System stabilizing system and system stabilizing method

Abstract

The objective of the present invention is to provide a technology that enables appropriate determination of a power generator and a load which are to be controlled, and a control amount with respect to the power generator and load. A system stabilizing system includes a control content calculation unit that, if it is determined, on the basis of a system model, that an overload or an abnormal voltage is to occur, calculates control content including a control target and a control amount of the control target, by optimal power flow calculation, and on the basis of the system model and facility information. The control content includes a cutoff amount, which is a control amount of a generator and / or a load that are to be controlled.

Description

Power system stabilization system and power system stabilization method

[0001] The present disclosure relates to a power grid stabilization system and a power grid stabilization method.

[0002] Various techniques have been proposed for controlling power systems. For example, Patent Literature 1 proposes a technique for calculating reactive power that should be output by a power source when a fault occurs in the power system.

[0003] Japanese Patent Application Laid-Open No. 2022-21919

[0004] When a fault occurs in a power system, a protective relay system clears the fault to prevent the effects of the fault from spreading over a wide area. However, if this opens a transmission line or transformer, the voltage and current state of the power system may suddenly change, which may result in overload and abnormal voltage of the transmission line. Therefore, in order to resolve such overload and abnormal voltage, a power system stabilization system or the like performs source limiting or load limiting, which cuts off generators or loads from the power system.

[0005] However, when the power system becomes complicated, the conventional technology has a problem in that it is not possible to appropriately determine which generators and loads should be shedding and at what level.

[0006] Therefore, the present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technology that can appropriately determine the generators and loads to be controlled and their control amounts.

[0007] The first system stabilization system according to the present disclosure includes an acquisition unit that acquires measurement information of a power system including a generator and a load; an accident occurrence determination unit that determines whether an accident has occurred in the power system based on the measurement information; a model generation unit that generates a system model based on the measurement information and equipment information of the power system when it is determined that the accident has occurred; and a control content calculation unit that calculates control content including a control object and a control amount of the control object by optimal power flow calculation based on the system model and the equipment information when it is determined that an overload or abnormal voltage will occur based on the system model, wherein the control content includes a cutoff amount that is the control amount of at least one of the generator and the load that are the control objects.

[0008] A second power system stabilization system according to the present disclosure includes a central processing unit and a slave station device capable of communicating with the central processing unit, wherein the central processing unit includes a first acquisition unit that acquires measurement information of a power system including a generator and a load, a model generation unit that generates a power system model for each of a plurality of predetermined fault patterns based on the measurement information, equipment information of the power system, and a plurality of predetermined fault patterns, and a model generation unit that, when it is determined that an overload or abnormal voltage will occur based on the power system model of the fault pattern, optimizes control content including a control target and a control amount of the control target based on the power system model and the equipment information. and a control content calculation unit that performs calculations using power flow calculations and generates a control table that associates the fault pattern with the control content, the control content including a cutoff amount that is the control quantity of at least one of the generator and the load that are the control targets, and the slave station device includes a second acquisition unit that acquires the measurement information and the control table, an fault occurrence determination unit that determines whether the fault pattern in the control table has occurred in the power system based on the measurement information, and a control content determination unit that determines the control content associated in the control table with the fault pattern that has been determined to have occurred.

[0009] According to the present disclosure, control content including a control target and a control amount of the control target is calculated by an optimal power flow calculation based on a system model and facility information, and the control content includes a shedding amount, which is a control amount of at least one of the generator and the load, which are the control targets. With this configuration, it is possible to appropriately determine the generator and the load to be controlled and their control amount.

[0010] The objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0011] 1 is a schematic diagram showing a power system using a power system stabilization system according to embodiment 1. FIG. 2 is a block diagram showing the configuration of the power system stabilization system according to embodiment 1. FIG. 3 is a diagram showing the concept of a system model according to embodiment 1. FIG. 4 is a flowchart showing the operation of the power system stabilization system according to embodiment 1. FIG. 5 is a block diagram showing the configuration of the power system stabilization system according to embodiment 2. FIG. 6 is a diagram showing a model used in a sensitivity calculation unit according to embodiment 2. FIG. 7 is a block diagram showing the configuration of the power system stabilization system according to embodiment 3. FIG. 8 is a flowchart showing the operation of the power system stabilization system according to embodiment 3. FIG. 9 is a schematic diagram showing a power system using a power system stabilization system according to embodiment 4. FIG. 10 is a block diagram showing the configuration of a central processing unit of the power system stabilization system according to embodiment 4. FIG. 11 is a block diagram showing the configuration of a slave station device of the power system stabilization system according to embodiment 4. FIG. 12 is a flowchart showing the operation of the central processing unit of the power system stabilization system according to embodiment 4. FIG. 13 is a flowchart showing the operation of a slave station device of the power system stabilization system according to embodiment 4. FIG. 14 is a block diagram showing the hardware configuration of a power system stabilization system according to another modified example. FIG. 15 is a block diagram showing the hardware configuration of a power system stabilization system according to another modified example.

[0012] <First Embodiment> Fig. 1 is a schematic diagram showing a power system using a power system stabilization system 8 according to the present embodiment 1. The power system in Fig. 1 includes a power transmission and distribution system 1, a generator 2, a load 3, a renewable energy power source (hereinafter referred to as "renewable energy power source") 4, a storage battery 5, a voltage control device 6, a measurement device 7, and a power system stabilization system 8.

[0013] The power transmission and distribution system 1 connects a generator 2, a load 3, a renewable energy power source 4, a storage battery 5, and a voltage control device 6 so that power can be transferred among them. The power transmission and distribution system includes, for example, a transmission line and a bus bar.

[0014] The generator 2 includes at least one of generators such as a nuclear generator, a thermal generator, a hydroelectric generator, etc. In this specification, for example, at least one of A, B, C, ..., and Z means any one of all combinations of one or more types extracted from the group A, B, C, ..., and Z.

[0015] The load 3 includes, for example, a consumer device that uses power from the power grid. The renewable energy power source 4 includes, for example, a device with an inverter, such as a solar power generator or a wind power generator. The storage battery 5 includes, for example, at least one of a secondary battery system composed of a lithium-ion battery, a NAS battery, or the like, a flywheel battery, and an electric double-layer capacitor. The voltage control device 6 is a voltage control device other than the renewable energy power source 4 and the storage battery 5, and includes, for example, a phase modifying device and a flexible AC transmission system (FACTS) device such as an SVC (static variable capacitance capacitor) or a STATCOM (statically excited static synchronous compensator).

[0016] The measurement device 7 generates measurement information of the power system including the generator 2, the load 3, the renewable energy power source 4, the storage battery 5, and the voltage control device 6. The measurement information includes, for example, measurement results of the voltage, current, power, frequency, and opening and closing of protective relays in each part of the power transmission and distribution system 1.

[0017] Protective relays (not shown) are provided, for example, in the transmission lines and busbars, generators 2, loads 3, and renewable energy sources 4 in the power transmission and distribution system 1, and detect overvoltages, overcurrents, etc. that occur due to accidents, and electrically cut off the power equipment at the location of the accident to prevent the accident from spreading over a wide area, thereby clearing the accident.

[0018] The power interruption device or load interruption device (not shown) is provided, for example, between the power transmission and distribution system 1 and the generator 2, load 3, and renewable energy power source 4, and interrupts the connection between the power transmission and distribution system 1 and the generator 2, load 3, and renewable energy power source 4 by a commanded amount. In the following description, when there is no need to distinguish between the generator 2, load 3, renewable energy power source 4, storage battery 5, voltage control device 6, measurement device 7, power interruption device, and load interruption device, they will be referred to as equipment.

[0019] The grid stabilization system 8 is connected to the facilities via a communication network indicated by the dashed line in Fig. 1. When the grid stabilization system 8 determines that a fault has occurred in the power grid based on the measurement results of the measurement device 7, it determines, by calculation, control contents including the control target and the control amount of the control target to be controlled in order to eliminate a grid abnormality state, such as an overload or abnormal voltage, that occurs when the fault is cleared. The grid stabilization system 8 then transmits (commands) the control contents to the facilities that are the control targets, thereby making it possible to eliminate a grid abnormality state that occurs after the fault is cleared.

[0020] Fig. 2 is a block diagram showing the configuration of the power grid stabilization system 8 according to the present embodiment 1. The power grid stabilization system 8 in Fig. 2 includes a communication unit 11 which is an acquisition unit, a recording unit 12, a fault occurrence determination unit 13, a model generation unit 14, and a control content calculation unit 15.

[0021] The communication unit 11 sequentially (e.g., periodically) receives and acquires measurement information of the power system from the measurement device 7. The communication unit 11 also transmits (commands) the control content, which is the calculation result of the control content calculation unit 15, to the equipment to be controlled.

[0022] The recording unit 12 records the measurement information collected by the communication unit 11, the equipment information of the power system, the calculation results of the control content calculation unit 15, and the control performance of the equipment up to now (e.g., the history of controlled variables). The equipment information includes, for example, the connection relationships between the equipment, and the impedances and reactances between the equipment.

[0023] The fault occurrence determination unit 13 determines whether or not a fault has occurred in the power system based on the measurement information. Generally, when a fault occurs in the power system, the voltage, current, and power flow change suddenly, causing a protective relay to operate. Therefore, the fault occurrence determination unit 13 may determine whether or not a protective relay has operated based on the measurement information, and if it is determined that a protective relay has operated, determine that a fault has occurred in the power system.

[0024] When the accident occurrence determination unit 13 determines that an accident has occurred, the model generation unit 14 generates a system model based on the measurement information and the equipment information. The system model is a model that shows the state of the power system. Conceptually, the system model is a model that shows the connection relationships and operating states of the equipment, to which the impedance between the equipment, the generated power, the consumed power, etc. are added, as shown in to in Fig. 3 . In reality, the system model includes the impedance between the equipment, the generated power, the consumed power, etc., and is expressed by a plurality of equations that show the relationships between the equipment in accordance with the physical laws of the power system.

[0025] The system model makes it possible to calculate, for example, the voltage, current, and power flow states of the power system, the power generation amount of the generator 2, the load amount of the load 3, and the operating states of the renewable energy power source 4, the storage battery 5, and the voltage control device 6. When the model generation unit 14 generates a system model based on measurement information and facility information when an accident occurs in the power system, a system model is generated in which a transmission line or a transformer is opened to remove the accident.

[0026] The control content calculation unit 15 determines whether an overload or an abnormal voltage will occur based on the grid model. For example, when the state of the power grid indicated by the grid model is a predetermined power grid state (e.g., a state in which a predetermined transmission line is open), the control content calculation unit 15 may determine that an overload or an abnormal voltage will occur. Furthermore, for example, when the calculation result of the grid model using the measurement information indicates predetermined voltage, current, and power flow states and predetermined operating states of equipment, the control content calculation unit 15 may determine that an overload or an abnormal voltage will occur.

[0027] When it is determined that an overload or abnormal voltage will occur, the control content calculation unit 15 calculates the control content, including the control object and the control amount of the control object, by optimal power flow calculation (hereinafter sometimes referred to as "OPF") based on the system model and equipment information.

[0028] The control content includes a cutoff amount, which is a control amount of at least one of the generator 2 and the load 3, which are the control targets. In other words, the control content includes a cutoff amount of at least one of the generator 2 and the load 3.

[0029] Furthermore, in the first embodiment, the control content further includes at least one of the interruption amount, which is a control amount of the renewable energy power source 4 that is the control target, and the active power and the reactive power, which are control amounts of the renewable energy power source 4, the storage battery 5, and the voltage control device 6 that are the control targets. In other words, the control content further includes at least one of the interruption amount of the renewable energy power source 4, the active power of the renewable energy power source 4, the reactive power of the renewable energy power source 4, the active power of the storage battery 5, the reactive power of the storage battery 5, the active power of the voltage control device 6, and the reactive power of the voltage control device 6. The calculation of the control content will be described in detail later.

[0030] The control content calculation unit 15 discretizes the control amount as necessary. Note that discretization of the control amount will be described in detail later.

[0031] <Calculation of Control Contents> Next, we will explain the calculation of control contents using OPF in the control content calculation unit 15. OPF is a calculation to find the value of variables that minimizes an objective function represented by variables under constraint conditions. In the following explanation, the objective function, constraint conditions, and OPF will be explained in this order.

[0032] <Objective Function> In the following description, the objective function is represented as f(x, u, z). The variable x is a set of voltage solutions, for example, a voltage vector composed of the magnitude and phase angle of the bus voltage.

[0033] The variable u is a control variable, and is a set of variables that can be controlled by a control system such as the grid stabilization system 8. In the first embodiment, the variable u includes the amount of power interruption of the generator 2, the load 3, and the renewable energy power source 4 by the power interruption device or the load interruption device, and the active power and reactive power of the renewable energy power source 4, the storage battery 5, and the voltage control device 6.

[0034] The variable z is a dependent variable and is a set of variables that are determined by determining the variable u. For example, the variable z includes an active power flow and a reactive power flow of a transmission line that are determined by determining the interruption amounts of the generator 2, the load 3, and the renewable energy power source 4.

[0035] The objective function f(x, u, z) according to the first embodiment is a function for optimizing a certain item of the power system. Some examples of the objective function will be described below.

[0036] <Objective Function of First Example> The objective function of the first example is an objective function for minimizing the amount of shedding of the generator 2, the load 3, and the renewable energy power source 4 by a power shedding device or a load shedding device, and is expressed as the following formula (1). Note that the notation of the variables x, u, and z is omitted on the right side of formula (1), and similarly, the notation of the variables x, u, and z may also be omitted on the right sides of other formulas. Furthermore, due to notation constraints in the specification, letters expressed as subscripts in formulas will be expressed as simple subscripts in the specification.

[0037]

[0038] R ｉ Ｇｃｕｒ , R ｉ Ｌｃｕｒ , R ｉ ＲＥＳｃｕｒ is the amount of interruption of generator (i), load (i), and renewable energy source (i). P ｉ Ｇ０ , P ｉ Ｌ０ , P ｉ ＲＥＳ０ is the steady-state active power of the generator (i), the load (i), and the renewable energy source (i). Ｇ１ , K Ｌ１ , K ＲＥＳ１is a weighting coefficient of the objective function. Note that since the interruption amount is expressed as the product of the interruption rate and the steady-state active power, the objective function may be expressed as in the following equation (2).

[0039]

[0040] R ｉ Ｇ , R ｉ Ｌ , R ｉ ＲＥＳ is the interruption rate of generator (i), load (i), and renewable energy source (i).

[0041] <Objective Function of Second Example> The objective function of the second example is an objective function for minimizing the amount of change in output of the renewable energy power source 4, the storage battery 5, and the voltage control device 6, the output of which is controlled in response to an output command from the grid stabilization system 8, and is expressed as in the following equation (3). In this example, the voltage control device 6 includes, but is not limited to, a phase modifying equipment, an SVC, and a STATCOM.

[0042]

[0043] P ｉ ＲＥＳ , P ｉ ＲＥＳ０ is the active power and steady-state active power of the renewable energy source (i). P ｉ ＥＳＳ , P ｉ ＥＳＳ０ is the active power and steady-state active power of the storage battery (i). Q ｉ ＲＥＳ , Q ｉ ＥＳＳ , Q ｉ ＳＣＳｈＳ , Q ｉ ＳＶＣ , Q ｉ ＳＴＡＴＣＯＭ is the reactive power of renewable energy source (i), storage battery (i), phase modifying equipment (i), SVC (i), and STATCOM (i). Q ｉ ＲＥＳ０ , Q ｉ ＥＳＳ０ , Q ｉ ＳＣＳｈＳ０ , Q ｉ ＳＶＣ０ , Q ｉ ＳＴＡＴＣＯＭ０is the steady-state reactive power of renewable energy source (i), storage battery (i), phase modifying equipment (i), SVC (i), and STATCOM (i). K ＲＥＳ，Ｐ , K ＲＥＳ，Ｑ , K ＥＳＳ，Ｐ , K ＥＳＳ，Ｑ , K ＳＣＳｈＲ，Ｑ , K ＳＶＣ，Ｑ , K ＳＴＡＴＣＯＭ，Ｑ is the weighting coefficient of the objective function.

[0044] <Objective Function of Third Example> The objective function of the third example is an objective function for minimizing the amount of violation of voltage and power flow, and is expressed as the following equation (4).

[0045]

[0046] V ｉ ｖｉｏ , V ｉ , V ｉ ｍａｘ , V ｉ ｍｉｎ are the voltage violation amount, voltage, maximum voltage value, and minimum voltage value of node (i). ｉ ｖｉｏ , S ｉ , S ｉ ｍａｘ are the apparent power flow violation amount, apparent power flow, and apparent power capacity of the transmission line (i). ｉ ＲＥＳ０ -P ｉ ＲＥＳ Instead of |, the square of the value in the absolute value (for example, (P ｉ ＲＥＳ０ -P ｉ ＲＥＳ ) ２ ) may also be used.

[0047] Although examples of the objective function according to the first embodiment have been described above, the present invention is not limited to the above examples. For example, the objective function according to the first embodiment may be an objective function for minimizing the fuel cost of the generator 2, an objective function for minimizing the transmission loss, or an objective function for minimizing the voltage deviation from the target voltage. The objective function may be changed as appropriate depending on the operation goal of the user. In addition, the objective function according to the first embodiment may be a function for minimizing the fuel cost of the generator 2, an objective function for minimizing the transmission loss, or an objective function for minimizing the voltage deviation from the target voltage. Ａ , KＢ Using two or more weighting factors such as Ａ (x, u, z), f Ｂ K, which combines two or more objective functions such as (x, u, z). Ａ f Ａ (x, u, z) + K Ｂ f Ｂ It may be an objective function such as (x, u, z).

[0048] Constraints (also called constraint expressions) are the conditions that variables x, u, and z must satisfy. Ａ Inequalities such as (x, u, z) ≦ 0 and h Ａ The inequality constraints are expressed by at least one of equations such as (x, u, z) = 0. Examples of the inequality constraints include capacity constraints on the generator 2, renewable energy power source 4, and storage battery 5, and upper limits on the amount of power interruption from the generator 2, load 3, and renewable energy power source 4. Examples of the equality constraints include a power flow equation (also called a state equation).

[0049] Note that constraint conditions may be used in place of the objective function. For example, instead of using the objective function of the third example, constraint conditions for upper and lower voltage limits (V ｉ ｍｉｎ ≦V ｉ ≦V ｉ ｍａｘ ) and the apparent power flow constraint (0≦S ｉ ≦S ｉ ｍａｘ ) may also be used.

[0050] <OPF> The objective function and constraints described above are described by parameters that are fixed values ​​in the OPF, in addition to the variables x, u, and z that are variable values ​​in the OPF. The fixed parameters include values ​​based on the system model and facility information, such as constants of the power system equipment, line impedance, upper and lower limits of the bus voltage, upper and lower limits of the active power output and reactive power output of the generator 2, and upper and lower limits of the facility capacity.

[0051] The control content calculation unit 15 performs OPF to calculate variables x, u, and z that minimize the objective function under constraint conditions. The OPF solution may be, for example, a simplex method, an interior point method, or a primal-dual interior point method, or may use metaheuristics such as a genetic algorithm or particle swarm optimization (PSO), or may use other solution methods.

[0052] The variables x, u, and z obtained by the OPF can minimize the objective function. For example, the variables x, u, and z obtained by the OPF of the objective function that combines the objective function of the first example and the objective function of the third example can reduce overload and abnormal voltage by minimizing the voltage violation amount and the power flow violation amount while minimizing the interruption amount of the generator 2, the load 3, and the renewable energy power source 4. The constraints (V ｉ ｍｉｎ ≦V ｉ ≦V ｉ ｍａｘ , 0≦S ｉ ≦S ｉ ｍａｘ The variables x, u, and z obtained by OPF with ) can also be similarly minimized and reduced.

[0053] Furthermore, for example, the variables x, u, and z obtained by the OPF of the objective function that combines the objective function of the second example and the objective function of the third example can reduce overload and abnormal voltage by minimizing the voltage violation amount and the power flow violation amount while minimizing the change from the steady state of the active power and reactive power output of the renewable energy power source 4, the storage battery 5, and the voltage control device 6. The objective function of the second example and the constraint condition (V ｉ ｍｉｎ ≦V ｉ ≦V ｉ ｍａｘ , 0≦S ｉ ≦S ｉ ｍａｘ The variables x, u, and z obtained by OPF with ) can also be similarly minimized and reduced.

[0054] The variable u includes control content including a control object and a control amount of the control object, and in the first embodiment, includes the interruption amounts of the generator 2, the load 3, and the renewable energy power source 4, and the active power and reactive power of the renewable energy power source 4, the storage battery 5, and the voltage control device 6. Note that the interruption amount and the interruption rate have a one-to-one relationship and are substantially the same, so the control amount is substantially the same as the interruption amount of the generator 2, the load 3, and the renewable energy power source 4 and the interruption rate of the generator 2, the load 3, and the renewable energy power source 4. For this reason, the interruption amount may be a broad concept that includes the interruption rate.

[0055] The interruption rates of the generator 2, the load 3, and the renewable energy power source 4 obtained by the OPF may be discrete values ​​such as 0 or 1, or may be continuous values ​​from 0 to 1. Furthermore, in cases such as when simulating multiple generators 2, loads 3, and renewable energy power sources 4 aggregated together, the interruption amounts of the generator 2, the load 3, and the renewable energy power source 4 obtained by the OPF may be discrete values ​​such as 0, the steady-state value of one piece of equipment, or the sum of a combination thereof, or may be continuous values ​​such as 0 to the steady-state value after aggregation. Furthermore, the active power and reactive power of the renewable energy power source 4, the storage battery 5, and the voltage control device 6 obtained by the OPF may also be discrete values ​​or continuous values.

[0056] <Discretization of Control Variable> The control content calculation unit 15 discretizes the control variable as needed. For example, the generator 2, the load 3, and the renewable energy power source 4 are controlled to either be interrupted (interruption rate 1) or not (interruption rate 0). Furthermore, when multiple generators 2, loads 3, and renewable energy power sources 4 are aggregated, control is performed in increments of the interruption amount corresponding to each facility. Furthermore, some renewable energy power sources 4, storage batteries 5, and voltage control devices 6 can output any value, while others can only adjust output in discrete values, such as in increments of 10 kW. In particular, the phase-modifying equipment of the voltage control device 6 can only adjust output in increments of the capacity of each power capacitor and shunt reactor. In the above situation, when the control variable obtained by the OPF is a continuous value, the control content calculation unit 15 may discretize the control variable and convert it into a discrete-value control variable actually used in the controlled object.

[0057] For example, the control content calculation unit 15 calculates the value of 0≦Rｉ Ｇ <0.5, R ｉ Ｇ = 0, and 0.5≦R ｉ Ｇ R if ≦1 ｉ Ｇ The control amount may be discretized by rounding off so that .times. ...

[0058] <Operation> FIG. 4 is a flowchart showing the operation of the grid stabilization system 8 according to the first embodiment, that is, the grid stabilization method.

[0059] In step S1 , the communication unit 11 sequentially receives and acquires measurement information of the power system from the measurement device 7 .

[0060] In step S2, the accident occurrence determination unit 13 determines whether or not an accident has occurred in the power grid based on the measurement information. If it is determined that an accident has occurred in the power grid, the process proceeds to step S3, and if it is not determined that an accident has occurred in the power grid, the process proceeds to step S1.

[0061] In step S3, the model generator 14 generates a system model based on the measurement information and the equipment information.

[0062] In step S4, the control content calculation unit 15 determines whether an overload or an abnormal voltage will occur based on the system model. If it is determined that an overload or an abnormal voltage will occur, the process proceeds to step S5, and if it is not determined that an overload or an abnormal voltage will occur, the process proceeds to step S1.

[0063] In step S5, the control content calculation unit 15 calculates control content including a control target and a control amount of the control target by the OPF based on the system model and the facility information. In the first embodiment, the control content includes the interruption amount of the generator 2, the load 3, and the renewable energy power source 4 by the power interruption device or the load interruption device, and the active power and reactive power of the renewable energy power source 4, the storage battery 5, and the voltage control device 6.

[0064] In step S6, the control content calculation unit 15 discretizes the control amount as necessary.

[0065] In step S7, the communication unit 11 transmits the control content, including the control amount and the control object, which are discretized as necessary, to the equipment determined as the control object. As a result, the equipment determined as the control object performs control based on the control amount. Then, the operation of FIG. 4 ends.

[0066] Summary of First Embodiment According to the system stabilization system 8 of the first embodiment described above, when it is determined based on the system model that an overload or abnormal voltage will occur, control details including a control target and a control amount are calculated by an optimal power flow calculation based on the system model and facility information. The control details include the shedding amounts (shedding rates) of the generator 2 and the load 3. With this configuration, it is possible to appropriately determine the generator 2 and the load 3 to be controlled and their shedding amounts (shedding rates) while realizing reductions in the control amount, as well as voltage violations and power flow violations.

[0067] Furthermore, in the first embodiment, the control content further includes at least one of the interruption amount (interruption rate) of the renewable energy power source 4, and the active power and reactive power of the renewable energy power source 4, the storage battery 5, and the voltage control device 6. With this configuration, it is possible to appropriately determine the interruption amount (interruption rate) of the renewable energy power source 4, while realizing reductions in the control amount, voltage violation amount, and power flow violation amount.

[0068] <Embodiment 2> Fig. 5 is a block diagram showing the configuration of a power system stabilization system 8 according to Embodiment 2. The configuration in Fig. 5 is the same as the configuration in Fig. 2 with a sensitivity calculation unit 16 added.

[0069] The sensitivity calculation unit 16 calculates the sensitivity of at least one of the power flow in the power system transmission lines and the voltage of the bus bars of the power system based on the control content calculated by the control content calculation unit 15. For example, the sensitivity calculation unit 16 calculates the sensitivity of the control target to the control amount included in the control content, or the sensitivity of the control target node to the control amount included in the control content, by numerical analysis simulation.

[0070] In the following, in the first calculation example, the active power (P （ｉ）Ｇ ) and reactive power (Q （ｉ） Ｇ ) of the node (i) to be controlled. （ｉ） ) and reactive power (Q （ｉ） ) will be described. Note that even when the controlled object is not a generator but other equipment such as a load 3 or a renewable energy power source 4, the sensitivity can be calculated in the same manner as below.

[0071] <First Calculation Example> In a system model in which it is determined that an overload or abnormal voltage will occur, the sensitivity calculation unit 16 performs a power flow calculation, which is a system calculation, by changing the operating state (output state) of one control object. For example, if the control object of the control content is a generator (i) and the control amount of the control content is an active power (P （ｉ） Ｇ ), the sensitivity calculation unit 16 calculates the effective power (P （ｉ） Ｇ ) may be changed to 10 MW or 100 MW. In the power flow calculation, unlike the OPF, the generated power of the generator 2 and the consumed power of the load 3 are fixed values, and the power flow through the transmission line, etc., as well as the voltage and phase of each part are calculated based on these fixed values.

[0072] The sensitivity calculation unit 16 performs the power flow calculation in a simulation to calculate the change in power flow in the transmission line where an overload occurs and the change in voltage of the bus where an abnormal voltage occurs. For example, when the change in the active power of the generator (i) is ΔP （ｉ） Ｇ When the power flow of the transmission line (k) is changed by the active power flow, the reactive power flow, and the apparent power flow, ΔP （ｋ） ｆ , ΔQ （ｋ） ｆ , ΔS （ｋ） ｆ is calculated, and the voltage change of the bus (j) is ΔV （ｊ） In this case, the sensitivity calculation unit 16 calculates ΔP by the following equation (5): （ｉ） Ｇ ΔP for （ｋ） ｆ , ΔQ （ｋ） ｆ , ΔS（ｋ） ｆ , ΔV （ｊ） Calculate the sensitivity of

[0073]

[0074] For example, the change in the active power of generator (i) is ΔQ （ｉ） Ｇ When the power flow of the transmission line (k) is changed by the active power flow, the reactive power flow, and the apparent power flow, ΔP （ｋ） ｆ , ΔQ （ｋ） ｆ , ΔS （ｋ） ｆ is calculated, and the voltage change of the bus (j) is ΔV （ｊ） In this case, the sensitivity calculation unit 16 calculates ΔQ （ｉ） Ｇ ΔP for （ｋ） ｆ , ΔQ （ｋ） ｆ , ΔS （ｋ） ｆ , ΔV （ｊ） Calculate the sensitivity of

[0075]

[0076] The sensitivity calculation unit 16 calculates the sensitivity for each control object, each transmission line where an overload occurs, and each bus where an abnormal voltage occurs. The sensitivity calculation unit 16 may calculate the sensitivity multiple times for one control object and one transmission line or one bus. For example, the sensitivity calculation unit 16 may calculate the sensitivity multiple times while adjusting the degree of change in the operating state of the equipment in a simulation, and obtain the average or median of the multiple sensitivities that are the results of the multiple calculations as the final sensitivity. Specifically, suppose the control object of the control content is a generator (i), and the control amount of the control content is an active power (P （ｉ） Ｇ ), the sensitivity calculation unit 16 calculates the effective power (P （ｉ） Ｇ ) is changed from −200 MW to 200 MW in increments of 50 MW to calculate nine sensitivities. The sensitivity calculation unit 16 may then calculate the average value of the nine sensitivities as the final sensitivity.

[0077] <Second Calculation Example> The sensitivity calculation unit 16 calculates the effective power (P （ｉ） ) and reactive power (Q （ｉ） ) and calculates a voltage sensitivity matrix that indicates a change in the voltage of node (i) with respect to a change in voltage (V). For example, the sensitivity calculation unit 16 calculates the voltage sensitivity matrix by calculating the partial derivative of the power flow equation. The power flow equation is an equation that indicates the relationship between the active power and reactive power flowing into a node and the voltage of the node, and is expressed as the following equation (7).

[0078]

[0079] P （ｉ） and Q （ｉ） are the active power and reactive power flowing into node (i), respectively. （ｉ） (^・ means that a ・ is placed on the character immediately before it) is the voltage of node (i), and V （ｉ） exp(jV （ｉ） ) is expressed as Y^. ｉｋ is the nodal admittance matrix.

[0080] The equation (7) representing the power flow equation is expressed as V for the real and imaginary parts, respectively. （ｉ） and δ （ｉ） When partially differentiated with respect to , the following equation (8) is obtained.

[0081]

[0082] Equation (8) expresses the change in voltage (ΔV （ｉ） , Δδ （ｉ） ) the change in the active power and reactive power of node (i) (ΔP （ｉ） , ΔQ （ｉ） ) The matrix J is called the Jacobian matrix of the power flow equation. The inverse matrix J of the matrix J is given in equation (8). －１ By multiplying from the left, the following equation (9) is obtained.

[0083]

[0084] Equation (9) expresses the change in active and reactive power (ΔP （ｉ） , ΔQ （ｉ）) to the change in voltage (ΔV （ｉ） , Δδ （ｉ） ) Therefore, the inverse matrix J of the Jacobian matrix －１ is a voltage sensitivity matrix. For example, if the node to be controlled is node (i) and the node where an abnormal voltage occurs is node (j), the change in active power and reactive power (ΔP （ｉ） , ΔQ （ｉ） ) to the change in voltage (ΔV （ｊ） ) is expressed as the following equation (10).

[0085]

[0086] The sensitivity calculation unit 16 calculates the voltage sensitivity matrix (J －１ ) is calculated, and a power flow sensitivity matrix is ​​calculated that indicates changes in the active power flow and reactive power flow of the transmission line with respect to changes in node voltage. For example, in a model such as that shown in FIG. 6, the active power flow (P （ｋ） ｆ ) and reactive power flow (Q （ｋ） ｆ ) and the voltage of node (i) (V^· （ｉ） ) and the voltage of node (j) (V^· （ｊ） ) the relationship of the following equation (11) holds.

[0087]

[0088] y^・ ｋ is the admittance of the transmission line (k). （ｉ） , δ （ｉ） , V （ｊ） and δ （ｊ） When partially differentiated with respect to, the following equation (12) is obtained.

[0089]

[0090] Equation (12) expresses the change in voltage (ΔV （ｉ） , Δδ （ｉ） ) the change in the active and reactive power flows of the transmission line (k) relative to （ｋ） ｆ , ΔQ （ｋ）ｆ ) Therefore, the matrix P is the load flow sensitivity matrix.

[0091] Substituting equation (9) into equation (12) gives the change in active power and reactive power (ΔP （ｉ） , ΔQ （ｉ） ) the change in the active and reactive power flows of the transmission line (k) relative to （ｋ） ｆ , ΔQ （ｋ） ｆ ) is obtained as follows:

[0092]

[0093] The sensitivity calculation unit 16 calculates the voltage sensitivity matrix (J －１ ) and the power flow sensitivity matrix (P) are combined to calculate the sensitivity using equation (13). For example, if the node to be controlled is node (i) and the transmission line where an overload has occurred is transmission line (k), the change in active power and reactive power (ΔP （ｉ） , ΔQ （ｉ） ) the change in the active and reactive power flows of the transmission line (k) relative to （ｋ） ｆ , ΔQ （ｋ） ｆ ) are expressed as in the following equations (14) and (15):

[0094]

[0095]

[0096] <Summary of Second Embodiment> The control targets of the grid stabilization system 8 may include facilities of power generation companies and general consumers as well as the general electricity transmission and distribution company (electric power company) that operates the grid stabilization system 8. When controlling the facilities of power generation companies and general consumers, the operator of the grid stabilization system 8 may need to explain the appropriateness of the control contents to the power generation companies, consumers, etc.

[0097] Therefore, the grid stabilization system 8 according to the second embodiment calculates the sensitivity of at least one of the power flow in the power transmission lines of the power grid and the voltage of the bus bars of the power grid based on the control content. With this configuration, for example, the operator of the grid stabilization system 8 can explain the effectiveness and appropriateness of the control content in eliminating overloads and abnormal voltages by referring to the calculated sensitivity.

[0098] The sensitivity calculation unit 16 may also calculate sensitivities for other control targets, such as transmission line and bus equipment. In this case, for example, the operator of the grid stabilization system 8 can use the calculated sensitivity as a reference to explain why the equipment was not selected as a control target in resolving overload and abnormal voltage. Furthermore, the grid stabilization system 8 may use AI (artificial intelligence) to machine-learn (train) an explanation of the validity of the control content based on the calculated sensitivity so that the explanation can be presented to the operator of the grid stabilization system 8.

[0099] <Embodiment 3> Fig. 7 is a block diagram showing the configuration of a power system stabilization system 8 according to Embodiment 3. The configuration in Fig. 7 is the same as the configuration in Fig. 2 with a coefficient setting unit 17 added.

[0100] In the third embodiment, the first to fourth configurations described below make it possible to prevent control from concentrating on a specific piece of equipment among the controlled objects, or to make a specific piece of equipment among the controlled objects more or less difficult to control. Note that the third embodiment may be provided with at least one of the first to fourth configurations.

[0101] <First Configuration> In the first configuration, the coefficient setting unit 17 sets a weighting coefficient for adjusting a control value, which is at least one of the control amount and the number of times of control, for each of a plurality of control targets, and the control content calculation unit 15 uses an objective function including the set weighting coefficient in the OPF. For example, the coefficient setting unit 17 sets a weighting coefficient W ｉ ＰＧ , W ｉ ＰＬ , W ｉＰＲＥＳ In the following description, the weighting coefficient W ｉ ＰＧ , W ｉ ＰＬ , W ｉ ＰＲＥＳ When there is no need to distinguish between these two, they are referred to as weighting coefficients W. The control content calculation unit 15 calculates the weighting coefficients W by using the formula (2). ｉ ＰＧ , W ｉ ＰＬ , W ｉ ＰＲＥＳ The objective function expressed by the following equation (16) including the above is used in the OPF.

[0102]

[0103] For example, the weighting factor W in equation (16) ｉ ＰＧ The larger the weighting coefficient W in equation (16), the smaller the control value of the generator (i) becomes, and the less likely the generator (i) is to be controlled. ｉ ＰＧ The smaller the value, the larger the control value of the generator (i), and the more likely the generator (i) is to be controlled.

[0104] Therefore, the coefficient setting unit 17 sets the weighting coefficient W of the control object to a larger value so that the control value of the control object becomes smaller as the past control value of the control object becomes larger. On the other hand, the coefficient setting unit 17 sets the weighting coefficient W of the control object to a smaller value so that the control value of the control object becomes larger as the past control value of the control object becomes smaller.

[0105] According to the first configuration, it is possible to prevent control from being concentrated on a specific piece of equipment among the controlled objects, and therefore it is possible to make the control of the controlled objects fair (uniform).

[0106] The objective function including the weighting coefficients set by the control content calculation unit 15 is not limited to equation (16), and may be, for example, an objective function including equation (3) and a weighting coefficient. Furthermore, the coefficient setting unit 17 may set the weighting coefficients determined by trial and error by the operator of the grid stabilization system 8 as they are, or may set weighting coefficients calculated by the following equations (17) and (18), or may set weighting coefficients other than these.

[0107]

[0108]

[0109] P ｉ Ｇｔｏｔａｌ is the cumulative control amount in the operation of the generator (i) up to now, and a Ｇ , b Ｇ , c Ｇ is a parameter for calculating the weighting coefficient.

[0110] <Second Configuration> In the second configuration, similarly to the first configuration, the coefficient setting unit 17 sets a weighting coefficient W that adjusts the control value of each of a plurality of control objects, and the control content calculation unit 15 uses, in the OPF, an objective function that includes the set weighting coefficient W. However, the coefficient setting unit 17 sets the weighting coefficient W of the control object so that a predetermined piece of equipment is less likely or more likely to be selected as a control object, or so that, when selected, the control value is smaller or larger.

[0111] For example, when a facility for which continuous operation or a stable supply of power is desired is set as the predetermined facility, the coefficient setting unit 17 sets the weighting coefficient W of the facility to a large value so that the facility is less likely to be selected as the facility to be controlled and the control value thereof is smaller than that of other facilities. Facilities for which continuous operation or a stable supply of power is desired include, for example, hospitals or must-run power sources necessary for stabilizing the power system.

[0112] On the other hand, when a facility that is preferably the control target is set as the predetermined facility, the coefficient setting unit 17 sets the weighting coefficient W of the control target to a small value so that the facility is more likely to be selected as the control target and the control value is larger than that of other facilities. A facility that is preferably the control target is, for example, a power plant that can be quickly restored even if it is stopped or that requires low cost for restoration.

[0113] According to the second configuration, it is possible to make a specific piece of equipment that is the object of control more difficult to control or more easily controllable.

[0114] <Third Configuration> In the third configuration, the control content calculation unit 15 generates an objective function for minimizing the variation in the control amounts of multiple control objects and uses the generated objective function in the OPF. For example, when performing the OPF using a certain objective function, the control content calculation unit 15 performs the OPF using an objective function for minimizing the variation in the control amounts of multiple control objects. The objective function for minimizing the variation in the control amounts of multiple control objects is expressed, for example, as in the following equation (19).

[0115]

[0116] Furthermore, K Ｇ３ , K Ｌ３ , K ＲＥＳ３ is a weighting coefficient of the objective function. This weighting coefficient may be constant or may be changed based on the history of the control amounts of multiple controlled objects. σ ２ ＰＧ , σ ２ ＰＬ , σ ２ ＰＲＥＳ is a variance indicating the variation in the interruption amount of the generator 2, the load 3, and the renewable energy power source 4. The variance of the interruption amount of the generator 2 is expressed, for example, as the following equation (20), and the variance of the interruption amount of the load 3 and the renewable energy power source 4 can be expressed in a similar manner.

[0117]

[0118] In the above description, the variation in the controlled variables among a plurality of control targets is the variation in the interruption amounts of the generator 2, the load 3, and the renewable energy power source 4. However, this is not limited to this, and it may be, for example, the variation in the interruption amounts of the generator 2, the load 3, and the renewable energy power source 4 as a whole. Furthermore, in the above description, the variation in the controlled variables is the variance of the controlled variables, but it is not limited to this, and it may be, for example, the standard deviation, average deviation, or difference between the maximum and minimum values ​​of the controlled variables.

[0119] According to the third configuration, it is possible to prevent control from being concentrated on a specific piece of equipment among the controlled objects, thereby making it possible to make the control of the controlled objects fair (uniform).

[0120] In the fourth configuration, the control content calculation unit 15 adjusts the control amounts of the multiple control objects based on the history of the control amounts of the multiple control objects when the control effects of the multiple control objects correspond to each other. The control effects of the multiple control objects corresponding to each other include, for example, at least one of the following: the electrical distance between the multiple control objects is equal to or less than a threshold; and the difference between the power flow change and the voltage change of the multiple control objects is equal to or less than a threshold.

[0121] For example, if the control effect of a first control object corresponds to the control effect of a second control object, the control content calculation unit 15 may determine, based on the control amount history, whether the total value of the control amounts of the first control object to date is greater than a first threshold and whether the total value of the control amounts of the second control object to date is less than a second threshold that is less than the first threshold. If the control content calculation unit 15 determines that the total value of the first control object is greater than the first threshold and the total value of the second control object is less than the second threshold, the control content calculation unit 15 may replace the current control amount of the first control object with the current control amount of the second control object. Alternatively, the control content calculation unit 15 may set the average value of the control amount of the first control object calculated by the current OPF and the control amount of the second control object calculated by the current OPF as the control amounts of the first control object and the second control object.

[0122] For example, if the control effect of the first control object corresponds to the control effect of the second control object, the control content calculation unit 15 may replace the control amount of the first control object calculated by the current OPF with the control amount of the second control object calculated by the current OPF according to the rotation table.

[0123] According to the fourth configuration, it is possible to prevent control from being concentrated on a specific piece of equipment among the controlled objects, thereby making it possible to make the control of the controlled objects fair (uniform).

[0124] <Operation> Fig. 8 is a flowchart showing the operation of the power grid stabilization system 8 according to the third embodiment. The operation in Fig. 8 is the same as the operation in Fig. 4 except that step S11 is added and steps S5 and S6 in Fig. 4 are changed to steps S5a and S6a. Therefore, the following description will mainly focus on steps S11, S5a, and S6a.

[0125] If it is determined in step S4 that an overload or abnormal voltage will occur, the process proceeds to step S11. In step S11, the coefficient setting unit 17 sets the weighting coefficients described in the first and second configurations. Thereafter, the process proceeds to step S5a.

[0126] In step S5a, the control content calculation unit 15 calculates the control content including the control target and the control amount of the control target by the OPF based on the system model and the equipment information. The objective function used in the OPF includes, for example, at least one of the objective functions described in the first to third configurations.

[0127] In step S6a, the control content calculation unit 15 adjusts the control amount as described in the fourth configuration, or discretizes the control amount, if necessary.

[0128] Summary of Third Embodiment According to the power system 8 according to the third embodiment, the first to fourth configurations can prevent control from being concentrated on a specific piece of equipment among the controlled objects, and can make the specific piece of equipment among the controlled objects more or less difficult to control. As a result, the controlled objects can be appropriately controlled.

[0129] <Fourth Embodiment> Fig. 9 is a schematic diagram showing a power system using a power system stabilization system 8 according to the fourth embodiment. The power system stabilization system 8 in Fig. 9 includes a central processing unit 8a and one or more slave station devices 8b that can communicate with the central processing unit 8a. Except for this point, the power system in Fig. 9 is similar to the power system in Fig. 1.

[0130] The central processing unit 8a acquires measurement information of the power system from the measurement devices 7 via the slave station devices 8b and generates a control table that associates predetermined fault patterns with control contents. When the slave station device 8b determines, based on the measurement information, that a fault pattern in the control table has occurred in the power system, it determines the control contents associated with the fault pattern in the control table. The slave station device 8b then transmits (commands) the control contents to the equipment to be controlled, thereby making it possible to resolve the system abnormality that occurs after the fault is cleared.

[0131] <Central Processing Unit 8a> Fig. 10 is a block diagram showing the configuration of the central processing unit 8a. The central processing unit 8a in Fig. 10 includes a communication unit 21 which is a first acquisition unit, a recording unit 22, a postulated accident setting unit 23, a model generation unit 24, and a control content calculation unit 25.

[0132] The communication unit 21 sequentially (e.g., periodically) receives and acquires measurement information of the power system from the measurement device 7 via the slave station device 8 b. The communication unit 21 also appropriately transmits control tables generated by the central processing unit 8 a to the slave station device 8 b.

[0133] The recording unit 22 records the measurement information collected by the communication unit 21, the equipment information of the power system, the calculation results of the control content calculation unit 25, and the control performance of the equipment to date (e.g., the history of the control amount).

[0134] The contingency setting unit 23 sets a plurality of contingency patterns that may occur in the current power system based on the measurement information and the facility information. The contingency patterns include, for example, a ground fault or short circuit of a predetermined first power transmission line due to a lightning strike, a fallen tree, contact with a flying object, etc., and an opening of a predetermined second power transmission line to suppress the impact of a ground fault or short circuit of the first power transmission line. Note that the plurality of contingency patterns do not necessarily have to be predetermined by the contingency setting unit 23, but may be predetermined by the operator of the power system stabilization system 8.

[0135] The model generation unit 24 generates a system model for each of a plurality of accident patterns based on the measurement information, the equipment information, and a plurality of predetermined accident patterns. The generation of the system model by the model generation unit 24 is similar to the generation of the system model by the model generation unit 14 in Fig. 2. In the system model generated by the model generation unit 24, for example, the parts of the connection relationships between the equipment that are disconnected differ depending on the accident pattern.

[0136] The control content calculation unit 25 determines whether an overload or an abnormal voltage will occur based on a system model of a fault pattern, similar to the control content calculation unit 15 described in embodiment 1. Then, when it is determined that an overload or an abnormal voltage will occur, the control content calculation unit 25 calculates the control content by the OPF based on the system model and facility information, similar to the control content calculation unit 15 described in embodiment 1. Note that the control content only needs to include an interruption amount, which is a control amount of at least one of the generator 2 and the load 3, which are the control targets, and may also include an interruption amount, which is a control amount of the renewable energy power source 4, which is the control target, similar to embodiment 1.

[0137] The control content calculation unit 25 generates a control table that associates accident patterns with control contents calculated from the accident patterns. When the control content calculation unit 25 calculates multiple control contents from multiple accident patterns, the multiple accident patterns and the multiple control contents are associated with each other in the control table.

[0138] The components of the central processing unit 8a are not limited to those described above. For example, the central processing unit 8a may further include the sensitivity calculation unit 16 described in the second embodiment, or the coefficient setting unit 17 described in the third embodiment.

[0139] <Slave Station Device 8b> Fig. 11 is a block diagram showing the configuration of the slave station device 8b. The slave station device 8b in Fig. 11 includes a communication unit 31 which is a second acquisition unit, a recording unit 32, an accident occurrence determination unit 33, and a control content determination unit 34.

[0140] The communication unit 31 sequentially (e.g., periodically) receives and acquires measurement information of the power system from the measurement devices 7, and transmits the measurement information to the central processing unit 8a as appropriate. The communication unit 31 also receives and acquires control tables from the central processing unit 8a, and transmits (commands) the control contents determined by the control content determination unit 34 to the equipment to be controlled.

[0141] The recording unit 32 records the facility information of the power system under the control of the slave station device 8 b, and the measurement information and control table acquired by the communication unit 31 .

[0142] 2, the fault occurrence determination unit 33 determines whether or not a fault pattern in the control table has occurred in the power system based on the measurement information. In the fourth embodiment, the fault pattern corresponds to the operating state of a protective relay in the power system, or an overload or an abnormal voltage.

[0143] The control content determination unit 34 determines the control content associated in the control table with the accident pattern determined to have occurred.

[0144] <Operation> FIG. 12 is a flowchart showing the operation of the central processing unit 8a according to the fourth embodiment.

[0145] In step S21, the communication unit 21 sequentially receives and acquires measurement information of the power system from the measurement device 7 via the slave station device 8b.

[0146] In step S22, the assumed fault setting unit 23 or the operator sets a plurality of fault patterns that may occur in the current power system.

[0147] In step S23, the model generator 24 generates a system model for each of the plurality of accident patterns based on the measurement information, the equipment information, and the plurality of accident patterns.

[0148] In step S24, the control content calculation unit 25 determines whether an overload or an abnormal voltage will occur based on the system model of one fault pattern. If it is determined that an overload or an abnormal voltage will occur, the process proceeds to step S25, and if it is not determined that an overload or an abnormal voltage will occur, the process proceeds to step S26.

[0149] In step S25, the control content calculation unit 25 calculates one control content using the OPF based on the system model of one fault pattern and the facility information, and associates one fault pattern with one control content in a control table. Note that the control content determination unit 25 may discretize the control variables included in the control content, as necessary, similar to the control content calculation unit 15 in FIG. 2.

[0150] In step S26, the control content calculation unit 25 determines whether or not the determination in step S24 has been performed for all of the multiple accident patterns. If the determination in step S24 has been performed for all of the multiple accident patterns, the process proceeds to step S27. If the determination in step S24 has not been performed for all of the multiple accident patterns, the process proceeds to step S24.

[0151] In step S27, the communication unit 21 transmits the control table to the slave station device 8b, and then the operation of FIG.

[0152] 13 is a flowchart showing the operation of the slave station device 8b according to the present embodiment 4. It is assumed that before this operation is performed, the slave station device 8b has already received the control table from the central processing unit 8a.

[0153] In step S31, the communication unit 31 sequentially receives and acquires measurement information of the power system from the measurement devices 7, and transmits the measurement information to the central processing unit 8a as appropriate.

[0154] In step S32, the fault occurrence determination unit 33 determines whether or not a fault pattern in the control table has occurred in the power system based on the measurement information. If it is determined that a fault pattern has occurred in the power system, the process proceeds to step S33, and if it is not determined that a fault has occurred in the power system, the process proceeds to step S31.

[0155] In step S33, the control content determination unit 34 determines the control content associated in the control table with the accident pattern determined to have occurred. Note that the control content determination unit 34 may discretize the control amount included in the control content, as necessary, similar to the control content calculation unit 15 in FIG. 2.

[0156] In step S34, the communication unit 31 transmits the control content to the equipment determined as the control target. As a result, the equipment determined as the control target performs control based on the control amount. Thereafter, the operation of FIG. 13 ends.

[0157] Summary of Fourth Embodiment According to the power system stabilization system 8 according to the fourth embodiment, the central processing unit 8 a can create a control table including control contents before an accident occurs in the power system and transmit the control table to the slave station device 8 b. Then, when an accident occurs in the power system, the slave station device 8 b can determine the control contents without communicating with the central processing unit 8 a.

[0158] This reduces the processing load on the central processing unit 8a after an accident and allows the slave station device 8b to quickly transmit control information to the controlled object. This eliminates the need for a high-performance computer and a wide-area, high-speed communication network. To more quickly transmit control information from the slave station device 8b to the controlled object, it is preferable that the electrical distance between the slave station device 8b and the controlled object be shorter than the electrical distance between the central processing unit 8a and the controlled object.

[0159] <Other Modifications> The communication unit 11, the accident occurrence determination unit 13, the model generation unit 14, and the control content calculation unit 15 shown in FIG. 2 are hereinafter referred to as the "communication unit 11, etc." The communication unit 11, etc. are realized by a processing circuit 81 shown in FIG. 14. That is, the processing circuit 81 includes the communication unit 11 that acquires measurement information of the power system, the accident occurrence determination unit 13 that determines whether an accident has occurred in the power system based on the measurement information, the model generation unit 14 that generates a power system model based on the measurement information and equipment information of the power system when it is determined that an accident has occurred, and the control content calculation unit 15 that calculates control content including a control object and a control amount of the control object by optimal power flow calculation based on the power system model and the equipment information when it is determined that an overload or abnormal voltage will occur based on the power system model. The control content includes a shedding amount, which is a control amount of at least one of the generator and the load, which are the control objects. The processing circuit 81 may be implemented by dedicated hardware or a processor that executes a program stored in a memory. Examples of processors include central processing units, processing units, arithmetic units, microprocessors, microcomputers, and DSPs (Digital Signal Processors).

[0160] When the processing circuitry 81 is dedicated hardware, the processing circuitry 81 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The functions of each unit, such as the communication unit 11, may be realized by a circuit in which processing circuits are distributed, or the functions of each unit may be realized by a single processing circuit.

[0161] When the processing circuit 81 is a processor, the functions of the communication unit 11 and the like are realized in combination with software and the like. The software and the like may include, for example, software, firmware, or both software and firmware. The software and the like are written as a program and stored in a memory. As shown in FIG. 15 , the processor 82 applied to the processing circuit 81 realizes the functions of each unit by reading and executing a program stored in a memory 83. That is, the power grid stabilization system 8 includes a memory 83 for storing a program that, when executed by the processing circuit 81, results in the following steps: acquiring measurement information of the power grid; determining whether an accident has occurred in the power grid based on the measurement information; generating a power grid model based on the measurement information and equipment information of the power grid if it is determined that an accident has occurred; and calculating control details, including a control target and a control amount of the control target, by optimal power flow calculation based on the power grid model and the equipment information if it is determined that an overload or abnormal voltage will occur based on the power grid model. In other words, this program can be said to cause a computer to execute the procedures and methods of the communication unit 11 and the like. Here, the memory 83 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory), a HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), a drive device for any of these, or any storage medium to be used in the future.

[0162] The above describes a configuration in which each function of the communication unit 11 and the like is realized either by hardware or software, etc. However, the present invention is not limited to this, and a configuration in which part of the communication unit 11 and the like is realized by dedicated hardware and another part is realized by software, etc. For example, the function of the communication unit 11 can be realized by a processing circuit 81 as dedicated hardware, and the other functions can be realized by the processing circuit 81 as a processor 82 reading and executing a program stored in a memory 83.

[0163] As described above, the processing circuit 81 can realize the above-mentioned functions by hardware, software, or a combination of these. Note that the components of the power grid stabilization system 8 in Fig. 5, the components of the power grid stabilization system 8 in Fig. 7, the components of the central processing unit 8a in Fig. 10, and the components of the slave station device 8b in Fig. 11 are similar to those described above.

[0164] It should be noted that the embodiments and modifications may be freely combined, and the embodiments and modifications may be modified or omitted as appropriate.

[0165] The above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned.

[0166] 2 Generator, 3 Load, 4 Renewable energy power source, 5 Storage battery, 6 Voltage control device, 8 System stabilization system, 8a Central processing unit, 8b Slave station device, 11, 21, 31 Communication unit, 13, 33 Fault occurrence determination unit, 14, 24 Model generation unit, 15, 25 Control content calculation unit, 16 Sensitivity calculation unit, 17 Coefficient setting unit, 34 Control content determination unit.

Claims

1. A power system stabilization system comprising: an acquisition unit that acquires measurement information of a power system including a generator and a load; an accident occurrence determination unit that determines whether or not an accident has occurred in the power system based on the measurement information; a model generation unit that, when it is determined that the accident has occurred, generates a power system model based on the measurement information and equipment information of the power system; and a control content calculation unit that, when it is determined based on the power system model that an overload or abnormal voltage will occur, calculates control content including a control object and a control amount of the control object by optimal power flow calculation based on the power system model and the equipment information, wherein the control content includes a cutoff amount that is the control amount of at least one of the control objects, the generator and the load.

2. A power system stabilization system according to claim 1, wherein the power system further includes a renewable energy power source, a storage battery, and a voltage control device, and the control content further includes at least one of: a cutoff amount, which is the control amount of the renewable energy power source that is the control target; and active power and reactive power, which are the control amounts of the renewable energy power source, the storage battery, and the voltage control device that are the control targets.

3. A power system stabilization system according to claim 1 or 2, further comprising a sensitivity calculation unit that calculates the sensitivity of at least one of the power flow in the transmission lines of the power system and the voltage of the bus bars of the power system based on the control content.

4. A system stabilization system according to claim 3, wherein the sensitivity calculation unit calculates the sensitivity by changing the operating state of the controlled object and performing a system calculation.

5. A power system stabilization system according to claim 3, wherein the sensitivity calculation unit calculates the sensitivity using a voltage sensitivity matrix, which is an inverse matrix of a Jacobian matrix of a power flow equation and which represents a change in voltage of the node to be controlled in response to a change in active power and reactive power of the node, and a power flow sensitivity matrix which represents a change in active power flow and reactive power flow of the transmission line in response to a change in voltage of the node.

6. A power system stabilization system according to any one of claims 1 to 5, wherein the control content calculation unit uses an objective function for minimizing the variation in the control quantities of the plurality of control objects in the optimal power flow calculation.

7. A power system stabilization system according to any one of claims 1 to 6, wherein the control content calculation unit adjusts the control amounts of the plurality of control objects based on the history of the control amounts of the plurality of control objects when the control effects of the plurality of control objects correspond to each other.

8. A power system stabilization system according to any one of claims 1 to 7, further comprising a coefficient setting unit that sets a weighting coefficient for adjusting a control value, which is at least one of the control amount and the number of control times, for each of the plurality of control objects, and wherein the control content calculation unit uses an objective function including the weighting coefficient in the optimal power flow calculation.

9. A power system stabilization system according to claim 8, wherein the coefficient setting unit sets the weighting coefficient so that the larger the past control value of the controlled object, the smaller the control value of the controlled object, or so that the smaller the past control value of the controlled object, the larger the control value of the controlled object.

10. A power system stabilization system according to claim 8, wherein the coefficient setting unit sets the weighting coefficient when the controlled object is a predetermined facility so that the control value of the controlled object becomes large or small.

11. A system comprising: a central processing unit; and a slave station device capable of communicating with the central processing unit, wherein the central processing unit comprises: a first acquisition unit that acquires measurement information of a power system including a generator and a load; a model generation unit that generates a system model for each of a plurality of predetermined fault patterns based on the measurement information, equipment information of the power system, and a plurality of predetermined fault patterns; and a control content calculation unit that, when it is determined that an overload or abnormal voltage will occur based on the system model of the fault pattern, calculates control content including a control object and a control amount of the control object by optimal power flow calculation based on the system model and the equipment information, and generates a control table that associates the fault pattern with the control content, wherein the control content includes an interruption amount that is the control amount of at least one of the generator and the load that are the control objects; and the slave station device comprises: a second acquisition unit that acquires the measurement information and the control table; and an fault occurrence determination unit that determines whether or not the fault pattern in the control table has occurred in the power system based on the measurement information. a control content determination unit that determines the control content associated in the control table with the fault pattern that is determined to have occurred.

12. A system stabilization method comprising: acquiring measurement information of a power system including a generator and a load; determining whether or not an accident has occurred in the power system based on the measurement information; generating a system model based on the measurement information and equipment information of the power system when it is determined that an accident has occurred; calculating control details including a control object and a control amount of the control object by optimal power flow calculation based on the system model and the equipment information when it is determined that an overload or abnormal voltage will occur based on the system model; and calculating the control details including a cutoff amount, which is the control amount of at least one of the generator and the load, which are the control objects.

13. A system stabilization method for a system stabilization system, the system comprising: a central processing unit; and a slave station device capable of communicating with the central processing unit; the central processing unit acquires measurement information of a power system including a generator and a load; generates a system model for each of the plurality of predetermined fault patterns based on the measurement information, equipment information of the power system, and a plurality of predetermined fault patterns; when it is determined that an overload or abnormal voltage will occur based on the system model for the fault pattern, calculates control details including a control object and a control amount of the control object by optimal power flow calculation based on the system model and the equipment information, and generates a control table correlating the fault pattern with the control details; the control details include an interruption amount which is the control amount of at least one of the generator and the load which are the control objects; the slave station device acquires the measurement information and the control table; and determines whether or not the fault pattern in the control table has occurred in the power system based on the measurement information; and determines the control details associated in the control table with the fault pattern determined to have occurred.

Images