Operation stop plan support device and operation stop plan support method

Abstract

To plan a date and time of an operation stop plan in which system reliability is secured even when a large amount of renewable energy is introduced.SOLUTION: An operation stop plan support device includes a severest section determination unit and a date and time determination unit. The severest section determination unit calculates system reliability based on power flow calculation results at the time of operation stop in a power system and availability of a distributed power source and determines a time section to be severest for the system based on the calculated system reliability. The date and time determination unit selects a date and time so as to maximize the system reliability of the determined time section and moves the operation stop set to the date and time to another date so as not to deteriorate the system reliability when there is the date and time violating restrictions on a maximum number of operation stop settable to the same date and time.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a work stoppage planning support device and a work stoppage planning support method. [Background technology]

[0002] In recent years, it has become common for computers to create plans to shut down parts of the power system (outage plans) as part of power system maintenance. Currently, many computers input a fixed power flow cross section (scenario) and output an outage plan on the condition that various constraints (voltage constraints, transmission capacity constraints, etc.) are not violated. However, with the significant increase in renewable energy sources in recent years, the number of scenarios and constraint violations that must be considered when creating an outage plan has increased and become more complicated.

[0003] For example, in recent years, with the increase in the amount of photovoltaic (PV) power generation, a typical example of renewable energy, reverse power flow has begun to occur depending on weather conditions and time periods, and even in areas where there were no constraint violations during work stoppages, voltage constraint violations due to voltage increases have begun to occur. For this reason, when planning work stoppages, it has become necessary to determine areas where constraint violations occur due to renewable energy and the dates and times when renewable energy is not in operation. However, in the current work stoppage plans, the above-mentioned areas and dates and times are determined based on the experience of the system operator or on-site maintenance personnel. There is a concern that if the amount of renewable energy introduced in the future increases further, not only will the burden on the system operator increase, but it will also become difficult to plan appropriate work stoppage plans that ensure system reliability, based solely on current experience.

[0004] A document that describes a work suspension plan that takes into account the impact of renewable energy is Patent Document 1. The work suspension plan creation support device in Patent Document 1 inputs a scenario that includes the active power generated by renewable energy and the reactive power generated by renewable energy, and outputs candidate suspension periods and candidate operation measures.

[0005] Patent Document 2 is a document that describes a method for determining a date and time that maximizes system reliability. When a constraint violation occurs, the automatic equipment shutdown plan drafting device in Patent Document 2 focuses on the time slice with the lowest system reliability evaluation value. The automatic equipment shutdown plan drafting device then moves the work that is lowering the system reliability evaluation value in that time slice to another date and time with a higher system reliability evaluation value. By repeating this operation until there are no more constraint violations, the automatic equipment shutdown plan drafting device selects a date and time that ensures system reliability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-48729 [Patent Document 2] JP 2012-10501 A Summary of the Invention Problem that the invention is trying to solve

[0007] However, the work stoppage plan creation support device of Patent Document 1 must accept in advance as a work stoppage requirement a time period when renewable energy is not in operation in areas where constraint violations occur due to renewable energy. This may increase the burden on the grid operator, overlook areas where constraint violations are likely to occur, or select a date and time with low grid reliability, which may make the device difficult to use in practice. In addition, since the output result is limited to displaying stoppage period candidates, the date and time that maximizes grid reliability is not determined.

[0008] The automatic equipment shutdown planning device of Patent Document 2 does not have any input or processing related to renewable energy output, so the system reliability evaluation value and the method of selecting the date and time do not take into account the impact of renewable energy. For this reason, Patent Document 2 does not determine the date and time in a way that ensures system reliability even when a large amount of renewable energy is introduced. In addition, since the process in Patent Document 2 is aimed only at resolving constraint violations, if the amount of renewable energy introduced in the future increases, there is a possibility that work shutdowns will be concentrated on specific dates and times (for example, dates and times when the impact of reverse power flow from PV is small).

[0009] The present invention has been made in consideration of the above-mentioned points, and reduces the burden and negligence of the system operator by having the work suspension plan support device make a comprehensive judgment of areas where constraint violations occur due to renewable energy, time periods when renewable energy is not in operation, etc. In addition, the present invention aims to plan the date and time of a work suspension plan that ensures system reliability even when a large amount of renewable energy is introduced by adjusting the date and time so that system reliability is maximized after taking into account the impact of renewable energy. [Means for solving the problem]

[0010] The work stoppage planning support device of the present invention is characterized in that it comprises a most severe case section determination unit that calculates system reliability based on the results of power flow calculations at the time of work stoppage in the power system and the availability of distributed power sources, and determines the time section that will be the most severe for the system based on the calculated system reliability, and a date and time determination unit that selects a date and time so that the system reliability of the determined time section is maximized, and if there is a date and time that violates a constraint on the maximum number of work stoppages that can be set on the same date and time, moves the work stoppage set for that date and time to another day so as not to deteriorate system reliability. Effect of the Invention

[0011] According to the present invention, it is possible to plan the dates and times of work suspension plans that ensure system reliability even during large-scale introduction of renewable energy. [Brief description of the drawings]

[0012] [Figure 1]FIG. 2 is a diagram illustrating an example of a hardware configuration of a work stoppage plan support device. [Diagram 2] 2 is a diagram illustrating an example of a functional configuration of a work stoppage plan supporting device according to a first embodiment. FIG. [Diagram 3] FIG. 13 is a diagram illustrating an example of a work stoppage system DB. [Figure 4] FIG. 2 is a diagram showing an example of a data table constituting a lineage information DB. [Diagram 5] 4 is a flowchart illustrating an example of processing by a system model candidate constructing unit in the first embodiment. [Figure 6] 13 is an example of a system model before and after system switching. [Figure 7] FIG. 13 is a diagram illustrating an example of an operational capacity constraint DB. [Figure 8] FIG. 13 is a diagram illustrating an example of a reliability KPI attribute DB. [Figure 9] 13 is a flowchart showing an example of processing by a most severe cross section determining unit in the first embodiment. [Figure 10] FIG. 13 is a diagram illustrating an example of a reliability KPIDB. [Figure 11] 13 is a flowchart illustrating an example of processing by an operation policy decision unit in the first embodiment. [Figure 12] FIG. 13 is a diagram illustrating an example of a simultaneous work stoppage prohibition constraint DB. [Figure 13] FIG. 13 is a diagram illustrating an example of a work downtime constraint DB. [Figure 14] FIG. 13 is a diagram illustrating an example of a work stoppage order constraint DB. [Figure 15] FIG. 13 is a diagram illustrating an example of a simultaneous work stoppage possible number constraint DB. [Figure 16] 13 is a flowchart illustrating an example of processing by a date and time determination unit. [Figure 17] FIG. 13 is a diagram showing reliability KPIs for multiple work stoppages at a certain date and time. [Figure 18] 4 is a diagram showing an example of an output from a display unit in the first embodiment. FIG. [Figure 19] FIG. 11 is a diagram illustrating an example of a functional configuration of a work stoppage plan supporting device according to a second embodiment. [Figure 20] FIG. 13 is a diagram illustrating an example of a facility plan DB. [Figure 21] FIG. 13 is a diagram illustrating an example of a grid connection application DB. [Figure 22] 13 is a flowchart illustrating an example of processing by a system model candidate constructing unit in the second embodiment. [Figure 23] 13 is a flowchart showing an example of processing by a most severe cross section determining unit in the second embodiment. [Figure 24] 13 is a flowchart showing a specific process of step S3201. [Diagram 25] FIG. 1 is a diagram showing an example of renewable energy output fluctuation risk. [Figure 26] 13 is a flowchart illustrating an example of processing by an operation policy decision unit in the second embodiment. [Figure 27] FIG. 11 is a diagram showing an example of an output from a display unit in the second embodiment. [Figure 28] FIG. 13 is a diagram illustrating an example of a post-work stop DB. [Figure 29] 13 is a flowchart showing an example of processing by a post-work stoppage correction unit; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the work suspension plan support device and work suspension plan support method of the present invention will be described in detail with reference to the drawings. While embodiment 1 is a basic example applicable to a power system including distributed power sources, embodiment 2 is an example that is particularly effective when connecting renewable energy to a power system. Note that the present invention is not limited by each embodiment. Moreover, each embodiment can be appropriately combined within a range in which the processing contents are not contradictory.

[0014] Example 1 Fig. 1 is a diagram showing an example of a hardware configuration of a work stoppage planning support device 1. In Fig. 1, the work stoppage planning support device 1 includes a communication unit 11, an input means 12, a display device 13, a CPU (Central Processing Unit) 14, a memory 15, and a database 16. These are connected to each other via a bus 17.

[0015] The communication unit 11 includes a circuit and a communication protocol for connecting to a communication network. The communication network may be for automatically acquiring information such as the configuration of the power system and the current status. The input means 12 includes a device such as a keyboard, a mouse, a touch panel, etc., for allowing a user to input any information. The display device 13 includes a device such as a display device, a printer device, etc., for allowing a user to perceive any information.

[0016] The CPU 14 performs processes related to the work stoppage plan, such as searching for data stored in the database 16 or memory 15, executing computer programs, and storing calculation results in memory. The memory 15 is, for example, a RAM (Random Access Memory) or the like, and includes information storage means for computer programs, calculation results, image data, etc. The database 16 saves various data related to work stoppage. The database 16 stores each of the databases (DB) 51 to 63 described below.

[0017] FIG. 2 is a diagram showing an example of a functional configuration of the work stoppage planning support device 1 in the first embodiment. In FIG. 2, the database 16 of the work stoppage planning support device 1 stores a work stoppage system DB 51, a system information DB 52, an operation capacity constraint DB 53, a reliability KPI (Key Performance Indicator) attribute DB 54, a reliability KPI DB 55, a simultaneous work stoppage prohibition constraint DB 56, a work stoppage period constraint DB 57, a work stoppage order constraint DB 58, and a simultaneous work stoppage possible number constraint DB 59. The memory 15 of the work stoppage planning support device 1 includes a system model candidate construction unit 21, a most severe section determination unit 22, an operation policy determination unit 23, a date and time determination unit 24, and a display unit 25. These are computer programs that are the main subjects of each process. Hereinafter, each configuration will be described according to the flow of FIG. 2.

[0018] 3 is a diagram showing an example of the work stoppage system DB 51. The work stoppage system DB 51 stores the predicted number of days of the stoppage period and the work content for each piece of equipment scheduled for work stoppage. Each record (row) of the work stoppage system DB 51 is called a "work stoppage."

[0019] 4 is a diagram showing an example of a data table constituting the system information DB 52. Data table 521 shows the hourly generated power of a certain PV when it is sunny. Meanwhile, data table 522 shows the hourly generated power of the PV when it is raining. Furthermore, data table 523 shows the hourly load flow of a certain transmission line when it is heavy loaded. Meanwhile, data table 524 shows the hourly load flow of the same transmission line when it is light loaded. Furthermore, data table 525 shows the impedance for each transmission line.

[0020] The system model candidate construction unit 21 constructs a system model candidate using the work stop system DB 51 and the system information DB 52 as input.

[0021] FIG. 5 is a flowchart illustrating an example of processing performed by the system model candidate constructor 21 in the first embodiment. In step S2101, the system model candidate construction unit 21 judges whether or not the system model at the time of work stoppage changes from the system model at the time of normal operation due to system switching for each work stoppage stored in the work stoppage system DB 51. When the presence or absence and the location of system switching depend not only on the work stoppage location but also on a time slice such as a season, the system model candidate construction unit 21 may make the judgment for each time slice. For example, when it depends on the season, the system model candidate construction unit 21 may make the judgment for each spring, summer, fall, and winter. When the system model changes, the system model candidate construction unit 21 proceeds to step S2102, and when it does not, ends the process.

[0022] In step S2102, the system model candidate construction unit 21 constructs (outputs) a system model after system switching from the data stored in the system information DB 52. If the presence or absence of system switching and the location of system switching depend not only on the work stop location but also on a time slice such as a season, the system model candidate construction unit 21 may create the system model for each time slice. For example, if it depends on the season, the system model candidate construction unit 21 may create the system model for each of spring, summer, fall, and winter. The system model candidate construction unit 21 then ends the process.

[0023] Figure 6 shows an example of the system model before and after system switching when the system model at the time of work stoppage changes from the system model during normal operation due to system switching. The upper diagram (a) of Figure 6 shows the system model during normal operation before system switching. In the upper diagram (a) of Figure 6, there is one circuit that is always open. Note that "open" means that no power flows through that circuit because the switch is open.

[0024] The middle diagram (b) and the bottom diagram (c) of Figure 6 show system models during work stoppage after system switching. In the middle diagram (b) of Figure 6, the power supply to load a decreases as work on transmission line a stops, so the switch that was normally open is closed (shorted). In the bottom diagram (c) of Figure 6, the switch that was normally open is closed (shorted) as work on transmission line a stops, so there is a possibility that all of the generator's power flow will flow into transmission line a, violating the capacity constraint.

[0025] As shown in Fig. 6, the possibility and location of system switching during a work stoppage may be determined based on various constraint conditions such as capacity constraints, or may be determined based on the system configuration such as the presence of a switch that is normally open in the work stoppage system. Also, the possibility and location of system switching during a work stoppage may be determined based on the electrical distance between the work stoppage location and the controllable switch.

[0026] 7 is a diagram showing an example of the operation capacity constraint DB 53. Upper and / or lower limit values ​​of various constraint conditions are set for each piece of equipment listed in the first column of the operation capacity constraint DB 53. The upper and lower limit values ​​of the constraint conditions may be values ​​that secure a certain margin or more from the limit value in system operation.

[0027] 8 is a diagram showing an example of the reliability KPI attribute DB 54. The reliability KPI attribute DB 54 shows a basic formula of the reliability KPI in the first line, and shows formulas and conditions to be substituted into the basic formula in the second and subsequent lines. The reliability KPI shows the sum of the margins for various constraint conditions, and the lower this sum, the more severe the work stoppage is for the system. In the second and subsequent rows of the reliability KPI attribute DB 54, the severest cross section determination unit 22 determines the formula to be substituted into the basic formula according to the following conditions. -Whether transmission capacity or voltage is in violation of constraints ·Whether or not distributed power sources can be procured -Which constraint violation is more likely to occur due to voltage rise or voltage drop?

[0028] The most severe cross section determination unit 22 receives the system model constructed by the system model candidate construction unit 21, the work stop system DB 51, and the system information DB 52 as input, and outputs a reliability KPI.

[0029] FIG. 9 is a flowchart showing an example of processing by the most severe cross section determining unit 22 in the first embodiment. In step S2201, the severest section determination unit 22 focuses on one or more work stoppages. When the severest section determination unit 22 focuses on a plurality of work stoppages, the severest section determination unit 22 may determine a combination of work stoppages to be focused on based on, for example, the "work system candidate generation process (I)" described in "JP Patent Publication No. 2005-80471".

[0030] In step S2202, the severest section determination unit 22 judges whether or not the reliability KPI of the work stoppage of interest is calculated for the first time. If the reliability KPI is calculated for the first time, the severest section determination unit 22 proceeds to step S2203, otherwise, proceeds to step S2213. In step S2203, the severest section determination unit 22 selects one time section. The severest section determination unit 22 may select one of a total of 48 time sections, which are combinations of monthly (12 types), weekdays / holidays (2 types), and daytime / nighttime (2 types). In step S2204, the severest section determination unit 22 selects one of the system models constructed by the system model candidate construction unit 21. However, if the system models differ depending on the time section, the severest section determination unit 22 selects the system model corresponding to the selected time section.

[0031] In step S2205, the severest section determination unit 22 selects one weather condition, etc. The severest section determination unit 22 selects, for example, the weather (sunny / rainy), illuminance, temperature, wind speed, and load. However, it is preferable that the candidate weather condition, etc., be sufficient for determining the severest section taking into account the impact of renewable energy. In step S2206, the severest section determination unit 22 extracts any one of the data tables (scenario) from the system information DB 52 based on the selected time section, the system model, and the weather conditions, and performs a power flow calculation.

[0032] In step S2207, the most severe section determiner 22 extracts an equation for a reliability KPI that meets the conditions from the reliability KPI attribute DB 54 based on the power flow calculation result and the operational capacity constraint DB 53.

[0033] For example, it is assumed that the result of the power flow calculation and the operation capacity constraint DB 53 indicates that "there is no violation of the constraints, it is possible to control (procure) distributed power sources arbitrarily due to the transmission capacity, and it is easy for a violation of the constraints due to a voltage rise to occur." In this case, the most severe section determination unit 22 "Transmission capacity margin X = (Ps- P+Pr) / Ps" and "Voltage tolerance Y=(Vsmax- Vmax) / Vsmax" Substitute into the basic formula for reliability KPI: Reliability KPI = F(X) + G(Y) + ··· As a result, the most severe cross section determination unit 22 obtains the following equation. Reliability KPI=F((Ps-P+Pr) / Ps) +G((Vsmax-Vmax) / Vsmax)+...

[0034] Furthermore, if a constraint is violated, the margin for each constraint condition will take a large negative value. For example, if a transmission capacity constraint is violated, Ps-P will be negative and this will be multiplied by a large positive weighting coefficient A, resulting in a large negative margin. This is substituted into the basic formula for the reliability KPI, so if any one of the constraint conditions is violated, the reliability KPI will drop sharply. This makes it easy to identify abnormal values.

[0035] In step S2208, the most severe section determiner 22 calculates the reliability KPI by inputting the power flow calculation result and the numerical values ​​of the operation capacity constraint DB 53 into the formula extracted in step S2207. In step S2209, the severest cross section determination unit 22 judges whether or not all weather conditions, etc. have been selected, and if so, proceeds to the processing of step S2210. If not, the severest cross section determination unit 22 returns to step S2205 and selects the next weather condition, etc. In step S2210, the severest cross section determination unit 22 stores the lowest reliability KPI from among the calculated reliability KPIs and the weather conditions at that time in the reliability KPI DB 55 as the severest cross section.

[0036] In step S2211, the severest cross section determination unit 22 determines whether or not all system models have been selected, and if so, proceeds to the processing of step S2212. If not, the severest cross section determination unit 22 returns to step S2204 and selects the next system model. In step S2212, the severest section determination unit 22 judges whether or not all the time sections have been selected, and if so, proceeds to the process of step S2213. If not, the severest section determination unit 22 returns to step S2203 and selects the next time section. In step S2213, the severest section determination unit 22 judges whether or not all work stoppages have been considered, and if so, ends the process. If not, the severest section determination unit 22 returns to step S2201 and focuses on the next work stoppage.

[0037] 10 is a diagram showing an example of the reliability KPIDB 55. The first to fourth columns of the reliability KPIDB 55 indicate the conditions of the power flow calculation (facilities that are out of service, time sections, system models, weather conditions at the most severe sections, etc.). The fifth column indicates the margins of various constraints. The sixth column indicates the reliability KPI.

[0038] The operation policy decision unit 23 uses the reliability KPIDB 55 as an input and decides an operation policy for ensuring system reliability against a total work stoppage.

[0039] FIG. 11 is a flowchart illustrating an example of processing by the operation policy decision unit 23 in the first embodiment. In step S2301, the operation policy decision unit 23 focuses on one or more work stoppages. In step S2302, the operation policy determination unit 23 judges whether or not there is a time slice or a system model in which the reliability KPI is equal to or less than the reference value in the focused work stoppage. If there is even one that is less than the reference value, the operation policy determination unit 23 proceeds to step S2303, and if not, proceeds to step S2306.

[0040] The operation policy decision unit 23 may set target values ​​in advance for the margins (X, Y, etc.) of various constraint conditions, and use the reliability KPI calculated from the target values ​​as a reference value. Also, the operation policy decision unit 23 may use a work stoppage reliability KPI selected by a specific algorithm, such as the 100th from the top, from among all work stoppage reliability KPIs as a reference value.

[0041] In step S2303, the operation policy decision unit 23 judges whether or not the reliability KPI of a work stoppage whose reliability KPI was below the reference value can be increased to or above the reference value (improved) by limiting (changing) the time slice. For example, if the reliability KPI of a certain work stoppage is less than the reference value in the time slice "May, holiday, daytime" but can be increased to or above the reference value in the time slice "May, holiday, night", the operation policy decision unit 23 judges that improvement is possible by limiting the time slice. If improvement is possible, the operation policy decision unit 23 proceeds to step S2304, and if not, proceeds to step S2305.

[0042] In step S2304, the operation policy decision unit 23 adds a condition to the work stoppage period constraint DB 57 so that a time cross section below the reference value is not selected as the work stoppage period for the work stoppage determined to be improveable by limiting the time cross section. For example, if the reliability KPI of the work stoppage under consideration is below the reference value in the time cross section of "May, holiday, daytime", the operation policy decision unit 23 sets the time cross section other than the relevant time cross section as the work stoppage period in the work stoppage period constraint DB.

[0043] In step S2305, the operation policy determination unit 23 determines an operation policy for a work stoppage that is determined to be unimprovable even if the time slice is changed, such as adding equipment such as an SVC (Static Var Compensator). The method for determining this operation policy may be the one described in Patent Document 1 (JP Patent Publication No. 2021-48729).

[0044] In step S2306, the operation policy decision unit 23 judges whether or not the entire work stoppage has been focused on, and if so, ends the process. If not, the operation policy decision unit 23 returns to step S2301 and focuses on the next work stoppage.

[0045] 12 is a diagram showing an example of the simultaneous work stoppage prohibition constraint DB 56. Information on a work stop system is stored in the first to third columns of the simultaneous work stoppage prohibition constraint DB 56, and information on a work stoppage that cannot be performed simultaneously with the corresponding work stoppage is stored in the fourth column.

[0046] 13 is a diagram showing an example of the work downtime period constraint DB 57. The first to third columns of the work downtime period constraint DB 57 store information related to work downtime systems, and the fourth column stores work downtime period constraints (time slices during which the work downtime can be implemented).

[0047] 14 is a diagram showing an example of the work stoppage order constraint DB 58. The first to third columns of the work stoppage order constraint DB 58 store information related to work stoppage systems, and the fourth column stores work stoppage order constraints (the implementation order of the work stoppage).

[0048] 15 is a diagram showing an example of the simultaneous work stoppage possible number constraint DB 59. The first column of the simultaneous work stoppage possible number constraint DB 59 indicates a date and time. The second and third columns indicate the maximum number of work stoppages that can be performed simultaneously at the date and time. For example, according to the data in the first row, it can be seen that the maximum number of work stoppages that can be performed simultaneously in a certain month is one for the same system, and two for a combination with other systems.

[0049] The maximum number of possible simultaneous work stoppages may be calculated by dividing the total duration of all work stoppages by the number of days in a year. For example, the total duration of all work stoppages, 1000 days, may be divided by 365 days, and the result rounded up to the nearest whole number, "3", may be used as the maximum number of possible simultaneous work stoppages of the same system or different systems. In addition, to avoid simultaneous work stoppages of the same system, the maximum number of possible simultaneous work stoppages of the same system at all times and dates may be set to "1".

[0050] The date and time determination unit 24 uses as input the calculation results of the operation policy determination unit 23, the simultaneous work stoppage prohibition constraint DB56, the work stoppage period constraint DB57, the work stoppage order constraint DB58, and the simultaneous work stoppage possible number constraint DB59, and determines the date and time for all work stoppages with the aim of maximizing system reliability taking into account the impact of renewable energy.

[0051] FIG. 16 is a flowchart showing an example of processing by the date and time determination unit 24. In step S2401, the date and time determination unit 24 determines a date and time and a system model so as to satisfy the conditions of the work stoppage period constraint, the work stoppage order constraint, and the simultaneous work stoppage prohibition constraint, and to maximize the total value of the reliability KPI over a period, for example, one year. However, the processing of step S2401 alone may result in work stoppages being concentrated at specific dates and times (for example, at night). The following processing is for achieving both maintaining a high total value of the reliability KPI and dispersing work stoppage dates and times.

[0052] In step S2402, the date and time determination unit 24 extracts the maximum number of work stoppages that can be performed on the same date and time from the simultaneous work stoppage possible number constraint DB59. In step S2403, the date and time determination unit 24 focuses on work stoppages that are assigned to dates and times that exceed the maximum number. In step S2404, the date and time determination unit 24 moves the work stoppage under consideration to another day so as to maximize the sum of the reliability KPI over a period, for example, one year. This process will be described with reference to FIG.

[0053] 17 is a diagram showing the reliability KPI of multiple work stoppages at a certain date and time. At the stage of step S2401, both work stoppage A and work stoppage B are assigned to "8 / 1 18:00-24:00", which maximizes the sum of the reliability KPIs. Next, it is assumed that the processes of steps S2402 and S2403 reveal from the simultaneous work stoppage possible number constraint DB 59 that only one work stoppage is possible on "8 / 1". In this case, the date and time determination unit 24 needs to move either work stoppage A or work stoppage B to another day.

[0054] If work stop A is moved to the date and time of "8 / 1 06:00-12:00", which has the next highest reliability KPI, the total value of the reliability KPI of work stop A and work stop B becomes "8 + 12 = 20". On the other hand, if work stop B is moved to the date and time of "8 / 1 06:00-12:00", which has the next highest reliability KPI, the total value becomes "10 + 9 = 19". In this case, the date and time determination unit 24 moves work stop A to another day so that the total value of the reliability KPI becomes higher. Return to FIG. 16 for explanation.

[0055] In step S2405, the date and time determination unit 24 judges whether the number of work stoppages is equal to or less than the maximum number of simultaneous work stoppages at all dates and times. If the number of work stoppages is equal to or less than the maximum number of simultaneous work stoppages, the date and time determination unit 24 ends the process, otherwise returns to step S2403 and repeats the above process.

[0056] Fig. 18 is a diagram showing an example of output from the display unit 25 in the first embodiment. The data table 251 output by the display unit 25 shows, for each piece of work-stopped equipment, the most severe section and the tolerance of each constraint condition in that section. It can also be seen that, as a result of the operation policy decision unit 23 deciding an operation policy that limits the time section, the date and time have been decided to be "4 / 1-4 / 3 18:00-24:00". By displaying this information, the display unit 25 can encourage the system operator to understand the system status.

[0057] Example 2 Fig. 19 is a diagram showing an example of a functional configuration of a work suspension plan support device 1 in a second embodiment. In Fig. 19, the work suspension plan support device 1 includes a facility plan DB 60, a grid connection application DB 61, a renewable energy output fluctuation risk DB 62, a post-work suspension DB 63, and a post-work suspension correction unit 35 in addition to the configuration of the first embodiment. In addition, with the addition of the configuration, the processing contents of the system model candidate construction unit 21, the most severe section determination unit 22, the operation policy determination unit 23, and the display unit 25 in the first embodiment are partially changed. The "b" at the end of the symbol of the OO part means that a part of the processing contents of the OO part has changed compared to the processing contents of the OO part of the same name in the first embodiment.

[0058] Hereinafter, each component will be described according to the flow of Fig. 19. However, the description of the components that have already been described in the first embodiment will be omitted.

[0059] 20 is a diagram showing an example of the installation plan DB 60. The installation plan is a work plan for equipment modification of the power system, such as the addition or removal of a power transmission line. The installation plan DB 60 indicates the target equipment, date and time, and work content of the installation plan.

[0060] 21 is a diagram showing an example of the grid connection application DB 61. A grid connection application is an application to a power transmission and distribution company to connect a distributed power source such as a PV to the power grid. The grid connection application DB 61 indicates the date and time, location, type of generator, rated power, etc., when a distributed power source is newly connected to the power grid.

[0061] The system model candidate constructing unit 21b receives the work suspension system DB 51, the system information DB 52, the facility plan DB 60, and the interconnection application DB 61 as input, and constructs (outputs) a system model candidate.

[0062] Fig. 22 is a flowchart showing an example of processing by the system model candidate constructor 21b in Example 2. Compared with the processing by the system model candidate constructor 21 in Example 1 (Fig. 5), step S3101 is added.

[0063] In step S3101, the system model candidate construction unit 21b extracts a power system whose configuration changes due to the addition of a power transmission line, etc., from the facility plan DB 60, and constructs a system model candidate. Similarly, the system model candidate construction unit 21b extracts a power system whose configuration changes due to the interconnection of PV, etc., from the interconnection application DB 61, and constructs a system model candidate.

[0064] In the conventional technology, the information on the facility plan and the grid connection application is not linked to the work stoppage plan support device. However, if the amount of renewable energy introduced increases in the future, the change in the system configuration due to the increase may change the most severe section. For this reason, the system model candidate construction unit 21b may construct a system model candidate as described above and create a work stoppage plan that can also handle the increase in the amount of renewable energy introduced in the future.

[0065] The most severe section determiner 22b receives the system model constructed by the system model candidate constructor 21b, the work-suspended system DB 51, and the system information DB 52 as input, and outputs the reliability KPI and the renewable energy output fluctuation risk.

[0066] Fig. 23 is a flowchart showing a processing example of the severest section determination unit 22b in the second embodiment. Compared with the processing (Fig. 9) of the severest section determination unit 22 in the first embodiment, step S3201 is added. In step S3201, the severest section determination unit 22b calculates a renewable energy output fluctuation risk, and stores the result in the renewable energy output fluctuation risk DB 62. In step S2202 in Fig. 23, the severest section determination unit 22b judges whether or not to obtain the renewable energy output fluctuation risk for the first time in addition to the reliability KPI of the work stoppage under consideration.

[0067] FIG. 24 is a flowchart showing a specific process of step S3201. In step S32011, the severest cross section determination unit 22b acquires the reliability KPI at the severest cross section.

[0068] In step S32012, the most severe scenario determination unit 22b calculates the increase or decrease in renewable energy output due to the new installation of PV and unobserved weather conditions in the future. The most severe scenario determination unit 22b calculates the reliability KPI in a scenario (weather conditions, etc.) that is more severe than the reliability KPI of the most severe scenario calculated immediately before due to this renewable energy output fluctuation. The future increase in PV, etc. may be a value estimated from a probability distribution such as the Markov Chain Monte Carlo method (MCMC).

[0069] In step S32013, the severest section determiner 22b judges whether the reliability KPI calculated in step S32012 is equal to or greater than a reference value. If it is equal to or greater than the reference value, the severest section determiner 22b proceeds to step S32014, otherwise, the severest section determiner 22b proceeds to step S32015. With regard to the reference value, the severest section determiner 22b may set target values ​​in advance for the margins (X, Y, etc.) of various constraint conditions, and use the reliability KPI calculated from the target values ​​as the reference value.

[0070] In step S32014, the most severe section determiner 22b stores in the renewable energy output fluctuation risk DB 62 information indicating that the renewable energy output fluctuation risk is “low” for the work stoppage whose reliability KPI was equal to or greater than the reference value. In step S32015, the most severe section determiner 22b stores in the renewable energy output fluctuation risk DB 62 information indicating that the renewable energy output fluctuation risk is “high” for the work stoppage whose reliability KPI is less than the reference value.

[0071] In step S32016, the severest section determination unit 22b determines whether or not there is a work stoppage in which the reliability KPI is equal to or greater than the reference value in a section other than the severest section in step S32011. If there is such a work stoppage, the severest section determination unit 22b proceeds to step S32017, and if not, ends the process.

[0072] In step S32017, the most severe section determination unit 22b extracts the section with the lowest risk among the sections for work stoppages that have sections (weather conditions, etc.) above the standard value, and stores this in the renewable energy output fluctuation risk DB 62 as a low-risk work condition.

[0073] 25 is a diagram showing an example of the renewable energy output fluctuation risk DB 62. The renewable energy output fluctuation risk DB 62 indicates the renewable energy output fluctuation risk and low-risk working conditions for each work stop facility, each time slice, and each system model.

[0074] The operation policy determination unit 23b receives the reliability KPI DB 55 and the renewable energy output fluctuation risk DB 62 as input and determines an operation policy for ensuring system reliability against a total work stoppage.

[0075] Fig. 26 is a flowchart showing an example of processing by the operation policy decision unit 23b in the embodiment 2. Compared with the processing by the operation policy decision unit 23 in the embodiment 1 (Fig. 11), steps S3301 and S3302 are added. In Fig. 26, if step S2302 is "No", the process proceeds to step S3301.

[0076] In step S3301, the operation policy determination unit 23b judges whether or not the renewable energy output fluctuation risk stored in the renewable energy output fluctuation risk DB 62 is “high.” If the renewable energy output fluctuation risk is “high,” the operation policy determination unit 23b proceeds to step S3302, and if the renewable energy output fluctuation risk is “low,” the operation policy determination unit 23b proceeds to step S3306.

[0077] In step S3302, the operation policy determination unit 23b determines a candidate adjustment date and time or operation policy for a work stoppage with a "high" risk of fluctuation in renewable energy output in case the prediction of the renewable energy output is incorrect, in accordance with low-risk work conditions.

[0078] In this way, the operation policy determination unit 23b may incorporate into the work suspension plan a mechanism for adjusting a plan made in advance in response to a risk of fluctuation in renewable energy output due to weather changes or the like.

[0079] Fig. 27 is a diagram showing an example of output of the display unit 25b in Example 2. Compared with the example of output of the display unit 25 in Example 1 (Fig. 18), in the data table 341 (Fig. 27) displayed by the display unit 25b, in addition to Example 1, it can be seen that the renewable energy output fluctuation risk is "low" and the low-risk work conditions are "weekday, night" and "rainy, cloudy". By displaying this information, the display unit 25b makes it possible to adjust the work stop date and time in the short term in accordance with the renewable energy output fluctuation accompanying the change in weather conditions, etc.

[0080] For example, it may be found that the actual weather conditions on the day of the work stoppage are more severe than the weather conditions predicted several days before the work stoppage. In this case, the operation policy determination unit 23b can fine-tune the work stoppage date and time in the short term, taking into account the renewable energy output fluctuation, by searching for a date and time in the vicinity where the grid operator has low-risk work conditions. Usually, a work stoppage plan is created one year in advance.

[0081] Fig. 28 is a diagram showing an example of the post-work stoppage DB 63. In the post-work stoppage DB 63, a data table 631 indicates the work stoppage date and time, the tolerance of various constraint conditions, and the power flow at the time of planning for a certain work stoppage last year. Meanwhile, a data table 632 indicates the work stoppage date and time, the tolerance of various constraint conditions, and the power flow at the time of actual work for the same work stoppage. The post-work stoppage DB 63 stores such data on the power flow etc. at the time of planning and the corresponding data on the power flow etc. at the time of actual work for each work stoppage.

[0082] The post-work stoppage correction unit 35 receives the post-work stoppage DB 63 as an input and automatically corrects the information stored in the system information DB 52 .

[0083] FIG. 29 is a flowchart showing an example of processing by the post-work stoppage correction unit 35. In step S3501, the post-work stoppage correction unit 35 calculates, from the post-work stoppage DB 63, the difference between the planned time and the actual time of work with respect to the margins or flows of various constraint conditions for each work stoppage.

[0084] In step S3502, the post-work stoppage correction unit 35 judges, for each work stoppage, from the calculation result in step S3501, whether or not the constraint conditions, etc. during actual work are harsher for the system than those at the time of planning. If they are harsher, the post-work stoppage correction unit 35 proceeds to step S3503, and if not, ends the process.

[0085] In step S3503, the post-work stoppage correction unit 35 refers to information about a work stoppage where the work is judged to be more severe than planned, and updates the power flow and system configuration stored in the system information DB 52, or adds a scenario.

[0086] In this way, the post-work stoppage correction unit 35 may provide feedback on performance information after a work stoppage is implemented, and use the feedback in planning the next work stoppage, in order to reduce the burden on the operator.

[0087] The present invention encompasses the technical ideas described in the following appendices. (Appendix 1) a most severe case section determination unit that calculates system reliability based on a power flow calculation result at the time of work stoppage in the power system and the availability of distributed power sources, and determines a time section that is most severe for the system based on the calculated system reliability; Selecting a date and time so as to maximize the system reliability of the determined time slice; a date and time determination unit that, when a date and time violates a constraint on the maximum number of work stoppages that can be set at the same date and time, moves the work stoppage set at that date and time to another date so as not to deteriorate system reliability; A work stoppage planning support device comprising:

[0088] (Appendix 2) a system model candidate construction unit that constructs a system model taking into account system switching due to work stoppage; an operation policy decision unit that decides an operation policy including limiting a time slice in which work can be stopped or adding equipment in order to improve the system reliability of the determined time slice; 2. A work stoppage planning support device according to claim 1, comprising:

[0089] (Appendix 3) a display unit that displays the result determined by the most severe section determination unit, the result limited or determined by the operation policy determination unit, and the result moved by the date and time determination unit; 3. A work stoppage planning support device according to claim 2, comprising:

[0090] (Appendix 4) The most severe cross section determination unit is Calculate the fluctuation of renewable energy output caused by future expansion of renewable energy and unobserved weather conditions, Evaluate the risk that the calculated renewable energy output fluctuations pose to system reliability, Preserving weather conditions that ensure system reliability; 4. A work stop planning support device according to claim 3,

[0091] (Appendix 5) The operation policy decision unit includes: Determining an adjustment date and time or an operation measure in case the forecast for the determined time slice is not met based on the risk of the renewable energy output fluctuation and the weather conditions under which system reliability is ensured; 5. A work stop planning support device according to claim 4,

[0092] (Appendix 6) The display unit is Displaying the risk of renewable energy output fluctuation and weather conditions under which system reliability is ensured; The work stop planning support device according to claim 5,

[0093] (Appendix 7) The system model candidate construction unit includes: Construct a grid model based on facility plan information, including the expansion of transmission lines, and application information for interconnection of distributed power sources. 3. A work stop planning support device according to claim 2, characterized in that

[0094] (Appendix 8) A post-work suspension correction unit is provided for updating past power flow cross sections and system configurations after a work suspension based on performance information including power flow cross sections generated during the work suspension; 2. A work stoppage planning support device according to claim 1,

[0095] (Appendix 9) The most severe section determination unit of the work stoppage planning support device is Calculating system reliability based on a power flow calculation result during work stoppage in the power system and the availability of distributed power sources, and determining a time section that is most severe for the system based on the calculated system reliability; The date and time determination unit of the work stoppage planning support device Selecting a date and time so as to maximize the system reliability of the determined time slice; If there is a violation of the constraint on the maximum number of work outages that can be set on the same date and time, the work outages set on that date and time are moved to another date so as not to deteriorate the system reliability; A work stoppage planning support method comprising the steps of: [Explanation of symbols]

[0096] 1. Work stoppage planning support device 11 Communications Department 12 Input Methods 13 Display device 14 CPU 15 Memory 16 Database 21, 21b System model candidate construction section 22, 22b Most severe cross section determination section 23, 23b Operational Policy Decision-making Department 24 Date and time determination department 25, 25b Display section 35 Correction section after work stoppage 51 Work stop system DB (database) 52 Lineage information DB 53 Operational capacity constraint DB 54 Reliability KPI attribute DB 55 Reliability KPIDB 56 Simultaneous work stoppage prohibition constraint DB 57 Work stoppage period constraint DB 58 Work stop order constraint DB 59 Constraints on the number of simultaneous work stoppages DB 60 Facility Planning DB 61 Interconnection Application DB 62 Renewable energy output fluctuation risk DB 63 DB after work stoppage

Claims

1. a most severe case section determination unit that calculates system reliability based on a power flow calculation result at the time of work stoppage in the power system and the availability of distributed power sources, and determines a time section that is most severe for the system based on the calculated system reliability; Selecting a date and time so as to maximize the system reliability of the determined time slice; a date and time determination unit that, when a date and time violates a constraint on the maximum number of work stoppages that can be set at the same date and time, moves the work stoppage set at that date and time to another date so as not to deteriorate system reliability; A work stoppage planning support device comprising:

2. a system model candidate construction unit that constructs a system model taking into account system switching due to work stoppage; an operation policy decision unit that decides an operation policy including limiting a time slice in which work can be stopped or adding equipment in order to improve the system reliability of the determined time slice; The work stoppage planning support device according to claim 1, further comprising:

3. a display unit that displays the result determined by the most severe section determination unit, the result limited or determined by the operation policy determination unit, and the result moved by the date and time determination unit; The work stoppage planning support device according to claim 2, further comprising:

4. The most severe cross section determination unit is Calculate the fluctuation of renewable energy output caused by future expansion of renewable energy and unobserved weather conditions, Evaluate the risk that the calculated renewable energy output fluctuations pose to system reliability, Preserving weather conditions that ensure system reliability; 4. The work stoppage planning support device according to claim 3, further comprising:

5. The operation policy decision unit includes: Determining an adjustment date and time or an operation measure in case the forecast for the determined time slice is not met based on the risk of the renewable energy output fluctuation and the weather conditions under which system reliability is ensured; 5. The work stoppage planning support device according to claim 4, further comprising:

6. The display unit is Displaying the risk of renewable energy output fluctuation and weather conditions under which system reliability is ensured; 6. The work stoppage planning support device according to claim 5,

7. The system model candidate construction unit includes: Construct a grid model based on facility plan information, including the expansion of transmission lines, and application information for interconnection of distributed power sources.

3. The work stoppage planning support device according to claim 2, further comprising:

8. A post-work suspension correction unit is provided for updating past power flow cross sections and system configurations after a work suspension based on performance information including power flow cross sections generated during the work suspension; 2. The work stoppage planning support device according to claim 1,

9. The most severe section determination unit of the work stoppage planning support device is Calculating system reliability based on a power flow calculation result during work stoppage in the power system and the availability of distributed power sources, and determining a time section that is most severe for the system based on the calculated system reliability; The date and time determination unit of the work stoppage planning support device Selecting a date and time so as to maximize the system reliability of the determined time slice; If there is a violation of the constraint on the maximum number of work outages that can be set on the same date and time, the work outages set on that date and time are moved to another date so as not to deteriorate the system reliability; A work stoppage planning support method comprising the steps of:

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