system. The power system stabilization system 100 transmits a command to cut off the selected control target to the circuit breaker 93. The control target is equipment such as a generator, transmission line, bus, transformer, phase modulation equipment, circuit breaker, and circuit breaker that is selected as a cut-off target in order to stabilize the power system 91 when an assumed accident occurs.

[0014] System information D101 is information regarding the connection status of the power system 91 and the power supply and demand status. System information D101 includes, for example, on / off information regarding the connection status of the power system 91 and measurement information regarding the power supply and demand status. On / off information refers to information regarding the open / closed status of circuit breakers 93, disconnectors, etc. (not shown) installed in the power system 91. Measurement information includes information regarding the output of the generator 92, loads, active and reactive power of transmission lines, transformers, etc., and busbar voltages of each substation.

[0015] The power system 91 is a series of facilities for transmitting electricity generated by the generator 92 to the load equipment (not shown) of consumers, and consists of power equipment (also called system equipment) such as busbars, transformers, transmission lines, phase adjustment equipment, circuit breakers, and disconnectors. The power system 91 may also include power generation equipment.

[0016] [1-1-2. Configuration of Power System Stabilizer 1] The power system stabilization device 1 is a device that creates a control table for stabilizing the power system 91. The power system stabilization device 1 is a device composed of a computer, etc. When a hypothetical fault occurs in the power system 91, the power system stabilization device 1 selects the control target to be shut off. The power system stabilization device 1 is sometimes called a central processing unit.

[0017] The power system stabilization device 1 is connected to the power system 91 via a communication line. The power system stabilization device 1 is also connected to the central control unit 6 via a communication line.

[0018] The power system stabilization device 1 has a calculation unit 10 and a storage unit 20.

[0019] The calculation unit 10 of the power system stabilization device 1 is connected to the power system 91 and the central control unit 6 via a communication line. The calculation unit 10 is also connected to the storage unit 20. The calculation unit 10 includes an information transmission unit 101, a system model creation unit 102, a state determination unit 103, a hypothetical fault setting unit 104, a stability calculation unit 105, a control table creation unit 106, and a control information transmission unit 107.

[0020] Each of the above-mentioned components constituting the calculation unit 10 of the power system stabilization device 1 may be composed of a calculation unit in a computer or a software module. Each of the above-mentioned components constituting the calculation unit 10 of the power system stabilization device 1 may be realized, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Furthermore, some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integrated Circuit), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Catalog Array), or GPU (Graphics Processing Unit), or by the cooperation of software and hardware.

[0021] Furthermore, each of the above-mentioned components constituting the power system stabilization device 1 may be composed of individual devices or may be composed as an integrated unit.

[0022] The information transmission unit 101 is a receiving module or receiving device that receives system information D101 from the power system 91. The information transmission unit 101 includes a transmitting and receiving circuit. The information transmission unit 101 is connected via a communication line to an information collection device and a fault detection device (not shown) located in the power system 91. The information transmission unit 101 is also connected to the system model creation unit 102.

[0023] The information transmission unit 101 periodically receives system information D101 from the power system 91. System information D101 is information regarding the connection status and power supply and demand status of the power system 91. System information D101 is transmitted from information collection devices and fault detection devices (not shown) located in the power system 91.

[0024] The information transmission unit 101 transmits the received system information D101 to the system model creation unit 102.

[0025] The system model creation unit 102 is a calculation module or calculation device that creates the system model D102. The system model creation unit 102 is connected to the information transmission unit 101 and the state determination unit 103.

[0026] The system model creation unit 102 receives system information D101 from the information transmission unit 101 and creates a system model D102 based on the system information D101.

[0027] The system model creation unit 102 creates a system model D102 that shows the current system connection status based on the system information D101 received from the information transmission unit 101 and the system equipment data D201, which will be described later and is stored in the storage unit 20 in advance. The system model D102 is used to calculate the current power flow status of the power system 91. The system information D101 includes equipment connection information. The system model creation unit 102 transmits the created system model D102 to the status determination unit 103.

[0028] The state determination unit 103 is a calculation module or calculation device that creates the calculation system model D103. The state determination unit 103 is connected to the system model creation unit 102 and the assumed accident setting unit 104.

[0029] The state determination unit 103 performs state estimation calculations and power flow calculations based on the system model D102 created by the system model creation unit 102 and the system information D101 received by the information transmission unit 101, determines a system state that is closer to the current state, and creates a system model D103 for calculation. The state determination unit 103 transmits the created system model D103 for calculation to the assumed fault setting unit 104.

[0030] The assumed accident setting unit 104 is a calculation module or calculation device that creates assumed accident data D104. The assumed accident setting unit 104 is connected to the state determination unit 103 and the stability calculation unit 105.

[0031] The assumed accident setting unit 104 creates assumed accident data D104 based on the calculation system model D103 created by the state determination unit 103 and the assumed accident information D202, which will be described later and is stored in the storage unit 20 in advance. The assumed accident data D104 is data in which assumed accidents to be subject to stabilization calculations have been selected. The assumed accident setting unit 104 transmits the created assumed accident data D104 to the stability calculation unit 105.

[0032] The stability calculation unit 105 is a calculation module or calculation device that creates the control target information D105. The stability calculation unit 105 is connected to the assumed accident setting unit 104 and the control table creation unit 106.

[0033] The stability calculation unit 105 creates control target information D105 based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control priority order table D203, which is stored in the storage unit 20 in advance and will be described later. The control priority order table D203 is a table in which the control priority to be selected by the stability calculation unit 105 is predetermined for each assumed accident group, including progressing accidents. In a group of simultaneous accidents that occur within a predetermined time, an accident resulting from the failure to repair at least one accident is called a pre-progression accident, and an accident that occurs following a pre-progression accident is called a post-progression accident. Pre-progression accidents and post-progression accidents are collectively referred to as progressing accidents.

[0034] The stability calculation unit 105 performs a stability calculation for the assumed fault related to the assumed fault data D104, based on the calculation system model D103 created by the state determination unit 103. The stability calculation unit 105 performs a stability determination on the results of the stability calculation, and if it determines that the power system 91 is unstable, it selects additional control targets and performs the stability calculation again. If the stability calculation unit 105 determines that the power system 91 is stable, it creates control target information D105 using the selected multiple control targets.

[0035] The control target information D105 is information in which the control target to be used to maintain the stability of the power system 91 in the event of a hypothetical fault is selected. The stability calculation unit 105 transmits the created control target information D105 to the control table creation unit 106.

[0036] The control table creation unit 106 is a calculation module or calculation device that creates the control table D106. The control table creation unit 106 is connected to the stability calculation unit 105 and the control information transmission unit 107.

[0037] The control table creation unit 106 selects a control target for each assumed accident case based on the control target information D105 created by the stability calculation unit 105, and creates a control table D106. The control table creation unit 106 then transmits the created control table D106 to the control information transmission unit 107.

[0038] The control information transmission unit 107 is a transmission module or transmission device that transmits the control table D106. The control information transmission unit 107 includes a transmit / receive circuit. The control information transmission unit 107 is connected to the control table creation unit 106 and the central control device 6.

[0039] The control information transmission unit 107 transmits the control table D106 created by the control table creation unit 106 to the central control unit 6 via the communication line.

[0040] The storage unit 20 is composed of a storage medium such as a hard disk or semiconductor memory. The storage unit 20 may be composed of, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory such as SSD (Solid State Drive), or HDD (Hard Disk Drive). The storage unit 20 is connected to the arithmetic unit 10. The storage unit 20 may be composed of an external device to the power system stabilization device 1.

[0041] The memory unit 20 stores system equipment data D201, assumed accident information D202, and control priority order table D203.

[0042] System equipment data D201 is information about power generation equipment and distribution equipment located in the power system 91. System equipment data D201 includes information about electrical connections such as loads, generators, transmission lines, circuit breakers, and switches located in the power system 91. System equipment data D201 includes information such as the connection location of circuit breakers, the rated active power of power generation equipment such as synchronous generators and renewable energy sources, and the impedance and capacitance of transmission lines. System equipment data D201 is pre-set and stored in the storage unit 20.

[0043] The assumed accident information D202 is information regarding the location and nature of an assumed accident in the power system 91. The assumed accident information D202 is pre-set and stored in the memory unit 20.

[0044] The control priority order table D203 contains information regarding the priority order in the control of the power system 91. The control priority order table D203 shows the control targets and control priority for each assumed fault indicated in the assumed fault information D202. The control priority order table D203 pre-defines the control priority order of the control equipment to be controlled for each assumed fault, including the progressing fault described later. The control priority order table D203 is pre-set and stored in the storage unit 20.

[0045] [1-1-3. Configuration of the startup terminal device 5] The activation terminal device 5 is a device that receives system information D501 and fault information D502 from the power system 91. The activation terminal device 5 is composed of a computer and the like. The activation terminal device 5 is connected to the central control unit 6 and the power system 91 via a communication line. The activation terminal device 5 is installed in the substations that are subject to the assumed faults in the power system 91.

[0046] The startup terminal device 5 has an accident information detection unit 501. The accident information detection unit 501 may be composed of a computer's arithmetic unit or a software module. The accident information detection unit 501 includes a transmit / receive circuit.

[0047] The accident information detection unit 501 receives system information D501 and accident information D502 as information about the power system 91 managed by the substation where the startup terminal device 5 is installed. System information D501 includes information about the output, load, active power and reactive power of the power transmission lines, and voltage of the generator 92 of the power system 91 to be managed. Accident information D502 is information about an accident that occurred in power equipment such as power transmission lines in the power system 91, and for example, it indicates the power equipment where the accident occurred and the nature of the accident. When an accident occurs in the power system 91, the accident information detection unit 501 detects the accident and determines the accident case. The accident information detection unit 501 transmits the received system information D501 and accident information D502 to the central control unit 6.

[0048] [1-1-4. Configuration of the Central Control Unit 6] The central control unit 6 is a device that generates control commands D601 for controlled objects connected to the power system 91. The central control unit 6 is composed of a computer and the like. The central control unit 6 is connected to the power system stabilization device 1, the startup terminal device 5, and the control terminal device 7.

[0049] The central control unit 6 has a control target determination unit 601. The control target determination unit 601 may be composed of a computer's arithmetic unit or a software module. The control target determination unit 601 receives the control table D106 from the power system stabilization device 1.

[0050] The control target determination unit 601 periodically receives system information D501 and accident information D502 from the activation terminal device 5, and selects a control target based on the latest system status. Based on the accident information D502 received from the activation terminal device 5, the control target determination unit 601 detects an actual accident that has occurred.

[0051] The control target determination unit 601 compares the fault detected based on the fault information D502 with the control table D106 and selects the control target. Based on the control table D106 created by the power system stabilization device 1, the control target determination unit 601 creates a control command D601 to shut off the equipment to be controlled, such as generators and transmission lines. The control target determination unit 601 transmits the created control command D601 to the control terminal device 7.

[0052] [1-1-5. Configuration of Control Terminal Device 7] The control terminal device 7 is a device that transmits control command D601 to the circuit breaker 93. The control terminal device 7 is composed of a computer, etc. The control terminal device 7 is connected to the circuit breaker 93 via a communication line. The control terminal device 7 is installed in substations, power plants, etc.

[0053] The control terminal device 7 has a control unit 701. The control unit 701 may be composed of an arithmetic unit in a computer or a software module. The control unit 701 includes a transmit / receive circuit.

[0054] The control unit 701 receives control command D601 from the central control unit 6. The control unit 701 transmits the control command D601 received from the central control unit 6 to the circuit breaker 93 connected to the controlled equipment. The control unit 701 selects the circuit breaker 93 connected to the equipment to be tripped in control command D601 and transmits the control command D601.

[0055] When the circuit breaker 93 receives the control command D601, it interrupts the circuit and disconnects the electrical equipment to be controlled from the power system 91. This stabilizes the power system 91.

[0056] The above describes the configuration of the power grid stabilization system 100 and the power grid stabilization device 1 according to this embodiment.

[0057] [1-2. Effect] Next, the operation of the power grid stabilization system 100 and the power grid stabilization device 1 of this embodiment will be explained based on Figures 1 to 7. [Overview of the operation of the power grid stabilization system 100 and power grid stabilization device 1 according to this embodiment]

[0058] The calculation unit 10 of the power system stabilization device 1 selects a control target common to pre-progression accidents, which are accidents resulting from the repair failure of at least one accident among multiple simultaneous accidents that occurred within a predetermined time period, and post-progression accidents, which are accidents that occurred following a pre-progression accident, among the pre-progression accidents indicated in the pre-progression accident information D202. The repair failure of an accident in the power system 91 includes reclosing failures.

[0059] The stability calculation unit 105 selects control targets common to both pre-progression and post-progression faults based on the control priority order table D203, which indicates the control priority of the control targets.

[0060] The power system stabilization system 100, using the stability calculation unit 105 of the calculation unit 10 of the power system stabilization device 1, selects control targets common to pre-progression and post-progression faults based on the control priority order table D203 which indicates the control priority of the control targets, creates a control command, and transmits it to the control targets of the power system 91.

[0061] The information transmission unit 101 of the power system stabilization device 1 periodically receives system information D101 from the power system 91. The system model creation unit 102 creates a system model D102 that shows the current system connection status based on the system information D101 received from the information transmission unit 101 and system equipment data D201 previously stored in the storage unit 20.

[0062] The state determination unit 103 performs state estimation calculations and power flow calculations based on the system model D102 created by the system model creation unit 102 and the system information D101 received by the information transmission unit 101, selects a system state that is closer to the current state, and creates a system model D103 for calculations.

[0063] The assumed accident setting unit 104 creates assumed accident data D104 based on the calculation system model D103 created by the state determination unit 103 and the assumed accident information D202 previously stored in the storage unit 20.

[0064] The stability calculation unit 105 selects a control target that will stabilize the power system 91 based on the control priority order table D203, which indicates the priority order of control of the control targets. The calculation unit 10 of the power system stabilization device 1 selects a control target that is common to both pre-progression and post-progression faults, based on the stability calculation unit 105.

[0065] The stability calculation unit 105 creates control target information D105 based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control priority order table D203 stored in advance in the storage unit 20. The control priority order table D203 is a table that shows the priority of control targets for each assumed accident group, including progressing accidents. The stability calculation unit 105 selects control targets in the order of priority shown in the control priority order table D203.

[0066] The stability calculation unit 105 performs a stability calculation for the assumed fault related to the assumed fault data D104, based on the calculation system model D103 created by the state determination unit 103. If the stability calculation unit 105 determines that the power system 91 is unstable based on the stability calculation, it selects additional control targets and performs the stability calculation again. If the stability calculation unit 105 determines that the power system 91 is stable, it creates control target information D105 for the selected control targets to be used as countermeasures for the assumed fault.

[0067] The control target information D105 is information in which the control targets necessary for maintaining the stability of the power system 91 have been selected. The stability calculation unit 105 creates the control target information D105 using the program shown in Figure 2, which will be described later. The stability calculation unit 105 transmits the created control target information D105 to the control table creation unit 106.

[0068] The control table creation unit 106 selects a control target for each assumed accident case based on the control target information D105 created by the stability calculation unit 105, and creates a control table D106. The control table creation unit 106 then transmits the created control table D106 to the control information transmission unit 107.

[0069] The control information transmission unit 107 transmits the control table D106 created by the control table creation unit 106 to the central control unit 6 via the communication line.

[0070] The startup terminal device 5 receives system information D501 indicating the status of the power system 91 and accident information D502 indicating an accident in the power system 91 from the power system 91, and identifies the type of accident in the power system 91. The startup terminal device 5 transmits the system information D501 and accident information D502 received from the power system 91 to the central control unit 6.

[0071] The central control unit 6 selects a control target and creates a control command D601 based on the fault type identified by the activation terminal device 5 and the control table D106 created by the power system stabilization device 1. The central control unit 6 transmits the created control command D601 to the control terminal device 7.

[0072] The control terminal device 7 transmits the control command D601, created by the central control unit 6, to the circuit breaker 93 to control the controlled object. The circuit breaker 93 connected to the controlled object receives the control command D601, interrupts the circuit, and disconnects the controlled electrical equipment from the power system 91. As a result, the power system 91 is stabilized.

[0073] The power system stabilization device 1 derives the control targets for faults in the power system 91, including progressive faults described later, through pre-calculation. The power system stabilization device 1 creates a control table D106 for stabilizing the power system 91. The power system stabilization system 100 creates a control command D601 based on the control table D106, and stabilizes the power system 91 more quickly and appropriately, even if multiple faults occur in the power system at different times following multiple faults that occurred in close proximity.

[0074] [Regarding the progress accident] In a system of simultaneous faults occurring within a predetermined time period, at least one fault resulting from a repair failure is called a pre-progression fault, and any faults that occur following a pre-progression fault are called post-progression faults. Both pre-progression and post-progression faults are collectively referred to as a progression fault. Reclosing failure is a form of repair failure. In a power system, multiple faults occurring in close proximity are considered simultaneous faults. Multiple faults occurring at different times following multiple faults occurring in close proximity are considered progression faults.

[0075] Figure 3 shows an example of a progressing fault in a simultaneous fault across multiple transmission routes. In a fault across multiple transmission routes in power system 91, the faults on each transmission route may occur with a time difference. A fault in another transmission route that occurs within a predetermined time from the time a fault occurs in one transmission route is considered a simultaneous fault. The predetermined time for a simultaneous fault may be determined by the fault detection cycle of the activation terminal device 5. The time of occurrence of each fault in each transmission route is measured by the activation terminal device 5.

[0076] Figure 3 shows an example of a four-circuit fault occurring in two transmission routes, transmission route A and transmission route B. Figure 3 shows that after fault 1 occurs in transmission routes A and B, which are considered simultaneous faults, fault 2 (pre-progression fault) occurs due to a failure to reclose transmission route A, and then fault 3 (post-progression fault) occurs due to a failure to reclose transmission route B. Control 1 is executed in response to fault 1, control 2 in response to fault 2, and control 3 in response to fault 3.

[0077] The power system stabilization system implements control to shut off the controlled system. If reclosing fails on transmission route A, where the initial fault occurred, the power system stabilization system detects the fault again and implements control for transmission route A. Subsequently, if reclosing fails on transmission route B, it detects this as two separate faults due to reclosing failures on transmission routes A and B, and implements control accordingly.

[0078] An accident involving a reclosing failure on transmission route A that occurs first is called a pre-progression accident, and an accident involving a reclosing failure on transmission route B that occurs later is called a post-progression accident. Both pre-progression and post-progression accidents are collectively referred to as a progression accident.

[0079] Figure 4 shows an example of the occurrence pattern of transmission route progression faults. Figure 4 shows the occurrence pattern of progression faults in a total of four circuits across two transmission routes, transmission route A and transmission route B.

[0080] Figure 4 shows an example of a progression fault pattern, illustrating that there are a total of six patterns: three patterns A1, A2, and A3 for progression faults starting with a single circuit outage on transmission route A, and three patterns B1, B2, and B3 for progression faults starting with a single circuit outage on transmission route B.

[0081] Figure 3 shows an example in Pattern A1 or Pattern A2 of Figure 4 where a 3-circuit outage progresses to a 4-circuit outage. As shown in Figure 3, in response to Fault 1, which is considered a simultaneous fault in transmission routes A and B, a 3-circuit outage (transmission route A: 2-circuit outage, transmission route B: 1-circuit outage) occurs due to Fault 2, a pre-progression fault caused by the reclosing failure of transmission route A. Subsequently, a 4-circuit outage (transmission route A: 2-circuit outage, transmission route B: 2-circuit outage) occurs due to Fault 3, a post-progression fault caused by the reclosing failure of transmission route B.

[0082] If both transmission route A and transmission route B have a two-circuit configuration, in the event of a simultaneous fault in multiple transmission routes, it is expected that the fault will progress from an N-circuit disconnection fault caused by the initial reclosing failure shown in Figure 4 to an N+α-circuit disconnection fault caused by subsequent reclosing failures.

[0083] [Control using conventional technology] In conventional power grid stabilization systems, the same control was implemented for stabilizing simultaneous faults in multiple transmission routes of power grid 91 as for stabilizing a single transmission route fault. The power grid stabilization device of the conventional power grid stabilization system selects the control targets for faults in multiple transmission routes of power grid 91 through pre-calculation. When simultaneous faults in multiple transmission routes are detected by the startup terminal device, the power grid stabilization device implements the control selected by pre-calculation for the control targets when the actual fault occurs.

[0084] In the case of a fault in multiple power transmission routes, the faults in each transmission route may occur with a time difference. Among the multiple power transmission routes targeted for fault detection, a fault in another transmission route that occurs within a predetermined time from the time a fault occurs in one transmission route is considered a simultaneous fault. The time period for a simultaneous fault may be determined by the fault detection cycle of the activation terminal device 5. For faults in multiple power transmission routes that are considered simultaneous faults, control is implemented to electrically control the control target selected by pre-calculation.

[0085] The time it takes to restore power through reclosing of multiple transmission routes that were considered to have simultaneous accidents may vary depending on the transmission route. In addition, reclosing may fail if some of the causes of the accident in the transmission route have not been eliminated. Although control is implemented even in the event of reclosing failure, conventional power system stabilization systems implemented control without confirming whether the accidents in the multiple transmission routes were progressing accidents.

[0086] In other words, conventional power grid stabilization systems, if reclosing fails in the transmission route where the initial fault occurred, detect the number of circuit outages caused by the fault as a separate fault at the time of the reclosing failure and implement control for that transmission route. Subsequently, if reclosing fails in another transmission route, the power grid stabilization system detects the number of circuit outages as two separate faults—one in the transmission route where the initial fault occurred and another in the other transmission route—and implements control accordingly.

[0087] If faults occur in multiple transmission routes within a very short timeframe, even if reclosing fails in one of the transmission routes, the faults in the multiple transmission routes will be detected at a single timing. Therefore, the power system stabilization system controls both the initial simultaneous fault (initial fault) and the fault in the multiple transmission routes caused by the reclosing failure as a single unit.

[0088] However, if reclosing fails and another fault occurs after a predetermined time has elapsed, the initial fault is considered a simultaneous fault, but subsequent faults in the transmission route due to reclosing failures may not be considered simultaneous faults. This is because there is a time difference in the occurrence of faults due to reclosing failures for each transmission route.

[0089] Therefore, conventional power grid stabilization systems, when reclosing failed in multiple transmission routes, would individually detect the fault caused by the reclosing failure in each transmission route and perform individual control.

[0090] If the control targets for a pre-progression fault and the control targets for a post-progression fault are selected independently, excessive control (hereinafter sometimes referred to as "over-control") may be selected. Over-control is undesirable because it may impair the stability of the power system 91 and may result in insufficient power generation capacity in the power system 91.

[0091] Figure 5 shows an example of overcontrol when conventional control methods are used to control simultaneous faults in multiple transmission routes. In the pre-calculation performed by the conventional power system stabilization device, in the event of simultaneous faults in transmission route A (2Φ3LG) and transmission route B (3Φ4LG), if two circuits are disconnected in transmission route A and one circuit is disconnected in transmission route B, generators G1 and G3 are selected as targets for disconnection. If two circuits are disconnected in transmission route A and two circuits are disconnected in transmission route B, generators G2 and G4 are selected as targets for disconnection.

[0092] In the notation "3φ4LG", "3φ" indicates that a fault has occurred in at least one of the three phases of a three-phase, two-circuit transmission line. In addition, in the notation "3φ4LG", "4LG" indicates that a ground fault has occurred in four of the three phases of a three-phase, two-circuit transmission line.

[0093] In the actual accident, as mentioned above, the accidents on transmission route A and transmission route B occur with a time difference, and the accident progresses due to the time difference in reclosing after the accidents on transmission route A and transmission route B.

[0094] If a fault involving two circuit failures on transmission route A and one circuit failure on transmission route B progresses to a fault involving two circuit failures on transmission route A and two circuit failures on transmission route B, control targets G1 and G3 are selected for the fault involving two circuit failures on transmission route A and one circuit failure on transmission route B. Subsequently, control targets G2 and G4 are selected for the progress of the fault involving two circuit failures on transmission route A and two circuit failures on transmission route B. As a result, control targets G1, G2, G3, and G4 are selected for the series of faults, resulting in overcontrol.

[0095] Conventional power system stabilization devices, as described above, select control targets independently for each transmission route in the event of simultaneous faults on multiple transmission routes. However, if control targets are selected independently for each transmission route before and after the progression of a fault through pre-calculation, the fault mitigation measures in the event of an actual fault may result in over-control. Over-control is undesirable because it can have adverse effects on the power system 91, such as causing the system frequency to drop below a predetermined frequency due to insufficient power generation.

[0096] To suppress excessive control, it is conceivable to select control for a pre-progression fault, and then, by referring to that control, select control for a post-progression fault. However, depending on the number of transmission routes and fault types, there are many possible combinations of progressing faults. Therefore, it may be difficult to select the control target in a short time after a pre-progression fault occurs. This is because, in order to suppress excessive control, a large number of fault types must be calculated sequentially, and a long time is required to select the control target for all faults.

[0097] The power system stabilization device 1 according to this embodiment derives the control target for faults, including progressive faults, in the power system 91 through pre-calculation. The power system stabilization device 1 creates a control table D106 for stabilizing the power system 91. As a result, the power system stabilization system 100 creates a control command D601 based on the control table D106, and stabilizes the power system 91 more quickly and appropriately, even if multiple faults occur in the power system 91 at different times following multiple faults that occurred in close proximity.

[0098] [Details of the operation of the power grid stabilization system 100 and power grid stabilization device 1 according to this embodiment] The information transmission unit 101 of the power system stabilization device 1 periodically receives system information D101 from the power system 91. System information D101 is information regarding the connection status and power supply and demand status of the power system 91. The information transmission unit 101 receives information from an information collection device and a fault detection device (not shown) located in the power system 91.

[0099] System information D101 includes, for example, on / off information regarding the connection status of the power system 91 and measurement information regarding the power supply and demand status. The measurement information includes information on the output of the generator 92, load, active power and reactive power of the transmission lines, and busbar voltage of each substation. Accidents and faults in the power system 91 are detected based on the system information D101. The information transmission unit 101 transmits the received system information D101 to the system model creation unit 102.

[0100] The system model creation unit 102 receives system information D101 from the information transmission unit 101 and creates a system model D102 based on the system information D101. The system model D102 consists of nodes and branches. Nodes are data representations of busbars, generators, and loads. Each node is assigned a node number, which is identification information. Information such as generator output, active power and reactive power of loads, and busbar voltage are associated with the node number.

[0101] A branch is a digital representation of equipment such as power transmission lines and transformers. Each branch is assigned a branch number, which serves as identification information. This branch number is associated with information such as the node numbers of the connected nodes (start and end nodes), the number of operational lines, and impedance.

[0102] The system model creation unit 102 creates a system model D102 that shows the current system connection status based on the system information D101 received from the information transmission unit 101 and the system equipment data D201 previously stored in the storage unit 20. The system model D102 is used to calculate the current power flow status of the power system 91. The system information D101 includes equipment connection information. The system model creation unit 102 transmits the created system model D102 to the status determination unit 103.

[0103] The state determination unit 103 performs state estimation calculations and power flow calculations based on the system model D102 created by the system model creation unit 102 and the system information D101 received by the information transmission unit 101, selects a system state that is closer to the current state, and creates a system model D103 for calculation. The state determination unit 103 transmits the created system model D103 for calculation to the assumed fault setting unit 104.

[0104] The assumed accident setting unit 104 creates assumed accident data D104 based on the calculation system model D103 created by the state determination unit 103 and the assumed accident information D202 previously stored in the storage unit 20. The assumed accident data D104 is data in which assumed accidents to be subject to stabilization calculations have been selected. The assumed accident setting unit 104 transmits the created assumed accident data D104 to the stability calculation unit 105.

[0105] The stability calculation unit 105 creates control target information D105 based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control priority order table D203 stored in advance in the storage unit 20. Figure 6 shows an example of the control priority order table D203. The control priority order table D203 is a table in which the control priority order to be selected by the stability calculation unit 105 is predetermined for each assumed accident group that takes into account progressing accidents.

[0106] As shown in Figure 6(a), the control priority order table D203 represents the priority order of the controlled objects. For example, the control priority order of controlled object G1 is 1st, and the control priority order of controlled object G2 is 2nd. The stability calculation unit 105 selects the controlled objects in the order of priority shown in the control priority order table D203.

[0107] The stability calculation unit 105 creates a priority order for control target combinations that represents the control order when an accident occurs, based on the control priority order table D203. The priority order for control target combinations is shown in Figure 6(b). For example, the stability calculation unit 105 selects control target G1, which has a control priority of 1, and makes it the control target with the first control order when an accident occurs. The stability calculation unit 105 selects control target G2, which has a control priority of 2, and adds it to control target G1, which has a control priority of 1, making it the control target with the second control order when an accident occurs. The control priority order table D203 may represent the control order when an accident occurs, as shown in Figure 6(b).

[0108] The stability calculation unit 105 performs a stability calculation for the assumed fault related to the assumed fault data D104, based on the calculation system model D103 created by the state determination unit 103. The stability calculation unit 105 performs a stability determination on the results of the stability calculation, and if it determines that the power system 91 is unstable, it selects additional control targets and performs the stability calculation again. If the stability calculation unit 105 determines that the power system 91 is stable, it creates control target information D105 for the selected control targets to be used as countermeasures for the assumed fault.

[0109] The control target information D105 is information in which the control targets necessary for maintaining the stability of the power system 91 have been selected. The stability calculation unit 105 transmits the created control target information D105 to the control table creation unit 106.

[0110] The operation of the stability calculation unit 105 is realized by the computer program shown in Figure 2. The computer program shown in Figure 2 is built into the power system stabilizer 1. The program is executed before a fault occurs in the power system 91.

[0111] The stability calculation unit 105 receives the assumed fault data D104 created by the assumed fault setting unit 104 and executes the following program. For each power transmission route interruption status corresponding to the fault phase, the program's processes 1a, 1b, ..., 1n (not shown) are executed. Processes 1a, 1b, ..., 1n may be executed in parallel or at different times. The stability calculation unit 105 selects a control target according to the fault phase. Figure 7 shows an example of control target selection.

[0112] As an example, each process in the program shown in Figure 2 is executed according to the following accident scenarios and power transmission route interruption status. [Process 1a] [Accident Details] Transmission Route A (2Φ3LG) + Transmission Route B (3Φ4LG) [Power transmission route disruption status] Power transmission route A: 2 lines down + Power transmission route B: 1 line down (This corresponds to the three-circuit outage faults shown in fault patterns A1 and A2 in Figure 4.) [Process 1b] [Accident Details] Transmission Route A (2Φ3LG) + Transmission Route B (3Φ4LG) [Power transmission route disruption status] Power transmission route A: 2 lines down + Power transmission route B: 2 lines down (This corresponds to the four-circuit outage faults in fault patterns A1 and A2 shown in Figure 4.)

[0113] The above is not limited to the above, and the program may be configured to execute processes 1a to 1n depending on the power transmission route interruption status corresponding to the accident type.

[0114] The following steps S101a to S105a are executed as process 1a. Process 1a derives a control target corresponding to power transmission route A: 2 circuit outages + power transmission route B: 1 circuit outage.

[0115] (Step S101a: Calculate synchronous stability) The stability calculation unit 105 calculates the synchronous stability for the assumed fault. The stability calculation unit 105 performs the synchronous stability calculation for the assumed fault (transmission route A: 2 circuit outages + transmission route B: 1 circuit outage) related to the assumed fault data D104 created by the assumed fault setting unit 104, based on the state determination calculation results for the calculation system model D103 created by the state determination unit 103.

[0116] (Step S102a: Determining whether power system 91 is unstable) The stability calculation unit 105 determines whether the power system 91 is unstable based on the synchronous stability calculated in step S101a. If it determines that the power system 91 is unstable (YES in step S102a), the program proceeds to step S103a. If it does not determine that the power system 91 is unstable (NO in step S102a), the program proceeds to step S105a.

[0117] (Step S103a: Refer to control priority order table D203) If the stability calculation unit 105 determines in step S102a that the power system 91 is unstable, it refers to the control priority order table D203. The control priority order table D203 is a table that defines the priority order of controlled objects for each assumed fault group, including progressing faults. Controlled objects include generators, transmission lines, busbars, transformers, phase adjustment equipment, circuit breakers, disconnectors, etc.

[0118] (Step S104a: Select the control target) The stability calculation unit 105 selects a control target based on the priority order of control targets in the control priority order table D203 referenced in step S103a. The stability calculation unit 105 selects a control target based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control priority order table D203 previously stored in the storage unit 20.

[0119] Subsequently, the program proceeds to step S101a, where the stability calculation unit 105 recalculates the synchronous stability when control is performed by the selected control target for the assumed fault. Based on the synchronous stability calculated in step S101a, the stability calculation unit 105 repeats the operations of steps S101a to S104a until it determines in step S102a that the power system 91 is stable.

[0120] If the stability calculation unit 105 determines in step S102a that the power system 91 is unstable, it selects additional control targets again based on the priority order of control targets in the control priority order table D203. In step S104a, the stability calculation unit 105 creates control target information D105, including the additional control targets selected again. If the program determines in step S102a that the power system 91 is stable, it proceeds to step S105a.

[0121] (Step S105a: Update the controlled object) If the stability calculation unit 105 determines in step S102a that the power system 91 is stable, it updates the control targets in the control target information D105. The stability calculation unit 105 selects G1 and G2 as control targets, including the additional control targets selected in step S104a, as shown in Figure 7. The stability calculation unit 105 creates the control target information D105, including the selected control targets.

[0122] Control target information D105 is information that includes the control target that maintains the stability of the assumed fault in the power system 91 (transmission route A: 2 circuit failures + transmission route B: 1 circuit failure). The control target for the pre-calculation in Figure 7 is the control target information D105. The control target information D105 is transmitted to the control table creation unit 106.

[0123] The following steps S101b to S105b are executed as process 1b. Process 1b derives a control target corresponding to power transmission route A: 2-circuit failure + power transmission route B: 2-circuit failure.

[0124] The same process as in steps S101a to S105a of process 1a is executed as process 1b in steps S101b to S105b.

[0125] (Step S101b: Calculate synchronous stability) The stability calculation unit 105 performs a synchronous stability calculation based on the state determination calculation results for the calculation system model D103 created by the state determination unit 103, for the assumed fault (transmission route A: 2 circuit outages + transmission route B: 2 circuit outages) related to the assumed fault data D104 created by the assumed fault setting unit 104.

[0126] (Step S102b: Determining whether power system 91 is unstable) The stability calculation unit 105 determines whether the power system 91 is unstable based on the synchronous stability calculated in step S101b. If it determines that the power system 91 is unstable (YES in step S102b), the program proceeds to step S103b. If it does not determine that the power system 91 is unstable (NO in step S102b), the program proceeds to step S105b.

[0127] (Step S103b: Refer to control priority order table D203) If the stability calculation unit 105 determines in step S102b that the power system 91 is unstable, it refers to the control priority order table D203.

[0128] (Step S104b: Select the control target) The stability calculation unit 105 selects the control target based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control priority order table D203 referenced in step S103b.

[0129] Subsequently, the program moves to step S101b, where the stability calculation unit 105 recalculates the synchronous stability when control is performed by the selected control target for the assumed fault. The stability calculation unit 105 repeats the operations of steps S101b to S104b until it determines in step S102b that the power system 91 is stable.

[0130] If the stability calculation unit 105 determines in step S102b that the power system 91 is unstable, it selects additional control targets again based on the priority order of control targets in the control priority order table D203. In step S104b, the stability calculation unit 105 creates control target information D105, including the additional control targets selected again. If the program determines in step S102b that the power system 91 is stable, it proceeds to step S105b.

[0131] (Step S105b: Update the controlled object) If the stability calculation unit 105 determines in step S102b that the power system 91 is stable, it updates the control targets in the control target information D105. The stability calculation unit 105 selects G1, G2, and G3 as control targets, including the additional control targets selected in step S104b, as shown in Figure 7. The stability calculation unit 105 creates the control target information D105, including the selected control targets.

[0132] Control target information D105 is information that includes the control target that maintains the stability of the assumed fault in the power system 91 (transmission route A: 2 circuit failures + transmission route B: 2 circuit failures). The control target for the pre-calculation in Figure 7 is the control target information D105. The control target information D105 is transmitted to the control table creation unit 106.

[0133] Depending on the power transmission route interruption status corresponding to the type of accident, the program may be configured to execute processes 1a through 1n.

[0134] Depending on the nature of the accident, similar processing is performed as processing 1n in steps S101n to S105n (not shown). A control target related to processing 1n is selected and included in the control target information D105. The control target information D105 is transmitted to the control table creation unit 106.

[0135] The steps S101a to S105a for process 1a, steps S101b to S105b for process 1b, and steps S101n to S105n for process 1n select the controlled object based on the priority of controlled objects in the control priority order table D203. This selects a common controlled object, thereby preventing over-control.

[0136] The control table creation unit 106 selects a control target for each assumed accident case based on the control target information D105 created by the stability calculation unit 105, and creates a control table D106. The control table creation unit 106 then transmits the created control table D106 to the control information transmission unit 107.

[0137] The control information transmission unit 107 transmits the control table D106 created by the control table creation unit 106 to the central control unit 6 via the communication line.

[0138] The fault information detection unit 501 of the startup terminal device 5 receives system information D501 and fault information D502. System information D501 includes information on the output, load, active power and reactive power of the power transmission lines, and voltage of the generator 92 of the power system 91 to be managed. Fault information D502 is information on a fault that occurred in power equipment such as power transmission lines in the power system 91, and indicates, for example, the power equipment where the fault occurred and the nature of the fault. When a fault occurs in the power system 91, the fault information detection unit 501 detects the fault and determines the fault case. The fault information detection unit 501 transmits the received system information D501 and fault information D502 to the central control device 6.

[0139] The control target determination unit 601 of the central control unit 6 periodically receives system information D501 and accident information D502 from the startup terminal device 5. Based on the system information D501 and accident information D502 received from the startup terminal device 5, the control target determination unit 601 detects an actual accident that has occurred.

[0140] The control target determination unit 601 compares the fault detected based on the fault information D502 with the control table D106 and selects the control targets. As an example, the control target determination unit 601 selects the control targets G1, G2, and G3 related to the "actual fault" in Figure 7. Based on the control table D106 created by the power system stabilization device 1, the control target determination unit 601 creates a control command D601 to shut off the equipment to be controlled, such as generators, transmission lines, busbars, transformers, phase adjustment equipment, circuit breakers, and disconnectors. The control target determination unit 601 transmits the created control command D601 to the control terminal device 7.

[0141] The control unit 701 of the control terminal device 7 receives control command D601 from the central control unit 6. The control unit 701 transmits the control command D601 received from the central control unit 6 to the circuit breaker 93 connected to the controlled object. The control unit 701 selects the circuit breaker 93 connected to the controlled object selected as the object to be tripped and transmits the control command D601.

[0142] The circuit breaker 93 receives the control command D601, interrupts the circuit, and disconnects the controlled electrical equipment from the power system 91. This stabilizes the power system 91.

[0143] The above describes the details of the operation of the power grid stabilization system 100 and the power grid stabilization device 1 according to this embodiment.

[0144] [1-3. Effects] (1) According to this embodiment, the power system stabilization device 1 has a calculation unit 10 that selects a common control target for pre-progression accidents, which are accidents resulting from the failure to repair at least one accident, and post-progression accidents, which are accidents that occur following a pre-progression accident, among a plurality of simultaneous accidents that occurred within a predetermined time period among the assumed accidents shown in the assumed accident information D202. Therefore, even if a plurality of accidents occur at different times following a plurality of accidents that occurred in close proximity in the power system 91, the power system stabilization device 1 can create control information that suppresses over-control and maintains the stability of the power system more appropriately.

[0145] Since a control target common to both pre- and post-accident situations is selected, the selection of individual control targets for each pre- and post-accident situation is suppressed, thereby reducing the likelihood of over-control.

[0146] (2) According to this embodiment, the calculation unit 10 of the power system stabilization device 1 has a stability calculation unit 105 that selects a control target that will stabilize the power system 91 based on a control priority order table D203 that indicates the priority order of control of the control targets, and the stability calculation unit 105 selects a control target that is common to both pre-progression and post-progression faults. As a result, a control target common to both pre-progression and post-progression faults is selected according to the priority order of control of the control targets, so that the selection of an individual control target for each pre-progression and post-progression fault is suppressed, and excessive control is reduced.

[0147] (3) According to this embodiment, the calculation unit 10 of the power system stabilization device 1 selects control targets that are common to both pre-progression faults and post-progression faults. Therefore, control targets for pre-progression faults that are unnecessary when taking measures against post-progression faults are excluded, and excessive control by the power system stabilization system 100 is reduced.

[0148] [2. Second Embodiment] [2-1. Structure and Function] Referring to Figures 8 to 10, the power system stabilization system 100 and power system stabilization device 1 according to the second embodiment will be described. The power system stabilization device 1 according to the second embodiment differs from the power system stabilization device 1 according to the first embodiment in that the calculation unit 10 has a control content replacement unit 111. The power system stabilization device 1 according to the second embodiment does not need to store the control priority order table D203 in the storage unit 20.

[0149] The configuration of the power grid stabilization system 100 and power grid stabilization device 1 according to the other second embodiment is the same as the configuration of the power grid stabilization system 100 and power grid stabilization device 1 according to the first embodiment shown in Figure 1. Components identical to those in the power grid stabilization system 100 and power grid stabilization device 1 according to the first embodiment are denoted by the same reference numerals, and redundant explanations may be omitted.

[0150] The calculation unit 10 of the power system stabilization device 1 selects a control target common to pre-progression accidents, which are accidents resulting from the repair failure of at least one accident among multiple simultaneous accidents that occurred within a predetermined time period, and post-progression accidents, which are accidents that occurred following a pre-progression accident, among the pre-progression accidents indicated in the pre-progression accident information D202. The repair failure of an accident in the power system 91 includes reclosing failures.

[0151] The stability calculation unit 105 of the calculation unit 10 selects a control target that will stabilize the power system 91 based on stability calculations, and the control content replacement unit 111 replaces control targets with a greater control effect among the control targets selected by the stability calculation unit 105 for both pre-progression and post-progression faults. The calculation unit 10 then uses the control content replacement unit 111 to select control targets common to both pre-progression and post-progression faults.

[0152] The control content replacement unit 111 replaces the control target selected by the stability calculation unit 105 with a control target common to each of the progressing faults. The calculation unit 10 of the power system stabilization device 1 uses the control content replacement unit 111 to select at least one control target common to each of the multiple simultaneous faults that occurred within a predetermined time, and to the progressing faults that occurred following the multiple simultaneous faults.

[0153] The control content replacement unit 111 selects the control target with the greatest control effect among the control targets of the pre-progression accident or post-progression accident, and replaces the control targets with a smaller control effect than the selected control target with a larger control effect among the control targets of the pre-progression accident or post-progression accident.

[0154] The control content replacement unit 111 may select a control target with an even greater control effect from among the control targets with the greatest control effect among the control targets of the pre-progression or post-progression accident, and replace the control target with a less effective control effect.

[0155] The power system stabilization system 100, using the control content replacement unit 111 of the calculation unit 10 of the power system stabilization device 1, selects control targets that have a large control effect common to both pre-progression and post-progression faults, creates a control command, and transmits it to the control targets of the power system 91.

[0156] The details of the operation of the power grid stabilization system 100 and the power grid stabilization device 1 according to this embodiment are as follows.

[0157] The information transmission unit 101 of the power system stabilization device 1 periodically receives system information D101 from the power system 91. The system information D101 is information regarding the connection status and power supply and demand status of the power system 91. The information transmission unit 101 transmits the received system information D101 to the system model creation unit 102.

[0158] The system model creation unit 102 creates a system model D102 that shows the current system connection status based on the system information D101 received from the information transmission unit 101 and the system equipment data D201 previously stored in the storage unit 20. The system model creation unit 102 transmits the created system model D102 to the status determination unit 103.

[0159] The state determination unit 103 performs state estimation calculations and power flow calculations based on the system model D102 created by the system model creation unit 102 and the system information D101 received by the information transmission unit 101, selects a system state that is closer to the current state, and creates a system model D103 for calculation. The state determination unit 103 transmits the created system model D103 for calculation to the assumed fault setting unit 104.

[0160] The assumed accident setting unit 104 creates assumed accident data D104 based on the calculation system model D103 created by the state determination unit 103 and assumed accident information D202 previously stored in the storage unit 20. The assumed accident setting unit 104 transmits the created assumed accident data D104 to the stability calculation unit 105.

[0161] The stability calculation unit 105 creates control target information D105 based on the assumed fault data D104 created by the assumed fault setting unit 104. The stability calculation unit 105 performs a stability calculation for the assumed fault related to the assumed fault data D104 based on the calculation system model D103 created by the state determination unit 103. The stability calculation unit 105 performs a stability judgment on the results of the stability calculation, and if it determines that the power system 91 is unstable, it selects additional control targets and performs the stability calculation again. If the stability calculation unit 105 determines that the power system 91 is stable, it creates control target information D105 for the selected control targets to be used as control targets for countermeasures against assumed faults.

[0162] The stability calculation unit 105 may select a control target without relying on the control priority order table D203, or it may select a control target based on the control priority order table D203.

[0163] The control target information D105 is information in which the control target necessary for maintaining the stability of the power system 91 has been selected. The created control target information D105 is transmitted to the control content replacement unit 111.

[0164] The control content replacement unit 111 replaces the control target selected by the stability calculation unit 105 with a control target common to each of the progression accidents.

[0165] The control content replacement unit 111 compares the control targets selected by the stability calculation unit 105 for pre-accident and post-accident situations. The control content replacement unit 111 selects the control target with the greatest control effect among the pre-accident or post-accident control targets and makes it the replacement control target. The control content replacement unit 111 replaces the control targets with a smaller control effect than the replacement control target among the pre-accident or post-accident control targets and updates the control target information D105.

[0166] The control content replacement unit 111 performs a synchronous stability calculation of the power system 91 that has been replaced with the replacement control target. If it determines that the power system 91 is unstable, it changes the control target back to the control target before the replacement and updates the control target information D105.

[0167] The operation of the control content replacement unit 111 is realized by the computer program shown in Figure 9. The computer program shown in Figure 9 is built into the power system stabilizer 1. The program is executed before a fault occurs in the power system 91.

[0168] As an example, each process in the program shown in Figure 9 is executed according to the following accident scenarios and power transmission route interruption status. [Process 2a] [Accident Details] Transmission Route A (2Φ3LG) + Transmission Route B (3Φ4LG) [Power transmission route disruption status] Power transmission route A: 2 lines down + Power transmission route B: 1 line down (This corresponds to the three-circuit outage faults shown in fault patterns A1 and A2 in Figure 4.) [Process 2b] [Accident Details] Transmission Route A (2Φ3LG) + Transmission Route B (3Φ4LG) [Power transmission route disruption status] Power transmission route A: 2 lines down + Power transmission route B: 2 lines down (This corresponds to the four-circuit outage faults in fault patterns A1 and A2 shown in Figure 4.)

[0169] The above is not limited to the above, and the program may be configured to execute processes 2a to 2n depending on the power transmission route interruption status corresponding to the accident type.

[0170] (Step S201: Comparison of controlled objects) The control content replacement unit 111 compares the control targets of the pre-progression or post-progression fault selected by the stability calculation unit 105. The control content replacement unit 111 compares the control targets of the pre-progression and post-progression faults and detects the magnitude of the control effect. Among the control targets of the pre-progression and post-progression faults, the control target with the greatest control effect is called the replacement control target. As an example, in step S201, control targets G2 and G4, which have a large control effect, are designated as replacement control targets.

[0171] (Step S202: Determining whether replacement is necessary) The control content replacement unit 111 determines whether the control targets of the pre-progression and post-progression accidents require replacement. The control content replacement unit 111 compares the control targets of the pre-progression and post-progression accidents and determines that replacement is necessary if there are control targets with a smaller control effect than the replacement control target. If it is determined that replacement is necessary (YES in step S202), the program proceeds to steps S203a and S203b. If it is not determined that replacement is necessary (NO in step S202), the program terminates.

[0172] The following steps S203a to S208a are executed as process 2a. Process 2a derives a control target corresponding to power transmission route A: 2 circuit outages + power transmission route B: 1 circuit outage.

[0173] (Step S203a: Comparison of controlled objects for each accident) The control content replacement unit 111 compares the control targets for each accident. The control content replacement unit 111 compares whether the control effect of the control target corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 1 line out) is less than the control effect of the control target that was replaced in step S201.

[0174] Figure 10 shows an example of the selection of control targets by the power system stabilization device 1 according to this embodiment. As an example, the control content replacement unit 111 compares whether the control effect of control targets G1 and G3 corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 1 line out) is less than the control effect of replacement control targets G2 and G4.

[0175] (Step S204a: Determination of whether replacement is necessary) The control content replacement unit 111 determines whether the controlled object needs to be replaced for each accident. In step S203a, the control content replacement unit 111 compares whether the control effect of the controlled object corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 1 line out) is less than the control effect of the replacement controlled object.

[0176] If the control effect of controlled objects G1 and G3 is less than the control effect of replaced objects G2 and G4, the program determines that replacement is necessary (YES in step S204a) and proceeds to step S205a. If the control effect of controlled objects G1 and G3 is not less than the control effect of replaced objects G2 and G4, the program does not determine that replacement is necessary (NO in step S204a) and terminates.

[0177] (Step S205a: Replace the controlled object) If the control content replacement unit 111 determines in step S204a that a replacement is necessary, it replaces the control target. The control content replacement unit 111 replaces the control target corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 1 line out) with the replacement control target.

[0178] As shown in Figure 10, the control content replacement unit 111 replaces the control targets G1 and G3 of an accident where the power transmission route interruption status is [power transmission route A: 2 lines out + power transmission route B: 1 line out] with the replacement control targets G2 and G4.

[0179] (Step S206a: Calculate synchronous stability) The control content replacement unit 111 calculates the synchronous stability for the assumed fault. The control content replacement unit 111 performs the synchronous stability calculation for the assumed fault (transmission route A: 2 circuit failures + transmission route B: 1 circuit failure) when the control targets are replaced control targets G2 and G4.

[0180] (Step S207a: Determining whether power system 91 is unstable) The control content replacement unit 111 determines whether the power system 91 is unstable based on the synchronous stability calculated in step S206a. If it determines that the power system 91 is unstable (YES in step S207a), the program proceeds to step S208a. If it does not determine that the power system 91 is unstable (NO in step S207a), the program terminates.

[0181] (Step S208a: Return to the control target before replacement) If the control content replacement unit 111 determines in step S207a that the power system 91 is unstable, it returns to the control target before the replacement. If the control content replacement unit 111 determines that the power system 91 is unstable, it returns the control target from the replaced control targets G2 and G4 to the control targets G1 and G3 for the assumed fault (transmission route A: 2 lines out + transmission route B: 1 line out).

[0182] The control content replacement unit 111 creates control target information D105, including the control target replaced in step S205a, or the control target that was restored to its state before replacement in step S208a.

[0183] Control target information D105 is information that includes control targets that maintain the stability of the assumed fault in the power system 91 (transmission route A: 2 circuit failures + transmission route B: 1 circuit failure). The control targets after replacement for the pre-calculation in Figure 10 are considered to be control target information D105. Control target information D105 is transmitted to the control table creation unit 106.

[0184] As process 2b, steps S203b to S208b are executed. Process 2b derives a control target corresponding to power transmission route A: 2-circuit failure + power transmission route B: 2-circuit failure.

[0185] The same process as in steps S203a to S208a of process 2a is executed as process 2b in steps S203b to S208b.

[0186] (Step S203b: Comparison of controlled objects for each accident) The control content replacement unit 111 compares the control targets for each accident. The control content replacement unit 111 compares whether the control effect of the control target corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 2 lines out) is less than the control effect of the control target that was replaced in step S201.

[0187] The control content replacement unit 111 compares whether the control effect of the controlled targets G2 and G4 corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 2 lines out) is less than the control effect of the replaced controlled targets G2 and G4.

[0188] (Step S204b: Determining whether replacement is necessary) The control content replacement unit 111 determines whether the controlled object needs to be replaced for each accident. In step S203b, the control content replacement unit 111 compares whether the control effect of the controlled object corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 2 lines out) is less than the control effect of the replacement controlled object.

[0189] If the control effect of controlled G2 and G4 is less than the control effect of replaced G2 and G4, the program determines that replacement is necessary (YES in step S204b) and proceeds to step S205b. If the control effect of controlled G2 and G4 is not less than the control effect of replaced G2 and G4, the program does not determine that replacement is necessary (NO in step S204b) and terminates.

[0190] In process 2b, the control effect of controlled targets G2 and G4 corresponding to the two circuit failures on power transmission route A and power transmission route B is not less than the control effect of the substituted controlled targets G2 and G4, so the program terminates.

[0191] If the control effect of the controlled object in process 2b is less than the control effect of the substituted controlled object, steps S205b to S208b are executed in the same way as steps S205a to S208a of process 2a.

[0192] The control content replacement unit 111 creates control target information D105 using the pre-replacement control target shown in Figure 10 as the post-replacement control target. The control target information D105 is information that includes control targets that maintain the stability of the assumed fault in the power system 91 (transmission route A: 2 line failures + transmission route B: 2 line failures). The post-replacement control target for the pre-calculation in Figure 10 is the control target information D105. The control target information D105 is transmitted to the control table creation unit 106.

[0193] Depending on the power transmission route interruption status corresponding to the type of accident, the program may be configured to execute processes 2a through 2n.

[0194] Depending on the nature of the accident, a similar process is performed as process 2n in steps S203n to S208n (not shown). A control target for process 2n is selected and included in the control target information D105. The control target information D105 is transmitted to the control table creation unit 106.

[0195] The steps S203a to S208a for process 2a, steps S203b to S208b for process 2b, and steps S203n to S208n for process 2n select the control target based on the substituted control target. This allows for the selection of more common control targets and suppresses over-control.

[0196] The control table creation unit 106 selects a control target for each assumed accident case based on the control target information D105 created by the stability calculation unit 105, and creates a control table D106. The control table creation unit 106 then transmits the created control table D106 to the control information transmission unit 107.

[0197] The control information transmission unit 107 transmits the control table D106 created by the control table creation unit 106 to the central control unit 6 via the communication line.

[0198] The fault information detection unit 501 of the startup terminal device 5 receives system information D501 and fault information D502. System information D501 includes information on the output, load, active power and reactive power of the power transmission lines, and voltage of the generator 92 of the power system 91 to be managed. Fault information D502 is information on a fault that occurred in power equipment such as power transmission lines in the power system 91, and indicates, for example, the power equipment where the fault occurred and the nature of the fault. When a fault occurs in the power system 91, the fault information detection unit 501 detects the fault and determines the fault case. The fault information detection unit 501 transmits the received system information D501 and fault information D502 to the central control device 6.

[0199] The control target determination unit 601 of the central control unit 6 periodically receives system information D501 and accident information D502 from the startup terminal device 5. Based on the system information D501 and accident information D502 received from the startup terminal device 5, the control target determination unit 601 detects an actual accident that has occurred.

[0200] The control target determination unit 601 compares the fault detected based on the fault information D502 with the control table D106 and selects the control targets. As an example, the control target determination unit 601 selects the control targets G2 and G4 related to the "actual fault" in Figure 10. Based on the control table D106 created by the power system stabilization device 1, the control target determination unit 601 creates a control command D601 to shut off the equipment to be controlled, such as generators, transmission lines, busbars, transformers, phase adjustment equipment, circuit breakers, and disconnectors. The control target determination unit 601 transmits the created control command D601 to the control terminal device 7.

[0201] The control unit 701 of the control terminal device 7 receives control command D601 from the central control unit 6. The control unit 701 transmits the control command D601 received from the central control unit 6 to the circuit breaker 93 connected to the controlled object. The control unit 701 selects the circuit breaker 93 connected to the controlled object selected as the object to be tripped and transmits the control command D601.

[0202] The circuit breaker 93 receives the control command D601, interrupts the circuit, and disconnects the controlled electrical equipment from the power system 91. This stabilizes the power system 91.

[0203] The above describes the details of the operation of the power grid stabilization system 100 and the power grid stabilization device 1 according to this embodiment.

[0204] [2-2. Effects] (1) According to this embodiment, the power system stabilization device 1 has a system model D102 that shows the state of the power system 91 that supplies power, and assumed accident information D202 that shows accidents that are expected to occur in the power system 91. The calculation unit 10 has a calculation unit 10 that selects a control target common to a plurality of simultaneous accidents that occurred within a predetermined time among the assumed accidents shown in assumed accident information D202, which are accidents resulting from the failure to repair at least one accident, and an accident that occurred following the pre-accident. The calculation unit 10 selects a control target that will stabilize the power system 91 by performing a stability calculation. The power system stabilization device 1 includes a stability calculation unit 105 and a control content replacement unit 111 that replaces control targets with a smaller control effect with control targets with a larger control effect among the control targets selected by the stability calculation unit 105 for pre-progression and post-progression faults. Since the control content replacement unit 111 selects control targets common to both pre-progression and post-progression faults, even if multiple faults occur in the power system 91 at different times following multiple faults that occurred in close proximity, it is possible to provide a power system stabilization device 1 that creates control information that suppresses excessive control and maintains the stability of the power system more appropriately.

[0205] The control content replacement unit 111 selects control targets by replacing those with a smaller control effect with those with a larger control effect among the control targets for pre-progression and post-progression accidents. Therefore, it is possible to select control targets common to both pre-progression and post-progression accidents without referring to the control priority order table.

[0206] Furthermore, the control content replacement unit 111 selects control targets by replacing those with a smaller control effect with those with a larger control effect among the control targets for pre-progression and post-progression accidents. As a result, a smaller number of control targets are selected, and the selection of individual control targets for each pre-progression and post-progression accident is suppressed, thereby reducing the likelihood of over-control.

[0207] (2) According to this embodiment, the power system stabilization device 1 replaces the control target for simultaneous fault countermeasures of multiple power transmission routes, selected by the stability calculation unit 105, with a control target that has a greater control effect within a predetermined progression fault pattern using the control content replacement unit 111. Therefore, even when a progression fault occurs during an actual fault, the control will not be excessive, and the power system 91 can be stabilized.

[0208] (3) According to this embodiment, the calculation unit 10 of the power system stabilization device 1 selects control targets that are common to both pre-progression faults and post-progression faults. Therefore, control targets for pre-progression faults that are unnecessary when taking measures against post-progression faults are excluded, and excessive control by the power system stabilization system 100 is reduced.

[0209] In the event of an actual fault, if the fault progresses from 3-circuit failure to 4-circuit failure, control of control targets G2 and G4 is first performed when the 3-circuit failure is confirmed. When the 4-circuit failure is confirmed, the control targets remain the same G2 and G4, so no additional control is performed. The final control targets for both the pre-fault and post-fault progression are control targets G2 and G4. This reduces the number of control targets compared to the conventional control targets G1, G3 + G2, G4 for progression faults shown in Figure 5. This reduces the likelihood of over-control.

[0210] [3. Third Embodiment] [3-1. Structure and Function] Referring to Figures 11 to 15, the power system stabilization system 100 and power system stabilization device 1 according to the third embodiment will be described. The power system stabilization device 1 according to the third embodiment differs from the power system stabilization device 1 according to the first embodiment in that the calculation unit 10 has a specific control content replacement unit 112, and the storage unit 20 stores a control combination priority order table D204 instead of a control priority order table D203.

[0211] The configuration of the power grid stabilization system 100 and power grid stabilization device 1 according to the third embodiment is the same as the configuration of the power grid stabilization system 100 and power grid stabilization device 1 according to the first embodiment shown in Figure 1. Components identical to those in the power grid stabilization system 100 and power grid stabilization device 1 according to the first embodiment are denoted by the same reference numerals, and redundant explanations may be omitted.

[0212] The calculation unit 10 of the power system stabilization device 1 selects a control target common to pre-progression accidents, which are accidents resulting from the repair failure of at least one accident among multiple simultaneous accidents that occurred within a predetermined time period, and post-progression accidents, which are accidents that occurred following a pre-progression accident, among the pre-progression accidents indicated in the pre-progression accident information D202. The repair failure of an accident in the power system 91 includes reclosing failures.

[0213] The stability calculation unit 105 of the calculation unit 10 selects a control target that will stabilize the power system 91 based on a stability calculation, using a control combination priority order table D204 that indicates the control priority of control target combinations, in which control targets that are undesirable to interrupt are given a lower priority regardless of the magnitude of the control effect.

[0214] The specific control content replacement unit 112 replaces control targets with low control effects among the control targets selected by the stability calculation unit 105 for pre-progression and post-progression accidents with control targets with higher control effects. By replacing control targets with low control effects with control targets with higher control effects, the specific control content replacement unit 112 selects control targets common to both pre-progression and post-progression accidents.

[0215] The specific control content replacement unit 112 replaces the control target selected by the stability calculation unit 105 based on the priority order shown in the control combination priority order table D204. The replacement is performed when the specific control content replacement unit 112 determines that the control target selected by the stability calculation unit 105 needs to be replaced.

[0216] The power system stabilization system 100, using the stability calculation unit 105 of the calculation unit 10 of the power system stabilization device 1, or the specific control content replacement unit 112, selects control targets with a large control effect common to both pre-progression and post-progression faults, creates a control command, and transmits it to the control targets of the power system 91.

[0217] The details of the operation of the power grid stabilization system 100 and the power grid stabilization device 1 according to this embodiment are as follows.

[0218] The information transmission unit 101 periodically receives system information D101 from the power system 91. The system information D101 is information regarding the connection status and power supply and demand status of the power system 91. The information transmission unit 101 transmits the received system information D101 to the system model creation unit 102.

[0219] The system model creation unit 102 creates a system model D102 that shows the current system connection status based on the system information D101 received from the information transmission unit 101 and the system equipment data D201 previously stored in the storage unit 20. The system model creation unit 102 transmits the created system model D102 to the status determination unit 103.

[0220] The state determination unit 103 performs state estimation calculations and power flow calculations based on the system model D102 created by the system model creation unit 102 and the system information D101 received by the information transmission unit 101, selects a system state that is closer to the current state, and creates a system model D103 for calculation. The state determination unit 103 transmits the created system model D103 for calculation to the assumed fault setting unit 104.

[0221] The assumed accident setting unit 104 creates assumed accident data D104 based on the calculation system model D103 created by the state determination unit 103 and assumed accident information D202 previously stored in the storage unit 20. The assumed accident setting unit 104 transmits the created assumed accident data D104 to the stability calculation unit 105.

[0222] The stability calculation unit 105 creates control target information D105 based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control combination priority order table D204 stored in advance in the storage unit 20. The control combination priority order table D204 is a table in which the priority order of controls to be selected by the stability calculation unit 105 is predetermined for each assumed accident group that takes into account progressing accidents. The control combination priority order table D204 shows the priority order of controls for controls, with controls that are undesirable to block regardless of the magnitude of the control effect being given a lower priority.

[0223] Figure 14 shows an example of the control combination priority order table D204. In the control combination priority order table D204, the control priority of controlled object G1 is 1st, and the control priority of controlled objects G1 and G2 is 2nd.

[0224] In the control combination priority order table D204, even if the control effect is far greater than that of other controlled objects, controlled objects that are not desirable to shut off (hereinafter sometimes referred to as "special controlled objects") are given a lower priority. For example, controlled objects such as high-output generators, inter-regional transmission lines, and transmission routes where system separation occurs are designated as special controlled objects. In Figure 14, controlled object GL is designated as a special controlled object.

[0225] The stability calculation unit 105 selects control targets in the order of priority shown in the control combination priority order table D204. The stability calculation unit 105 performs a stability calculation for the assumed fault related to the assumed fault data D104, based on the calculation system model D103 created by the state determination unit 103. The stability calculation unit 105 performs a stability judgment on the results of the stability calculation, and if it determines that the power system 91 is unstable, it selects additional control targets and performs the stability calculation again. If the stability calculation unit 105 determines that the power system 91 is stable, it creates control target information D105 for the selected control targets to be used as control targets for countermeasures against the assumed fault.

[0226] The control target information D105 is information in which the control targets necessary for maintaining the stability of the power system 91 have been selected. The stability calculation unit 105 transmits the created control target information D105 to the specific control content replacement unit 112.

[0227] The operation of the stability calculation unit 105 is realized by the computer program shown in Figure 12. The computer program shown in Figure 12 is built into the power system stabilizer 1. The program is executed before a fault occurs in the power system 91.

[0228] As an example, each process in the program shown in Figure 12 is executed according to the following fault scenarios and power transmission route interruption status. [Process 3a] [Accident Details] Transmission Route A (2Φ3LG) + Transmission Route B (3Φ4LG) [Power transmission route disruption status] Power transmission route A: 2 lines down + Power transmission route B: 1 line down (This corresponds to the three-circuit outage faults shown in fault patterns A1 and A2 in Figure 4.) [Process 3b] [Accident Details] Transmission Route A (2Φ3LG) + Transmission Route B (3Φ4LG) [Power transmission route disruption status] Power transmission route A: 2 lines down + Power transmission route B: 2 lines down (This corresponds to the four-circuit outage faults in fault patterns A1 and A2 shown in Figure 4.)

[0229] The above is not limited to the above, and the program may be configured to execute processes 3a to 3n depending on the power transmission route interruption status corresponding to the accident type.

[0230] The following steps S301a to S305a are executed as process 3a. Process 3a derives a control target corresponding to power transmission route A: 2 circuit outages + power transmission route B: 1 circuit outage.

[0231] (Step S301a: Calculate synchronous stability) The stability calculation unit 105 calculates the synchronous stability for the assumed fault. The stability calculation unit 105 performs the synchronous stability calculation for the assumed fault (transmission route A: 2 circuit outages + transmission route B: 1 circuit outage) related to the assumed fault data D104 created by the assumed fault setting unit 104, based on the state determination calculation results for the calculation system model D103 created by the state determination unit 103.

[0232] (Step S302a: Determining whether power system 91 is unstable) The stability calculation unit 105 determines whether the power system 91 is unstable based on the synchronous stability calculated in step S301a. If it determines that the power system 91 is unstable (YES in step S302a), the program proceeds to step S303a. If it does not determine that the power system 91 is unstable (NO in step S302a), the program proceeds to step S305a.

[0233] (Step S303a: Refer to Control Combination Priority Order Table D204) If the stability calculation unit 105 determines in step S302a that the power system 91 is unstable, it refers to the control combination priority order table D204. The control combination priority order table D204 is a table that defines the priority order of controlled objects for each assumed fault group, including progressing faults. Controlled objects include generators, transmission lines, busbars, transformers, phase adjustment equipment, circuit breakers, disconnectors, etc.

[0234] In the control combination priority order table D204, even if the control effect is far greater than that of other controlled objects, controlled objects GL that are not desirable to block are designated as special controlled objects and given a lower priority.

[0235] (Step S304a: Select the control target) The stability calculation unit 105 selects a control target based on the priority order of control targets in the control combination priority order table D204 referenced in step S303a. The stability calculation unit 105 selects a control target based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control combination priority order table D204 previously stored in the storage unit 20.

[0236] Subsequently, the program proceeds to step S301a, where the stability calculation unit 105 recalculates the synchronous stability when control is performed by the selected control target for the assumed fault. Based on the synchronous stability calculated in step S301a, the stability calculation unit 105 repeats the operations of steps S301a to S304a until it determines in step S302a that the power system 91 is stable.

[0237] If the stability calculation unit 105 determines in step S302a that the power system 91 is unstable, it selects additional control targets again based on the priority order of control targets in the control combination priority order table D204. In step S304a, the stability calculation unit 105 creates control target information D105, including the additional control targets selected again. If the program determines in step S302a that the power system 91 is stable, it proceeds to step S305a.

[0238] (Step S305a: Update the controlled object) If the stability calculation unit 105 determines in step S302a that the power system 91 is stable, it updates the control targets in the control target information D105. The stability calculation unit 105 selects G1, G2, G3, and G4 as control targets, including the additional control targets selected in step S304a, as shown in Figure 15. The stability calculation unit 105 creates the control target information D105 using the selected control targets G1, G2, G3, and G4 as the control targets before replacement.

[0239] Control target information D105 is information that includes control targets that maintain the stability of the assumed fault in the power system 91 (transmission route A: 2 circuit failures + transmission route B: 1 circuit failure). The control target before replacement for the pre-calculation in Figure 15 is considered to be control target information D105. Control target information D105 is transmitted to the specific control content replacement unit 112.

[0240] As process 3b, steps S301b to S305b are executed. Process 3b derives a control target corresponding to power transmission route A: 2-circuit failure + power transmission route B: 2-circuit failure.

[0241] The same process as steps S301a to S305a of process 3a is executed as process 3b in steps S301b to S305b.

[0242] (Step S301b: Calculate synchronous stability) The stability calculation unit 105 performs a synchronous stability calculation based on the state determination calculation results for the calculation system model D103 created by the state determination unit 103, for the assumed fault (transmission route A: 2 circuit outages + transmission route B: 2 circuit outages) related to the assumed fault data D104 created by the assumed fault setting unit 104.

[0243] (Step S302b: Determining whether power system 91 is unstable) The stability calculation unit 105 determines whether the power system 91 is unstable based on the synchronous stability calculated in step S301b. If it determines that the power system 91 is unstable (YES in step S302b), the program proceeds to step S303b. If it does not determine that the power system 91 is unstable (NO in step S302b), the program proceeds to step S305b.

[0244] (Step S303b: Refer to Control Combination Priority Order Table D204) If the stability calculation unit 105 determines in step S302b that the power system 91 is unstable, it refers to the control priority order table D203.

[0245] (Step S304b: Select the control target) The stability calculation unit 105 selects the control target based on the assumed accident data D104 created by the assumed accident setting unit 104 and the control combination priority order table D204 referenced in step S303b.

[0246] Subsequently, the program proceeds to step S301b, where the stability calculation unit 105 recalculates the synchronous stability when control is performed by the selected control target for the assumed fault. The stability calculation unit 105 repeats the operations of steps S301b to S304b until it determines in step S302b that the power system 91 is stable.

[0247] If the stability calculation unit 105 determines in step S302b that the power system 91 is unstable, it selects additional control targets again based on the priority order of control targets in the control combination priority order table D204. In step S104b, the stability calculation unit 105 creates control target information D105, including the control targets selected again. If the program determines in step S302b that the power system 91 is stable, it proceeds to step S305b.

[0248] (Step S305b: Update the controlled object) If the stability calculation unit 105 determines in step S302b that the power system 91 is stable, it updates the control target in the control target information D105. The stability calculation unit 105 selects GL as the control target, including the control target selected in step S304b, as shown in Figure 15. The stability calculation unit 105 creates the control target information D105 using the previously selected control target GL as the pre-replacement control target.

[0249] Control target information D105 is information that includes a control target that maintains the stability of the assumed fault in the power system 91 (transmission route A: 2 circuit failures + transmission route B: 2 circuit failures). The control target for the pre-calculation in Figure 15 is the control target information D105. The control target information D105 is transmitted to the specific control content replacement unit 112.

[0250] Depending on the power transmission route interruption status corresponding to the type of accident, the program may be configured to execute processes 3a through 3n.

[0251] Depending on the nature of the accident, similar processing is performed as processing 3n in steps S301n to S305n (not shown). A control target for processing 3n is selected and included in the control target information D105. The control target information D105 is transmitted to the specific control content replacement unit 112.

[0252] The steps S301a to S305a for process 3a, steps S301b to S305b for process 3b, and steps S301n to S305n for process 3n select the controlled object based on the priority of controlled objects in the control combination priority order table D204. This selects a common controlled object, thus preventing over-control.

[0253] The specific control content replacement unit 112 replaces the control target selected by the stability calculation unit 105 with a control target common to each of the progressing accidents.

[0254] The specific control content replacement unit 112 compares the control targets of the pre-progress accident and the post-progress accident for the control target selected by the stability calculation unit 105. The specific control content replacement unit 112 selects the control target with the greatest control effect among the control targets of the pre-progress accident or the post-progress accident as the replacement control target. The specific control content replacement unit 112 replaces the control target with a smaller control effect than the replacement control target among the control targets of the pre-progress accident or the post-progress accident with the replacement control target and updates the control target information D105.

[0255] The specific control content replacement unit 112 performs a synchronous stability calculation on the power grid 91 replaced by the replacement control target. If it is determined that the power grid 91 is unstable, the control target is changed back to the control target before replacement, and the control target information D105 is updated.

[0256] The operation of the specific control content replacement unit 112 is realized by the computer program shown in FIG. 13. The computer program shown in FIG. 13 is built into the power grid stabilizer 1. The program is executed before the accident of the power grid 91 occurs.

[0257] As an example, the program shown in FIG. 13 executes process 4a for the power transmission route interruption situation corresponding to the accident aspect related to the above-mentioned process 3a, and executes process 4b for the power transmission route interruption situation corresponding to the accident aspect related to the above-mentioned process 3b.

[0258] Not limited to the above, according to the power transmission route interruption situation corresponding to the accident aspect, the program may be executed from processes 4a to 4n.

[0259] (Step S401: Detection of special control target and replacement control target) The specific control content replacement unit 112 detects the special control target included in the control target of the pre-progress accident or the post-progress accident selected by the stability calculation unit 105. The special control target is a control target that is not preferably interrupted. In FIGS. 14 and 15, the control target GL is the special control target.

[0260] In addition, the specific control content replacement unit 112 detects the replacement control target included in the control target of the pre-progress accident or the post-progress accident selected by the stability calculation unit 105. The specific control content replacement unit 112 compares the control targets of the pre-progress accident and the post-progress accident, and detects the magnitude of the control effect. Among the control targets of the pre-progress accident and the post-progress accident, the control target with the largest control effect shall be called the replacement control target. As an example, the control target GL with a large control effect is used as the replacement control target.

[0261] (Step S402: Judgment of whether replacement is necessary) The specific control content replacement unit 112 determines whether the control targets of the pre-progress accident and the post-progress accident need to be replaced. The specific control content replacement unit 112 determines that replacement is necessary when the special control target is included in the control targets of the pre-progress accident and the post-progress accident. If it is determined that replacement is necessary (YES in step S402), the program proceeds to steps S403a and S403b. If it is determined that replacement is not necessary (NO in step S402), the program ends.

[0262] As processing 4a, the following steps S403a to step S408a are executed. By processing 4a, the control target corresponding to transmission line route A: double line interruption + transmission line route B: single line interruption is derived.

[0263] (Step S403a: Comparison of control targets for each accident) The specific control content replacement unit 112 compares the control targets for each accident. The specific control content replacement unit 112 compares whether the control target corresponding to the transmission line interruption situation (transmission line route A: double line interruption + transmission line route B: single line interruption) is included in the replacement control target.

[0264] FIG. 15 shows an example of selection of a control target by the power system stabilization device 1 according to the present embodiment. As an example, the specific control content replacement unit 112 compares whether the control targets G1, G2, G3, and G4 corresponding to the transmission line interruption situation (transmission line route A: double line interruption + transmission line route B: single line interruption) are included in the replacement control target GL.

[0265] (Step S404a: Determining whether replacement is necessary) The specific control content replacement unit 112 determines whether a control target needs to be replaced for each accident. In step S403a, the specific control content replacement unit 112 compares whether the control target corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 1 line out) is included in the replacement control targets.

[0266] If the controlled elements G1, G2, G3, and G4 are not included in the replacement controlled element GL, the program determines that replacement is necessary (YES in step S404a) and proceeds to step S405a. If the controlled elements G1, G2, G3, and G4 are included in the replacement controlled element GL, the program does not determine that replacement is necessary (NO in step S404a) and terminates.

[0267] (Step S405a: Replace the controlled object) If the specific control content replacement unit 112 determines in step S404a that a replacement is necessary, it replaces the control target. The specific control content replacement unit 112 replaces the control target corresponding to the power transmission route interruption status (power transmission route A: 2 lines out + power transmission route B: 1 line out) with the replacement control target.

[0268] As shown in Figure 15, the specific control content replacement unit 112 replaces the control targets G1, G2, G3, and G4 of the fault where the power transmission route interruption status is [power transmission route A: 2 lines out + power transmission route B: 1 line out] with the replacement control target GL.

[0269] (Step S406a: Calculate synchronous stability) The specific control content replacement unit 112 calculates the synchronous stability for the assumed fault. The specific control content replacement unit 112 performs the synchronous stability calculation for the assumed fault (transmission route A: 2 circuit failures + transmission route B: 1 circuit failure) when the control target is replaced with the control target GL.

[0270] (Step S407a: Determining whether power system 91 is unstable) The specific control content replacement unit 112 determines whether the power system 91 is unstable based on the synchronous stability calculated in step S406a. If it determines that the power system 91 is unstable (YES in step S407a), the program proceeds to step S408a. If it does not determine that the power system 91 is unstable (NO in step S407a), the program terminates.

[0271] (Step S408a: Return to the control target before replacement) If the specific control content replacement unit 112 determines in step S407a that the power system 91 is unstable, it returns the control target to the one before the replacement. If the control content replacement unit 111 determines that the power system 91 is unstable, it returns the control target to the control targets G1, G2, G3, and G4 from the replaced control target GL for the assumed fault (transmission route A: 2 lines out + transmission route B: 1 line out).

[0272] The specific control content replacement unit 112 creates control target information D105, including the control target replaced in step S405a, or the control target that was restored to its pre-replacement state in step S408a.

[0273] Control target information D105 is information that includes control targets that maintain the stability of the assumed fault in the power system 91 (transmission route A: 2 circuit failures + transmission route B: 1 circuit failure). The control targets after replacement for the pre-calculation in Figure 15 are considered to be control target information D105. Control target information D105 is transmitted to the control table creation unit 106.

[0274] As process 4b, steps S403b to S408b are executed. Process 4b derives a control target corresponding to power transmission route A: 2-circuit failure + power transmission route B: 2-circuit failure.

[0275] The same process as in steps S403a to S408a of process 4a is executed as process 4b in steps S403b to S408b.

[0276] (Step S403b: Comparison of controlled objects for each accident) The specific control content replacement unit 112 compares the control targets for each accident. The specific control content replacement unit 112 compares whether the control target corresponding to the power transmission route interruption status (Power transmission route A: two lines interrupted + Power transmission route B: two lines interrupted) is included in the replacement control target.

[0277] The specific control content replacement unit 112 compares whether the control target GL corresponding to the power transmission route interruption status (Power transmission route A: two lines interrupted + Power transmission route B: two lines interrupted) is included in the replacement control target GL.

[0278] (Step S404b: Judgment on whether replacement is required) The specific control content replacement unit 112 determines whether the control target needs to be replaced for each accident. The specific control content replacement unit 112 compares whether the control target corresponding to the power transmission route interruption status (Power transmission route A: two lines interrupted + Power transmission route B: two lines interrupted) in step S403b is included in the replacement control target.

[0279] If the control target is not included in the replacement control target, it is determined that replacement is required (YES in step S404b), and the program proceeds to step S405b. If the control target is included in the replacement control target, it is not determined that replacement is required (NO in step S404b), and the program ends.

[0280] In process 4b, the control target GL corresponding to Power transmission route A: two lines interrupted + Power transmission route B: two lines interrupted is included in the replacement control target GL, so the program ends.

[0281] If the control target in process 4b is not included in the replacement control target, steps S405b to S408b are executed in the same manner as steps S405a to S408a in process 4a.

[0282] The specific control content replacement unit 112 creates control target information D105 using the pre-replacement control target shown in Figure 15 as the post-replacement control target. The control target information D105 is information that includes control targets that maintain the stability of the assumed fault in the power system 91 (transmission route A: 2 line outages + transmission route B: 2 line outages). The post-replacement control target for the pre-calculation in Figure 15 is the control target information D105. The control target information D105 is transmitted to the control table creation unit 106.

[0283] Depending on the power transmission route interruption status corresponding to the type of accident, the program may be configured to execute processes 4a to 4n.

[0284] Depending on the nature of the accident, similar processing is performed as process 4n in steps S403n to S408n (not shown). A control target for process 4n is selected and included in the control target information D105. The control target information D105 is transmitted to the control table creation unit 106.

[0285] The steps S403a to S408a related to process 4a, steps S403b to S408b related to process 4b, and steps S403n to S408n related to process 4n select the control target based on the replacement control target. This allows for the selection of more common control targets and suppresses over-control.

[0286] In the above, the controlled GL is given a lower priority in the control combination priority order table D204 because it is undesirable to shut it off. For this reason, in process 4a, controlled objects G1, G2, G3, and G4 were selected as the controlled objects to be replaced. However, in process 4b, selecting controlled objects G1, G2, G3, and G4 as the controlled objects to be replaced would not stabilize the power system 91, so the controlled object GL, which has the next priority in the control combination priority order table D204, was selected. As a result, controlled objects G1, G2, G3, and G4, which were the controlled objects to be replaced in process 4a, are replaced by controlled object GL, which has a greater control effect.

[0287] The control table creation unit 106 selects a control target for each assumed accident case based on the control target information D105 updated by the specific control content replacement unit 112, and creates a control table D106. The control table creation unit 106 then transmits the created control table D106 to the control information transmission unit 107.

[0288] The control information transmission unit 107 transmits the control table D106 created by the control table creation unit 106 to the central control unit 6 via the communication line.

[0289] The startup terminal device 5 transmits the system information D501 and fault information D502 received from the power system 91 to the central control unit 6. Based on the system information D501 and fault information D502 received from the startup terminal device 5, the central control unit 6 detects a fault, selects a control target, creates a control command D601, and transmits it to the control terminal device 7.

[0290] The control terminal device 7 transmits the control command D601 received from the central control unit 6 to the controlled equipment. The circuit breaker 93 receives the control command D601 and disconnects the controlled electrical equipment from the power system 91. This stabilizes the power system 91.

[0291] The above describes the details of the operation of the power grid stabilization system 100 and the power grid stabilization device 1 according to this embodiment.

[0292] [3-2. Effects] (1) According to this embodiment, the power system stabilization device 1 has a system model D102 that shows the state of the power system 91 that supplies power, and assumed accident information D202 that shows accidents that are expected to occur in the power system 91, and a calculation unit 10 that selects a control target common to a pre-progression accident, which is an accident resulting from the failure to repair at least one accident, and a post-progression accident, which is an accident that occurred following a pre-progression accident, among a plurality of simultaneous accidents that occurred within a predetermined time among the assumed accidents shown in assumed accident information D202, and the calculation unit 10 has a control combination priority order table that shows the priority of control of control targets, in which control targets that are not desirable to shut off are given a lower priority regardless of the magnitude of the control effect Based on Rule D204, the power system stabilization device 1 includes a stability calculation unit 105 that selects control targets that stabilize the power system 91 through stability calculations, and a specific control content replacement unit 112 that replaces control targets with a smaller control effect among the control targets for pre-progression and post-progression faults selected by the stability calculation unit 105 with control targets with a larger control effect. Since the specific control content replacement unit 112 selects control targets common to both pre-progression and post-progression faults, even if multiple faults occur in the power system 91 at different times following multiple faults that occurred in close proximity, the power system stabilization device 1 can create control information that suppresses excessive control and maintains the stability of the power system more appropriately.

[0293] The stability calculation unit 105 selects the control target that will stabilize the power system 91 based on the control combination priority order table D204, so that the control targets can be selected in the desired priority order regardless of the magnitude of the control effect.

[0294] The specific control content replacement unit 112 selects control targets by replacing those with a low control effect with those with a higher control effect among the control targets for pre-progression and post-progression accidents. Therefore, if the control by the control target selected by the stability calculation unit 105 is insufficient, the control target can be modified and updated. This makes it possible to select a control target common to both pre-progression and post-progression accidents.

[0295] Furthermore, the specific control content replacement unit 112 selects control targets by replacing those with a smaller control effect with those with a larger control effect among the control targets for pre-progression and post-progression accidents. As a result, a smaller number of control targets are selected, and the selection of individual control targets for each pre-progression and post-progression accident is suppressed, thereby reducing the likelihood of over-control.

[0296] (2) According to this embodiment, the power system stabilization system 100 replaces the control targets for simultaneous fault countermeasures of multiple transmission routes, which have been selected by the stability calculation unit 105 of the power system stabilization device 1, with control targets that have a greater control effect within a predetermined progression fault pattern using the specific control content replacement unit 112. Therefore, even when a progression fault occurs during an actual fault, the control will not be excessive, and the power system 91 can be stabilized.

[0297] (3) According to this embodiment, the calculation unit 10 of the power system stabilization device 1 selects control targets that are common to both pre-progression faults and post-progression faults. Therefore, control targets for pre-progression faults that are unnecessary when taking measures against post-progression faults are excluded, and excessive control by the power system stabilization system 100 is reduced.

[0298] In the event of an actual fault, if the fault progresses from 3-circuit failure to 4-circuit failure, control of the controlled GL is first performed when the 3-circuit failure is confirmed. When the 4-circuit failure is confirmed, the controlled object remains the same controlled GL, so no additional control is performed. The final controlled object for both the pre-fault and post-fault progression is the controlled GL. This reduces the number of controlled objects compared to the conventional controlled objects G1, G3+G2, and G4 for progression faults shown in Figure 5. This reduces the likelihood of over-control.

[0299] [4. Other Embodiments] While embodiments, including variations, have been described, these embodiments are presented as examples only 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 variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. The following is an example.

[0300] (1) In the above embodiment, the calculation unit 10 of the power system stabilization device 1 selects a common control target for progression faults in two transmission routes, transmission route A and transmission route B. However, the calculation unit 10 is not limited to progression faults in two transmission routes, but may also select a common control target for progression faults in three or more transmission routes.

[0301] (2) In the above embodiment, the calculation unit 10 of the power system stabilization device 1 selects common control targets for multiple progressing faults in transmission route A and transmission route B such that the control target for one progressing fault encompasses the control target for the other progressing fault. In the above embodiment, for example, control targets G1 and G2 are selected as control targets for pre-progression faults, and control targets G1, G2, and G3 are selected as control targets for post-progression faults so that the control targets for post-progression faults are selected to encompass the control targets for pre-progression faults.

[0302] However, the calculation unit 10 of the power system stabilization device 1 may select control targets for multiple progressing faults in transmission route A and transmission route B in such a way that the control targets for one progressing fault do not include the control targets for the other progressing fault, and that some control targets are common to both. For example, control targets G1 and G4 may be selected as control targets for pre-progression faults, control targets G1, G2, and G3 may be selected as control targets for post-progression faults, and control target G1 may be selected as a control target common to both pre-progression and post-progression faults.

[0303] (3) In the above embodiment, the information transmission unit 101 of the calculation unit 10 receives system information D101 from the power system 91. However, the information transmission unit 101 of the calculation unit 10 may also receive system information D101 from the power system 91 via the power supply information network 80.

[0304] For example, the power system stabilization device 1 according to the first embodiment may receive system information D101 from the power system 91 via the power supply information network 80 using the information transmission unit 101 of the calculation unit 10, as shown in Figure 16. The power supply information network 80 is a communication network that enables communication between the power system 91 and the power system stabilization device 1. The power supply information network 80 communicates by wire or wireless. The power supply information network 80 includes communication circuits, communication devices, information management devices, etc., and may be composed of a dedicated communication line using, for example, microwave radio or optical fiber.

[0305] Similarly, the power system stabilization device 1 according to the second and third embodiments may also be configured to receive system information D101 from the power system 91 via the power supply information network 80 through the information transmission unit 101 of the calculation unit 10. [Explanation of Symbols]

[0306] 1...Power system stabilization device 10... Arithmetic section 101... Information Transmission Department 102...System Model Creation Department 103...State determination unit 104... Accident Simulation Section 105...Stability calculation section 106...Control Table Creation Section 107...Control Information Transmission Unit 111...Control Content Replacement Section 112...Specific control content replacement section 20...Storage section 100... Power grid stabilization system 5. Startup terminal device 501... Accident Information Detection Unit 6. Central Control System 601...Control target determination unit 7. Control terminal device 701... Control Unit 80... Power supply information network 91...Power system 92... Generator 93... Circuit breaker

Claims

1. Based on a system model that shows the state of the power system supplying electricity, and assumed accident information that shows accidents that are expected to occur in the power system, The system has a calculation unit that selects a common control target for a pre-progression accident, which is an accident resulting from the repair failure of at least one of the multiple simultaneous accidents that occurred within a predetermined time period among the assumed accidents shown in the assumed accident information, and for a post-progression accident, which is an accident that occurred following the pre-progression accident. Power system stabilizer.

2. The aforementioned arithmetic unit, The stability calculation unit selects a control target that stabilizes the power system based on a control priority order table indicating the priority of control of the control target, through stability calculation. The stability calculation unit selects the control target that is common to both the pre-progression accident and the post-progression accident. The power grid stabilization device according to claim 1.

3. The aforementioned arithmetic unit, The stability calculation unit selects the control target such that the power system becomes stable through stability calculation, The control content replacement unit replaces, among the control targets selected by the stability calculation unit, control targets with a small control effect for the pre-progression fault and the post-progression fault with control targets with a larger control effect. The control content replacement unit selects the control target that is common to both the pre-progression accident and the post-progression accident. The power grid stabilization device according to claim 1.

4. The aforementioned arithmetic unit, Regardless of the magnitude of the control effect, a stability calculation unit selects a control target that stabilizes the power system based on a control combination priority order table indicating the control priority of the control targets, in which control targets that are undesirable to shut off are given a lower priority, through stability calculation. The control content replacement unit replaces, among the control targets selected by the stability calculation unit, control targets with a small control effect for the pre-progression accident and the post-progression accident with control targets with a larger control effect. The specific control content replacement unit selects the control target that is common to both the pre-progression accident and the post-progression accident. The power grid stabilization device according to claim 1.

5. Based on a system model that shows the state of the power system supplying electricity, and assumed accident information that shows accidents that are expected to occur in the power system, A power system stabilizer having a calculation unit that selects a common control target and creates a control table for pre-progression accidents, which are accidents resulting from the repair failure of at least one of the multiple simultaneous accidents that occurred within a predetermined time period among the assumed accidents shown in the assumed accident information, and for post-progression accidents, which are accidents that occurred following the pre-progression accident, among the assumed accidents shown in the assumed accident information, A startup terminal device that receives system information indicating the status of the power system and accident information indicating an accident in the power system from the power system, and identifies the type of accident in the power system, A central control unit selects the control target and creates a control command based on the fault pattern identified by the activation terminal device and the control table created by the power system stabilization device, A control terminal device that transmits the control command created by the central control unit to the control target of the power system, Power grid stabilization system.

6. On the computer, Based on a system model that shows the state of the power system supplying electricity, and assumed accident information that shows accidents that are expected to occur in the power system, Among the assumed accidents shown in the assumed accident information, the calculation step is performed to select a common control target for the pre-progression accident, which is an accident resulting from the repair failure of at least one of the simultaneous accidents that occurred within a predetermined time, and the post-progression accident, which is an accident that occurred following the pre-progression accident. Computer program for power grid stabilization devices.

7. Based on a system model that shows the state of the power system supplying electricity, and assumed accident information that shows accidents that are expected to occur in the power system, The calculation procedure includes selecting a common control target for a pre-progression accident, which is an accident resulting from the repair failure of at least one of the multiple simultaneous accidents that occurred within a predetermined time period among the assumed accidents shown in the assumed accident information, and a post-progression accident, which is an accident that occurred following the pre-progression accident. Power system stabilization method.

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