Power system operation planning device, power system operation planning system, and power system operation planning method

Abstract

A power system operation planning device (200) is characterized by being provided with a plan creation unit (15) that creates a system operation plan on the basis of any of a system disturbance scenario, system operation information, system facility information, and a contribution of a generator to system inertia, the system operation plan including a start / stop state of the generator, a power generation output of the generator, and a control command for an inverter power supply.

Description

Power system operation planning device, power system operation planning system, and power system operation planning method

[0001] The present invention relates to a power system operation planning device, a power system operation planning system, and a power system operation planning method.

[0002] An electric power system is composed of many generators, loads, power transmission and distribution equipment, and control devices. To operate the power system stably and at low cost, it is necessary to formulate a power system operation plan to maintain a balance between the power supply and the ever-changing power demand. In order to achieve highly efficient system operation while introducing large amounts of renewable energy sources, whose output fluctuates greatly depending on the weather, countries are moving toward a market-driven power system operation.

[0003] Necessary functions for realizing such power system operation include the Security Constrained Unit Commitment (SCUC) and Security Constrained Economic Dispatch (SCED) functions in next-generation central load dispatching centers, which make it possible to formulate power generation commitment plans and output allocations that satisfy wide-area merit orders and various operational constraints. The optimization problem for determining power generation plans in the above-mentioned SCUC / SCED functions sets the objective function as minimizing operating costs, and the operational constraints to be observed are power generation unit constraints (output upper and lower limits, output ramp rate, minimum commitment times, etc.) and system constraints (power flow constraints, etc.).

[0004] Recently, the increasing introduction of renewable energy sources, including solar and wind power, into the power grid has led to a corresponding decrease in the number of synchronous generators, including thermal power generators, which has resulted in a decrease in system inertia. This decrease in system inertia has led to an increase in the rate of change of frequency (RoCoF) and a decrease in the frequency drop (Frequency Nadir) in response to system disturbances, which could result in a chain reaction of power source trips due to the activation of RoCoF relays and under-frequency relays (UFR), leading to simultaneous parallel-off of generators and blackouts.

[0005] To address this issue, a promising solution is to provide grid inertia from the inverter power supply by adding a control function simulating a synchronous machine to inverter equipment installed alongside renewable energy sources, thereby stabilizing grid operation.In particular, the provision of multiple control modes, such as virtual synchronous generator control (VSG), droop control, and virtual oscillator control (VOC), is being considered for inverter power supplies called grid-forming inverters, which contribute to grid stabilization by operating as voltage sources.

[0006] In light of the above, methods for controlling inverter power supplies for various system states have been devised. For example, Patent Document 1 states that "the system includes an identification unit that, based on power flow information, identifies the power system as a supply area, which is the outflow side of the power flow, from a point where a disturbance occurs, and a consumption area, which is the inflow side of the power flow, and a control unit that performs control so as to effectively increase the overall capacity of grid-forming inverter power supplies in the supply area when the disturbance occurs."

[0007] Furthermore, Patent Document 2 describes a voltage-type inverter control device that controls a power converter that converts DC power to AC power in accordance with a desired AC voltage signal, the voltage-type inverter control device comprising: a current reference creation unit that creates a current reference used when generating a control signal for controlling the power converter, the current reference being a value based on a current value flowing in an electric power system to which AC power converted by the power converter is supplied; a fault detection unit that detects the occurrence of a system fault, such as at least one of a short circuit and a ground fault, in the electric power system to which AC power converted by the power converter is supplied; a recovery detection unit that detects recovery from the system fault; and a current reference switching unit that, when the occurrence of the system fault is detected, switches the current reference to a current value supplied to the electric power system a predetermined period before the occurrence of the system fault, and, when recovery from the system fault is detected, switches the current reference to the current value flowing in the electric power system.

[0008] JP 2024-019980 A JP 2023-093949 A

[0009] In recent years, renewable energy sources such as solar and wind power have been introduced into the power grid in large quantities. These renewable energy sources are subject to sudden and difficult-to-predict fluctuations in power output, which can result in significant changes in the power supply and demand situation. The situation can also be significantly affected by fluctuations in power demand due to unexpected weather conditions that deviate from weather forecasts, or by overlapping periods of work stoppages on generators and power grid equipment. Furthermore, the electrical characteristics of the power grid can change in response to system disturbance events such as generator trips, system faults including transmission line ground faults and short-circuit faults, and system isolation.

[0010] The amount of system inertia required for each system area and the system inertia that can be provided by the grid-forming inverter power supply vary depending on the various system operation conditions described above. Therefore, it is necessary to formulate a power system operation plan that takes into account various system operation conditions, adds the system inertia supply amount according to the control mode and control parameters of the grid-forming inverter power supply, and further reduces operation costs to the extent that stable operation of the power system is possible.

[0011] The technologies described in Patent Documents 1 and 2 are capable of switching the control mode or control parameters of the grid-forming inverter power supply depending on the location or timing of the grid disturbance, but do not take into account the required system inertia, which changes depending on the system operation status, including the power flow state, at the time of the grid disturbance.As a result, there is a possibility that a shortage of the system inertia supply will occur, and a power outage will occur due to a chain reaction of power source trips.Furthermore, the technologies described in Patent Documents 1 and 2 do not take into account compliance with system operation constraints, such as ensuring system inertia by changing the start / stop state of power generation, including thermal power generators, and power generation output, or maintaining the supply-demand balance, which may result in increased operating costs.

[0012] Therefore, an object of the present invention is to formulate an operation plan that achieves reduction in operation costs through wide-area merit orders while ensuring the inertia of the power system.

[0013] In order to solve the above-mentioned problems, the power system operation planning device of the present invention is characterized by comprising a plan formulation unit that formulates a system operation plan including a start / stop state of the generator, the power generation output of the generator, and a control command to an inverter power source based on any of a system disturbance scenario, system operation information, system equipment information, and a contribution of the generator to system inertia.

[0014] The power system operation planning system of the present invention is characterized by comprising a plan formulation unit that formulates a system operation plan including a start / stop state of the generator, the power generation output of the generator, and a control command to an inverter power source based on any of a system disturbance scenario, system operation information, system equipment information, and a contribution of the generator to system inertia.

[0015] The power system operation planning method of the present invention is characterized by comprising the steps of: an inertia contribution evaluation unit calculating a system inertia contribution of the inverter power supply for each system disturbance scenario, each system state, each control mode of the inverter power supply, and each parameter of the inverter power supply based on system disturbance scenarios, system equipment information, system operation information, and equipment data including a control mode and parameters of the inverter power supply; a plan formulation unit formulating a system operation plan including a start / stop state of the generator, a power generation output of the generator, and a control command for the inverter power supply based on any of the system disturbance scenarios, the system operation information, the system equipment information, and the contribution of the generator to the system inertia; and a plan evaluation unit calculating an operation cost and a system inertia evaluation index based on the system operation plan. Other means will be described in the description of the embodiment of the invention.

[0016] According to the present invention, it is possible to formulate an operation plan that achieves reduction in operation costs through a wide-area merit order while ensuring the inertia of the power system.

[0017] 1 shows an example of the functional configuration of a power system operation planning device of this embodiment; 2 shows an example of the hardware configuration of a power system operation planning device of this embodiment; 3 shows an example of the configuration of a power system operation planning system of this embodiment; 4 shows an example of the overall processing of a plan formulation process; 5 shows an example of the data configuration of plan disturbance information; 6 shows an example of the data configuration of system operation information; 7 shows an example of the data configuration of system equipment information; 8 shows an example of the data configuration of system inertia contribution information; 9 shows an example of the data configuration of system operation plan information; 10 shows an example of the data configuration of system operation plan evaluation information.

[0018] Hereinafter, embodiments of the present invention will be described. Note that the following is merely an example of implementation, and the invention itself is not intended to be limited to the specific contents below. The embodiments of the present invention will be described below with reference to the drawings.

[0019] FIG. 1 shows the functional configuration of a power system operation planning device 200 according to this embodiment. The power system operation planning device 200 according to this embodiment includes a power system operation plan determination unit 10, an information storage unit 30, a display unit 17, and a control command unit 18. The power system operation plan determination unit 10 may be connected to system measurement devices 21a to 21d shown in FIG. 2. The system measurement device 21a measures measurement information at a point 210a. The system measurement device 21b measures measurement information at a point 210b. The system measurement device 21c measures measurement information at a point 210c. The system measurement device 21d measures measurement information at a point 210d. The information storage unit 30 stores a system disturbance scenario database 31, a system operation information database 32, a system equipment information database 33, and a past plan information database 34.

[0020] The power system operation plan determination unit 10 includes a system disturbance scenario acquisition unit 11 , a system operation information acquisition unit 12 , a system equipment information acquisition unit 13 , an inertia contribution evaluation unit 14 , a plan formulation unit 15 , and a plan evaluation unit 16 .

[0021] The system disturbance scenario acquisition unit 11 acquires system disturbance scenario information from a system disturbance scenario database 31. The system operation information acquisition unit 12 acquires system operation information from a system operation information database 32. The system equipment information acquisition unit 13 acquires system equipment information from a system equipment information database 33.

[0022] The inertia contribution evaluation unit 14 calculates the amount of system inertia supplied by each piece of system equipment as an evaluation value, based on the system disturbance scenario acquired by the system disturbance scenario acquisition unit 11, the system operation information acquired by the system operation information acquisition unit 12, and the system equipment information acquired by the system equipment information acquisition unit 13. The inertia contribution evaluation unit calculates the contribution of the inverter power supply to the system inertia for each system disturbance scenario, system state, inverter power supply control mode, and inverter power supply parameter, based on the system disturbance scenario, the system equipment information, and equipment data including the system state indicated by the system operation information, and the control mode and parameters of the inverter power supply.

[0023] The planner 15 formulates a power system operation plan based on facility operation constraint information included in any of the system disturbance scenario, system operation information, and system equipment information, and on the contribution of generators to system inertia. The power system operation plan includes generator activation / shutdown states, generator power output, and control commands to inverter power sources. Here, known mathematical programming methods called security constrained unit commitment (SCUC) and security constrained economic dispatch (SCED) functions may be applied as the planning method, minimizing operation costs as the objective function, and generating unit constraints or system constraints may be set as operation constraints to be observed. The generating unit constraints include upper and lower output limits, output ramp rate, and minimum activation / shutdown time, while the system constraints include upper and lower power flow limits and system inertia constraints. The planner 15 formulates a generator activation / shutdown plan based on the results of the system inertia contribution evaluation.

[0024] Furthermore, the applied objective functions and operational constraints are not limited to those described above, and various objective functions and / or operational constraints that are applied in the current power system operation may be set. In this case, the calculated power system operation plan includes the start / stop states of the generators, the power generation output of the generators, and the control modes and control parameters of the generators. The control command unit 18 calculates control commands for system devices such as thermal power plants, substations, and inverter power supplies based on the power system operation plan information and output allocation calculated by the plan formulation unit 15.

[0025] The plan evaluation unit 16 calculates a power system operation plan evaluation value including an operation cost and a system stability index for the power system operation plan calculated by the plan formulation unit 15. The plan evaluation unit 16 evaluates whether stability constraints are satisfied for the activation / shutdown plan, the output allocation plan, and the control mode command plan.

[0026] The display unit 17 displays any of the system disturbance scenario, the system operation information, the system equipment information, the power system operation plan calculated by the plan formulation unit 15, and the power system operation plan evaluation result calculated by the plan evaluation unit 16. The display unit 17 displays any of the power system operation plan and the power system operation plan evaluation result on the display device 202.

[0027] The object of the present invention is to formulate an operation plan that achieves reductions in operation costs through a wide-area merit order while ensuring system inertia by formulating a power system operation plan that includes generator start / stop, output allocation, and inverter power supply control modes and control parameters, taking into account operation constraints that reflect the system operation state and the system inertia supply capacity.

[0028] Fig. 2 shows a hardware configuration of a power system operation planning device 200 in this embodiment. As shown in Fig. 2, the power system operation planning device 200 in this embodiment includes a generator 101, a substation 102, a phase modifying device 103, a power load 104, an external power system 105, system measurement devices 21a, 21b, 21c, and 21d, an information and communication network 108, and the power system operation planning device 200. Hereinafter, the power system including the generator 101, the substation 102, the phase modifying device 103, the power load 104, and the system measurement devices 21a to 21d may be referred to as the local system.

[0029] The generator 101 generates power by any of a variety of power generation methods, including thermal power generation, hydroelectric power generation, nuclear power generation, solar power generation, wind power generation, biomass power generation, and tidal power generation. The generator 101a is a large-scale generator, such as a thermal power generation, hydroelectric power generation, or nuclear power generation, installed on the high-voltage side of a substation 102 in the power system, and transmits system state quantities, including the amount of power generated, to the power system operation planning device 200 via a system measurement device 21a and an information and communication network 108. The generator 101a also receives control command information transmitted from the power system operation planning device 200 via the system measurement device 21a and the information and communication network 108, and changes the system state quantities, including the amount of power generated, in accordance with the control command information. The generator 101b is a small- to medium-scale generator, such as a solar power generation, wind power generation, or cogeneration, installed on the low-voltage side of the substation 102 in the power system, and transmits system state quantities, including the amount of power generated, to the power system operation planning device 200 via the system measurement device 21b and the information and communication network 108.

[0030] The substation 102 is installed between transmission lines in the power system, changes the voltage value of the power transmitted from the high-voltage side where a large-scale generator 101a is installed, and transmits the power to the low-voltage side where a power load 104 is installed. The substation 102 is connected to a phase modifying device 103 such as a power capacitor and a shunt reactor.

[0031] The phase modifying devices 103 are devices that control the voltage distribution in the power system by changing the reactive power in the power system, and are configured to include a power capacitor, a shunt reactor, a static synchronous compensator (STATCOM), a static var compensator (SVC), etc. Some of the phase modifying devices 103 receive control command information transmitted from the power system operation planning device 200 via the system measurement device 21c and the information and communication network 108, and change system state quantities including the amount of power generation according to the control command information.

[0032] The power load 104 is a facility including an electric motor, lighting equipment, etc. that consumes power, and represents a facility such as a home, a factory, a building, etc. The external power system 105 is an external power system that cannot be controlled by the power system operation planning device 200, and is connected to the power system itself by an interconnection line.

[0033] The system measurement device 21a includes a sensor that measures the amount of power generated by the generator 101a. The system measurement device 21c includes sensors that measure system state quantities such as the amount of phase modification in the phase modifying device 103, and the power flow value and voltage value in the transmission line. The system state quantities measured by these system measurement devices 21a to 21d are transmitted to the power system operation planning device 200 via the information and communication network 108.

[0034] The information and communication network 108 is a network capable of transmitting data bidirectionally. The information and communication network 108 is, for example, a wired network, a wireless network, or a combination thereof. The information and communication network 108 may be the so-called Internet or a dedicated line network.

[0035] The power system operation planning device 200 in Figure 2 shows various hardware components for realizing the power system operation planning device 200 shown in Figure 1. The power system operation planning device 200 receives system state quantities measured by system measurement devices 21a, 21b, 21c, and 21d via the information and communication network 108. The power system operation planning device 200 also transmits control command information calculated using the transmitted system state quantities and information stored internally to the system measurement devices 21a to 21d via the information and communication network 108.

[0036] The power system operation planning device 200 includes an internal configuration including a CPU (Central Processing Unit) 201, a display device 202, a communication unit 203, an input unit 204, a memory 205, and a storage device 206, all connected via a bus line 211. The CPU 201 executes a calculation program stored in the storage device 206 to calculate the system state, generate control signals, generate image data, and display the image data on the display device 202. The memory 205 is a memory, such as a random access memory (RAM), that temporarily stores image data for display, calculation result data of the system state, and the like. The communication unit 203 acquires system state quantities, such as power flow values ​​and voltage values, from the system measurement devices 21a to 21d via the information and communication network 108. The system disturbance scenario acquisition unit 11 receives time-series measurement information measured by the multiple system measurement devices 21a to 21d using the communication unit 203.

[0037] A user (administrator) of the power system operation planning apparatus 200 can set or change parameters such as various thresholds through a predetermined interface of the input unit 204, and appropriately set the operation of the power system operation planning apparatus 200 for its own system. In addition, the user can select the type of data that he or she wants to check through the predetermined interface of the input unit 204, and display it on the display device 202.

[0038] The storage device 206 stores various programs and data. The storage device 206 is, for example, a hard disk drive (HDD) or a flash memory. The storage device 206 stores, for example, programs and data that can realize various functions described below. The programs and data stored in the storage device 206 are read and executed by the CPU 201 as needed. The storage device 206 also realizes the information storage unit 30 and stores various databases.

[0039] The system measurement device 21 measures measurement information at measurement points in the system and transmits it to the system disturbance scenario acquisition unit 11. The measurement information includes at least one type of information among active power flow, reactive power flow, system voltage, system current, and voltage phase. The system measurement device 21 includes system measurement devices 21a, 21b, 21c, and 21d that are respectively placed at a plurality of measurement points. The system measurement devices 21a, 21b, 21c, and 21d are, for example, PMUs, and perform periodic measurements related to power and transmit time-series measurement information.

[0040] The information storage unit 30 includes a system disturbance scenario database 31 that stores system disturbance scenarios to be considered in power system operation planning, system operation information that stores the operation status of the power system, and a system equipment information database 33 that stores equipment characteristic information of the system equipment that makes up the power system. The system disturbance scenario database 31 stores system disturbance scenarios that include various data items such as the type of system disturbance, the target equipment that causes the system disturbance, and a time sequence that includes the occurrence times of various events related to the system disturbance phenomenon.

[0041] The system operation information database 32 stores system operation information including various data items such as the start / stop status and power generation output of various power generators, total power demand, active and reactive power flows and system voltages in various system facilities. The system facility information database 33 stores constraint information including various data items such as target facilities subject to various constraint items, facility capacities of the target facilities, upper and lower output limits that define the upper and lower limits of the operational power generation output of various facilities, output change rates that define the maximum power generation output change per unit time of the operational output of various facilities, and minimum start / stop times that define the minimum times that various facilities are continuously started or stopped.

[0042] 3 shows an example of the configuration of a power system operation planning system 240, which is one aspect of realizing the present invention. The power system operation planning system 240 includes an information storage device 241, an operation plan formulation device 242, and a control command device 243. The power system operation planning system 240 receives system measurement information from the system measurement device 230 and transmits control commands to the system control device 231. The information storage device 241 in FIG. 3 corresponds to the information storage unit 30 in FIG. 1.

[0043] The information storage device 241 stores system measurement information transmitted from the external system measurement device 230, stores offline information including facility information, and stores operation plan information calculated by the operation plan development device 242. The operation plan development device 242 calculates operation plan information based on the offline information including various online system measurement information and facility information stored in the information storage device 241. The control command device 243 calculates control commands for system devices such as the thermal power plant 106, the substation 107, and the inverter power supply 109 based on the operation plan information calculated by the operation plan development device 242.

[0044] The system measurement device 230 receives system measurement information including power generation output, power flow, and system voltage from system devices including the thermal power plant 106, the substation 107, and the inverter power supply 109. The system measurement device 230 transmits this system measurement information to the power system operation planning system 240.

[0045] The system control device 231 receives control commands calculated by a control command device 243 included in the power system operation planning system 240, and transmits the control commands to system devices including the thermal power plant 106, the substation 107, and the inverter power supply 109.

[0046] Here, the plan formulation process by the power system operation planning device 200 will be described. Figure 4 shows the overall process of the plan formulation process. First, the system disturbance scenario acquisition unit 11 acquires a system disturbance scenario required for formulating a power system operation plan from the system disturbance scenario database 31 in the information storage unit 30 (step S301). A system disturbance scenario refers to a scenario in which the power system is disturbed. Here, the system disturbance scenario may be acquired by manual input by a user using analysis tool software, by importing a file in which the system disturbance scenario is stored, or by linking a database with another system.

[0047] Fig. 5 shows an example of a power system disturbance scenario 311 stored in the power system disturbance scenario database 31. For the power system disturbance scenario 311 shown in the table of Fig. 5, setting values ​​are stored for the target equipment that causes the power system disturbance, the type of event that causes the power system disturbance, and a time sequence including the occurrence times of various events related to the power system disturbance phenomenon.

[0048] Here, as an example of the setting values, in scenario #1, the event type for generator a-1 is a system disturbance due to a generator trip, and the fault sequence indicates that the generator tripped at time 0.00 s. Here, as an example of the setting values, in scenario #2, the event type for transmission line A-1 is a system disturbance due to a three-phase, four-wire ground fault, and the fault sequence indicates that after a transmission line ground fault occurs at time 0.00 s, fault clearance is performed at time 0.05 s and reclosing is performed at time 0.40 s.

[0049] 4, the explanation will be continued. The system operation information acquisition unit 12 acquires system operation information required for formulating a power system operation plan from the system operation information database 32 included in the information storage unit 30 (step S302). Here, the system operation information may be acquired by manual input by a user using analysis tool software, importing a file in which the system operation information is stored, or linking a database with another system.

[0050] 6 shows an example of system operation information 320 stored in the system operation information database 32. The system operation information 320 is information related to the operation of the power system, and includes information on the total power demand within the target area for each period, the power generation output of multiple generators, and various types of system equipment other than generators. That is, the system operation information 320 stores information on transmission lines, substations, power loads, and power flow rates and system voltages at interconnection nodes. Here, in addition to being set for each period, the system operation information 320 may also be set for period types, including fiscal years, seasons, days of the week, and weekday / holiday types, or for evaluation scenarios.

[0051] 4 , the explanation will be continued. The power system facility information acquisition unit 13 acquires power system facility information 331, 332, and 333 required for formulating an operation plan for the power system from the power system facility information database 33 included in the information storage unit 30 (step S303). Here, the power system facility information 331, 332, and 333 may be acquired by manual input by a user using analysis tool software, by importing a file in which power system facility information is stored, or by linking a database with another system.

[0052] 7 shows an example of the system equipment information 331, 332, and 333 stored in the system equipment information database 33. Information about each generator connected to this power system is stored in the system equipment information 331. The system equipment information 331 includes a rated capacity column, an output upper limit column, an output lower limit column, an output change rate column, a minimum start-up time column, a minimum stop time column, and an inertia constant column.

[0053] Information about each transmission line connected to this power system is stored in the system facility information 332. The system facility information 332 includes a start node column, an end node column, a power flow upper limit column, a power flow lower limit column, a resistance column, a reactance column, and a capacitance column.

[0054] Information about each substation connected to this power system is stored in the system facility information 333. The system facility information 333 includes a start node column, an end node column, a power flow upper limit column, a power flow lower limit column, a tap position column, and a reactance column.

[0055] Furthermore, the power grid equipment information acquisition unit 13 may include selectable control modes and control parameters for each inverter power supply in the power grid equipment information. Here, the control modes selectable by each inverter power supply include any of droop control, virtual synchronous machine control, power synchronization control (PSC), direct power control (DPC), and virtual oscillator control.

[0056] Here, droop control refers to a control in which, when a certain physical quantity is the object of manipulation and an observable quantity corresponding to this physical quantity is specified, the physical quantity is increased or decreased as the observable quantity increases. The manner in which the physical quantity increases or decreases in this way is called the droop characteristic.

[0057] Virtual synchronous machine control is a control method that gives a voltage source inverter characteristics simulating a synchronous generator when converting DC power from a storage battery to AC power. By using virtual synchronous machine control, inertia is added to the AC power generated using a storage battery, making it possible to improve stability against load fluctuations.

[0058] Power synchronization control is a control method for inverters that automatically varies the output power to suppress fluctuations in the grid frequency and power fluctuations in the interconnected grid. Power synchronization control has the same grid stabilization effect as a synchronous generator.

[0059] Direct power control is a method of directly controlling the instantaneous active and reactive power of inverters and converters. Direct power control enables high-speed operation and miniaturization of energy storage elements.

[0060] Virtual oscillator control is an inverter control method that controls output voltage and current by imitating a specific oscillation pattern. Virtual oscillator control is particularly useful in power conversion systems and power supply systems, achieving stable power supply.

[0061] The control parameters of each inverter power supply include any one of an active power target value, a cutoff frequency of a low-pass filter, a gain, a time constant, a damper coefficient, and a current upper limit value.

[0062] 4, the inertia contribution evaluation unit 14 calculates the contributions to the system inertia of the various generators and inverter power supplies using the system disturbance scenario, system equipment information, and system operation information stored in the information storage unit 30 (step S304). An example of system inertia contribution information 141 calculated by the inertia contribution evaluation unit 14 is shown in FIG.

[0063] 8, the system inertia contribution information 141 is defined using the total power demand in the target area, the power generation output of multiple generators, and the power flow rate and system voltage of various system facilities other than generators when the system state is 001, 002, or 003. The various system facilities other than generators include transmission lines, substations, power loads, interconnection nodes, etc.

[0064] For these system states, the contributions to system inertia when the control mode of generator a-1, generator a-2, and inverter power supply b-1 is set to virtual synchronous machine control and when the control mode is set to droop control are calculated and stored as system inertia contribution information.

[0065] In this case, for the thermal power generators (generator a-1, generator a-2), which are synchronous machines, the system inertia contribution of each generator may be calculated by multiplying the sensitivity coefficient for the system inertia contribution to a power source trip by the inertia constant of each generator. Note that the value obtained by adding up the system inertia contribution of each generator within the target area is defined as the inertial force (Msys).

[0066] The relationship and detailed information regarding the inertial force (Msys), sensitivity coefficient, and inertia constant mentioned above is described in "Document 3: Status of consideration of technical issues and countermeasures for 'Making renewable energy the main power source' - Analysis of sensitivity coefficient characteristics and estimate of future inertial force securing status," published in May 2022 by the 73rd Committee on Adjustment Capacity and Supply-Demand Balance Assessment of the Organization for Cross-regional Coordination of Transmission Operators.

[0067] Specifically, the degree to which the inertial force of each area contributes to reducing the rate of frequency change in response to a power system disturbance in the area where a power source has been tripped is calculated as a sensitivity coefficient.Then, the required amount and cost of future inertial force can be calculated using the sensitivity coefficient and the inertial force control value, as the inertial force shortfall section and the required amount and cost of countermeasures in the master plan interim summary scenario.

[0068] In addition, regarding the system inertia contribution for each control mode of the inverter power supply, the simulation results including the frequency response and active power output from a system simulation that simulates each control mode of each inverter power supply can be compared with the system simulation results in which a thermal power generator with the same installed capacity is connected to the system instead at a system connection point equivalent to the inverter power supply mentioned above, and the value of the inertia constant of the thermal power generator when the errors in the frequency response and active power output in both simulation results are within a certain range can be calculated as the system inertia contribution for each control mode of the inverter power supply.

[0069] Returning to Fig. 4, the explanation will be continued. The plan formulation unit 15 calculates a power system operation plan based on the system disturbance scenario, the system operation information, the system equipment information, and the system inertia contribution information of each generator calculated by the inertia contribution evaluation unit 14 (step S305). At this time, the optimization problem may be formulated as shown in the following example, and a power system operation plan including the start / stop states of generators, output allocation, and control modes of inverter power supplies may be calculated based on the calculation results of the optimization problem. Here, an example of the objective function is expressed by the following equation (1).

[0070] Here, t is an index representing the time, i is an index representing the generator, C i (p): Operating cost SUC of generator i for power output p i :Start-up cost of generator i D i (r): Operation cost of generator i for adjustment capacity contribution r PC: Penalty cost due to constraint violation

[0071] The constraints include one or more of the following: Here, generator operation constraints and system operation constraints other than those listed below may also be set as constraints in the optimization problem.

[0072] (a) Supply and demand balance constraint: The power demand to be allocated matches the total power generation output. (b) Upper and lower limit constraint on generator output: Each generator takes an output value within the range from the lower limit to the upper limit of the output. (c) Generator output change rate constraint: The range of change in the output value of each generator between different times must be within the upper limit of the output change rate. (d) Minimum start-up time / minimum stop-down time constraint: The generator is operated so that its continuous start-up or stop time is equal to or longer than the specified minimum time.

[0073] (e) Designated start / stop period: The generator is forcibly stopped or started during a period designated by the operator. (f) Operating reserve / required adjustment capacity constraint: The required amount of generator reserve capacity is secured to correct the difference between the power demand during actual operation and the power system operation plan.

[0074] (g) System inertia constraint: A system operation plan is made so that the sum of the system inertia supplied by each generator exceeds the system inertia requirement in the target area. In this case, as an alternative to the above, compliance with the system inertia constraint may be determined by checking whether the frequency change rate, the lowest point of frequency change, etc., which are indicators in the results of a system simulation when a system disturbance occurs, take on values ​​within a certain range.

[0075] Here, in the iterative calculations for solving the optimization problem, each time the start / stop states and output allocations of each generator in the system operation plan as the intermediate calculation results are updated, a system state corresponding to the start / stop states and output allocations may be defined, a value of the system inertia contribution in that system state may be calculated, and this value may be used as the value of the system inertia contribution in the next iterative calculation. That is, the system state may be defined using the start / stop states and output allocations of each generator calculated in the nth calculation of the optimization calculation in the plan formulation unit 15, the inertia contribution of each power source may be calculated and updated using the system state as input information to the inertia contribution evaluation unit 14, and the updated value of the system inertia contribution may be used as input information for the (n+1)th calculation of the optimization calculation in the plan formulation unit 15.

[0076] 9 shows an example of the system operation plan information 151 calculated by the plan formulation unit 15. In FIG. 9, the system operation plan information 151 shows the start / stop status, power generation output, and control mode of power generators in the target area for each period as data items. Here, the system operation plan information may include other information indicating the operation status of each power generator, such as bandwidth, various adjustment capacity contribution amounts, reserve capacity, and start / stop duration. In addition, the system operation plan information may include the power flow rate, system voltage, tap position, etc. of power transmission lines, transformers, and other system facilities other than generators.

[0077] Here, a part of the input information in the plan formulation unit 15 may be changed to calculate a plurality of pieces of operation plan information such as plan 001 and plan 002. For example, in the optimization calculation for calculating plan 001, the plan formulation unit 15 sets the amount of reserve under the system inertia reserve constraint as X1. The plan formulation unit 15 may set the same values ​​for the other system operation information and constraint conditions and calculate plan 001.

[0078] In the optimization calculation for calculating plan 002, the plan formulation unit 15 sets the amount of reserve under the system inertia reserve constraint as X2, which is different from X1. The plan formulation unit 15 sets the same values ​​for the other system operation information and constraint conditions, and calculates plan 002.

[0079] Returning to Fig. 4, the explanation will be continued. When the plan evaluation unit 16 calculates the system operation plan evaluation information 161 shown in Fig. 10 based on the system operation plan calculated by the plan formulation unit 15 (step S306), the processing in Fig. 4 ends. The system operation plan evaluation information 161 includes the operating cost of each power generator.

[0080] FIG. 10 illustrates an example of the system operation plan evaluation information 161 calculated by the plan evaluation unit 16. As illustrated in FIG. 10 , for each plan, such as plan 001 or plan 002, the plan evaluation unit 16 calculates, as the system operation plan evaluation information, the operation cost and the system inertia reserve amount for each period as evaluation indicators, as well as the average values ​​of the operation cost and the system inertia reserve amount for the entire period. Here, the plan evaluation unit 16 may calculate the operation cost for each plan as the sum of the operation costs of each generator in the plan within the target area. The plan evaluation unit 16 may also calculate the system inertia reserve amount for each plan as the sum of the system inertia within the target area, taking into account the control mode of each generator in the plan. In addition to the above, the plan evaluation unit 16 may also calculate, as the system operation plan evaluation information, the frequency change rate and the lowest point of frequency change, which are indicators of frequency response in the results of a system simulation when a system disturbance occurs.

[0081] The configuration and effects of the present invention will be described below. [1] A power system operation planning device (200) comprising: a plan formulation unit (15) that formulates a system operation plan including a start / stop state of a generator, a power generation output of the generator, and a control command to an inverter power source, based on any of a system disturbance scenario, system operation information, system equipment information, and a contribution of the generator to system inertia.

[0082] This makes it possible to formulate an operation plan that achieves operational cost reductions through wide-area merit orders while maintaining the inertia of the power system.

[0083] [2] The power system operation planning device (200) according to claim 1, further comprising an inertia contribution evaluation unit (14) that calculates a contribution of the inverter power source to system inertia for each of the system disturbance scenarios, each of the system states, each of the control modes of the inverter power source, and each of the parameters of the inverter power source, based on the system disturbance scenarios, the system states indicated by the system equipment information and the system operation information, and equipment data including control modes and parameters of the inverter power source.

[0084] This makes it possible to formulate an operation plan that achieves reductions in operation costs through wide-area merit orders while ensuring the inertia of the power system, based on the contribution of each inverter power source to the system inertia.

[0085] [3] The power system operation planning device (200) according to claim 1, further comprising: a plan evaluation unit (16) that calculates a system inertia evaluation index based on the system operation plan.

[0086] This makes it possible to appropriately evaluate the system operation plan.

[0087] [4] The power system operation planning device (200) according to claim 3, wherein the system inertia evaluation index calculated by the plan evaluation unit (16) includes an operation cost.

[0088] This makes it possible to appropriately evaluate the system operation plan in terms of operation costs.

[0089] [5] The power system operation planning device (200) according to claim 1, characterized in that the system disturbance scenario includes any one of a power source trip, a transmission line ground fault, a transmission line short circuit, a system switching, a system separation, a renewable energy output fluctuation, and a demand fluctuation.

[0090] This makes it possible to formulate system operation plans in the event of disturbances in the power system caused by power source failures, transmission line ground faults, transmission line short circuits, system switching, system separation, fluctuations in renewable energy output, and demand fluctuations.

[0091] [6] The power system operation planning device (200) according to claim 1, wherein the control command includes any one of droop control, virtual synchronous machine control, power synchronization control, direct power control, and virtual oscillator control.

[0092] This makes it possible to realize the formulated system operation plan by combining control commands.

[0093] [7] The power system operation planning device (200) according to claim 1, characterized in that the evaluation index of the system inertia for the generator includes any one of a weighted sum of inertia constants in a target area, a frequency change rate and an improvement amount of the frequency change rate, and a lowest frequency change point and an improvement amount of the lowest frequency change point.

[0094] This makes it possible to appropriately evaluate the system inertia.

[0095] [8] A power system operation planning system (240) comprising: a plan formulation unit (15) that formulates a system operation plan including a start / stop state of the generator, a power generation output of the generator, and a control command to an inverter power source, based on any of a system disturbance scenario, system operation information, system equipment information, and a contribution of the generator to system inertia.

[0096] This makes it possible to formulate an operation plan that achieves operational cost reductions through wide-area merit orders while maintaining the inertia of the power system.

[0097] [9] A power system operation planning method comprising: a step (S304) in which an inertia contribution evaluation unit (14) calculates a system inertia contribution of the inverter power supply for each system disturbance scenario, each system state, each control mode of the inverter power supply, and each parameter of the inverter power supply based on system disturbance scenarios, system states indicated by system equipment information and system operation information, and equipment data including a control mode and parameters of the inverter power supply; a step (S305) in which a plan formulation unit (15) formulates a system operation plan including a start / stop state of the generator, a power generation output of the generator, and a control command for the inverter power supply based on any of the system disturbance scenarios, the system operation information, the system equipment information, and the contribution of the generator to the system inertia; and a step (S306) in which a plan evaluation unit (16) calculates an operation cost and a system inertia evaluation index based on the system operation plan.

[0098] This makes it possible to formulate an operation plan that achieves operational cost reductions through wide-area merit orders while maintaining the inertia of the power system.

[0099] (Modifications) The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0100] The above-described configurations, functions, processing units, processing means, etc. may be implemented in part or in whole by hardware such as an integrated circuit. The above-described configurations, functions, etc. may also be implemented by software, with a processor interpreting and executing a program that implements each function. Information such as the program, table, and file that implements each function can be stored in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or on a recording medium such as a flash memory card or a DVD (Digital Versatile Disk).

[0101] In each embodiment, the control lines and information lines shown are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are interconnected.

[0102] 10 Power system operation plan determination unit 11 System disturbance scenario acquisition unit 12 System operation information acquisition unit 13 System equipment information acquisition unit 14 Inertia contribution evaluation unit 15 Plan formulation unit 16 Plan evaluation unit 17 Display unit 21 System measurement device 21a to 21d System measurement device 210a to 210d Location 31 System disturbance scenario database 32 System operation information database 320 System operation information 33 System equipment information database 331 System equipment information 332 System equipment information 333 System equipment information 34 Past plan information database 30 Information storage unit 101 Generator 102 Substation 103 Phase modifying device 104 Power load 105 External power system 108 Information and communication network 106 Thermal power plant 107 Substation 109 Inverter power supply 200 Power system operation planning device 201 CPU 203 Communication unit 204 Input unit 205 Memory 206 Storage device 141 System inertia contribution information 151 System operation plan information 161 System operation plan evaluation information

Claims

1. A power system operation planning device comprising: a plan formulation unit that formulates a system operation plan including a start / stop state of the generator, the power output of the generator, and control commands to an inverter power source based on any of a system disturbance scenario, system operation information, system equipment information, and the contribution of the generator to system inertia.

2. The power system operation planning device according to claim 1, further comprising an inertia contribution evaluation unit that calculates the contribution of the inverter power supply to system inertia for each of the system disturbance scenarios, each of the system states, each of the control modes of the inverter power supply, and each of the parameters of the inverter power supply, based on the system disturbance scenarios, the system states indicated by the system equipment information and the system operation information, and equipment data including the control modes and parameters of the inverter power supply.

3. The power system operation planning device according to claim 1, further comprising: a plan evaluation unit that calculates a system inertia evaluation index based on the system operation plan.

4. The power system operation planning device according to claim 3, wherein the system inertia evaluation index calculated by the plan evaluation unit includes an operation cost.

5. The power system operation planning device according to claim 1, characterized in that the system disturbance scenario includes any one of a power source trip, a transmission line ground fault, a transmission line short circuit, a system switching, a system separation, a renewable energy output fluctuation, and a demand fluctuation.

6. The power system operation planning device according to claim 1, wherein the control command includes any one of droop control, virtual synchronous machine control, power synchronization control, direct power control method, and virtual oscillator control.

7. The power system operation planning device according to claim 1, characterized in that the evaluation index of the system inertia for the generator includes any one of a weighted sum of inertia constants within the target area, a frequency change rate and an improvement amount of the frequency change rate, and a lowest point of frequency change and an improvement amount of the lowest point of frequency change.

8. A power system operation planning system comprising: a plan formulation unit that formulates a system operation plan including a start / stop state of the generator, the power generation output of the generator, and control commands to an inverter power source based on any of a system disturbance scenario, system operation information, system equipment information, and the contribution of the generator to system inertia.

9. A power system operation planning method comprising: a step in which an inertia contribution evaluation unit calculates the system inertia contribution of the inverter power supply for each system disturbance scenario, each system state, each control mode of the inverter power supply, and each parameter of the inverter power supply based on system disturbance scenarios, system states indicated by system equipment information and system operation information, and equipment data including a control mode and parameters of the inverter power supply; a step in which a plan formulation unit formulates a system operation plan including a start / stop state of the generator, the power generation output of the generator, and a control command for the inverter power supply based on any of the system disturbance scenarios, the system operation information, the system equipment information, and the contribution of the generator to the system inertia; and a step in which a plan evaluation unit calculates an operation cost and a system inertia evaluation index based on the system operation plan.

Images