Future cross-section creation system, future cross-section creation method

Abstract

To create future cross sections by setting appropriate reactive power.SOLUTION: A future system cross section creation system includes: an initial value calculation unit that calculates an initial setting value of an amount of introduced reactive power resources, which is an amount of introduced reactive power resources, using supply and demand data, system configuration data, a voltage profile, power flow calculation conditions, and generator parameters; an optimal power flow calculation unit that performs optimal power flow calculation using the initial setting value calculated by the initial value calculation unit; and an adjustment unit that uses calculation results of the optimal power flow calculation section to modify the initial setting value and create a future cross section of the power system.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a future cross section creation system and a future cross section creation method. [Background technology]

[0002] Power systems are composed of generators, power transmission and distribution equipment, consumers, and other components, and are known to be influenced by many factors. Traditionally, designs and plans were based on a set scenario, but in recent years, with the introduction of new equipment such as renewable energy sources, plans have come to require greater versatility. In order to formulate multifaceted plans, it is necessary to consider multiple future scenarios. When verifying future scenarios, it is necessary to evaluate future snapshots that allocate demand by time period and region. Patent Document 1 discloses a power generation plan determination system including: a power generation demand prediction value determination unit that determines a power generation demand prediction value, which is a prediction value of the amount of power required of the generators, based on a demand prediction value in power system equipment in which a plurality of renewable energy power sources and a plurality of generators are connected, and an output prediction value, which is a prediction value of the amount of power output by the renewable energy power sources; an initial power generation plan determination unit that determines an initial power generation plan for the generators, based on the power generation demand prediction value determined by the power generation demand prediction value determination unit; an output fluctuation pattern creation unit that creates a plurality of output fluctuation patterns of the output prediction value, based on the output prediction value and a plurality of fluctuating output prediction values ​​having different occurrence probabilities; and an optimal power generation plan determination unit that derives a transient stability of the power system equipment predicted after the anticipated accident, based on information about the anticipated accident and the plurality of output fluctuation patterns created by the output fluctuation pattern creation unit, and determines an optimal power generation plan that can maintain the transient stability in the output fluctuation pattern, based on the derived transient stability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-65368 Summary of the Invention [Problem to be solved by the invention]

[0004] The invention described in Patent Document 1 is unable to set appropriate reactive power. [Means for solving the problem]

[0005] A future power system cross section creation system according to a first aspect of the present invention includes an initial value calculation unit that calculates an initial setting value for a reactive power resource introduction amount, which is the amount of reactive power resources to be introduced, using supply and demand data, system configuration data, a voltage profile, power flow calculation conditions, and generator parameters; an optimal power flow calculation unit that performs an optimal power flow calculation using the initial setting value calculated by the initial value calculation unit; and an adjustment unit that corrects the initial setting value using a calculation result of the optimal power flow calculation unit and creates a future cross section of the power system. A future power system cross section creation method according to a second aspect of the present invention is a computer-executed method for creating a future power system cross section, and includes an initial value calculation process for calculating an initial setting value for a reactive power resource introduction amount, which is the amount of reactive power resources to be introduced, using supply and demand data, system configuration data, a voltage profile, power flow calculation conditions, and generator parameters; an optimal power flow calculation process for performing an optimal power flow calculation using the initial setting value calculated by the initial value calculation process; and an adjustment process for correcting the initial setting value using a calculation result of the optimal power flow calculation process to create a future cross section of the power system. [Effects of the Invention]

[0006] According to the present invention, a future cross section can be created by setting an appropriate reactive power. [Brief explanation of the drawings]

[0007] [Figure 1] Power system configuration diagram [Figure 2] Future cross-section creation system configuration diagram [Figure 3] Functional configuration diagram of a calculation unit in the first embodiment [Figure 4] An example of a supply database [Figure 5] An example of a system configuration DB [Figure 6] A diagram showing an example of a generator parameter DB [Figure 7] An example of a voltage profile DB [Figure 8] An example of a power flow calculation condition DB [Figure 9] An example of a reactive power resource introduction amount DB [Figure 10] FIG. 10 is a diagram showing an example of a reactive power resource schedule DB. [Figure 11] 1 is a flowchart showing the processing of the initial value calculation unit in the first embodiment. [Figure 12] Flowchart showing the processing of the optimal power flow calculation unit [Figure 13] Flowchart showing the process of the adjustment unit [Figure 14] FIG. 10 is a diagram showing an example of a display screen displayed on a display unit. [Figure 15] Functional configuration diagram of a calculation unit in the second embodiment [Figure 16] 10 is a flowchart showing the processing of the initial value calculation unit in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] -First embodiment- A first embodiment of a future cross section creation system will be described below with reference to Figures 1 to 14. Note that the following is merely one embodiment, and it is not intended that the invention itself be limited to the specific content described below.

[0009] <Power system configuration> Figure 1 is a configuration diagram of a power system 1 targeted by the future cross-section creation system. The power system 1 is composed of a generator 10, a load 14, and a photovoltaic power generation system 15, which are connected via branches (lines) 12, nodes (buses) 11, and transformers 13, respectively, and a phase modifying equipment 16 connected to the bus. Reactive power resources include the tap position of the transformer 13, the reactive power output of the generator 10 and the photovoltaic power generation system 15, the reactive power consumed and generated by the load 14, and the phase modifying equipment 16.

[0010] The phase modifying equipment 16 includes a power capacitor (SC: Shunt Capacitor), a shunt reactor, a static voltage compensator, a synchronous coder (SC: Synchronous Coder), etc. Although not shown in FIG. 1 , resources related to reactive power, such as storage batteries, are also included as reactive power resources. In this embodiment, the main purpose is to set the state and introduction amount of the phase modifying equipment 16, and these calculations are performed by the future cross-section creation system 100.

[0011] <Configuration of the future cross-section creation system> 2 is a configuration diagram of a future cross section creation system 100 according to a first embodiment of the present invention. The future cross section creation system 100 includes one or more computer systems, and is equipped with a display unit 101, an input unit 102, a communication unit 103, a processor 104, a memory 105, and multiple databases described below. These devices that make up the future cross section creation system 100 are each connected to a bus 106, and exchange information using this bus 106. Hereinafter, the processor 104 and the memory 105 will be collectively referred to as a calculation unit 110.

[0012] The display unit 101 is, for example, a display device. The display unit 101 may be configured to use a printer device, an audio output device, or the like instead of or together with the display device. The input unit 102 is configured to include, for example, at least one of a keyboard switch, a pointing device such as a mouse, a touch panel, an audio instruction device, or the like. The communication unit 103 includes a line connection method and a communication protocol for communicating with the future cross-section creation system 100.

[0013] The processor 104 executes a calculation program to instruct image data to be displayed and to search for data in various databases. The processor 104 may be configured as one or more semiconductor chips, or as a computer device such as a calculation server. The memory 105 may be configured, for example, with a RAM (Random Access Memory) and a ROM (Read Only Memory). For example, the ROM may store a computer program, and the RAM may temporarily store calculation result data, image data, processing programs, etc. required for each process. Furthermore, for example, screen data stored in the memory 105 may be sent to the display unit 101 and displayed.

[0014] The future cross section creation system 100 includes a plurality of databases (hereinafter referred to as "DBs") described below. That is, the future cross section creation system 100 includes a program DB41, a supply and demand DB42, a system configuration DB43, a generator parameter DB44, a voltage profile DB45, a power flow calculation condition DB46, a reactive power resource introduction amount DB47, and a reactive power resource schedule DB48. Data is stored in advance in the program DB41, the supply and demand DB42, the system configuration DB43, the generator parameter DB44, the voltage profile DB45, and the power flow calculation condition DB46. Data is added to the reactive power resource introduction amount DB47 and the reactive power resource schedule DB48 through processing described below. Details of these databases will be described later.

[0015] <Functional configuration of the calculation unit> 3 is a functional configuration diagram of the calculation unit 110. The calculation unit 110 has, as its functions, an initial value calculation unit 111, an optimal power flow calculation unit 112, and an adjustment unit 113. These functions are realized by the processor 104 executing a program read from the program DB 41 into the memory 105. The calculation unit 110 obtains data required for calculation from the supply and demand DB 42, the system configuration DB 43, the generator parameter DB 44, the voltage profile DB 45, and the power flow calculation condition DB 46. The calculation results of the initial value calculation unit 111, the optimal power flow calculation unit 112, and the adjustment unit 113 are stored in the reactive power resource introduction amount DB 47 and the reactive power resource schedule DB 48 via the bus 106.

[0016] <Database> The program DB 41 stores programs that realize the initial value calculation unit 111, the optimal power flow calculation unit 112, and the adjustment unit 113 that constitute the calculation unit 110.

[0017] Fig. 4 is a diagram showing an example of the supply and demand DB 42. The supply and demand DB 42 stores the supply amount of each power source for each cross section and the demand amount for each load. In the example shown in Fig. 4, the cross sections are hourly, but the time intervals are arbitrary.

[0018] FIG. 5 is a diagram showing an example of the system configuration DB 43. The system configuration DB 43 stores parameters for each transmission line. Specifically, for each transmission line name, the sending end, receiving end, impedance, upper and lower limits of current and voltage, etc. are recorded. The system configuration DB 43 is used for power flow calculations, as will be described later. Note that while FIG. 5 shows a bus branch model that omits circuit breakers, the system may be configured as a node breaker model that includes circuit breakers, etc.

[0019] Fig. 6 is a diagram showing an example of the generator parameter DB 44. The generator parameter DB 44 stores parameters for each generator, specifically, rated capacity, minimum output, rated power factor, power factor limit, etc. In addition to the parameters shown in Fig. 6, parameters related to the ramp rate of the generator, continuous startup time, or dynamic characteristics of the generator may also be stored.

[0020] 7 is a diagram showing an example of the voltage profile DB 45. The voltage profile DB 45 stores target voltages for each cross section and each bus.

[0021] FIG. 8 is a diagram showing an example of the power flow calculation condition DB 46. The power flow calculation condition DB 46 stores the power flow calculation condition for each bus. Specifically, for each bus and for each type, one of the following power flow calculation conditions is stored: PV-specified, PQ-specified, or Vδ-specified. The power flow calculation conditions can be set separately for the initial and subsequent power flow calculations. Here, the initial power flow calculation refers to the power flow calculation performed by the initial value calculation unit 111, and the power flow calculations from the initial onwards refer to the optimal power flow calculation and power flow calculation in the optimal power flow calculation unit 112 and the adjustment unit 113.

[0022] 9 is a diagram showing an example of the reactive power resource introduction amount DB 47. The reactive power resource introduction amount DB 47 stores the introduction amount of reactive power resources for each bus. For example, among the reactive power resources, the installed capacities of SC and ShR are stored as the introduction amount of phase modifying equipment for each bus.

[0023] Fig. 10 is a diagram showing an example of the reactive power resource schedule DB 48. The reactive power resource schedule DB 48 stores, for each cross-sectional time, the amount of parallel connection of regulating equipment on the bus, the transformer tap, the reactive power output, and the like, for each bus and for each time period. By utilizing this data, it is possible to create an appropriate power flow cross-section and evaluate future stability scenarios. However, it is not essential to use all three of the amount of parallel connection of regulating equipment, the transformer tap, and the reactive power output as reactive power resources; it is sufficient to use at least one of them.

[0024] <Arithmetic section> The initial value calculation unit 111 receives as input the supply and demand data stored in the supply and demand DB 42, the system information stored in the system configuration DB 43, the generator parameters stored in the generator parameter DB 44, the reference voltage stored in the voltage profile DB 45, and the system constraints stored in the power flow calculation condition DB 46, and calculates an initial setting value for the amount of phase modifying equipment to be installed. The initial value calculation unit 111 then outputs the calculated initial setting value for the amount of phase modifying equipment to the optimal power flow calculation unit 112. The optimal power flow calculation unit 112 receives as input the initial setting value for the amount of phase modifying equipment to be installed calculated by the initial value calculation unit 111, the supply and demand data stored in the supply and demand DB 42, the system information stored in the system configuration DB 43, the generator parameters stored in the generator parameter DB 44, and the power flow calculation condition DB 46, and creates time series data for a future system cross section. The optimal power flow calculation unit 112 then outputs the created time series data for the future system cross section to the adjustment unit 113.

[0025] The adjustment unit 113 calculates the amount of phase modifying equipment to be introduced, the amount of phase modifying equipment to be connected in parallel, the transformer tap position, and the generator reactive power output, using as input the initial setting value of the amount of phase modifying equipment to be introduced calculated by the initial value calculation unit 111 and the time series data of the future system cross section created by the optimal power flow calculation unit 112. The adjustment unit 113 then sends the calculated amount of phase modifying equipment to be introduced, the amount of phase modifying equipment to be connected in parallel, the transformer tap position, and the generator reactive power output to the reactive power resource introduction amount DB 47 and the reactive power resource schedule DB 48. The processing of each component of the calculation unit 110 will be described below with reference to a flowchart.

[0026] 11 is a flowchart showing the processing of the initial value calculation unit 111. First, in step S100, the initial value calculation unit 111 sets constraint conditions for the power flow calculation, and then proceeds to step S101. Specifically, the initial value calculation unit 111 reads upper and lower limit values ​​of the voltage and current of each transmission line to be calculated from the system configuration DB 43. In step S101, the initial value calculation unit 111 initializes a variable, time T, to "1", and then proceeds to step S102.

[0027] In step S102, the initial value calculation unit 111 sets the power flow calculation conditions. Specifically, the initial value calculation unit 111 acquires supply and demand data from the supply and demand DB 42 and a voltage profile from the voltage profile DB 45, and sets the conditions for power flow calculation for each bus in the target cross section. For example, for a bus designated as PV, the active power designated value is set from the supply and demand data and the voltage designated value is set from the voltage profile. Generally, one of PV designation, PQ designation, and Vδ (slack bus) designation is set, and for a bus on which a phase modifying equipment is installed, by setting it to PV designation, the amount of reactive power injection required to achieve the set voltage designation can be calculated, and the amount of phase modifying equipment to be installed can be estimated from the amount of reactive power.

[0028] In step S103, the power flow calculation is performed. In step S104, the power flow calculation is determined to have converged. If convergence is confirmed, the process proceeds to step S105. If convergence is not confirmed, the process proceeds to step S106. The initial value calculation unit 111 can determine whether the power flow calculation has converged, for example, by checking whether the difference in output per loop is equal to or less than a predetermined value. In step S105, the initial value calculation unit 111 determines whether the result of the power flow calculation in step S103 satisfies the voltage and current constraints. Specifically, the initial value calculation unit 111 determines whether the voltage is between a predetermined lower limit and an upper limit, and whether the current is between a predetermined lower limit and an upper limit, in the result of the power flow calculation. These voltage and current conditions are stored in the system configuration DB 43. If the initial value calculation unit 111 determines that the result of the power flow calculation satisfies the constraints, the process proceeds to step S107. If the initial value calculation unit 111 determines that the constraints are not satisfied, the process proceeds to step S106.

[0029] In step S106, the initial value calculation unit 111 modifies the conditions for the power flow calculation, and the process returns to step S103. Specifically, the initial value calculation unit 111 calculates an evaluation value α for all sections in which the calculation conditions for the buses at both ends are PV-specified, using the following equation 1.

[0030] α=|V(1)-V(2)| / |Z(12)| …(Equation 1)

[0031] Here, V(1) and V(2) are the designated voltage values ​​of each bus at time T, and Z(12) is the impedance of the transmission line connecting the buses. The designated voltage value of each bus at each time is stored in the voltage profile DB 45. The impedance of each transmission line is stored in the system configuration DB 43. The initial value calculation unit 111 then changes the designation of one of the buses in the section with the lowest evaluation value α from PV designation to PQ designation. Note that the value of Q in this case is a value that is predetermined for each section.

[0032] The significance of the processing in this step is as follows. Power flow calculations used in power system analysis typically involve minimizing the difference between the power flowing into and out of a bus from the initial point, as with the Newton-Raphson method. The Jacobian matrix used in this calculation is calculated using factors such as the transmission line impedance between the buses, and is generally used to solve simultaneous equations using techniques such as LU decomposition. In this case, if the transmission line impedance between the PV-designated buses is small compared to the others in the modeling, the Jacobian matrix elements may approximate zero, potentially resulting in a singular Jacobian matrix. In this case, there is a concern that the simultaneous equations cannot be solved and the calculations will not converge. Therefore, for locations where both end buses are designated as PV, an index α that represents the convergence of the power flow calculation is calculated, and locations where convergence is unlikely are changed from PV designated to PQ designated, making convergence easier.

[0033] In step S107, the initial value calculation unit 111 records the amount of reactive power injected into the bus connected to the phase modifying equipment based on the result of the power flow calculation for the target time section. In the following step S108, the initial value calculation unit 111 determines whether time T is greater than a predetermined time T_MAX, that is, whether calculation for a predetermined period of time has been completed. If the initial value calculation unit 111 determines that time T is greater than the predetermined time T_MAX, the process proceeds to step S110, and if it determines that time T is equal to or less than the predetermined time T_MAX, the process proceeds to step S109. In step S109, the initial value calculation unit 111 updates time T to a number that is only one greater than the predetermined time T_MAX, and returns to step S102. In step S110, the initial value calculation unit 111 sets an initial value for the amount of phase modifying equipment to be introduced based on the result of the power flow calculation, and the process shown in FIG. 11 ends.

[0034] FIG. 12 is a flowchart showing the processing of the optimal power flow calculation unit 112. First, in step S200, the optimal power flow calculation unit 112 sets an objective function for the optimal power flow calculation. This objective function is used in the optimal power flow calculation in step S203, which will be described later. For example, when implementing voltage and reactive power control operations, the objective function can be set to at least one of minimizing active power loss, minimizing reactive power loss, and minimizing the number of times the phase modifying equipment operates. In the following step S201, the optimal power flow calculation unit 112 sets constraints for the optimal power flow calculation. These constraints are the upper and lower limits of the voltage and current of each transmission line stored in the system configuration DB 43 and the amount of phase modifying equipment installed calculated by the initial value calculation unit 111.

[0035] In the following step S202, the variable time T is initialized to "1", and the process proceeds to step S203. In step S203, the optimal power flow calculation unit 112 performs the optimal power flow calculation. Specifically, the optimal power flow calculation unit 112 performs the optimal power flow calculation in accordance with the objective function of the optimal power flow calculation set in step S200 and the constraint conditions of the optimal power flow calculation set in step S201. For example, when implementing the operation of voltage and reactive power control, the explanatory variables are the voltage of each bus, the parallel amount of phase modifying equipment, the transformer tap position, and the generator reactive power output or voltage specified value.

[0036] In the next step S204, optimal power flow calculation unit 112 records the results of the optimal power flow calculation. In the next step S205, it is determined whether time T is greater than a predetermined time T_MAX, i.e., whether calculation for a predetermined period of time has been completed. If optimal power flow calculation unit 112 determines that time T is greater than the predetermined time T_MAX, it ends the processing shown in Figure 12, but if it determines that time T is equal to or less than the predetermined time T_MAX, it proceeds to step S206. In step S206, optimal power flow calculation unit 112 increments time T by one and returns to step S203.

[0037] 12, voltage and reactive power control is given as an example of optimal power flow calculation, but load frequency control may also be implemented. Also, the objective function of voltage and reactive power control is not limited to the above example, and may be reactive power loss minimization, or an objective function may be defined by combining multiple objectives.

[0038] 13 is a flowchart showing the processing of the adjustment unit 113. The adjustment unit 113 first determines whether the constraint conditions are satisfied in step S300, and terminates the processing shown in FIG. 13 if it determines that the constraint conditions are satisfied. If it determines that the constraint conditions are not satisfied, the adjustment unit 113 proceeds to step S301. Specifically, the adjustment unit 113 determines whether the calculation results by the optimal power flow calculation unit 112 satisfy the upper and lower limit conditions of the voltage and current of each transmission line stored in the system configuration DB 43. The adjustment unit 113 determines that the constraint conditions are satisfied when the voltage is equal to or greater than the lower limit and equal to or less than the upper limit, and the current is equal to or greater than the lower limit and equal to or less than the upper limit, for all transmission lines that are the subject of the calculation. The adjustment unit 113 determines that the constraint conditions are not satisfied when the voltage is less than the lower limit or greater than the upper limit, or the current is less than the lower limit or greater than the upper limit, for one or more transmission lines that are the subject of the calculation.

[0039] In step S301, the adjustment unit 113 extracts cross sections that deviate from the constraint conditions, i.e., violating cross sections, from the results of the optimal power flow calculation. In step S302, the adjustment unit 113 corrects the amount of phase modifying equipment to be introduced. Specifically, the adjustment unit 113 corrects the amount of phase modifying equipment to be introduced for the violating cross sections extracted in step S301. This correction can be performed, for example, by using the sensitivity to the violating node calculated during the power flow calculation process and solving an optimization problem for the amount of phase modifying equipment correction to calculate the minimum amount of phase modifying equipment correction. Specifically, the objective function shown in Equation 2 and the constraint condition shown in Equation 3 are used.

[0040]

number

[0041]

number

[0042] Here, ΔQ i is the phase modifying equipment correction amount of node i, LV i is the lower limit of the voltage at node i, UV i is the voltage upper limit of node i, α i is the voltage sensitivity to reactive power at node i obtained during the power flow calculation process. In the optimization problem above, the upper voltage limit value at each node is used as a constraint, and a quadratic function of the change in the phase modifier equipment correction amount is used as the objective function, so it is possible to calculate the minimum amount of phase modifier equipment that eliminates the constraint deviation. Note that a solution to this optimization problem can be obtained by applying an optimization method such as quadratic programming.

[0043] In step S303, adjustment unit 113 initializes a variable, time T, to "1" and proceeds to step S304. In step S304, adjustment unit 113 performs an optimal power flow calculation at time T. In the following step S305, adjustment unit 113 records the result of the optimal power flow calculation in step S304. In step S306, adjustment unit 113 determines whether time T is greater than a predetermined time T_MAX, that is, whether calculation for a predetermined period of time has been completed. If adjustment unit 113 determines that time T is greater than the predetermined time T_MAX, it proceeds to step S308, and if it determines that time T is equal to or less than the predetermined time T_MAX, it proceeds to step S307. In step S307, adjustment unit 113 updates time T to a number that is "1" larger, and returns to step S304.

[0044] In step S308, adjustment unit 113 determines whether the calculation result in step S304 satisfies the constraint conditions. The processing in this step is the same as step S300 except for the object to be evaluated. If adjustment unit 113 determines that the calculation result in step S304 satisfies the constraint conditions, it proceeds to step S309, and if it determines that the calculation result in step S304 does not satisfy the constraint conditions, it returns to step S301. In step S309, adjustment unit 113 records the amount of phase modifying equipment introduced as a result of the power flow calculation, and ends the processing shown in FIG. 13.

[0045] <Display section> FIG. 14 is a diagram showing an example of a display screen 101A displayed on the display unit 101. The upper part of the display screen 101A displays a combination of the reactive power resource introduction amount stored in the reactive power resource introduction amount DB 47 and the system configuration stored in the system configuration DB 43. In FIG. 14, the introduction amount of phase modifying equipment is shown as the reactive power resource, but other reactive power resources such as upper and lower reactive power limits of generators and tap widths of transformer taps may also be shown. The lower part of FIG. 14 displays a graph of a schedule of reactive power resources. In FIG. 14, the parallel connection amount of phase modifying equipment, transformer tap positions, and generator reactive power output are shown as reactive power resources, but the present invention is not limited to these. Furthermore, the upper limit of the reactive power supply amount may also be shown in addition to these graphs.

[0046] According to the first embodiment described above, the following advantageous effects can be obtained. (1) The future cross-section creation system 100 includes an initial value calculation unit 111 that calculates an initial setting value for the reactive power resource introduction amount, which is the amount of reactive power resources introduced, using a supply and demand DB 42, a system configuration DB 43, a voltage profile DB 45, a power flow calculation condition DB 46, and a generator parameter DB 44, an optimal power flow calculation unit 112 that performs an optimal power flow calculation using the initial setting value calculated by the initial value calculation unit 111, and an adjustment unit 113 that corrects the initial setting value using the calculation result of the optimal power flow calculation unit 112 and creates a future cross-section of the power system. Therefore, it is possible to create a future cross-section by setting appropriate reactive power. Specifically, this is as follows.

[0047] The initial value calculation unit 111 can calculate the initial amount of phase modifying equipment to be introduced by specifying PV as the power flow calculation condition for the bus for which the amount of phase modifying equipment to be introduced is to be calculated. Furthermore, after the optimal power flow calculation unit 112 creates a future cross section using the initial introduction cost of the phase modifying equipment calculated by the initial value calculation unit 111 as a constraint condition, if there is a violation in the result of the optimal power flow calculation unit 112, the adjustment unit 113 adjusts the amount of introduction of the phase modifying equipment, thereby making it possible to calculate the amount of introduction of the phase modifying equipment and its schedule that will not result in a voltage violation. This makes it possible to create a system cross section that allows for appropriate evaluation of system stability.

[0048] (2) In step S106 of Fig. 11, the initial value calculation unit 111 calculates an index α, which indicates the convergence of the power flow calculation, for each section using the power flow calculation conditions, and modifies the power flow calculation conditions for the section with the lowest index α. As a result, the accuracy of the calculation results decreases, but the convergence can be improved.

[0049] (3) To implement voltage and reactive power control as an optimal power flow calculation, the optimal power flow calculation unit 112 sets at least one of minimizing active power loss, minimizing reactive power loss, and minimizing tap operation as an objective function. Therefore, the objective function can be changed as appropriate.

[0050] (4) In step S302 of Fig. 13, the adjustment unit 113 uses a reactive power resource introduction amount minimization problem using sensitivity coefficients for violating nodes generated in the process of power flow calculation as a method for correcting the initial setting values. Therefore, it is possible to appropriately set the initial setting values ​​for violating nodes that do not satisfy the constraint conditions.

[0051] (5) The phase modifying equipment is targeted as a reactive power resource, and the initial value calculation unit 111 calculates the initial introduction amount of the phase modifying equipment, the optimal power flow calculation unit 112 calculates the parallel amount of the phase modifying equipment, and the adjustment unit 113 corrects the introduction amount of the phase modifying equipment and recalculates the parallel amount.

[0052] (6) The target reactive power resource is a transformer tap, and the optimal power flow calculation unit 112 calculates the tap position of the transformer, and the adjustment unit 113 recalculates the tap position.

[0053] (7) Using a generator as a reactive power resource, the optimal power flow calculation unit 112 calculates the reactive power output of the generator, and the adjustment unit 113 recalculates the reactive power output.

[0054] (Variation 1) In the first embodiment, a phase modifying facility, a transformer tap, and a generator reactive power output are exemplified as reactive power resources. However, other reactive power resources such as a storage battery and a STATCOM (Static Synchronous Compensator) may also be used.

[0055] (Variation 2) The initial value calculation unit 111 corrected the power flow calculation conditions for the section with the smallest evaluation value α in step S106 in Fig. 11. However, the initial value calculation unit 111 may change the power flow calculation conditions for two or more sections in step S106. For example, the initial value calculation unit 111 may change the power flow calculation conditions for the section with the smallest evaluation value α and the section with the second smallest evaluation value α.

[0056] --Second embodiment-- A second embodiment of the future cross section creation system will be described with reference to Figures 15 and 16. In the following description, the same components as in the first embodiment are given the same reference numerals, and differences will be mainly described. Points that are not particularly described are the same as in the first embodiment. This embodiment differs from the first embodiment mainly in that supply and demand data is grouped by similar scenarios using clustering.

[0057] Fig. 15 is a functional configuration diagram of a calculation unit 110a in the second embodiment. The difference from the functional configuration shown in Fig. 3 in the first embodiment is that an initial value calculation unit 111a is provided instead of the initial value calculation unit 111. The operations of the optimal power flow calculation unit 112 and the adjustment unit 113 are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0058] Fig. 16 is a flowchart showing the processing of the initial value calculation unit 111a in the second embodiment. The difference from the processing shown in Fig. 11 in the first embodiment is that steps S111 and S112 are provided instead of step S101, step S113 is provided instead of step S108, and step S114 is provided instead of step S109. The operations of the other processing steps are the same as those in the first embodiment, so a description thereof will be omitted.

[0059] In step S111, the initial value calculation unit 111a clusters the supply and demand data. Clustering methods that can be used include DBSCAN (Density-based spatial clustering of applications with noise) and the k-means method. In this clustering, similar scenarios are identified by clustering the supply and demand data using evaluation indices such as demand, thermal power generation amount, and renewable energy power generation amount. In the following step S112, the initial value calculation unit 111a sets a representative cross section of the cluster as a target cross section. The initial value calculation unit 111a may use the average value or median value of each cluster as the representative cross section.

[0060] In step S113, the initial value calculation unit 111a determines whether or not the power flow calculation has been completed for all representative cross sections. If the initial value calculation unit 111a determines that the power flow calculation has been completed for all representative cross sections, the process proceeds to step S110. If the initial value calculation unit 111a determines that there is a representative cross section for which the power flow calculation has not been completed, the process proceeds to step S114. In step S114, the initial value calculation unit 111a sets another representative cross section for which the power flow calculation has not been completed as the target cross section, and returns to step S102.

[0061] According to the second embodiment described above, the following advantageous effects can be obtained. (8) The initial value calculation unit 111a clusters the supply and demand data using the feature quantities of the supply and demand data, and calculates the initial setting value using the representative cross section of each cluster. Therefore, since the power flow calculation is performed for the representative cross section of each cluster, the calculation can be completed in a shorter time than in the first embodiment.

[0062] In each of the above-described embodiments and modifications, the functional block configurations are merely examples. Some functional configurations shown as separate functional blocks may be configured as an integrated unit, or a configuration shown in a single functional block diagram may be divided into two or more functions. Furthermore, some of the functions of each functional block may be provided by other functional blocks.

[0063] In the above-described embodiments and modifications, the programs are stored in the program database 41. However, in the future, the cross-section creation system 100 may be equipped with an input / output interface (not shown), and the programs may be loaded from another device via the input / output interface as needed. Here, the term "medium" refers to, for example, a storage medium detachable from the input / output interface, or a communication medium, i.e., a wired, wireless, or optical network, or a carrier wave or digital signal propagating through the network. Furthermore, some or all of the functions realized by the programs may be realized by a hardware circuit or FPGA.

[0064] The above-described embodiments and modifications may be combined with each other. Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0065] 111, 111a: Initial value calculation unit 112: Optimal power flow calculation section 113: Adjustment section 42: Supply and demand database 43: System configuration DB 44: Generator parameter DB 45: Voltage profile DB 46: Power flow calculation conditions DB 47: Reactive power resource introduction amount DB 48: Reactive power resource schedule DB α: Evaluation value

Claims

1. an initial value calculation unit that calculates an initial setting value of a reactive power resource introduction amount, which is an introduction amount of reactive power resources, using supply and demand data, system configuration data, a voltage profile, power flow calculation conditions, and generator parameters; an optimal power flow calculation unit that performs optimal power flow calculation using the initial setting values ​​calculated by the initial value calculation unit; an adjustment unit that corrects the initial setting value using the calculation result of the optimal power flow calculation unit and creates a future cross section of the power system.

2. 2. The future system cross section creation system according to claim 1, the initial value calculation unit calculates an index representing the convergence of the power flow calculation for each section using the power flow calculation conditions, and corrects at least the power flow calculation conditions for the section with the lowest index.

3. 2. The future system cross section creation system according to claim 1, The optimal power flow calculation unit A future power system cross section creation system that uses at least one of minimizing active power loss, minimizing reactive power loss, and minimizing tap operation as an objective function in order to implement voltage and reactive power control as an optimal power flow calculation.

4. 2. The future system cross section creation system according to claim 1, A future system cross-section creation system in which the adjustment unit uses a reactive power resource introduction amount minimization problem using sensitivity coefficients for violation nodes generated during the power flow calculation process as a method of correcting the initial setting values.

5. 2. The future system cross section creation system according to claim 1, The reactive power resource is a phase modifying equipment, the initial value calculation unit calculates an initial introduction amount of the phase modifying equipment, the optimal power flow calculation unit calculates the parallel amount of phase modifying equipment, The adjustment unit corrects the amount of phase modifying equipment introduced and recalculates the amount of paralleling, in a future system cross section creation system.

6. 2. The future system cross section creation system according to claim 1, The reactive power resource is a transformer tap; the optimal power flow calculation unit calculates a tap position of a transformer, The adjustment unit recalculates the tap position.

7. 2. The future system cross section creation system according to claim 1, The reactive power resource is a generator, the optimal power flow calculation unit calculates the reactive power output of the generator; The adjustment unit recalculates the reactive power output.

8. 2. The future system cross section creation system according to claim 1, The initial value calculation unit clusters the supply and demand data using a feature of the supply and demand data, and calculates the initial setting value using a representative cross section for each cluster.

9. A computer-implemented method for creating a future system cross section, comprising: an initial value calculation process for calculating an initial setting value of a reactive power resource introduction amount, which is an introduction amount of reactive power resources, using supply and demand data, system configuration data, voltage profile, power flow calculation conditions, and generator parameters; an optimal power flow calculation process that performs an optimal power flow calculation using the initial setting values ​​calculated by the initial value calculation process; and an adjustment process for correcting the initial setting value using a calculation result of the optimal power flow calculation process to create a future cross section of the power system.

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