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

Abstract

To provide a power system control device, a computer program for the power system control device, and a power system control method, capable of selecting an appropriate power supply path in a shorter time by reducing combinations in calculation of an opening / closing state of each switch.SOLUTION: A power system control device 1 opens and closes a plurality of switches on the basis of information on a configuration of a power system having the plurality of switches which become a power supply path by being closed, and does not stop power supply to each node in the power system. The power supply system includes: a constraint generation unit (12) which creates a power system model for supplying power to each node by one path; an objective function generation unit (13) which creates an objective function for the power system model created by the constraint generation unit (12); and a function solution calculation unit (14) which selects opening / closing of a switch so that the value of the objective function created by the objective function generation unit (13) is closer to a target value, and outputs information indicating opening / closing of the switch selected by the function solution calculation unit (14).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present embodiment relates to a power system control device that controls generators and switches connected to a power system that transmits and distributes electric power, a computer program for the power system control device, and a power system control method. [Background technology]

[0002] A generator that generates electric power is connected to a power grid that transmits and distributes electric power. The electric power output from the generator is supplied to a load via a switch. A power grid control device that controls the generator and the switch connected to the power grid is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-33848 [Non-patent literature]

[0004] [Non-Patent Document 1] A Survey of Relaxations and Approximations of the Power Flow Equations DK Molzahn1 and IA Hiskens 2019 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the connection of power sources that utilize natural energy, such as solar power and wind power, to the power grid has been promoted. Accordingly, institutional reforms are being promoted to connect so-called non-farm type power sources to the power grid. Such non-farm type power sources may be connected to the power grid even when there is no available capacity in the power grid.

[0006] These reforms to the power supply system have resulted in a large number of power generation facilities being connected to the power grid, which may cause congestion even during normal times. In the event of an accident in the power grid, congestion in the power grid will become even more pronounced.

[0007] According to conventional technology, congestion in the power grid is alleviated by suppressing the output of power generation facilities. This sometimes results in suppressing the output of renewable energy sources, which is inappropriate from the perspective of utilizing natural energy. Furthermore, because the generation costs of renewable energy sources are low, suppressing the output of renewable energy sources is sometimes undesirable.

[0008] In order to alleviate congestion in the power system and to utilize renewable energy sources, it is preferable to control switches arranged in the power system and select an appropriate power supply path to a load.

[0009] However, since a large number of switches are installed in a power system, the number of combinations of open and closed states of each switch is enormous. Therefore, there is a problem that it takes time to select an appropriate power supply path to a load. Even when there is no fault in the power system, it is preferable to select a power supply path in a short time.

[0010] In order to solve the above-mentioned problems, the present embodiment aims to provide a power system control device, a computer program for the power system control device, and a power system control method that can reduce the number of combinations in the calculation of the open / closed state of each switch and select an appropriate power supply path in a shorter time. [Means for solving the problem]

[0011] The power system control device of this embodiment has the following features. (1) A constraint generation unit is provided to create a power system model based on information about the configuration of a power system having a plurality of switches that become power supply paths when closed, by opening and closing the plurality of switches so that the power supply to each node in the power system is not interrupted and power is supplied to each node via a single path. (2) An objective function generation unit that generates an objective function related to the power system model generated by the constraint generation unit. (3) A function solution calculation unit is provided that selects opening and closing of the switch so that the value of the objective function created by the objective function generation unit approaches a target value. (4) Outputting information indicating the open / closed state of the switch selected by the function solution calculation unit. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a configuration of a power system control device according to a first embodiment; [Figure 2] FIG. 1 is a flowchart showing a program of a power system control device according to a first embodiment. [Figure 3] FIG. 1 is a diagram showing an example of the configuration of a power system that is the target of calculations by a power system control device according to a first embodiment; [Figure 4] FIG. 1 is a diagram showing an example of piecewise linear approximation of transmission loss characteristics in calculations of the power system control device according to the first embodiment; [Figure 5] FIG. 1 is a diagram showing an example of a power system model created by a power system control device according to a first embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0013] [1. First embodiment] [1-1.Configuration] The configuration of a power system control device 1, which is an example of this embodiment, will be described with reference to Fig. 1. The power system control device 1 is a device that reduces the number of combinations required for calculating the open / closed state of each switch arranged in a power system, and selects an appropriate power supply path in a shorter time.

[0014] The power system control device 1 is connected to a control target (not shown in the figure) connected to the power system via a communication line (not shown in the figure) and controls the control target. The control target is a power generation facility and a switch, such as a power source that generates electricity using hydroelectric power, thermal power, or nuclear power, or a non-farm type power source that uses natural energy such as solar power or wind power. The power system control device 1 is configured with a computer, etc. The power system control device 1 is installed in the office of a business operator that monitors or controls the power system.

[0015] The power system control device 1 has an approximate equation generation unit 11, a constraint generation unit 12, an objective function generation unit 13, a function solution calculation unit 14, an external transmission unit 15, and a storage unit 90. The approximate equation generation unit 11, the constraint generation unit 12, the objective function generation unit 13, the function solution calculation unit 14, and the external transmission unit 15 are functional blocks configured by an arithmetic unit in a computer or a software module. The approximate equation generation unit 11, the constraint generation unit 12, the objective function generation unit 13, the function solution calculation unit 14, the external transmission unit 15, and the storage unit 90 may be configured by hardware or individual units.

[0016] When the approximate equation generation unit 11, the constraint generation unit 12, the objective function generation unit 13, the function solution calculation unit 14, and the external transmission unit 15 are configured as software modules using a computer program, the approximate equation generation unit 11 may be referred to as an approximate equation generation step, the constraint generation unit 12 as a constraint generation step, the objective function generation unit 13 as an objective function generation step, the function solution calculation unit 14 as a function solution calculation step, and the external transmission unit 15 as an external transmission step.

[0017] The storage unit 90 is configured with a storage medium such as a semiconductor memory or a hard disk, and has a power system related database 91 (sometimes referred to as a "power system related DB 91"), a power plant related database 92 (sometimes referred to as a "power plant related DB 92"), and a load demand related database 93 (sometimes referred to as a "load demand related DB 93").

[0018] The power system related database 91 stores predetermined power system related data such as the configuration of the power system. The power plant related database 92 stores predetermined power plant related data such as upper and lower limit outputs of generators. The load demand related database 93 stores predetermined load demand related data such as load demand on a node basis.

[0019] In addition, the memory unit 90 may be configured to store the output of the regulated power source created using an approximate function by the approximate equation generation unit 11 described below, the transmission loss characteristics, the constraint equation created by the constraint generation unit 12, the objective function created by the objective function generation unit 13, and the optimal solution calculated by the function solution calculation unit 14.

[0020] The approximation equation generation unit 11 generates an approximation function for characteristics expressed by a nonlinear equation. The approximation function may be, for example, a linear equation or a second-order cone equation. The approximation equation generation unit 11 generates a piecewise linear approximation function for the output of the regulated power source. The approximation equation generation unit 11 also generates a piecewise linear approximation function for transmission loss characteristics.

[0021] For example, the approximate equation generating unit 11 generates a piecewise linear approximate function for the output of the regulated power supply by dividing the output range by a predetermined number. The approximate equation generating unit 11 generates a piecewise linear approximate function for the transmission loss characteristics by dividing the transmission loss L with respect to the phase difference angle δ of the transmission line by a predetermined number.

[0022] The constraint generation unit 12 creates a power system model based on various data. The power system model created by the constraint generation unit 12 may be expressed by mathematical expressions or may be expressed geometrically using graphics. The power system model expressed by mathematical expressions may be a constraint equation.

[0023] The constraint generation unit 12 generates constraint equations based on information about the configuration of the power system. The information about the configuration of the power system may include, in addition to the geometric configuration of the power system including the arrangement of switches, a piecewise linear approximation function related to the output of the regulated power source and a piecewise linear approximation function related to the transmission loss characteristics of the transmission line, which are generated by the approximation function generation unit 11.

[0024] The constraint generation unit 12 creates a constraint equation for at least one of the following constraints: a constraint for maintaining the configuration of a radial system; a constraint on a power equation including the open / close state of a switch; a constraint on the upper and lower limits of power flow in a transmission line; and a constraint on transmission loss in a transmission line.

[0025] The power system has a loop system configured in a ring shape and multiple radial systems configured by branching or radially branching from the loop system. The constraint for maintaining the configuration of the radial system may be a constraint that the system must be one or more branched or radial systems.

[0026] The objective function generator 13 generates an objective function related to the power system model created by the constraint generator 12. The objective function may be a function related to cost or a function related to transmission loss. As an example, the objective function generator 13 generates an objective function related to cost according to the power system model created by the constraint generator 12. The objective function may include terms related to power generation cost and cost spent on system switching. The objective function generator 13 generates the objective function based on the output and transmission loss characteristics of the regulated power sources created by the approximation function created by the approximation equation generator 11. As an example, the objective function generator 13 generates the sum of the regulation costs and system switching costs of all regulated power sources to be controlled in the power system as the objective function.

[0027] The function solution calculation unit 14 performs optimization calculations to bring the value of the objective function created by the objective function generation unit 13 closer to the target value, thereby calculating an optimal solution. The target value may be a minimum value, a maximum value, or a predetermined value. The function solution calculation unit 14 calculates the output of each regulated power source and the open / closed state of each switch through optimization calculations. As an example, the function solution calculation unit 14 sets the target value of the objective function to the minimum value, and selects the open / close of the switch so that the value related to cost of the objective function created by the objective function generation unit 13 becomes smaller.

[0028] The external transmitter 15 transmits the output of each regulated power source, which is the optimal solution calculated by the function solution calculator 14, and the open / close state of each switch to the controlled object, and issues a control command. The external transmitter 15 is configured to include a communication circuit (not shown in the figure). The external transmitter 15 is connected to the controlled object via a communication line. The controlled object is a power generation facility and a switch, such as a power source that generates electricity using hydroelectric power, thermal power, or nuclear power, or a non-farm type power source that uses natural energy such as solar power or wind power.

[0029] The above is the configuration of the power system control device 1 according to the first embodiment.

[0030] [1-2. Effect] Next, the operation of the power system control device 1 of this embodiment will be described with reference to FIGS.

[0031] The power system control device 1 reduces the number of combinations of open / closed states of switches in the power system, and selects an appropriate power supply path in a shorter time.

[0032] The operation of the power system control device 1 is outlined below.

[0033] The approximate expression generating unit 11 generates a piecewise linear approximate function for the output of the regulated power supply by dividing the output range by a predetermined number. The approximate expression generating unit 11 also generates a piecewise linear approximate function for the transmission loss characteristics.

[0034] The constraint generation unit 12 creates a power system model based on information about the configuration of a power system having a plurality of switches that become power supply paths when closed, by opening and closing the plurality of switches so that the power supply to each node in the power system is not interrupted and power is supplied to each node via one path.

[0035] The power system has a loop system configured in a ring shape and multiple radial systems that branch out or radiate from the loop system. Switches are placed between the multiple radial systems and inside the radial systems, and when closed, they become power supply paths.

[0036] The information regarding the configuration of the power system may include a piecewise linear approximation function regarding the output of the regulating power source placed in the power system, which is created using an approximation function by the approximation equation generation unit 11, and a piecewise linear approximation function regarding the transmission loss characteristics of the transmission lines placed in the power system.

[0037] The power system model created by the constraint generation unit 12 may be expressed by mathematical expressions or may be expressed geometrically using graphics. The power system model created by the constraint generation unit 12 may include a constraint equation relating to at least one of constraints for maintaining the configuration of a radial system, constraints on power equations including the open / closed states of switches, constraints on upper and lower limits of power flow in transmission lines arranged in the power system, and constraints on transmission losses in transmission lines.

[0038] The objective function generator 13 generates an objective function related to the power system model created by the constraint generator 12. As an example, the objective function generator 13 generates an objective function related to costs according to the power system model created by the constraint generator 12. The objective function may include terms related to power generation costs and costs spent on system switching.

[0039] The function solution calculation unit 14 performs optimization calculations to calculate an optimal solution so that the value of the objective function created by the objective function generation unit 13 approaches a target value. The target value may be a minimum value, a maximum value, or a predetermined value. As an example, the function solution calculation unit 14 sets the target value of the objective function to a minimum value, and selects whether to open or close the switch so that the value related to cost of the objective function created by the objective function generation unit 13 becomes smaller.

[0040] The external transmitter 15 outputs information indicating the open / closed state of the switch selected by the function solution calculator 14. The external transmitter 15 outputs information regarding the output of each regulated power supply together with the information indicating the open / closed state of the switch.

[0041] The details of the operation of the power system control device 1 are as follows: As an example, the operation of the power system control device 1 will be described when a function relating to costs according to a power system model is created as an objective function.

[0042] The operation of the power system control device 1 is realized, for example, by a computer program shown in Fig. 2. Fig. 2 shows a flow diagram of the computer program of the power system control device 1.

[0043] The computer program shown in Fig. 2 is executed when congestion occurs in the power grid or when congestion is predicted to occur. The computer program shown in Fig. 2 may be executed at predetermined intervals.

[0044] An example of the configuration of a power system is shown in Figure 3. The power system has a loop system configured in a ring shape and one or more radial systems configured by branching or radially branching from the loop system. The power generation equipment and switches installed in the power system are the control targets of the power system control device 1.

[0045] The power system related database 91 of the storage unit 90 stores pre-set power system related data including the configuration of the power system. The power plant related database 92 stores pre-set power plant related data including upper and lower limit outputs of generators. The load demand related database 93 stores pre-set load demand related data including load demand on a node-by-node basis.

[0046] (Step S1: Create a piecewise linear approximation function for the output of the regulated power supply) Step S1 is executed by the approximate equation generation unit 11. The approximate equation generation unit 11 receives power system related data from the power system related database 91, power plant related data from the power plant related database 92, and load demand related data from the load demand related database 93.

[0047] The approximation formula generation unit 11 generates an approximation function by piecewise linear approximation of the output of the regulated power supply based on the power plant-related data received from the power plant-related database 92. The approximation formula generation unit 11 generates an approximation function for characteristics expressed by a nonlinear equation. The approximation function is, for example, a linear equation or a second-order cone equation. The approximation formula generation unit 11 generates a piecewise linear approximation function for the output of the regulated power supply by dividing the output range by a predetermined number.

[0048] (Step S2: Create a piecewise linear approximation function of the transmission loss characteristics) Step S2 is executed by the approximation equation generation unit 11. The approximation equation generation unit 11 generates a piecewise linear approximation function of the transmission loss characteristics based on the power system related data received from the power system related database 91, the power plant related data received from the power plant related database 92, and the load demand related data received from the load demand related database 93. The approximation equation generation unit 11 generates an approximation function for the characteristics expressed by a nonlinear equation. The approximation function is, for example, a linear equation or a second-order cone equation.

[0049] The approximate equation generating unit 11 generates a piecewise linear approximate function for the transmission loss characteristics by dividing the transmission loss L with respect to the phase difference angle δ of the transmission line by a predetermined number. Fig. 4 shows an example of the piecewise linear approximate function for the transmission loss characteristics.

[0050] The transmission loss characteristics are approximately expressed by (Equation 1) using the phase difference angle δij and the conductance Gij in the branch between node i and node j.

number

[0051] (Steps S3 to S10) The constraint generation unit 12 creates constraint equations according to (Equation 2) to (Equation 9) in steps S3 to S10. The constraint equations according to (Equation 2) to (Equation 9) are one aspect of the power system model. The following steps S3 to S10 are processed in parallel. The parameters in the following equations are as follows:

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[0052] (Step S3: Create a constraint equation for the radial system) Step S3 is executed by the constraint generation unit 12. The constraint generation unit 12 generates constraint equations for the radial system based on the piecewise linear approximation function of the output of the regulating power source created in step S1, the piecewise linear approximation function of the transmission loss characteristics created in step S2, the power system related data received from the power system related database 91, the power plant related data received from the power plant related database 92, and the load demand related data received from the load demand related database 93.

[0053] The constraint generation unit 12 generates (Equation 2a), (Equation 2b), (Equation 2c), and (Equation 2d) as constraint equations for the radial grid. The constraint generation unit 12 generates a power grid model using (Equation 2a), (Equation 2b), (Equation 2c), and (Equation 2d).

number

[0054] (Step S4: Create a constraint equation for the power equation) Step S4 is executed by the constraint generation unit 12. The constraint generation unit 12 generates a constraint expression for the power equation based on the piecewise linear approximation function of the output of the regulating power source created in step S1, the piecewise linear approximation function of the transmission loss characteristics created in step S2, the power system related data received from the power system related database 91, the power plant related data received from the power plant related database 92, and the load demand related data received from the load demand related database 93.

[0055] The constraint generating unit 12 creates (Equation 3a) and (Equation 3b) as constraint equations for the power equation.

number

[0056] (Step S5: Create a constraint equation for the supply and demand balance) Step S5 is executed by the constraint generation unit 12. The constraint generation unit 12 creates a constraint equation for the supply and demand balance based on a piecewise linear approximation function of the output of the regulating power source, a piecewise linear approximation function of the transmission loss characteristics, power system related data, power plant related data, and load demand related data.

[0057] The constraint generation unit 12 creates (Equation 4) as a constraint equation for the supply and demand balance. The constraint generation unit 12 creates (Equation 4), which is a constraint equation for the supply and demand balance, by subtracting the total transmission loss from the total power generation output of the generators in operation in the power system. By using (Equation 4), which is a constraint equation for the supply and demand balance, the power flow related to the transmission loss of the transmission line is reflected in the constraint equation.

number

[0058] (Step S6: Create constraint equations for the upper and lower limits of the branch flow) Step S6 is executed by the constraint generation unit 12. The constraint generation unit 12 creates constraint equations for the upper and lower limits of power flow in the branch based on the piecewise linear approximation function of the output of the regulating power source, the piecewise linear approximation function of the transmission loss characteristics, the power system related data, the power plant related data, and the load demand related data.

[0059] The constraint generation unit 12 creates Equation 5 as a constraint equation for the upper and lower limits of power flow in the branch. The power flow in the transmission line is calculated using the phase difference angle δ and reactance X of the branch. The constraint generation unit 12 creates the constraint equation for the upper and lower limits of power flow in the branch, as shown in Equation 5, using the phase difference angle δ and reactance X of the branch. The constraint equation (Equation 5) determines the upper and lower limits of the branch that is subject to power flow constraint, and system constrained economic load dispatch (SCED) with congestion management is realized.

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[0060] (Step S7: Create constraint equations for the upper and lower limits of the regulated power supply output) Step S7 is executed by the constraint generation unit 12. The constraint generation unit 12 creates constraint equations for the upper and lower limits of the output of the regulated power source based on a piecewise linear approximation function of the output of the regulated power source, a piecewise linear approximation function of the transmission loss characteristics, power system related data, power plant related data, and load demand related data.

[0061] The constraint generating unit 12 creates (Equation 6) as a constraint equation for the upper and lower limits of the output of the regulated power supply.

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[0062] (Step S8: Create fixed constraint equations for power supply outputs other than regulated power supplies) Step S8 is executed by the constraint generation unit 12. The constraint generation unit 12 creates fixed constraint equations for the output of power sources other than the regulated power sources based on the piecewise linear approximation function of the output of the regulated power sources, the piecewise linear approximation function of the transmission loss characteristics, the power system related data, the power plant related data, and the load demand related data.

[0063] The constraint generating unit 12 creates (Equation 7) as a fixed constraint equation for the output of a power supply other than the regulated power supply.

number

[0064] (Step S9: Create a constraint equation for piecewise linear approximation of the output of the regulated power supply) Step S9 is executed by the constraint generation unit 12. The constraint generation unit 12 creates a constraint equation for piecewise linear approximation of the output of the regulated power source based on the piecewise linear approximation function of the output of the regulated power source, the piecewise linear approximation function of the transmission loss characteristics, power system related data, power plant related data, and load demand related data.

[0065] The constraint generating unit 12 generates (Equation 8a) and (Equation 8b) as constraint equations for piecewise linear approximation of the output of the regulated power supply.

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[0066] (Step S10: Create constraint equations for piecewise linear approximation of transmission loss characteristics) Step S10 is executed by the constraint generation unit 12. The constraint generation unit 12 creates a constraint equation for piecewise linear approximation of the transmission loss characteristics based on the piecewise linear approximation function of the output of the regulating power source, the piecewise linear approximation function of the transmission loss characteristics, power system related data, power plant related data, and load demand related data.

[0067] The constraint generating unit 12 generates (Equation 9a), (Equation 9b), and (Equation 9c) as constraint equations for piecewise linear approximation of the transmission loss characteristics.

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[0068] (Step S11: Create an objective function for adjustment costs) Step S11 is executed by the objective function generator 13. The objective function generator 13 generates an objective function related to the adjustment cost based on the constraint equations generated by the constraint generator 12 in steps S3 to S10. The constraint equations generated by the constraint generator 12 are piecewise linear approximation functions, as described above. The objective function generator 13 sets the sum of the adjustment costs and system switching costs of all the regulated power sources to be controlled as the objective function.

[0069] The objective function generator 13 creates (Equation 10) as an objective function related to the adjustment cost.

number

[0070] (Step S12: Calculate the output of each regulated power supply and the open / close state of each switch) Step S12 is executed by the function solution calculation unit 14. The function solution calculation unit 14 calculates an optimal solution to the objective function (Equation 10) created by the objective function generation unit 13 in step S11. The function solution calculation unit 14 calculates a solution that makes the objective function (Equation 10) smaller. The function solution calculation unit 14 performs optimization calculations using linear programming or the like based on the constraint equations (Equation 2) to (Equation 9) created by the constraint generation unit 12 in steps S3 to S10, and calculates an optimal solution to the objective function (Equation 10).

[0071] The function solution calculation unit 14 calculates the output of each regulated power supply and the open / closed state of each switch as a solution to the objective function (Equation 10).

[0072] (Step S13: Send an output command) Step S13 is executed by the external transmitter 15. The external transmitter 15 transmits the output of each regulated power source calculated as a solution to the objective function (Equation 10) to the power plant, and transmits the open / closed state of each switch to the control center.

[0073] The piecewise linear approximation function of the output of the regulated power source created in step S1, the piecewise linear approximation function of the transmission loss characteristics created in step S2, the constraint equations (Equation 2) to (Equation 9) created in steps S3 to S10, the objective function (Equation 10) related to the regulation cost calculated in step S11, and the output of each regulated power source and the open / closed state of each switch calculated in step S12 may be stored in memory unit 90.

[0074] By using the above program, the power system control device 1 according to this embodiment realizes appropriate system switching in the power system.

[0075] The constraint generation unit 12 of the power system control device 1 defines virtual quantities fij in the power system, and while maintaining the configuration of one or more radial systems, expresses the open / closed state of each switch using a 0-1 variable, thereby realizing system switching through power flow calculation.

[0076] The system configuration of one or more radial systems is maintained by the constraint equations (Equation 2a), (Equation 2b), (Equation 2c), and (Equation 2d) of the radial system created by the constraint generation unit 12 in step S3. The constraint equations (Equation 3a) and (Equation 3b) of the power equations created by the constraint generation unit 12 in step S4 define the relationship between the phase difference angle of each node corresponding to the open / closed state of the switch and the amount of power injection including transmission losses. This realizes a power flow calculation that maintains the system configuration of one or more radial systems.

[0077] In a power system where congestion has occurred, switching the system does not necessarily resolve the congestion. The supply and demand balance of the entire system is satisfied by the constraint equation for supply and demand balance (Equation 4) created by the constraint generation unit 12 in step S5. The constraints on the upper and lower limits of branch power flow are satisfied by the constraint equation for the upper and lower limits of branch power flow (Equation 5) created by the constraint generation unit 12 in step S6.

[0078] In step S7, the constraints on the upper and lower limits of the output of the regulated power supplies are satisfied by the constraint equation (Equation 6) for the upper and lower limits of the output of the regulated power supplies created by the constraint generation unit 12. In step S8, the constraints on fixing the output of power supplies other than the regulated power supplies are satisfied by the constraint equation (Equation 7) for fixing the output of power supplies other than the regulated power supplies created by the constraint generation unit 12. This achieves the elimination of grid congestion caused by the regulated power supplies.

[0079] The constraint equation (Equation 8) of the piecewise linear approximation of the output of the regulated power supply created by the constraint generation unit 12 in step S9 and the constraint equation (Equation 9) of the piecewise linear approximation of the transmission loss characteristics created in step S10 cause the output of the regulated power supply and the transmission loss characteristics to become values ​​of the piecewise linear functions created by the approximation equation generation unit 11. As a result, the output of the regulated power supply and the transmission loss characteristics are approximated by the piecewise linear functions, and the optimization calculation can be performed at high speed.

[0080] The power system model created by the constraint generating unit 12 may be expressed by the constraint equations (Equation 2) to (Equation 9), or may be expressed geometrically using graphics. Examples of a power system model expressed geometrically using graphics are shown in Figures 5(a) and 5(b). The created power system model may be called a spanning tree.

[0081] The above is an outline of the operation of the power system control device 1 according to the first embodiment.

[0082] [1-3.Effects] (1) According to this embodiment, the power system control device 1 includes a constraint generation unit 12 that opens and closes a plurality of switches based on information about the configuration of a power system having a plurality of switches that become power supply paths when closed, and creates a power system model in which power supply to each node in the power system is not interrupted and power is supplied to each node through a single path; an objective function generation unit 13 that creates an objective function for the power system model created by the constraint generation unit 12; and a function solution calculation unit 14 that selects the opening and closing of switches so that the value of the objective function created by the objective function generation unit 13 approaches a target value. The function solution calculation unit 14 outputs information indicating the opening and closing of the switches selected, thereby making it possible to provide a power system control device 1 that reduces the number of combinations in the calculation of the opening and closing states of each switch and can select an appropriate power supply path in a shorter time.

[0083] The power system model created by the constraint generation unit 12 is configured to open and close multiple switches so that the power supply to each node in the power system is not interrupted and power is supplied to each node via a single route. This reduces the number of combinations of switch open and closed states. As a result, an appropriate power supply route can be selected in a shorter time, and congestion in the power system can be alleviated more quickly.

[0084] (2) According to this embodiment, the objective function created by the objective function generation unit 13 of the power system control device 1 includes terms related to the power generation cost and the cost spent on system switching. Therefore, it is possible to select an appropriate power supply path that can further reduce not only the power generation cost but also the cost spent on system switching.

[0085] (3) According to this embodiment, the information on the configuration of the power system used to create the power system model by the constraint generation unit 12 of the power system control device 1 includes a piecewise linear approximation function created using approximation functions, which is related to the output of the regulating power sources arranged in the power system and a piecewise linear approximation function related to the transmission loss characteristics of the transmission lines arranged in the power system. Therefore, it is possible to select an appropriate power supply path in a shorter time.

[0086] Because the output of the regulated power source and the transmission loss characteristics of the transmission line are created using approximate functions, the function solution calculation unit 14 can more quickly calculate the output of each regulated power source and the open / close state of each switch through optimization calculations. As a result, an appropriate power supply route can be selected in a shorter time, and congestion in the power system can be more quickly alleviated.

[0087] (4) According to this embodiment, the power system includes a loop system configured in a ring shape and multiple radial systems configured by branching or branching radially from the loop system. Switches are arranged between the multiple radial systems and inside the radial systems, and when closed, they become power supply paths. The constraint generation unit 12 of the power system control device 1 creates a power system model based on information about the configuration of the power system. Switches arranged between the multiple radial systems and inside the radial systems are closed, so that power is exchanged not only inside the multiple branched radial systems but also between the multiple branched radial systems. As a result, a power supply path that exchanges power more efficiently is selected, and congestion in the power system can be more efficiently alleviated.

[0088] (5) According to this embodiment, the power system model created by the constraint generation unit 12 of the power system control device 1 includes a constraint equation related to at least one of the following constraints: a constraint for maintaining the configuration of a radial system; a constraint related to a power equation including the open / close states of switches; a constraint related to upper and lower limits of power flow in transmission lines arranged in the power system; and a constraint related to transmission losses in the transmission lines. This makes it possible to further reduce the number of combinations of the open / close states of switches. As a result, it is possible to select an appropriate power supply route in a shorter time, and to more quickly relieve congestion in the power system.

[0089] 2. Other Embodiments Although embodiments including modifications have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. The following is an example.

[0090] (1) In the above embodiment, the objective function generator 13 generates an objective function related to cost according to the power system model created by the constraint generator 12, and the function solution calculator 14 selects the opening and closing of switches so as to reduce the value related to cost of the objective function created by the objective function generator 13. However, the objective function created by the objective function generator 13 is not limited to a function related to cost according to the power system model. The objective function created by the objective function generator 13 may be a function related to the amount of power generated by renewable energy, a function related to output voltage, a function related to power transmission efficiency, or any other function.

[0091] In the above embodiment, the function solution calculation unit 14 selects whether to open or close the switches so as to reduce the value of the objective function created by the objective function generation unit 13. However, the function solution calculation unit 14 may also select whether to open or close the switches so that the value of the objective function created by the objective function generation unit 13 approaches a target value. The target value may be a minimum value, a maximum value, or a predetermined value.

[0092] For example, when the objective function generating unit 13 generates an objective function related to the amount of power generated from renewable energy, the function solution calculating unit 14 may set the target value of the objective function to the maximum value and select whether to open or close a switch so that the value related to the amount of power generated from renewable energy of the objective function generated by the objective function generating unit 13 becomes larger.

[0093] (2) Each unit in the above embodiment may be realized by steps according to a computer program for a power system control device or a procedure according to a power system control method. The steps executed by the constraint generation unit 12 may be constraint generation steps, and the procedure executed may be realized by the constraint generation procedure. The steps executed by the objective function generation unit 13 may be objective function generation steps, and the procedure executed may be realized by the objective function generation procedure. The steps executed by the function solution calculation unit 14 may be function solution calculation steps, and the procedure executed may be realized by the function solution calculation procedure.

[0094] (3) In the above embodiment, the power system related database 91, the power plant related database 92, and the load demand related database 93 are configured as the storage unit 90 within the power system control device 1. However, the power system related database 91, the power plant related database 92, and the load demand related database 93 may be configured outside the power system control device 1. For example, they may be configured as a cloud on the Internet.

[0095] (4) In the above embodiment, the approximation function is a function based on piecewise linear approximation or second-order cone approximation, but the approximation function is not limited to this. The approximation function may be a function based on other functions. [Explanation of symbols]

[0096] 1. Power system control device 11...Approximate expression generation part 12...Constraint generator 13. Objective function generator 14. Function solution calculation section 15. External transmitter 90...Storage section 91···Power System Related Database 92···Power Plant Related Database 93 Load Demand Related Database

Claims

1. a constraint generation unit that creates a power system model based on information about a configuration of a power system having a plurality of switches that become power supply paths when closed, by opening and closing the plurality of switches, so that power supply to each node in the power system is not interrupted and power is supplied to each node through one path; an objective function generation unit that generates an objective function related to the power system model generated by the constraint generation unit; a function solution calculation unit that selects opening and closing of the switch so that the value of the objective function created by the objective function generation unit approaches a target value, outputting information indicating the opening and closing of the switch selected by the function solution calculation unit; Power system control device.

2. the objective function generated by the objective function generation unit includes terms related to power generation costs and costs spent on grid switching; The power system control device according to claim 1 .

3. the information on the configuration of the power system includes a piecewise linear approximation function created using an approximation function for an output of an adjustable power source arranged in the power system, and a piecewise linear approximation function for a transmission loss characteristic of a transmission line arranged in the power system, The power system control device according to claim 1 .

4. The power system includes: A loop system configured in a ring shape; a plurality of radial systems branching out from the loop system in a branched or radial manner, the switches are arranged between the plurality of radial systems and inside the radial systems, and become power supply paths when closed; The power system control device according to claim 1 .

5. the power system model created by the constraint generation unit includes a constraint equation relating to at least one of a constraint for maintaining the configuration of the radial system, a constraint on a power equation including the open / closed state of the switch, a constraint on upper and lower limits of power flow in transmission lines arranged in the power system, and a constraint on transmission loss in the transmission lines; The power system control device according to claim 4.

6. On the computer, a constraint generation step of creating a power system model in which a plurality of switches are opened and closed based on information about the configuration of the power system having the plurality of switches that become power supply paths when closed, so that power supply to each node in the power system is not interrupted and power is supplied to each node via one path; an objective function generation step of generating an objective function related to the power system model generated by the constraint generation step; a function solution calculation step of selecting opening and closing of the switches so that the value of the objective function created in the objective function generation step approaches a target value, outputting information indicating whether the switch is open or closed, selected by the function solution calculation step; A computer program for power system control devices.

7. a constraint generation procedure for creating a power system model in which a plurality of switches are opened and closed based on information about the configuration of the power system having the plurality of switches that become power supply paths when closed, so that power supply to each node in the power system is not interrupted and power is supplied to each node via one path; an objective function generation step for generating an objective function for the power system model generated by the constraint generation step; a function solution calculation step of selecting opening and closing of the switches so that the value of the objective function created by the objective function generation step approaches a target value, outputting information indicating whether the switch is open or closed, selected by the function solution calculation procedure; Power system control methods.

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