Existing facility utilization plan formulation device and existing facility utilization plan formulation method

Abstract

To optimize a system reinforcement plan made by a power transmission and distribution company, and a return on investment when a decommissioned power generator of a power generation company is utilized as a synchronous phase modifier.SOLUTION: An existing facility utilizing plan making device 100 includes a storage unit that stores system reinforcement plan information for identifying a point where system reinforcement is required on the basis of a wide power system simulating a power system of each area, an index evaluation unit 119 that, by using the system reinforcement plan information stored in the storage unit, calculates an index of return on investment when a decommissioned power generator is utilized as a synchronous phase modifier, and a decommissioned power generator utilization determination unit 121 that determines the decommissioned power generator to be utilized as a synchronous phase modifier on the basis of the index.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an existing facility utilization plan formulation device and an existing facility utilization plan formulation method. [Background technology]

[0002] The Paris Agreement was adopted at the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change (COP21) in 2015, which outlined a new international framework for reducing greenhouse gas emissions from 2020 onwards. Within this international framework, Japan has set targets to reduce greenhouse gas emissions by 26.0% by 2030 compared to 2013 levels, and to reduce greenhouse gas emissions by 80% by 2050 compared to 2013 levels.

[0003] To achieve this goal, the Agency for Natural Resources and Energy announced in its 2015 Long-Term Energy Supply and Demand Outlook a policy of setting a medium-term target of a renewable energy ratio of 22-24% in the power generation mix by fiscal 2030. Under this policy, Japan is making progress in introducing renewable energy (RE) such as solar, wind, biomass, geothermal and hydroelectric power. The proportion of renewable energy in Japan's total power generation increased from 12% in fiscal 2014 to 16% in fiscal 2019, and this proportion is expected to continue to increase.

[0004] However, it is expected that power grids that incorporate renewable energy will face various challenges, such as supply-demand balance, excess transmission capacity, voltage fluctuations, frequency fluctuations, and stability. These challenges arise because the output of variable renewable energy (VRE) such as solar and wind power generation is affected by ever-changing weather conditions, the number of thermal power synchronous generators decreases, resulting in a smaller system inertia, and the limited number of suitable locations for solar and wind power generation increases the transmission capacity required to deliver electricity from variable renewable energy generation areas to demand areas, making localized transmission line overloads more likely.

[0005] In response to these issues, plans are being made to reinforce grids in order to ensure the stable delivery of electricity generated by variable renewable energy sources from supply points to demand points. For example, within Japan, where an increase in connection volume is expected in the future for offshore wind power plants in Chiba and off the coast of Akita, construction is being planned to increase the number of transmission lines to Tokyo, the demand area, and to increase transmission capacity. Similarly, in Kyushu, where an increase in connection volume is also expected in the future for solar power plants, plans are being made to increase the operating capacity of the Chugoku-Kyushu interconnector. However, the enormous costs involved in these grid reinforcement plans are an issue.

[0006] In this situation where it is necessary to not only simply increase the proportion of variable renewable energy but also to consider stability and economic efficiency, it is thought that utilizing decommissioned generators as synchronous phase condensers will become important in the future. A synchronous phase condenser is a device that supplies inertial and reactive power to the power grid by disconnecting the decommissioned generator from the turbine and receiving power from the power grid while the generator runs idle. The advantages of a synchronous phase condenser are that by utilizing an existing generator, it can be implemented at a lower cost than other solutions such as a static var compensator (STATCOM), which supplies reactive power in the same way as a synchronous phase condenser, and that it can supply inertial force, which a reactive power compensator does not, thereby suppressing generator oscillation for a few seconds during an accident.

[0007] In order to increase the amount of renewable energy connections in the future, it is necessary to curb investments for increasing the amount of renewable energy connections by not only investing in new facilities such as strengthening the grid, but also by utilizing and optimizing the operation of existing facilities.

[0008] The abstract of Patent Document 1 states, "To provide a power generation plan determination system, a power generation plan determination method, and a program that can ensure transient stability even when the capacity of a generator is reduced," and describes determining an optimal operation plan for existing generators as renewable energy increases. Furthermore, Patent Documents 2 and 3 describe using idle generators as synchronous phase modifiers to maintain the voltage of a power system and improve transient stability in the event of a system fault. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 8-198883 [Patent Document 2] Japanese Patent Application Publication No. 5-312995 [Patent Document 3] Japanese Patent Application Publication No. 2019-143626 Summary of the Invention [Problem to be solved by the invention]

[0010] As described in the background art, utilizing decommissioned generators as synchronous phase modifiers has the advantage of being cheaper than installing new facilities, addressing issues such as inertia and reactive power supply shortages associated with an increase in the amount of renewable energy connected. However, recent power system reforms and the unbundling of power generation and transmission have separated the national government, which decides renewable energy deployment plans, the power transmission and distribution companies responsible for power transmission and distribution, such as grid reinforcement, and the power generation companies that own decommissioned generators. As a result, there is no centralized organization that determines the process for utilizing decommissioned generators as synchronous phase modifiers. Therefore, a new framework that spans the national government, power transmission and distribution companies, and power generation companies is needed to determine the process for utilizing decommissioned generators as synchronous phase modifiers.

[0011] This paper explains from the perspectives of the government, power transmission and distribution companies, and power generation companies why there is no centralized organization that decides the process for utilizing decommissioned generators as synchronous phase modifiers. The country decides the amount of renewable energy to be introduced in each area based on the country's natural environment, such as wind conditions and solar radiation. In Japan, the above-mentioned areas include areas with different power transmission operators, such as Tokyo, Tohoku, and Kansai. At this stage, the amount of renewable energy to be introduced in each area is determined solely by the introduction potential of the natural environment, and does not take into account the potential for an increase in connection capacity by utilizing decommissioned generators as synchronous modifiers.

[0012] Next, because power generation and demand areas are geographically separated and power is transmitted across these areas, power transmission and distribution operators must consider not only their own power system jurisdiction but also the power systems under the jurisdiction of other power transmission and distribution operators when considering measures to deal with power system accidents. This is because suitable locations for introducing renewable energy are ubiquitous, and power generation and consumption areas are geographically separated. Therefore, a framework for collecting data from different power transmission and distribution operators is needed to identify issues when such long-distance power transmission occurs and to determine measures to resolve them.

[0013] Furthermore, power generation companies face the challenge of not being able to independently consider the return on investment of utilizing their own decommissioned generators as synchronous phase modifiers. Because grid expansion plans are the responsibility of transmission and distribution companies, a framework for discussing with them the benefits of utilizing decommissioned generators as synchronous phase modifiers within those plans is necessary. From the perspective of transmission and distribution companies, when considering the return on investment of utilizing decommissioned generators as synchronous phase modifiers, it is necessary to collect information such as construction costs and useful life through surveys conducted by power generation companies, so transmission and distribution companies also need a framework for exchanging information with power generation companies.

[0014] Therefore, an object of the present invention is to optimize the return on investment of power transmission and distribution companies' system reinforcement plans and power generation companies' investments in converting decommissioned generators into synchronous modifiers. [Means for solving the problem]

[0015] In order to solve the above-mentioned problems, the existing facility utilization plan formulation device of the present invention is a system reinforcement planning unit that obtains system reinforcement plan information that identifies locations where system reinforcement is required based on renewable energy introduction plan information that predicts the future amount of renewable energy introduced in each area under the jurisdiction of different power transmission companies and wide-area power system information that simulates a power system spanning each area under the jurisdiction of the power transmission companies; and a system countermeasure examination unit that selects, from the system reinforcement plan information, decommissioned generators owned by power generation companies that will improve system stability when used as synchronous phase modifiers. The present invention is characterized by comprising: Other means will be described in the detailed description of the invention. [Effects of the Invention]

[0016] According to the present invention, it is possible to optimize the return on investment of power transmission and distribution companies' grid expansion plans and power generation companies' investments in converting decommissioned generators into synchronous modifiers. Furthermore, it is also possible to optimize the return on investment of national renewable energy introduction plans. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a configuration diagram of an existing facility utilization plan formulation device according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a cross-sectional configuration diagram of a wide-area power system. [Figure 3] FIG. 10 is a diagram illustrating the configuration of contingency data. [Figure 4] FIG. 1 is a cross-sectional view showing a system fault situation. [Figure 5] FIG. 10 is a diagram showing a system fault analysis screen. [Figure 6] FIG. 1 is a cross-sectional view of a power system for explaining a procedure for identifying a generator to be utilized as a synchronous phase modifier. [Figure 7] FIG. 10 is a diagram showing a system fault analysis screen. [Figure 8A] FIG. 10 is a diagram showing investment evaluation information according to the second embodiment. [Figure 8B] FIG. 10 is a diagram showing investment evaluation information. [Figure 9] FIG. 11 is a diagram showing benefit assessment information according to the third embodiment. [Figure 10] FIG. 10 is a diagram showing a cost-benefit evaluation method according to a fourth embodiment. [Figure 11] FIG. 13 is a diagram showing a comparison function with other measures in cost-benefit evaluation according to the fifth embodiment. [Figure 12]FIG. 13 is a configuration diagram of an existing facility utilization plan formulation device according to a sixth embodiment. [Figure 13] FIG. 13 is a diagram showing a modification of a renewable energy introduction plan for each area according to the seventh embodiment. [Figure 14] 10 is a flowchart showing a process for correcting a renewable energy introduction plan for each area. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First Embodiment FIG. 1 is a configuration diagram of an existing facility utilization plan formulation device 100 according to a first embodiment of the present invention. The utilization plan formulation device 100 includes a renewable energy introduction planning unit 101, a grid reinforcement planning unit 102, a generator utilization planning unit 103, and an index evaluation unit 119. The utilization plan formulation device 100 formulates a plan to utilize existing decommissioned generators in connection with the decommissioning process of an existing power plant (e.g., a nuclear power plant). In the utilization plan formulation device 100, the functions of each unit are realized by a computer having, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and a storage unit executing a utilization plan formulation program (not shown).

[0019] The renewable energy introduction planning unit 101 is a component that stores, in a storage unit (not shown), renewable energy introduction plan information, which is a predicted value of the future amount of renewable energy connection for each area, and information on the amount of renewable energy introduction, in the renewable energy database 107. Here, the renewable energy introduction plan information includes current connection amount information or connection amount forecast information of the amount of connection of one or more renewable energies selected from wind power, offshore wind power, solar power, wave power, tidal power, running water, geothermal power, and biomass. The renewable energy introduction plan information includes current connection amount information or connection amount forecast information of the amount of connection of renewable energy for each area.

[0020] 1 illustrates an amount of introduced renewable energy 107a in area #1, an amount of introduced renewable energy 107b in area #2, and an amount of introduced renewable energy 107c in area #3. Information on the amounts of introduced renewable energy 107a, 107b, 107c, etc. is stored in a renewable energy database 107 and is referenced by the grid expansion planning unit 102. Note that the areas may be under the jurisdiction of the same power transmission and distribution company or different power transmission and distribution companies.

[0021] The system reinforcement planning unit 102 is a component that evaluates the effects of power system reinforcement plans. The system reinforcement planning unit 102 includes a wide-area system cross section creation unit 108, a contingency condition selection unit 109, a system impact assessment unit 110, a system countermeasure study unit 111, and an effect assessment unit 112. The system reinforcement planning unit 102 stores system reinforcement plan information that identifies locations where system reinforcement is required, based on a wide-area power system that simulates the power system of each area.

[0022] The wide-area system cross section creation unit 108 creates a simulated power system cross section across each area based on the renewable energy introduction plan information in the renewable energy database 107. For each area, the wide-area system cross section creation unit 108 creates a system cross section required for system impact assessment using information on the current connection amount or predicted connection amount of renewable energy, and the system configuration, system impedance, installed capacity, and generator data included in the system reinforcement plan information.

[0023] Here, the wide-area system cross section creation unit 108 stores the system configuration, line impedance (R+jX), earth capacitance (susceptance: jB), data necessary for system configuration and state estimation (such as batt data thresholds), generator data, and other data necessary for power flow calculation, state estimation, and time-series change calculation. In addition to this, the wide-area system cross section creation unit 108 references information from the renewable energy database 107 to simulate the power system when renewable energy is connected as assumed by the renewable energy introduction planning unit 101. The power system created by this wide-area system cross section creation unit 108 (see Figure 1) is shown in Figure 2, which will be described later.

[0024] Figure 2 is a cross-sectional diagram of the wide-area system. This wide-area system shows a cross section of the power system connecting area 20a (area #1) and area 20b (area #2). Area 20a is equipped with a renewable energy power generation unit 202 including renewable energy power sources 202a-202c, and is connected to an electricity demand area 201 by a transmission line 203a.

[0025] Area 20b is configured by power demand areas 201a and 201b connected by power transmission line 203b. Furthermore, renewable energy power generation unit 202 in area 20a and power demand area 201a are connected by power transmission line 21. As a result, renewable energy power generation unit 202 supplies power to power demand areas 201, 201a, and 201b.

[0026] At this time, the power demand area 201 a receives the power generated by the renewable energy power generation unit 202 via the power transmission line 21 . The wide-area system cross section creation unit 108 (see Figure 1) simulates not only the transmission line 21 connecting the renewable energy power generation unit 202 and the power demand area 201a, but also the transmission line 203a connecting the renewable energy power generation unit 202 and the power demand area 201 in area 20a, the transmission line 203b connecting the power demand area 201a in area 20b and another power demand area 201b in area 20b, and all transmission lines (not shown) in areas 20a and 20b.

[0027] Returning to Figure 1, we will continue with the explanation. The cross sections created by the wide-area system cross section creation unit 108 must take into account the fact that renewable energy output and generator output change from day to day and over the course of a year. The number of cross sections varies depending on the state of the target power system, but a day is divided into several hours, and a cross section for one year is prepared. For example, if a day is divided into 24 hours, the cross sections for one year are 8,640 cross sections, which is 24 multiplied by 365. The power system information created by the wide-area system cross section creation unit 108 is sent to the contingency fault condition selection unit 109.

[0028] The contingency condition selection unit 109 has a function of preparing a system fault scenario for evaluating stability (synchronization stability, voltage stability, frequency stability, etc.) in the event of a fault (ground fault in a transmission line, tripping of a generator, etc.) in the power system in the cross section created by the wide-area system cross section creation unit 108. In other words, the contingency condition selection unit 109 selects contingency conditions to be analyzed in the wide-area system cross section creation unit 108. Data of contingency cases prepared by the contingency condition selection unit 109 is shown in Fig. 3, which will be described later.

[0029] FIG. 3 is a diagram showing the structure of the contingency data. Conceivable failure data is stored in the contingent failure database 300. The contingent failure database 300 is a collection of data at each date and time, and each piece of data is assigned date and time data 301. The columns of each piece of data include a contingent failure case column 302, a failure location column 303, and a failure mode column 304, and the rows store data related to each contingent failure case.

[0030] The data stored in the contingency database 300 may be for any time interval. The fault mode column 304 stores the phase of the faulted line, the number of lines, a combination of the fault mode, and the like.

[0031] Here, "3φ6LG (ABCA'B'C')" stored in the fault mode column 304 indicates a three-phase six-wire ground fault in "3φ6LG", and "(ABCA'B'C')" indicates that phases A, B, C, A', B', and C' have ground faults.

[0032] Contingency case C1 indicates that a three-phase, six-wire ground fault occurs at the sending end of transmission line A1. Contingency case C2 indicates that a three-phase, six-wire ground fault occurs at the sending end of transmission line A2. Contingency case C3 indicates that a three-phase, six-wire ground fault occurs at the sending end of transmission line A1 and the sending end of transmission line A2.

[0033] The contingency case C4 indicates that a power supply site A1 will be disconnected. The contingency case C5 indicates that a three-phase, six-wire ground fault occurs at the sending end of the transmission line B1. By including such information, it is possible to evaluate the system impact for each contingency and select the contingency conditions.

[0034] Returning to Figure 1, the explanation will continue. The system influence assessment unit 110 calculates the system constraint conditions before the system fault (during normal operation) and during the system fault, based on the system cross section created by the wide-area system cross section creation unit 108 and the contingency fault cases selected by the contingency fault condition selection unit 109. Here, the system constraints include the generator internal phase difference angle in synchronous stability, the maximum and minimum frequency values in frequency stability, the load margin up to the nose point of the PV curve in voltage stability, transient voltage, and overload.

[0035] The system impact assessment unit 110 uses the cross section created by the wide-area system cross section creation unit 108 to simulate the contingency cases selected by the contingency condition selection unit 109, and evaluates stability in the event of a system fault. The system impact assessment unit 110 performs power flow calculations and transient stability calculations in the event of the fault selected by the contingency condition selection unit 109. An example of a system fault is shown in Fig. 4, which will be described later.

[0036] FIG. 4 is a cross-sectional diagram of a power system showing a system fault situation. The power system faults shown here cover the power systems related to area 20a and area 20b. Power system fault 401 is a fault related to power transmission line 203a. Power system fault 402 is a fault related to power transmission line 21. Power system fault 403 is a fault related to power transmission line 203b.

[0037] FIG. 5 is a diagram showing a system fault analysis screen 5. The system fault analysis screen 5 is a screen displayed on the display unit of the utilization plan development device 100. This system fault analysis screen 5 displays a system diagram 501, a legend 504, a date column 502a, a time column 502b, and a contingency condition selection result 503.

[0038] The system diagram 501 is an area illustrating the system targeted by the utilization plan development device 100, and is created by the wide-area system cross section creation unit 108 and displayed by the system impact evaluation unit 110. The system diagram 501 changes depending on the date and time displayed in the date column 502a and the time column 502b.

[0039] Legend 504 is an area that indicates the meaning of each icon and symbol shown in system diagram 501. System diagram 501 indicates system information such as synchronous generators, renewable energy power sources, loads, transformers, busbars, and lines as icons and symbols. The date and time of the system diagram 501 and the contingency condition selection result 503 are displayed in the date column 502a and the time column 502b.

[0040] The contingency condition selection result 503 is configured with a contingency case column 5031, a power supply control amount column 5032 and a negative control amount column 5033 in the grid stabilization control amount column, a generator phase angle column 5034, a voltage column 5035, and a frequency column 5036, and displays the analysis results of power flow calculation and transient stability. The contingency condition selection result 503 indicates whether grid constraints such as generator phase angle, voltage, and frequency can be met for each accident scenario listed in the contingency database 300. The controlled objects include generators and loads, but may also include batteries, rechargeable secondary batteries, electric vehicle storage batteries, flywheels, phase modifying equipment, etc. The grid constraints are appropriately defined, for example, such as maintaining a generator phase angle of 100 degrees or less even during a grid fault.

[0041] The contingency condition selection result 503 includes an indication of whether the grid constraints can be met, and in the generator phase angle column 5034, voltage column 5035, and frequency column 5036 in FIG. 5, a circle indicates that the grid constraints can be met, and an cross indicates that the grid constraints cannot be met.

[0042] Returning to Fig. 1, the explanation will be continued. The system countermeasure review unit 111 verifies the effect of improving system stability by replacing decommissioned generators with synchronous phase modifiers as a countermeasure when system constraints cannot be met during a system fault, based on the evaluation by the system impact evaluation unit 110. In other words, the system countermeasure review unit 111 formulates countermeasures for improving the stability of the power system based on the results of the evaluation by the system impact evaluation unit 110.

[0043] FIG. 6 is a cross-sectional view of a power system for explaining a procedure for identifying a generator to be used as a synchronous phase modifier. Fig. 6 shows that a grid fault 402 has occurred on the transmission line 21. This corresponds to the contingency case C4 in the contingency condition selection result 503 shown in Fig. 5. At this time, the grid constraints of the generator phase angle, voltage, and frequency cannot be ensured. If the grid constraint conditions cannot be satisfied in the evaluation of the grid constraint conditions by the grid impact evaluation unit 110, the grid measure review unit 111 identifies the location in the power grid where the problem occurs.

[0044] For a grid fault 402 in which grid constraints cannot be ensured at the time of the fault, the grid countermeasures examining unit 111 selects a generator 602 that can supply inertial force and reactive power. This generator 602 is connected to the power transmission line 21 on the area 20b side of the fault point of the grid fault 402, and is a decommissioned generator that can contribute to problem solving when utilized as a synchronous phase modifier.

[0045] The system countermeasure examining unit 111 analyzes the system fault 402 to see if the system stability can be improved by utilizing the selected generator 602 as a synchronous phase modifier.

[0046] FIG. 7 is a diagram showing the system fault analysis screen 5. The system fault analysis screen 5 in FIG. 7 displays a system diagram 501, a legend 504, a date column 502a, a time column 502b, and a result of selection of assumed fault conditions 503.

[0047] In this contingency condition selection result 503, "x → o" is displayed in the generator phase angle column 5034, voltage column 5035, and frequency column 5036 for contingency case C4. This indicates that if contingency case C4 occurred before the countermeasure, that is, before the obsolete generator was converted into a synchronous phase modifier, the generator phase angle difference, voltage, and frequency would not be able to satisfy the system constraints. Furthermore, it indicates that after the countermeasure, that is, after the obsolete generator was converted into a synchronous phase modifier, if contingency case C4 occurred, the generator phase angle difference, voltage, and frequency would be able to satisfy the system constraints.

[0048] The processing up to the display of the system fault analysis screen 5 in Fig. 7 will be described with reference to Fig. 1. The evaluation result of the system countermeasures planning unit 111 is transmitted to the effect evaluation unit 112. The effect evaluation unit 112 evaluates (verifies) the effect of utilizing the decommissioned generator as a synchronous phase modifier. This effect evaluation unit 112 evaluates (verifies) the effect of the countermeasures proposed by the system countermeasures planning unit 111.

[0049] The effect evaluation unit 112 selects, as the system constraint conditions, one or more of the following as effects to be evaluated: the generator internal phase angle in synchronous stability, the maximum and minimum frequency values in frequency stability, the load margin up to the nose point of the PV curve in voltage stability, transient voltage, and overload.

[0050] When the system countermeasure examining unit 111 confirms the value of improving system stability when utilizing the decommissioned generator as a synchronous phase modifier, it transmits information such as the location and required capacity of the selected generator to the generator utilization planning unit 103. This enables the generator utilization planning unit 103 to evaluate the details of construction work required to utilize the decommissioned generator as a synchronous phase modifier and its useful life.

[0051] The generator utilization planning unit 103 includes a generator database 116, which is a collection of generator information for two or more areas, a construction content determination unit 117, and an investment cost evaluation unit 118. The generator utilization planning unit 103 stores generator utilization plan information having information on decommissioned generators in each area in a storage unit (not shown). The generator database 116 includes, for example, generator information 116a for area A, generator information 116b for area B, and generator information 116c for area C. The generator information 116a, 116b, 116c, etc. includes one or more of the following information regarding the capacity of the decommissioned generator, its response speed to external commands, years of operation, service life, the maintenance status of the generator's stator windings, and local residents' understanding of generator utilization. The generator information 116a, 116b, 116c, etc. includes generator utilization plan information. The information in the generator database 116 is referenced by the construction content determination unit 117.

[0052] The construction content determination unit 117 determines specific construction content for utilizing the decommissioned generator as a synchronous phase modifier based on the information in the generator database 116, transmits the determined content to the investment cost evaluation unit 118, and further evaluates the performance of the synchronous phase modifier after modification. The construction content determination unit 117 selects one or more of the following construction content for utilizing the decommissioned generator as a synchronous phase modifier: installation of a driver, installation of a driver inverter, operation of the driver, protection of the driver, operation of the driver inverter, protection of the driver inverter, installation of a monitoring panel, installation of a central control room panel, turbine disconnection, installation of a lubricating oil device, installation of a cooling water device, installation of an inverter transformer, installation of a foundation for a turbine opening, and cable work. The investment cost evaluation unit 118 calculates (evaluates) the investment costs, such as construction costs, that will actually be required based on the determination details from the construction content determination unit 117, and transmits the calculated investment costs to the investment return evaluation unit 120 of the index evaluation unit 119. In other words, the investment cost evaluation unit 118 calculates the investment costs from one or more of the initial costs required for the construction content, the operating costs of the synchronous phase modifier, and the labor costs required for operating the synchronous phase modifier. Note that the investment cost evaluation unit 118 may apply a levelized cost calculation that takes a discount rate into consideration when calculating the investment costs.

[0053] The index evaluation unit 119 includes a return-on-investment evaluation unit 120 and a decommissioned generator utilization determination unit 122. The index evaluation unit 119 calculates an index of return-on-investment when utilizing a decommissioned generator as a synchronous phase modifier using renewable energy introduction plan information, generator utilization plan information, and grid reinforcement plan information. However, this is not limited to this, and the index evaluation unit 119 may calculate an index of return-on-investment when utilizing a decommissioned generator as a synchronous phase modifier using only the grid reinforcement plan information. Furthermore, the index evaluation unit 119 may calculate an index of return-on-investment when utilizing a decommissioned generator as a synchronous phase modifier using the grid reinforcement plan information and the renewable energy introduction plan information. Furthermore, the index evaluation unit 119 may calculate an index of return-on-investment when utilizing a decommissioned generator as a synchronous phase modifier using further information about decommissioned generators installed in each area. This information about decommissioned generators is stored in a storage unit (not shown).

[0054] The signal from the effect evaluation unit 112 and the signal from the investment cost evaluation unit 118 are transmitted to an investment return evaluation unit 120 of the index evaluation unit 119. The investment return evaluation unit 120 calculates an index of the investment return on investment of utilizing the decommissioned generator as a synchronous phase modifier, based on the effect evaluated by the effect evaluation unit 112 and the investment cost evaluated by the investment cost evaluation unit 118. The decommissioned generator utilization determination unit 122 determines which decommissioned generator to utilize as a synchronous phase modifier, based on the index of the investment return on investment.

[0055] Here, if there are any additional study items that are required to utilize the decommissioned generator as a synchronous phase modifier from the viewpoint of investment effectiveness, the information is transmitted to the system countermeasures study unit 111 .

[0056] The system countermeasure examining unit 111 evaluates the system stability when the decommissioned generators are utilized as synchronous phase modifiers in the same manner as described above, taking into account the additional examination items, and transmits the evaluation results to the effect evaluating unit 112 and the generator utilization planning unit 103. By exchanging information between the system reinforcement planning unit 102, the generator utilization planning unit 103, and the index evaluating unit 119 in this manner, the details of the construction work, i.e., which decommissioned generators should be utilized as synchronous phase modifiers, and the method of operation as synchronous phase modifiers are ultimately determined.

[0057] According to this embodiment, it is possible to optimize the return on investment of the grid reinforcement plan of the power transmission and distribution company and the power generation company by converting decommissioned generators into synchronous modifiers. Furthermore, it is also possible to optimize the return on investment of the national renewable energy introduction plan.

[0058] Second Embodiment In the investment cost evaluation unit 118 of the first embodiment, it is conceivable to estimate the investment cost from the construction cost and the operating cost. Therefore, in the second embodiment, information is prepared that organizes the investment cost from the perspective of the construction cost, which is the initial cost, and the other operating costs, and this information is utilized in the investment cost evaluation unit 118.

[0059] 8A and 8B are diagrams showing investment evaluation information according to the second embodiment. The investment cost evaluation unit 118 classifies the investment costs into construction costs (CAPEX: Capital Expenditure) and operating costs (OPEX: Operating Expenditure).

[0060] FIG. 8A is a diagram showing construction cost information 802. The construction cost information 802 is composed of an item column 8021 and an evaluation result column 8022 in the column direction, and information relating to each item is stored in the row direction.

[0061] The item column 8021 in the construction cost information 802 includes installation of a drive machine, installation of a drive inverter, protection of the drive machine, installation of a monitoring panel, installation of a cooling device, operation of the drive inverter, protection of the drive inverter, shutting down the turbine, installation of lubricating oil, installation of a cooling water device, installation of an inverter transformer, installation of a foundation for the turbine opening, cable installation, etc. Construction items other than those exemplified above may be added to the construction cost information 802. The evaluation result column 8022 of the construction cost information 802 lists the construction costs required for each construction item in yen.

[0062] FIG. 8B is a diagram showing the operating cost information 803. The operating cost information 803 is composed of an item column 8031 and an evaluation result column 8032 in the column direction, and information relating to each item is stored in the row direction.

[0063] The operating cost information 803 evaluates operating costs such as the operating costs (electricity costs) of the synchronous phase modifier and labor costs for operating the synchronous phase modifier. Note that construction items other than those listed as examples may be added to the operating cost information 803. The operating cost information 803 lists the costs required for each operation in yen per year.

[0064] Third Embodiment In the effect evaluation unit 112 of the first embodiment, it is conceivable to estimate the effect of replacing a decommissioned generator with a synchronous phase modifier in terms of the cost related to greenhouse gas reduction. Therefore, in the third embodiment, a database is prepared that organizes the effects of replacing a decommissioned generator with a synchronous phase modifier from items related to greenhouse gas reduction, and this database is used in the effect evaluation unit 112.

[0065] 9 is a diagram showing benefit assessment information 901 according to the third embodiment. The benefit assessment information 901 is an example of the results of assessment by the effect assessment unit 112. The benefit evaluation information 901 includes an item column 9011 and an evaluation result column 9012 in the column direction, and evaluation information relating to each item is stored in the row direction.

[0066] The item column 9011 lists, as evaluation items, costs related to greenhouse gas reduction, such as the cost of reducing fossil fuels due to an increase in the amount of renewable energy connected, the cost of reducing carbon dioxide emissions by purchasing carbon dioxide emission rights due to carbon dioxide emissions, and the cost of reducing the cost of strengthening the grid in the absence of a synchronous modifier. Note that items other than those listed as examples may be added to the item column 9011. The evaluation result column 9012 lists the benefit of each item in yen. The total of the evaluation result column 9012 is the benefit calculated by the effect evaluation unit 112.

[0067] In other words, the effect evaluation unit 112 selects, as the effect of utilizing the decommissioned generator identified by the system countermeasures examination unit 111 as a synchronous phase modifier, one of the following: the cost of reducing fossil fuels due to the decrease in output of thermal power plants that is relatively reduced due to the increase in the amount of renewable energy connected; the cost of reducing carbon dioxide emission rights purchases due to the decrease in carbon dioxide emissions due to the increase in the amount of renewable energy connected; and the cost of reducing system reinforcement that becomes unnecessary due to the use of a synchronous phase modifier.

[0068] Fourth Embodiment In the investment return evaluation unit 120 of the first embodiment, it is possible to use a cost-benefit ratio as an index used in the index evaluation unit 119. Therefore, in this embodiment, the investment return evaluation unit 120 uses the cost-benefit ratio for evaluation.

[0069] FIG. 10 is a diagram showing a cost-benefit evaluation method according to the fourth embodiment. In the fourth embodiment, the effect evaluation unit 112 evaluates, in monetary terms, the benefit of utilizing a decommissioned generator as a synchronous phase modifier. Examples of the benefit of utilizing a decommissioned generator as a synchronous phase modifier include the cost of reducing fossil fuel costs described in the third embodiment, the cost of reducing the purchase of carbon dioxide emission rights associated with carbon dioxide emissions, and the cost of reducing grid reinforcement. The effect evaluation unit 112 transmits the evaluated benefit to the investment return evaluation unit 120.

[0070] Furthermore, the investment cost evaluation unit 118 estimates the investment cost required to utilize the decommissioned generator as a synchronous phase modifier. Examples of the investment cost required to utilize the decommissioned generator as a synchronous phase modifier include the construction costs and operation costs described in the second embodiment. The investment cost evaluation unit 118 transmits the estimated investment cost to the investment effect evaluation unit 120.

[0071] The investment return evaluation unit 120 calculates the cost-benefit ratio based on the benefits calculated by the effect evaluation unit 112 and the costs calculated by the investment cost evaluation unit 118. Specifically, the investment return evaluation unit 120 calculates the cost-benefit ratio by dividing the costs from the benefits. The greater the benefits relative to the costs, the greater the cost-benefit ratio. A large cost-benefit ratio indicates a more beneficial investment.

[0072] In other words, the return on investment evaluation unit 120 calculates the economic benefit of utilizing a decommissioned generator as a synchronous phase condenser and the costs required to utilize the decommissioned generator as a synchronous phase condenser, and selects the cost-benefit ratio, obtained by dividing the benefit by the costs, as an indicator of return on investment. The return on investment evaluation unit 120 calculates the economic benefit of utilizing a decommissioned generator as a synchronous phase condenser by adding up one or more of the following: the cost of reducing fossil fuels due to the relative decrease in output of thermal power plants caused by the increase in the amount of renewable energy connected; the reduced cost required to purchase carbon dioxide emission credits; and the reduced cost of grid reinforcement that becomes unnecessary due to the use of a synchronous phase condenser. The return on investment evaluation unit 120 calculates the costs required to utilize a decommissioned generator as a synchronous phase condenser from one or more of the initial costs required for the construction work, the operating costs of the synchronous phase condenser, and the labor costs required to operate the synchronous phase condenser.

[0073] The decommissioned generator utilization determination unit 122 compares the cost-benefit ratio with a reference value, and if the cost-benefit ratio is greater than the reference value, determines to utilize this decommissioned generator as a synchronous phase modifier. In this way, the decommissioned generator utilization determination unit 122 can determine which decommissioned generator to utilize as a synchronous phase modifier based on the cost-benefit ratio calculated by the investment effect evaluation unit 120.

[0074] Fifth Embodiment When calculating the return on investment of a synchronous phase modifier for a decommissioned generator in the return on investment assessment unit 120 of the first embodiment, it is necessary not only to calculate the return on investment but also to compare the calculated return on investment with the effects of other measures. Therefore, in the fifth embodiment, a function for making comparisons from various perspectives, such as cost-benefit ratios and evaluation of the impact on grid constraints, has been invented to add to the return on investment assessment unit 120 in order to compare the return on investment when utilizing a decommissioned generator as a synchronous phase modifier with other measures.

[0075] FIG. 11 is a diagram showing a comparison screen 1100 with other measures in a cost-benefit evaluation according to the fifth embodiment. This comparison screen 1100 includes, in the column direction, a countermeasure case column 1101, a cost-benefit evaluation column 1102, an inertia column 1103, a reactive power column 1104, and a reactive power column 1105, and displays, in the row direction, a table showing the results for each countermeasure case. This comparison screen 1100 is displayed by the investment return evaluation unit 120 shown in FIG. 1.

[0076] The countermeasure case column 1101 is a column displaying countermeasures such as replacing the decommissioned generator with a synchronous phase modifier, installing a reactive power compensator, strengthening the power transmission line system, and using storage batteries and electric vehicles. The cost-benefit evaluation column 1102 is a column for displaying an index for evaluating the investment effectiveness of each measure, and displays the cost-benefit evaluation of the fourth embodiment. The inertia column 1103, the reactive power column 1104, and the reactive power column 1105 are columns that display evaluation items related to grid constraints.

[0077] Returning to Fig. 1, the function of the investment return evaluation unit 120 will now be described. In this embodiment, in order to compare the investment return for each of several measures, several countermeasure cases are examined in advance. The countermeasure cases include converting decommissioned generators into synchronous phase modifiers, as well as installing reactive power compensators, strengthening the transmission line system, and using storage batteries and electric vehicles.

[0078] The power system countermeasure examining unit 111 formulates other countermeasures using reactive power supply equipment. Here, the reactive power supply equipment is a static var compensator or a self-commutated var compensator. The effect evaluation unit 112 calculates a cost-benefit ratio by dividing the costs of these other measures by the benefits of these other measures as an indicator of the return on investment of these other measures.The effect evaluation unit 112 calculates the benefits of these other measures by adding up one or more of the following: the cost of reducing fossil fuels due to the relative decrease in output of thermal power plants caused by the increase in the amount of renewable energy connected; and the reduced cost required to purchase carbon dioxide emission rights.The effect evaluation unit 112 calculates the costs of these other measures by adding up one or more of the construction costs, operating costs, and labor costs of the other measures.

[0079] Next, the investment return evaluation unit 120 displays the cost-benefit evaluation of the fourth embodiment in a cost-benefit evaluation column 1102 of the comparison screen 1100 as an index for evaluating the investment return. In calculating this cost-benefit evaluation, the system measure examining unit 111 and the effect evaluation unit 112 estimate the effect of each measure. In estimating the costs, in the case of a reactive power compensator, for example, the manufacturing costs and operating costs of the reactive power compensator are acquired from a server (not shown) that stores information related to the reactive power compensator, just like the generator utilization planning unit 103.

[0080] The index evaluation unit 119 calculates the cost-benefit ratio of each measure based on the costs and benefits associated with each measure, and displays it in the cost-benefit evaluation field 1102 of the comparison screen 1100. This allows the user to determine the most effective measure in terms of the cost-benefit ratio.

[0081] When comparing each countermeasure case, it is considered necessary to consider not only the cost-benefit ratio but also the impact on the grid constraints. Therefore, the investment effect evaluation unit 120 of this embodiment displays evaluation items related to the grid constraints in an inertia column 1103, a reactive power column 1104, and a reactive power column 1105 on the comparison screen 1100 so that they can be compared. In addition to these evaluation items, evaluation items related to the grid constraints, such as frequency stability and synchronizing ability, may also be evaluated and displayed on the comparison screen 1100, etc. By displaying the performance of each of these evaluation items so that they can be compared, the user can select a countermeasure that is necessary not only from the perspective of the cost-benefit ratio but also from the perspective of the grid constraints.

[0082] Sixth Embodiment The renewable energy introduction planning unit 101 described in the first embodiment does not take into consideration the evaluation of return on investment in the grid reinforcement planning unit 102, the generator utilization planning unit 103, and the index evaluation unit 119, as described in the second, third, fourth, and fifth embodiments.

[0083] However, if the investment return evaluation unit 120 predicts that there is a possibility of increasing the amount of renewable energy connected by utilizing synchronous generators in areas with high investment return, the amount of introduction for each area in the renewable energy introduction planning unit 101 may change, and the renewable energy database 107 may be revised. Therefore, in this embodiment, a function for reflecting the results of the investment return evaluation unit 120 in the renewable energy database 107 is added.

[0084] FIG. 12 is a configuration diagram of an existing facility utilization plan formulation device 100 according to the sixth embodiment. The renewable energy introduction planning unit 101 includes a renewable energy introduction plan correction unit 121. This renewable energy introduction plan correction unit 121 has a function of receiving the result of the decommissioned generator utilization determination unit 122, correcting the renewable energy database 107 in response to that result, and displaying the contents of the renewable energy database 107 on a renewable energy introduction plan correction screen 1401. This renewable energy introduction plan correction unit 121 corrects the amount of renewable energy introduced in each area based on the capacity of the synchronous phase modifier determined by the decommissioned generator utilization determination unit 122 and analysis information of the power system in each area.

[0085] FIG. 13 is a flowchart showing the process of correcting the renewable energy introduction plan for each area. Upon receiving the result of the retired generator utilization determination unit 122, the renewable energy introduction plan correction unit 121 evaluates the capacity when the retired generator is utilized as a synchronous modifier (step S10). Then, the renewable energy introduction plan correction unit 121 analyzes the power system of each area (step S11). The renewable energy introduction plan correction unit 121 calculates the amount of renewable energy that can be introduced into each area based on the capacity of the synchronous phase modifier and the analysis result of the power system (step S12), and then ends the processing of FIG.

[0086] FIG. 14 is a diagram showing a renewable energy introduction plan correction screen 1401 for each area according to the sixth embodiment. The renewable energy introduction plan correction screen 1401 is configured to include, in the column direction, an area name column 14011, a renewable energy introduction amount before change column 14012, and a renewable energy introduction amount after change column 14013, and information on each area is arranged in the row direction.

[0087] 12 and 13, the amount of renewable energy introduced in each area changes depending on the signal from the renewable energy introduction plan correction unit 121. Here, if the location where the synchronous generator is installed is area #1, the amount of renewable energy introduced before the change is α, and the amount of renewable energy introduced after the change is α1, the installation of a synchronous phase modifier will increase the amount of renewable energy connection (α1-α). The amount of renewable energy introduced may also change for area #2 and area #3.

[0088] In other words, if the target value of the amount of renewable energy introduced is a constraint, in light of the increase in the amount of renewable energy connected in area #1, the total amount of renewable energy introduced in areas #2, #3, etc. may or may not be reduced by (α1-α). As a result, the total amount of renewable energy introduced in all areas after the change can be made greater than the total amount of renewable energy introduced in all areas before the change.

[0089] Seventh Embodiment In the first embodiment, the return on investment by the index evaluation unit 119 was calculated using all of the information from the renewable energy introduction planning unit 101, the grid reinforcement planning unit 102, and the generator utilization planning unit 103. However, depending on the constraints, the effects of the present invention can be obtained by using only two pieces of information from the renewable energy introduction planning unit 101, the grid reinforcement planning unit 102, and the generator utilization planning unit 103, and it becomes possible to achieve a reduction in greenhouse gas emissions while reducing the grid reinforcement costs when increasing the amount of renewable energy connected, which was an issue of the present invention. Therefore, in this embodiment, a definition of such constraints has been invented.

[0090] First, with regard to the generator utilization planning unit 103 of the first embodiment, if the investment required for evaluation in the investment return evaluation unit 120, such as the construction costs and useful life of converting a decommissioned generator into a synchronous phase modifier, is publicly known information that does not require information from the generator utilization planning unit 103, there is no need to transmit information from the effect evaluation unit 112 to the generator utilization planning unit 103. In this case, the investment return on utilization of a decommissioned generator's synchronous phase modifier can be determined by exchanging information only between the renewable energy introduction planning unit 101 and the grid reinforcement planning unit 102.

[0091] Furthermore, if the planned site for connecting renewable energy is located in a location where the supply of reactive power and synchronizing power by a synchronous phase modifier can be expected, the introduction of a synchronous phase modifier can be expected to increase the amount of renewable energy connected in the area. In such a case, even without estimates by the grid expansion planning unit 102, it is possible to carry out a study on converting a decommissioned generator into a synchronous phase modifier simply by exchanging information between the renewable energy introduction planning unit 101 and the generator utilization planning unit 103.

[0092] Furthermore, even if the renewable energy database 107 is not transmitted from the renewable energy introduction planning unit 101 to the grid expansion planning unit 102, the wide-area grid cross section creation unit 108 can independently create a wide-area grid cross section for future expansion of renewable energy connection capacity based on the publicly known current renewable energy introduction capacity and the target value of the renewable energy introduction capacity reported in national policies, and can then carry out subsequent evaluation. In this case, the exchange of information between the grid expansion planning unit 102 and the generator utilization planning unit 103 makes it possible to consider the utilization of synchronous modifiers for decommissioned generators.

[0093] As described above, in the seventh embodiment, the effects of the present invention can be achieved by using information from two of the renewable energy introduction planning unit 101, the grid reinforcement planning unit 102, and the generator utilization planning unit 103. Therefore, the present invention is not limited to an invention that uses all of the information from the renewable energy introduction planning unit 101, the grid reinforcement planning unit 102, and the generator utilization planning unit 103.

[0094] (Variation) The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0095] The above-described configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware such as an integrated circuit. The above-described configurations, functions, etc. may be realized by software by a processor interpreting and executing a program that realizes each function. Information such as the programs, tables, and files that realize each function can be stored in a storage device such as a memory, a hard disk, or an SSD (Solid State Drive), or on a storage medium such as a flash memory card or a DVD (Digital Versatile Disk).

[0096] In each embodiment, the control lines and information lines shown are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are interconnected.

[0097] The original claims of the original application are reproduced below.

[0098] [1] a storage unit that stores grid reinforcement plan information that identifies locations where grid reinforcement is required based on a wide-area power grid that simulates the power grid in each area; an index evaluation unit that calculates an index of return on investment when utilizing a decommissioned generator as a synchronous phase modifier, using the grid reinforcement plan information stored in the storage unit; a retired generator utilization determination unit that determines the retired generator to be utilized as a synchronous phase modifier based on the index; An existing facility utilization plan formulation device comprising: [2] The storage unit stores renewable energy introduction plan information that predicts the future introduction amount of renewable energy in each area, The index evaluation unit also uses the renewable energy introduction plan information when calculating an index of return on investment. 2. The existing facility utilization plan formulation device according to claim 1. [3] The storage unit stores information about decommissioned generators installed in each area, The index evaluation unit also uses information about decommissioned generators when calculating the index of return on investment. 2. The existing facility utilization plan formulation device according to claim 1. [4] The renewable energy introduction plan information includes current connection amount information or connection amount forecast information of one or more renewable energies selected from wind power, offshore wind power, solar power, wave power, tidal power, flowing water, geothermal power, and biomass; 3. The existing facility utilization plan formulation device according to claim 2. [5] The renewable energy introduction plan information includes current connection amount information or connection amount forecast information of the renewable energy connection amount, 3. The existing facility utilization plan formulation device according to claim 2. [6] Each of the areas is under the jurisdiction of the same electricity transmission and distribution company. 2. The existing facility utilization plan formulation device according to claim 1. [7] Each of the areas is under the jurisdiction of a different electricity transmission and distribution company. 2. The existing facility utilization plan formulation device according to claim 1. [8] a wide-area system cross section creation unit that creates a power system cross section across each of the areas based on the renewable energy introduction plan information; a contingency condition selection unit that selects a contingency condition to be analyzed in the wide-area system cross section creation unit; a system influence evaluation unit that performs a power flow calculation and a transient stability calculation when the fault selected by the contingency fault condition selection unit occurs; a power system countermeasures planning unit that plans countermeasures for improving the stability of the power system based on the results of evaluation by the power system influence evaluation unit; an effect evaluation unit that evaluates the effects of measures proposed by the system countermeasure examination unit; 3. The existing facility utilization plan formulation device according to claim 2. [9] The wide-area system cross section creation unit creates a system cross section required for system impact assessment for each area based on the renewable energy introduction plan information, using current connection amount or connection amount forecast information of the renewable energy connection amount, and the system configuration, system impedance, installation capacity, and generator data included in the system reinforcement plan information. 9. The existing facility utilization plan formulation device according to claim 8.

[10] the system influence evaluation unit calculates system constraint conditions during an accident and during normal operation based on the system cross section created by the wide-area system cross section creation unit and information on the contingency failure set by the contingency failure condition selection unit; 10. The existing facility utilization plan formulation device according to claim 9.

[11] The system influence evaluation unit selects, as the system constraint conditions, one or more of a generator internal phase angle in synchronous stability, a maximum value and a minimum value of frequency in frequency stability, a load margin up to the nose point of a PV curve in voltage stability, a transient voltage, and an overload. 11. The existing facility utilization plan formulation device according to claim 10.

[12] the power system measure examination unit identifies a location of the power system where a problem occurs if the power system constraint condition cannot be satisfied in the evaluation of the power system constraint condition by the power system impact evaluation unit; 11. The existing facility utilization plan formulation device according to claim 10.

[13] The system countermeasure examination unit selects a decommissioned generator that can contribute to solving the problem when used as a synchronous phase modifier for a position in the power system where the problem occurs. 13. The existing facility utilization plan formulation device according to claim 12.

[14] The effect evaluation unit verifies an effect when the decommissioned generator identified by the system countermeasure examination unit is utilized as the synchronous phase modifier. 14. The existing facility utilization plan formulation device according to claim 13.

[15] The effect evaluation unit selects, as the system constraint conditions, one or more of a generator internal phase angle in synchronous stability, a maximum value and a minimum value of frequency in frequency stability, a load margin up to the nose point of a PV curve in voltage stability, a transient voltage, and an overload as effects to be evaluated. 14. The existing facility utilization plan formulation device according to claim 13.

[16] The effect evaluation unit selects, as an effect when the decommissioned generator identified by the grid countermeasures examination unit is utilized as a synchronous phase modifier, one of the following: a reduction cost of fossil fuels due to a decrease in output of a thermal power plant that is relatively reduced due to an increase in the amount of connected renewable energy; a reduction cost of purchasing carbon dioxide emission rights due to a decrease in carbon dioxide emissions due to an increase in the amount of connected renewable energy; and a reduction cost of grid reinforcement that becomes unnecessary due to the utilization of the synchronous phase modifier. 14. The existing facility utilization plan formulation device according to claim 13.

[17] The storage unit further stores generator utilization plan information having information on decommissioned generators in each of the areas, a construction content determination unit that determines construction content for utilizing the decommissioned generator as the synchronous phase modifier based on the generator information of each of the areas included in the generator utilization plan information; an investment cost evaluation unit that evaluates investment costs based on the contents determined by the construction content determination unit; 17. The existing facility utilization plan formulation device according to claim 16, further comprising:

[18] The generator information for each of the areas includes one or more of the following information: capacity of the decommissioned generators, response speed to external commands, years of operation, service life, maintenance status of the generator stator windings, and understanding of local residents regarding the utilization of generators; 18. The existing facility utilization plan formulation device according to claim 17.

[19] The power generator information for each area includes the power generator utilization plan information. 18. The existing facility utilization plan formulation device according to claim 17.

[20] The construction content determination unit selects one or more of the following construction content for utilizing the decommissioned generator as the synchronous phase modifier: installation of a driving machine, installation of a driving inverter, operation of the driving machine, protection of the driving machine, operation of the driving inverter, protection of the driving inverter, installation of a monitoring panel, installation of a central control room panel, turbine disconnection, installation of a lubricating oil device, installation of a cooling water device, installation of an inverter transformer, installation of a foundation for a turbine opening, and cable construction; 18. The existing facility utilization plan formulation device according to claim 17. [twenty one] The investment cost evaluation unit calculates the investment cost from the initial cost required for the construction work. 21. The existing facility utilization plan formulation device according to claim 20. [twenty two] the investment cost evaluation unit calculates the investment cost from one or more of an operating cost of the synchronous phase condenser and a labor cost required for operating the synchronous phase condenser. 21. The existing facility utilization plan formulation device according to claim 20. [twenty three] The investment cost evaluation unit applies a levelized cost calculation that takes into account a discount rate when calculating the investment cost. 21. The existing facility utilization plan formulation device according to claim 20. [twenty four] The index evaluation unit includes an investment effect evaluation unit that calculates an index of investment effect of utilizing the decommissioned generator as a synchronous phase modifier based on the effect evaluated by the effect evaluation unit and the investment cost evaluated by the investment cost evaluation unit. 21. The existing facility utilization plan formulation device according to claim 20. [twenty five] the investment return evaluation unit calculates the economic benefit of utilizing the decommissioned generator as a synchronous phase modifier and the cost required to utilize the decommissioned generator as a synchronous phase modifier, and selects a cost-benefit ratio obtained by dividing the benefit by the cost as an indicator of the investment return; 25. The existing facility utilization plan formulation device according to claim 24.

[26] The investment return evaluation unit calculates the economic benefit of utilizing the decommissioned generator as a synchronous condenser by adding up one or more of the following: the cost of reducing fossil fuels due to the decrease in output of thermal power plants that is relatively reduced due to the increase in the amount of renewable energy connected; the reduced cost required to purchase carbon dioxide emission rights; and the cost of reducing grid reinforcement that becomes unnecessary due to the use of the synchronous condenser. 26. The existing facility utilization plan formulation device according to claim 25.

[27] The investment return evaluation unit calculates the cost required to utilize the decommissioned generator as a synchronous phase condenser from one or more of the initial cost required for the construction work, the operating cost of the synchronous phase condenser, and the labor cost required for operating the synchronous phase condenser. 26. The existing facility utilization plan formulation device according to claim 25.

[28] The system countermeasures examination department further develops other measures using reactive power supply equipment, The effect evaluation unit further calculates an index of the return on investment of the other measures. 26. The existing facility utilization plan formulation device according to claim 25.

[29] The system countermeasure examination unit selects a static var compensator or a self-commutated var compensator as the reactive power supply equipment. 29. The existing facility utilization plan formulation device according to claim 28.

[30] the effect evaluation unit calculates a cost-benefit ratio by dividing the cost of the other measure from the benefit of the other measure as an indicator of the return on investment of the other measure; 29. The existing facility utilization plan formulation device according to claim 28.

[31] The effect evaluation unit calculates, as the benefit of the other measures, one or more of the following: the cost of reducing fossil fuels due to the decrease in output of thermal power plants that is relatively reduced due to the increase in the amount of renewable energy connected; and the reduction in costs required for purchasing carbon dioxide emission rights. 31. The existing facility utilization plan formulation device according to claim 30.

[32] The effect evaluation unit calculates the cost of the other measures by adding up one or more of construction costs, operating costs, and labor costs of the other measures. 31. The existing facility utilization plan formulation device according to claim 30.

[33] Further provided is a renewable energy introduction plan correction unit that corrects the amount of renewable energy introduction in each of the areas based on the index calculated by the index evaluation unit, 2. The existing facility utilization plan formulation device according to claim 1.

[34] The renewable energy introduction plan correction unit corrects the amount of renewable energy introduced in each of the areas based on the capacity of the synchronous phase modifier determined by the decommissioned generator utilization determination unit and analysis information of the power system in each of the areas. 34. The existing facility utilization plan formulation device according to claim 33.

[35] a step in which an index evaluation unit calculates an index of return on investment when utilizing a decommissioned generator as a synchronous phase modifier, using grid reinforcement plan information that identifies locations where grid reinforcement is required based on a wide-area grid that simulates the grid in each area; a step in which a retired generator utilization determination unit determines the retired generator to be utilized as a synchronous phase modifier based on the index; A method for formulating a utilization plan for existing facilities, characterized by carrying out the following. [Explanation of symbols]

[0099] 100 Utilization Planning Device 101 Renewable Energy Introduction Planning Department 107 Renewable Energy Database 107a Renewable energy introduction amount 107b Renewable energy introduction amount 107c Renewable energy consumption 102 System Enhancement Planning Department 108 Wide-area System Cross-Section Creation Department 109 Contingency condition selection section 110 System Impact Assessment Unit 111 System Countermeasures Department 112 Effectiveness Evaluation Department 103 Generator Utilization Planning Department 116 Generator Database 116a Generator Information 116b Generator Information 116c Generator Information 117 Construction Contents Decision Department 118 Investment Cost Evaluation Department 119 Index Evaluation Department 120 Investment Evaluation Department 121 Renewable Energy Introduction Plan Revision Department 122 Decommissioned Generator Utilization Decision-Making Department 20a Area 20b Area 201,201a,201b Electricity demand area 21,203a,203b Power transmission line 202 Renewable Energy Power Generation Department 202a~202c Renewable energy sources 300 Contingency Database 301 Date and Time Data 302 Expected failure case column 303 Fault location column 304 Malfunction Symptoms 401~403 System accident 5 System accident analysis screen 501 Family Tree 502a Date column 502b Time field 503 Results of selection of expected failure conditions 5031 Expected failure case column 5032 Electricity control amount field 5033 Negative limit field 5034 Generator phase angle column 5035 Voltage column 5036 Frequency column 504 Legend 602 Generator 802 Construction cost information 8021 Item field 8022 Evaluation result column 803 Operating expense information 8031 Item field 8032 Evaluation result column 803 Investment Cost Evaluation Information 901 Benefits Assessment Information 9011 Item field 9012 Evaluation result column 1100 comparison screen 1101 Countermeasures Case Column 1102 Cost-benefit assessment column 1103 Inertia field 1104,1105 Reactive power column 1401 Renewable energy introduction plan revision screen 14011 Area name column 14012 Renewable energy introduction amount before change 14013 Renewable energy introduction amount after change

Claims

1. A system reinforcement planning unit that obtains system reinforcement plan information that identifies locations where system reinforcement is required based on renewable energy introduction plan information that predicts the future amount of renewable energy introduced in each area under the jurisdiction of different power transmission companies and wide-area power system information that simulates the power system across each area under the jurisdiction of the power transmission companies; a system countermeasures examination unit that selects a decommissioned generator owned by a power generation company that improves system stability when the decommissioned generator is utilized as a synchronous phase modifier based on the system reinforcement plan information; An existing facility utilization plan formulation device comprising:

2. A wide-area system cross section creation unit that creates a power system cross section across each of the areas based on the renewable energy introduction plan information; a contingency condition selection unit that selects a contingency condition to be analyzed in the wide-area system cross section creation unit; a system influence evaluation unit that performs a power flow calculation and a transient stability calculation when the fault selected by the contingency fault condition selection unit occurs; an effect evaluation unit that evaluates the effect of the decommissioned generator selected by the power system measure examination unit based on the evaluation result by the power system impact evaluation unit; 2. The existing facility utilization plan formulation device according to claim 1, further comprising:

3. The renewable energy introduction plan information includes current connection volume information or connection volume forecast information of one or more renewable energy sources selected from wind power, offshore wind power, solar power, wave power, tidal power, flowing water, geothermal power, and biomass.

3. The existing facility utilization plan formulation device according to claim 2.

4. The renewable energy introduction plan information includes current connection amount information or connection amount forecast information of the renewable energy connection amount.

4. The existing facility utilization plan formulation device according to claim 3.

5. An index evaluation unit that calculates a cost-benefit ratio, which is an index, based on the benefits brought about by the retired generator selected by the system countermeasures examination unit and the costs required to utilize the retired generator as a synchronous phase modifier; a retired generator utilization determination unit that determines the retired generator to be utilized as a synchronous phase modifier based on the index determined by the index evaluation unit; 2. The existing facility utilization plan formulation device according to claim 1, further comprising:

6. The system further includes a renewable energy introduction plan correction unit that corrects the amount of renewable energy introduction in each of the areas based on the index calculated by the index evaluation unit.

6. The existing facility utilization plan formulation device according to claim 5.

7. A step in which a system reinforcement planning unit obtains system reinforcement plan information that identifies locations where system reinforcement is required based on renewable energy introduction plan information that predicts the future amount of renewable energy to be introduced in each area under the jurisdiction of different transmission companies and wide-area power system information that simulates a power system that spans each area under the jurisdiction of the transmission companies; a step in which a system countermeasure examination unit selects, from the system reinforcement plan information, a decommissioned generator owned by the power generation company that improves system stability when the decommissioned generator is utilized as a synchronous phase modifier; A method for formulating a utilization plan for existing facilities, comprising:

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