JP7505929B2 - Power system management system and method - Google Patents

Description

The present invention relates to a power grid management system and method, and is suitable for use in a power grid management system that manages a power grid in which renewable energy devices such as offshore wind power generation devices are connected in a non-farm fashion, for example.

In recent years, the use of solar power generation and wind power generation, which have low _CO2 emissions, has been expanding in order to prevent global warming. Solar power generation, as typified by home solar power generation equipment, is installed close to the consumption area, but has the disadvantage of low average operation rate because it cannot generate electricity at night. In addition, the amount of power generated by solar power generation is greatly affected by weather conditions such as clouds and rain. For this reason, when predicting the amount of power generated by solar power generation the day before using weather forecasts, it is necessary to take into account a certain degree of prediction error.

On the other hand, wind power can generate electricity even at night, and large offshore wind power generation equipment, which is installed in the ocean rather than on land, is blessed with stable winds throughout the year and has the advantage of having a high average operating rate. However, when a typhoon or other storm approaches, there is a risk that all offshore wind power generation systems will stop at once if the winds are too strong, and there is also the disadvantage that the amount of power generated can fluctuate greatly depending on weather conditions.

In addition, the current capacity of transmission lines is designed based on the maximum design output value of existing power plants such as thermal and nuclear power plants, taking into consideration the shutdown of some equipment in the event of a lightning strike on a transmission line. Therefore, if new electricity generated by offshore wind power is to be transmitted through existing transmission lines, there is a risk that the available capacity of the transmission lines will be insufficient.

Furthermore, if the amount of power generated by a home solar power generation system falls short of what was predicted, this is equivalent to an increase in the load on the consumer who has installed that home solar power generation system, which will cause fluctuations in the power flowing through the transmission lines. If the transmission lines become overloaded in this case, it will become necessary to quickly curtail the output of offshore wind power generation and the power generated by thermal power generation systems.

Therefore, the introduction of a so-called non-farm type connection is being considered, in which the power flowing through the transmission line for the next 24 hours is estimated the day before, and the estimated result is compared with the maximum operational value of the tidal flow power that can flow through the transmission line, known as the operational limit value (also called the operational target value), which is obtained in advance using various calculation methods.When there is availability on the transmission line, the transmission line is used by renewable energy power generation equipment such as offshore wind power generation equipment, and when there is no availability on the transmission line for some reason, the output of the renewable energy power generation equipment is suppressed.

On the other hand, for example, during times when maintenance work is being carried out on a transmission line, it is necessary to shut down the transmission line in the work section, so the operational limit power of the transmission line will be temporarily lowered during the time when the work is being carried out. Also, when there are two routes of transmission lines with a high voltage class, such as a trunk system, during times when there is work there will temporarily be only one route, so it will be necessary to restrict the power that can flow through the lower voltage class transmission line connected to that transmission line. For this reason, the operational limit value of each transmission line must be determined by taking into account all the expected power flowing through multiple transmission lines.

JP 2015-130777 A JP 2019-149870 A

In recent years, many renewable energy devices such as wind power generation devices and solar power generation devices have been introduced in various places, causing large fluctuations in the power flowing through system equipment such as transmission lines and transformers, and increasing the risk of overload problems during normal times and problems maintaining stability in the event of an accident. To solve these problems, for example, Patent Document 1 proposes stopping renewable energy sources and generators to maintain stable operation.

Patent Document 2 also proposes a hybrid grid connection system that connects various renewable energy power generation facilities, such as wind power generation, solar power generation, geothermal power generation, and biomass power generation, to a commercial power grid using the grid supply capacity limits.

However, Patent Document 1 and Patent Document 2 do not disclose or suggest anything about making full use of the available capacity of power transmission lines and minimizing the amount of suppression of renewable energy devices, such as wind power generation devices and solar power generation devices, connected to the grid.

The present invention has been made in consideration of the above points, and aims to propose a power system stabilization system and method that can maximize the amount of power generated by renewable energy devices by making full use of available capacity on transmission lines and minimizing the amount of output suppression of renewable energy devices, thereby promoting the effective use of renewable energy.

In order to solve such problems, the present invention provides a power system management system that manages a power system in which renewable energy devices that generate renewable energy are connected in a non-farm type, comprising a first computer system that manages an entire area of the power system, a plurality of second computer systems that each manage a partial area that does not overlap with each other within the entire area, and a third computer system that directly or indirectly controls the amount of power generated by the renewable energy devices, and each of the second computer systems shares with the first computer system the power generation record within a partial area that is the partial area under its jurisdiction and the operational limit value of the transmission line within the partial area, and determines the amount of suppression of the renewable energy within the partial area under its jurisdiction based on the power generation record within the partial area and the operational limit value of the transmission line within the partial area. The third computer system calculates the amount of suppression of the renewable energy generated by the non-firm-type connected renewable energy device in the entire area based on the power generation record of the renewable energy in each of the partial areas and the operational limit value of the power transmission line, and notifies the first computer system of the calculated amount of suppression of the renewable energy, and the first computer system calculates the amount of suppression of the renewable energy generated by the non-firm-type connected renewable energy device in the entire area based on the power generation record of the renewable energy in each of the partial areas and the operational limit value of the power transmission line in each of the partial areas, corrects the calculated amount of suppression of the renewable energy based on the amount of suppression of the renewable energy notified by each of the second computer systems, and the third computer system controls the amount of power generation of the renewable energy device so as to suppress the amount of power generation of the renewable energy by the amount of suppression calculated and corrected by the first computer system.

In addition, the present invention provides a power system management method executed in a power system management system that manages a power system in which renewable energy devices that generate renewable energy are connected in a non-farm type, the power system management system having a first computer system that manages an entire area of the power system, a plurality of second computer systems that each manage a partial area that does not overlap with each other within the entire area, and a third computer system that directly or indirectly controls the power generation amount of the renewable energy devices, and each of the second computer systems shares with the first computer system the power generation record within a partial area that is the partial area under its jurisdiction and the operational limit value of the transmission line within the partial area, and determines the suppression amount of the renewable energy within the partial area under its jurisdiction based on the power generation record within the partial area and the operational limit value of the transmission line within the partial area. The method includes a first step of calculating the suppression amount of the renewable energy based on the operational limit value of the transmission line in the area and notifying the first computer system of the calculated suppression amount of the renewable energy, a second step of correcting the suppression amount of the renewable energy generated by the non-firm type connected renewable energy device in the entire area, which is calculated based on the power generation record of the renewable energy in each of the partial areas and the operational limit value of the transmission line in each of the partial areas, based on the suppression amount of the renewable energy notified by each of the second computer systems, and a third step of controlling the power generation amount of the renewable energy device so as to suppress the power generation amount of the renewable energy by the suppression amount calculated and corrected by the first computer system.

The power grid management system and method of the present invention allows for a faster calculation of the amount of suppression of renewable energy within the entire area, making it possible to calculate the amount of suppression of renewable energy based on information more in line with the actual situation and at a timing closer to the actual supply and demand cross-section. This allows for a smaller margin to be set for the operational limit value of the transmission line, and therefore allows for the free capacity of the transmission line allocated to renewable energy to be used without waste.

According to the present invention, it is possible to reduce the amount of suppression of non-farm-type connected renewable energy, minimize the amount of output suppression of the renewable energy device, and maximize the amount of power generated by the renewable energy device. This makes it possible to promote the effective use of renewable energy.

1 is a block diagram showing an overall configuration of a power system management system according to first and second embodiments; FIG. 13 is a conceptual diagram for explaining information sharing between a renewable energy grid stabilization system and a renewable energy grid stabilization subsystem. FIG. 2 is a block diagram illustrating information exchanged between the systems. FIG. 13 is a diagram for explaining the flow of creating a wind power generation plan after the introduction of a non-farm type connection. FIG. 1 is a conceptual diagram illustrating the available capacity of a main grid allocated to wind power generation in a non-farm type connection. 1A is a characteristic curve diagram explaining the forward power and available capacity of a main system, and FIG. 1B is a characteristic curve diagram showing the forward power flowing through a transformer. FIG. 1 is a conceptual diagram illustrating the available capacity of a main grid allocated to wind power generation in a non-farm type connection. 1A is a characteristic curve diagram explaining the forward power and available capacity of a main system, and FIG. 1B is a characteristic curve diagram showing the forward power flowing through a transformer. FIG. 1 is a conceptual diagram illustrating the available capacity of a main grid allocated to wind power generation in a non-farm type connection. 1A is a graph explaining the forward power flow and available capacity of a bulk grid, and FIG. 1B is a graph showing the forward power flowing through a transformer. FIG. 2 is a block diagram showing a hardware configuration of a renewable energy grid stabilization system according to the first and second embodiments. FIG. 2 is a block diagram showing a logical configuration of the renewable energy grid stabilization system according to the first embodiment. FIG. 2 is a block diagram showing a logical configuration of a renewable energy grid stabilization subsystem according to the first embodiment. 13 is a flowchart showing a processing procedure for an operational limit value calculation process. 2A is a system configuration diagram of “Area A” in FIG. 1 , (B) is a graph showing the predicted power generation amount of solar power generation and wind power generation and the power generation amount according to the power generation plan of the generator, and (C) is a graph showing the asynchronous power generation ratio. 13A and 13B are graphs used to explain the processing of the renewable energy output suppression amount calculation unit. 11 is a flowchart showing a processing procedure of a first renewable energy suppression amount calculation process. 13 is a flowchart showing a processing procedure of a second renewable energy suppression amount calculation process. FIG. 11 is a block diagram showing a logical configuration of a renewable energy grid stabilization system according to a second embodiment. 13 is a flowchart showing a processing procedure for an operation limit value raising process;

One embodiment of the present invention will be described in detail below with reference to the drawings.

(1) First embodiment (1-1) Configuration of the power system management system according to this embodiment In Fig. 1, 1 indicates the power system management system according to this embodiment as a whole. This power system management system 1 is a system for managing the operation of a power system consisting of power transmission facilities such as power transmission lines 2, 3 (3A, 3B) and transformers 4 ( _4A1 , _4A2 , 4B) owned by a general electricity transmission and distribution company, and generators 5 (5A, 5B, 5C) and 6 (6A, 6B) such as thermal power plants and hydroelectric power plants, and is configured with a central load dispatching center system 8, a renewable energy system stabilization system 9, and multiple renewable energy system stabilization subsystems 10 (10A, 10B) interconnected via a network 7.

The central load control center system 8 is a computer system that has the function of comprehensively managing the entire power system of the entire area under the jurisdiction of the general electricity transmission and distribution company (hereinafter, appropriately referred to as the entire area AR1).

The renewable energy grid stabilization system 9 is a computer system that has the function of executing various calculation processes to stabilize the power grid from renewable energy devices such as wind power generation devices 11 (11A, 11B) and solar power generation devices 12 (12A, 12B) within the entire area AR1 to the loads (consumers).

Each renewable energy system stabilization subsystem 10 is a computer system that has the function of executing various calculation processes to stabilize the power system from the renewable energy devices to the loads in a non-overlapping partial area (hereinafter referred to as partial area AR2 (AR2A, AR2B)) within the entire area AR1. The entire area AR1 is divided into multiple partial areas AR2, and a renewable energy system stabilization subsystem 10 that is responsible for each partial area AR2 is installed.

In the case of this power system management system 1, as shown in FIG. 2, each renewable energy system stabilization subsystem 10 manages the power generation results of each generator 6 (hereinafter referred to as generator power generation results), the power generation results of each wind power generation device 11 (hereinafter referred to as wind power generation results), and the power generation results of each solar power generation device 12 (hereinafter referred to as PV power generation results) in the partial area (hereinafter referred to as the jurisdictional partial area) AR2 under its own jurisdiction by registering them in the system data storage database 13 (13A, 13B) in its own subsystem.

The system data storage database 13 also stores the operational limit values of the power transmission lines 3 within the jurisdictional area AR2 notified by the renewable energy system stabilization system 9 as described below, the power generation plan values within the jurisdictional area AR2 for a 24-hour period for each specified time (hereinafter, 30 minutes), the renewable energy output forecast values, and the supply and demand forecast values.

Meanwhile, the renewable energy grid stabilization system 9 registers and manages the operational limit values of the power transmission lines 3 within the jurisdictional partial area AR2 of each renewable energy grid stabilization subsystem 10, as well as the generator power generation results, wind power generation results, and solar power generation results within the jurisdictional partial area AR2 of each renewable energy grid stabilization subsystem 10, which are notified from each renewable energy grid stabilization subsystem 10 as described below, in the grid data storage database 14 within its own system.

The system data storage database 14 also stores the operational limit values of each transmission line 2, 3 within the overall area AR1 notified by the central load dispatching center system 8, as described below, as well as the power generation plan values for the entire area AR1 every 30 minutes for 24 hours, and the predicted output values and supply and demand values of renewable energy.

Each renewable energy system stabilization subsystem 10 appropriately registers the generator power generation record, wind power generation record, and/or solar power generation record, which change from moment to moment, in the system data storage database 13, and notifies the renewable energy system stabilization system 9 of the registered generator power generation record, wind power generation record, and/or solar power generation record. The renewable energy system stabilization system 9 also sequentially registers the generator power generation record, wind power generation record, and/or solar power generation record transmitted from the renewable energy system stabilization subsystem 10 in its own system data storage database 14.

In this way, in this power grid management system 1, the various pieces of information described above registered in the grid data storage database 14 of the renewable energy grid stabilization system 9 and the grid data storage database 13 of each renewable energy grid stabilization subsystem 10 are shared in a synchronized state between the renewable energy grid stabilization subsystem 10 and the renewable energy grid stabilization system 9.

In the power grid management system 1 having the above configuration, the central load dispatching center system 8 predicts the ever-changing power demand in the supply and demand section for each time period every 30 minutes over a 24-hour period within the entire area AR1, as well as the amount of power of each renewable energy device (wind power generation device 11 and solar power generation device 12) present within the entire area AR1 in these supply and demand sections, and creates a power generation plan for generators 5 and 6 every 30 minutes over a 24-hour period based on the prediction results.

As shown in Fig. 3, the central load dispatching center system 8 notifies the renewable energy integrated stabilization system 9 of the power generation plan values for each supply and demand section for 24 hours every 30 minutes that were planned as described above, the forecast values of power demand for each of these supply and demand sections (hereinafter referred to as demand forecast values), and the forecast values of output of each renewable energy device within the entire area AR1 for each of these supply and demand sections (hereinafter referred to as renewable energy output forecast values). In addition to this information, the central load dispatching center system 8 notifies the renewable energy grid stabilization system 9 of the operational limit values of each transmission line 2, 3 that are set in advance.

The renewable energy grid stabilization system 9 stores and manages the power generation plan values, demand forecast values, and renewable energy output forecast values within the overall area AR1 for each supply and demand section notified by the central load dispatching center system 8, as well as the operational limit values of each transmission line 2, 3, in the grid data storage database 14 (Figure 2) as described above.

Then, the renewable energy grid stabilization system 9 transmits to each renewable energy grid stabilization subsystem 10, among the information on the power generation plan values, demand forecast values, and renewable energy output forecast values within the overall area AR1 in each of these supply and demand cross sections stored in the grid data storage database 14, the power generation plan values, demand forecast values, and renewable energy output forecast values within the partial area AR2 under the jurisdiction of that renewable energy grid stabilization subsystem 10, and the operational limit values of the transmission lines 3 within that partial area AR2 under its jurisdiction.

The renewable energy grid stabilization system 9 also calculates the available capacity of each transmission line 2, 3 in each supply and demand cross section, and when there is a partial area AR2 in which the available capacity in a certain supply and demand cross section is less than a preset threshold (hereinafter, this is referred to as the available capacity threshold) and it is possible to increase the operational limit value of the transmission line 3 in that partial area AR2, it calculates a new operational limit value in which the operational limit value of that transmission line 3 is increased as much as possible, and notifies the renewable energy grid stabilization subsystem 10 and the central load dispatching center system 8 that have jurisdiction over that partial area AR2 of the new calculated operational limit value.

Furthermore, the renewable energy grid stabilization system 9 calculates the amount of renewable energy to be suppressed (renewable energy suppression amount) within the entire area AR1 during these time periods and the adjustment amount of the output power of the generators 5 and 6 (hereinafter referred to as the generator output adjustment amount) based on the power generation plan values, demand forecast values, and renewable energy output forecast values for each supply and demand section within the entire area AR1 stored in the grid data storage database 14, and the generator power generation results, wind power generation results, and solar power generation results within each partial area AR2, and notifies the central load dispatching center system 8 of the calculated generator output adjustment amount.

On the other hand, the renewable energy grid stabilization subsystem 10 stores and manages the operational limit values of the power transmission lines 3 within the jurisdictional partial area AR2 notified by the renewable energy grid stabilization system 9, as well as the power generation plan values, demand forecast values, and renewable energy output forecast values within the jurisdictional partial area AR2, in the system data storage database 13 (Figure 2).

Then, based on this information and the generator power generation records, wind power generation records, and solar power generation records within the jurisdictional partial area AR2 stored in the system data storage database 13, the renewable energy system stabilization subsystem 10 calculates the operational limit values for each supply and demand cross section of the transmission line 3 within the jurisdictional partial area AR2, and the suppression amount of renewable energy in each supply and demand cross section that should be suppressed in order to observe the operational limit restrictions of the transmission line 3 within the jurisdictional partial area AR2.

Then, the renewable energy grid stabilization subsystem 10 notifies the renewable energy grid stabilization system 9 of the operational limit values of the power transmission lines 3 and the suppression amount of renewable energy in each supply and demand cross section calculated as described above, as well as the power generation results of the generators, wind power generation results, and solar power generation results within the jurisdictional partial area AR2.

The renewable energy grid stabilization system 9 stores this information notified from each renewable energy grid stabilization subsystem 10 in its own grid data storage database 14.

In addition, the renewable energy grid stabilization system 9 corrects the operational limit values of each transmission line 2, 3 within the overall area AR1 in each supply and demand cross section, the suppression amount of renewable energy, and the generator output adjustment amount calculated by itself as described above, as necessary, based on the operational limit values of the transmission line 3 and the suppression amount of renewable energy in each supply and demand cross section notified by each renewable energy grid stabilization subsystem 10, and notifies the central load dispatching center system 8 of this corrected information.

The central load dispatch center system 8 requests power generation companies that own non-farm-connected renewable energy devices to curtail renewable energy generation by publishing on the Internet, for example, the amount of renewable energy curtailment for each 30-minute time slot based on the amount of renewable energy curtailment in each supply-demand section notified by the renewable energy grid stabilization system 9. In addition, the central load dispatch center system 8 re-drafts the power generation plan to increase or decrease the necessary output of generators 5 and 6 based on the amount of generator output adjustment notified by the renewable energy grid stabilization system 9.

The central load control center system 8 then controls the amount of power generated by each of the generators 5 and 6 in the overall area AR1 by giving appropriate output command values (power values to be output) to each of the generators 5 and 6 in the overall area AR1 according to the re-drafted power generation plan.

(1-2) Flow of creating a renewable energy power generation plan after the introduction of a non-firm type connection Figure 4 shows the flow of creating a power generation plan by a renewable energy power generation company 20 when a "non-firm type connection" is introduced to the power system in Figure 1. As shown in Figure 4, the power generation company 20 first creates a power generation plan for the next day on the previous day (S1), and submits the created power generation plan to the general electricity transmission and distribution company 21 (S2).

The general electricity transmission and distribution company 21 makes a demand forecast and a power generation plan for the next day, and evaluates whether an overload (congestion) will occur in the power transmission equipment if renewable energy is generated according to the power generation plans submitted by each power generation company 20 (S3). If the general electricity transmission and distribution company 21 determines that an overload will occur in the power transmission equipment, it publishes on the Internet, for example on its own website, the amount of renewable energy suppression required to eliminate the overload (S4). Thus, the power generation company 20 reviews its power generation plan for the next day based on the published amount of renewable energy suppression (S5).

As described above, the power generation company 20 also creates a power generation plan at least 1+α (where α is, for example, 4 or 5) hours before the actual supply and demand cross section of the day in question and submits it to the general electricity transmission and distribution company 21 (S6, S7). Based on this power generation plan, the general electricity transmission and distribution company 21 evaluates the overload of the electricity transmission equipment (S8) and publishes the necessary amount of suppression of renewable energy on its own website on the Internet (S9). Thus, the power generation company 20 reviews the power generation plan for the actual supply and demand cross section based on the published amount of suppression of renewable energy (S10). The same process is repeated one hour before the actual supply and demand cross section (S11 to S15).

When a "non-farm type connection" is introduced in this way, the general electricity transmission and distribution company 21 decides the next day's amount of renewable energy suppression the day before, and the power generation company 20 reviews the power generation plan for the next day in accordance with this decision. The general electricity transmission and distribution company 21 also decides the amount of renewable energy suppression the morning of the day, and the power generation company 20 reviews the power generation plan for the day in accordance with this decision. Furthermore, the amount of renewable energy suppression is calculated again using the same procedure one hour before actual power generation.

As shown in Figure 5, a new renewable energy device (wind power generation device 22 in Figure 5) is connected to the main grid 2 in Figure 1 as a power source with a "non-farm type connection", and the sum (P1 + P2) of the flow power P1 flowing through one route 2A of the main grid 2 and the flow power P2 flowing through the other route 2B of the main grid 2 is considered to be the fence flow power (flow power (P1 + P2) of the main grid 2), and the difference between the operational limit value of the main grid 2 calculated in advance (e.g., 3620 MW) and the flow power (P1 + P2) (i.e., the available capacity of the main grid 2) is allocated to the wind-generated power from the wind power generation device 22, as shown by arrow a in Figure 6 (A).

In this case, the tidal power (P1+P2) of the main grid 2 is predicted every 30 minutes for 24 hours based on the predicted value of the power generation amount of the photovoltaic power generation device 12 (12A) for the next 24 hours on the previous day, the 24-hour prediction curve of the load 23 (Figure 5), and the 24-hour operation plan of the generator 5 (Figure 5). The difference between the tidal power (P1+P2) and the operational limit value is set as the power generation amount allowed for the wind power generation device 22.

As shown in FIG. 6(B), the forward power P3 (FIG. 4) flowing through the power line 3 connecting the main grid 2 and the transformer 4 (FIG. 5) is calculated as the sum of the power generation amount of the photovoltaic power generation device 12 and the power consumption amount of the load 23, and there are days when it drops significantly during the day and days when it does not drop significantly. Days when the forward power P3 drops significantly during the day are days when the power generation amount of the photovoltaic power generation device 12 is large, and as the forward power P3 decreases, the forward power (P1+P2) of the main grid 2 increases during the day. For this reason, the amount of power generation allowed for the non-farm-connected wind power generation device 22 becomes smaller.

On the other hand, Figures 7 and 8 show an example in which the position of the operational limit current is set near the generator 5 and the wind power generation device 22. In this case, when the solar power generation device 12 generates power during the day, the current current power P3 flowing through the transmission line 3 decreases, and the current current power (P1 + P2) flowing through the main grid 2 also decreases, so that, as is clear from Figures 8 (A) and (B), the amount of power generation allowed for the wind power generation device 22 increases. In other words, in this case, the amount of power generation allowed for the non-farm-type connected wind power generation device 22 shows a trend opposite to that of Figures 5 and 6.

On the other hand, Figures 9 and 10 are another example. In this example, the configuration is similar to the examples in Figures 5 and 6, but the amount of power generation allowed by the non-farm-type connected wind power generation device 22 does not change significantly without being greatly affected by the amount of power generation by the solar power generation device 12 (Figure 9). However, Figures 10 (A) and (B) are examples in which operational limits are set in both the positive and negative directions of the forward power P3. If the load 23 (Figure 9) is a large consumer and a facility such as a factory is stopped, much of the power generated by the solar power generation device 12 will flow back to the main grid 2 via the power transmission line 3, so it is necessary to suppress the amount of power generation by the solar power generation device 12 so as not to exceed the magnitude of the negative operational limit value of the forward power P3.

In this way, the available capacity of the main grid 2 that can be allocated to the "non-firm type connected" wind power generation device 22 varies depending on the output of the photovoltaic power generation device 12. Therefore, by quickly measuring the actual output of the photovoltaic power generation device 12, etc., and calculating the amount of suppression for the non-firm type connected wind power generation device 22, it is possible to utilize the available capacity of the main grid 2 without waste.

(1-3) Suppression of tidal power flowing through each transmission line The amount of power generated by renewable energy devices fluctuates depending on weather conditions. Therefore, in the power grid management system 1, if the number of renewable energy devices, such as wind power generation devices 11 and solar power generation devices 12, owned by consumers and power generation companies increases within the entire area AR1, it becomes difficult for the central load dispatching center system 8 to appropriately calculate the output command values to be given to each of the generators 5 and 6 within the entire area AR1 at every moment.

Meanwhile, for each transmission line 2, 3, the maximum value of the power that can be passed through that transmission line 2, 3 is set as the operational limit value as described above, as the amount of power that can maintain transient stability, voltage stability, and frequency stability even in the event of an accident. Therefore, when the central load dispatching center system 8 calculates the output command value to be given to each generator 5, 6, it is necessary to observe the operational limit constraint of each transmission line 2, 3, which is to keep the tidal flow power flowing through the transmission line 2, 3 below the operational limit value of the transmission line 2, 3.

Then, in order to comply with the operational limit constraints of the transmission lines 2 and 3, the central load dispatching center system 8 determines the output command value to be given to each generator 5 and 6 in the entire area AR1 while predicting the power generation capacity of each renewable energy device in the entire area AR1 so that the tidal power flowing through each transmission line 2 and 3 is equal to or less than the operational limit value set for that transmission line 2 and 3 with a certain margin.

The size of this margin depends heavily on the accuracy of the demand forecast within the entire area AR1 and the output forecast of each renewable energy device; the higher the accuracy of the forecast, the smaller the margin can be set, and the lower the accuracy of the forecast, the larger the margin must be set. For this reason, in a situation where the accuracy of the forecast is low, the free capacity of the transmission lines 2 and 3 that can be allocated to renewable energy becomes smaller as the margin is set larger, resulting in a problem that the amount of suppression of renewable energy output from "non-farm type connected" renewable energy devices becomes larger, making it difficult to promote effective use of renewable energy.

On the other hand, the operational limit value of each transmission line 2, 3 is temporarily lowered during times or periods when maintenance work is being carried out on the transmission lines 2, 3. For example, in the example of Figure 1, the trunk system transmission line 2 (hereinafter simply referred to as the trunk system 2) with a high voltage class has a two-route configuration, and the sum of the transmission limit values of each route 2A, 2B is defined as the operational limit value of this trunk system 2, and the sum (P1 + P2) of the flow powers P1, P2 flowing through each route 2A, 2B, respectively, is managed as the flow power of the trunk system 2.

In this case, if one of the routes 2A, 2B of the trunk system 2 is shut down for maintenance work, operation will be temporarily limited to one route during the work period (e.g., one month), so it will be necessary to suppress the forward flow powers P3, P4 flowing through each of the transmission lines 3 with lower voltage classes. For this reason, it is necessary to predict all of the forward flow powers P3, P4 flowing through these transmission lines 3 and use the prediction results to determine the operating limit values for each of these transmission lines 3 with lower voltage classes.

In order to suppress the tidal power (P1+P2) flowing through the main grid 2, in addition to suppressing the output of generators 5A and 5B, it is necessary to suppress the output of generator 6A, wind power generation device 11A, and solar power generation device 12A in partial area AR2A represented by "Area A" in Figure 1 to suppress the tidal power P3 of transmission line 3A, and to suppress the output of generator 6B, wind power generation device 11B, and solar power generation device 12B in partial area AR2B represented by "Area B" in Figure 1 to suppress the tidal power P4 of transmission line 3B.

In this way, the operational limit values of the power transmission lines 2 and 3 may fluctuate, and in order to keep up with the fluctuating operational limit values of the power transmission lines 2 and 3 and maintain the operational limit restrictions of each power transmission line 2 and 3, complex processing is required in which the output of each renewable energy device within the entire area AR1 and the output of each generator 5 and 6 must be appropriately adjusted.

In the power system management system 1 of this embodiment, such complicated processing can be performed in a shorter time by the central load dispatching center system 8, the renewable energy system stabilization system 9, and each renewable energy system stabilization subsystem 10 coordinating with each other. As a result, even if the output of photovoltaic power generation or the like fluctuates unexpectedly and significantly during the hour after the suppression amount is determined in step S13 of FIG. 4, the suppression amount of the "non-firm type connection" can be reviewed. Thus, it is possible to minimize the suppression amount of the renewable energy device while observing the operational limit restrictions of each transmission line 2, 3, and promote the effective use of renewable energy.

(1-4) Configuration of Renewable Energy Grid Stabilization System and Renewable Energy Grid Stabilization Subsystem Here, Fig. 11 shows the physical configuration of the renewable energy grid stabilization system 9 according to this embodiment. The renewable energy grid stabilization system 9 is configured from a general-purpose server device equipped with information processing resources such as a CPU (Central Processing Unit) 30, a main memory device 31, an auxiliary memory device 32, and a communication device 33.

The CPU 30 is a processor that controls the operation of the entire renewable energy grid stabilization system 9. The main memory device 31 is composed of, for example, a volatile semiconductor memory, and is used as a work memory for the CPU 30. The system configuration creation program 40, future power flow cross section calculation program 41, operation limit value calculation program 42, grid equipment overload resolution calculation program 43, renewable energy output suppression amount calculation program 44, and generator output adjustment amount calculation program 45, which will be described later, are stored and held in this main memory device 31.

The auxiliary storage device 32 is composed of a non-volatile storage device such as a hard disk device or SSD (Solid State Drive), and is used to store various programs and data that should be retained for a long period of time. The system data storage database 14 described above in FIG. 2 is stored and retained in this auxiliary storage device 32.

The communication device 33 is a device that performs protocol control during communication with each renewable energy grid stabilization subsystem 10 or the renewable energy grid stabilization system 9, and the central load dispatching center system 8 via the network 5 (FIG. 1), and is composed of, for example, a network interface card (NIC).

The physical configuration of the renewable energy grid stabilization subsystem 10 is similar to that of the renewable energy grid stabilization system 9, so a description thereof will be omitted here. However, in the case of the renewable energy grid stabilization subsystem 10, the generator output adjustment amount calculation program 45 is omitted.

Figure 12 shows the logical configuration of the renewable energy grid stabilization system 9 with respect to the calculation process of the suppression amount of renewable energy executed by the renewable energy grid stabilization system 9 in steps S3, S8, and S13 of Figure 4.

As shown in FIG. 12, the renewable energy system stabilization system 9 is configured to include a system data storage database 14, a system configuration creation unit 50, a future power flow cross section calculation unit 51, an operational limit value calculation unit 52, a system equipment overload resolution calculation unit 53, a renewable energy output suppression amount calculation unit 54, and a generator output adjustment amount calculation unit 55.

The system data storage database 14 is a database used to hold and manage various system data. As described above, the system data storage database 14 stores the operational limit values of each transmission line 2, 3 in the entire area AR1, the generator performance, wind power generation performance, and solar power generation performance of the partial area AR2 (Figure 1) under the jurisdiction of each renewable energy system stabilization subsystem 10, which the renewable energy system stabilization system 9 acquires from each renewable energy system stabilization subsystem 10, and the power generation plan values, demand forecast values, and renewable energy output forecast values in the supply and demand section for each time period every 30 minutes for 24 hours in the entire area AR1, which are provided by the central load dispatching center system 8.

The system configuration creation unit 50 is a functional unit that is realized by the CPU 30 of the renewable energy system stabilization system 9 executing the system configuration creation program 40 (FIG. 11) stored in the main memory device 31. The system configuration creation unit 50 holds information related to the topology of the power system within the entire area AR1, creates a configuration diagram of the power system that shows the connection relationships of the power transmission equipment such as the transmission lines 2 and 3 and the transformer 4, and outputs the information to the future power flow cross section calculation unit 51 and the operational limit value calculation unit 52.

The future power flow cross section calculation unit 51 is a functional unit embodied by the CPU 30 of the renewable energy system stabilization system 9 executing the future power flow cross section calculation program 41 stored in the main memory device 31. Based on the information on the configuration diagram of the power system in the entire area AR1 provided by the system configuration creation unit 50 and various information stored in the system data storage database 14, the future power flow cross section calculation unit 51 calculates the predicted value of the power flow power in the supply and demand cross section for each time period for 24 hours every 30 minutes from a predetermined time point (0:00 the next day in S3 of FIG. 4, 1+α hours later in S8, and 1 hour later in S13) for all transmission lines 2, 3 in the entire area AR1, and outputs the calculated predicted value of the power flow power in each supply and demand cross section of each transmission line 2, 3 to the system equipment overload resolution calculation unit 53. In addition, the future power flow cross section calculation unit 51 outputs the predicted values of the power flow cross section for 24 hours every 30 minutes of the power flow power (P1 + P2) of the main grid 2 (Figure 1) out of the calculated predicted values of the power flow power in each supply and demand cross section of each transmission line 2, 3 to the renewable energy output suppression amount calculation unit 54.

The operational limit value calculation unit 52 is a functional unit that is realized by the CPU 30 of the renewable energy grid stabilization system 9 executing the operational limit value calculation program 42 stored in the main memory device 31. The operational limit value calculation unit 52 notifies the grid equipment overload resolution calculation unit 53 of the pre-set operational limit values of each of the power transmission lines 2 and 3 notified by the central load dispatching center system 8.

In addition, based on the available capacity of the main grid 2 provided by the grid equipment overload resolution calculation unit 53 as described below, if the available capacity is less than the above-mentioned predetermined available capacity threshold, the operational limit value calculation unit 52 calculates the operational limit values of each of the power transmission lines 2 and 3 for each time period for the next 24 hours every 30 minutes, and outputs the calculation results to the grid equipment overload resolution calculation unit 53.

Furthermore, the operational limit value calculation unit 52 notifies the operational limit value of the transmission lines 3 in each partial area AR2 calculated as described above to the renewable energy system stabilization subsystem 10 that manages that partial area AR2. The operational limit value calculation unit 52 then corrects the operational limit values of each transmission line 2, 3 that it has calculated as described above based on the operational limit value of the main system 2 notified by each renewable energy system stabilization subsystem 10, and outputs the corrected operational limit values to the system equipment overload resolution calculation unit 53 and the central load dispatching center system 8.

The system equipment overload resolution calculation unit 53 is a functional unit realized by the CPU 30 of the renewable energy system stabilization system 9 executing the system equipment overload resolution calculation program 43 stored in the main memory device 31. The system equipment overload resolution calculation unit 53 determines (overload determination) whether or not the predicted values of the flow power of each supply and demand cross section exceed the operational limit value of the transmission lines 2, 3, based on the predicted values of the flow power in the supply and demand cross section for each time period for 24 hours every 30 minutes of each transmission line 2, 3 given by the future flow cross section calculation unit 51 and the operational limit value of each transmission line 2, 3 given by the operational limit value calculation unit 52.

Specifically, the system equipment overload resolution calculation unit 53 calculates the difference between the operational limit value and the predicted value of the tidal flow power of the supply and demand section of each of the transmission lines 2 and 3 every 30 minutes as the predicted value of the available capacity of each of the transmission lines 2 and 3, and judges whether the calculated predicted value of the available capacity is a positive value or not. The system equipment overload resolution calculation unit 53 then outputs the result of this judgment and the predicted value of the available capacity for 24 hours every 30 minutes of each of the transmission lines 2 and 3 to the renewable energy output suppression amount calculation unit 54, and outputs the predicted value of the available capacity of the main system 2 to the operational limit value calculation unit 52.

The renewable energy output suppression amount calculation unit 54 is a functional unit embodied by the CPU 30 of the renewable energy system stabilization system 9 executing the renewable energy output suppression amount calculation program 44 stored in the main storage device 31. The renewable energy output suppression amount calculation unit 54 calculates the amount of suppression of renewable energy, such as the extent to which the output of which renewable energy device (here, the wind power generation device 11) should be suppressed during a certain time period when the tidal flow power of the supply and demand cross section of a certain transmission line 2, 3 during that time period exceeds the operation limit value of that transmission line 2, 3, based on the predicted value of the tidal flow power for 24 hours for 30 minutes for each transmission line 2, 3 given by the future power flow cross section calculation unit 51, the judgment result of the overload judgment for 24 hours for 30 minutes for each transmission line 2, 3 given by the system equipment overload resolution calculation unit 53, and the predicted value of the available capacity for 24 hours for 30 minutes for each transmission line 2, 3. The renewable energy output suppression amount calculation unit 54 then outputs the calculation result as the renewable energy suppression amount to the generator output adjustment amount calculation unit 55 and the central load dispatching center system 8.

The generator output adjustment amount calculation unit 55 is a functional unit embodied by the CPU 30 of the renewable energy grid stabilization system 9 executing the generator output adjustment amount calculation program 45 stored in the main memory device 31. The generator output adjustment amount calculation unit 55 calculates the output adjustment amount of the generators 5, 6 (FIG. 1) based on the renewable energy output suppression amount in the supply and demand section for each time period for 24 hours every 30 minutes given by the renewable energy output suppression amount calculation unit 54. Specifically, when the output suppression amount of the renewable energy device is large (for example, 1000 MW or more), the system frequency drops, so the generator output adjustment amount calculation unit 55 calculates the output adjustment amount of the generators 5, 6 that can suppress such a drop in the system frequency. The generator output adjustment amount calculation unit 55 then notifies the central load dispatching center system 8 of the calculated output adjustment amount of the generators 5, 6 as the generator output adjustment amount.

Based on the renewable energy output suppression amount given by the renewable energy output suppression amount calculation unit 54, the generator output adjustment amount given by the generator output adjustment amount calculation unit 55, and the operational limit value of each transmission line 2, 3 given by the operational limit value calculation unit 52, the central load dispatching center system 8 uses calculation methods such as power flow calculation, transient stability calculation, and PV curve to determine whether transient stability can be maintained in the supply and demand cross section for each time period over a 24-hour period every 30 minutes, whether overload will not occur in all transmission lines 2, 3, whether the voltage fluctuation of each transmission line 2, 3 is within a specified range, and whether the frequency fluctuation of the power flow through each transmission line 2, 3 is within a specified range.

If the voltage fluctuations of the transmission lines 2, 3 are not within the specified range, or if the frequency fluctuations of the tidal power flowing through the transmission lines 2, 3 are not within the specified range, the central load dispatching center system 8 re-plans the power generation plan to increase or decrease the output of the necessary generators 5, 6 so that they are within the corresponding specified range during the corresponding time period. The central load dispatching center system 8 also publishes the renewable energy output suppression amount given by the renewable energy output suppression amount calculation unit 54 on its website, and requests the necessary renewable energy power generation companies to revise their power generation plans.

The above-mentioned judgment work may be performed by the renewable energy grid stabilization system 9 instead of the central load dispatching center system 8. Also, each renewable energy grid stabilization subsystem 10 may perform the same processing as described above for the partial power grid within its respective jurisdictional partial area AR2 (FIG. 1). In this case, the time change in the operational limit value for each partial area AR2 in FIG. 1 and the time change in the operational limit value of the main grid 2 are shared between the renewable energy grid stabilization system 9 and all the renewable energy grid stabilization subsystems 10, so that the appropriate power generation capacity of the renewable energy device and the output adjustment amount of the generators 5 and 6 can be calculated.

Furthermore, by actually measuring the output of each renewable energy device and the moment-to-moment output of generators 5 and 6, it is possible to determine the deviation of the actual measured current from the expected current, thereby improving the accuracy of calculating the possible output amount and suppression amount of the renewable energy device.

On the other hand, FIG. 13 shows the logical configuration of the renewable energy grid stabilization subsystem 10 with respect to the calculation process of the suppression amount of renewable energy executed by the renewable energy grid stabilization subsystem 10 in steps S3, S8, and S13 of FIG. 4.

As shown in FIG. 13, the renewable energy system stabilization subsystem 10 is configured to include a system data storage database 13, a system configuration creation unit 60, a future power flow cross section calculation unit 61, an operational limit value calculation unit 62, a system equipment overload resolution calculation unit 63, and a renewable energy output suppression amount calculation unit 64.

The system data storage database 13 is a database used to hold and manage various system data. The system data storage database 13 stores the operational limit values of the power transmission lines 3 in the jurisdictional partial area AR2 notified by the renewable energy system stabilization system 9 as described above, the power generation plan values, demand forecast values, and renewable energy output forecast values in the supply and demand section for each time period every 30 minutes for 24 hours in the jurisdictional partial area AR2, and the generator performance, wind power generation performance, and solar power generation performance in the jurisdictional partial area AR2.

The system configuration creation unit 60 is a functional unit that is realized by the CPU 30 of the renewable energy system stabilization subsystem 10 executing a system configuration creation program stored in the main storage device. The system configuration creation unit 60 holds information regarding the topology of the power system within the jurisdictional partial area AR2 of the renewable energy system stabilization subsystem 10, creates a configuration diagram of the power system that shows the connection relationships of the power transmission equipment such as the transmission lines 3 and transformers 4 within the jurisdictional partial area AR2, and outputs the information to the future power flow cross section calculation unit 61 and the operational limit value calculation unit 62.

The future power flow cross section calculation unit 61 is a functional unit embodied by the CPU 30 of the renewable energy system stabilization subsystem 10 executing a future power flow cross section calculation program stored in the main storage device. Based on the information on the configuration diagram of the power system in the jurisdictional partial area AR2 provided by the system configuration creation unit 60 and various information stored in the system data storage database 13, the future power flow cross section calculation unit 61 calculates the predicted value of the power flow power in the supply and demand cross section for each time period for 24 hours every 30 minutes from a predetermined time point (0:00 the next day in S3 of FIG. 4, 1+α hours later in S8, and 1 hour later in S13) for the transmission line 3 in the jurisdictional partial area AR2, and outputs the calculated predicted value of each power flow power to the system equipment overload resolution calculation unit 63. The future power flow cross section calculation unit 61 also outputs the calculated predicted value of the power flow power in each supply and demand cross section of the transmission line 3 to the renewable energy output suppression amount calculation unit 64.

The operational limit value calculation unit 62 is a functional unit embodied by the CPU 30 of the renewable energy grid stabilization subsystem 10 executing an operational limit value calculation program stored in the main storage device. The operational limit value calculation unit 62 notifies the system equipment overload resolution calculation unit 63 of the operational limit value of the corresponding transmission line 3 notified from the renewable energy grid stabilization system 9. In addition, based on the predicted value of the available capacity of the transmission line 3 in the jurisdictional partial area AR2 given by the system equipment overload resolution calculation unit 63 as described below, if there is a time period in which the predicted value of the available capacity of the transmission line 3 is less than the above-mentioned available capacity threshold, the operational limit value calculation unit 62 calculates a new operational limit value of the transmission line 3 for that time period, and outputs the calculation result to the system equipment overload resolution calculation unit 63 and the renewable energy grid stabilization system 9.

The system equipment overload resolution calculation unit 63 is a functional unit realized by the CPU 30 of the renewable energy system stabilization subsystem 10 executing a system equipment overload resolution calculation program stored in the main memory device. The system equipment overload resolution calculation unit 63 determines (overload determination) whether or not any of the predicted values of each demand section exceeds the operational limit value of the transmission line 3 based on the predicted values of the power flow power in each supply and demand section for 24 hours every 30 minutes of the transmission line 3 in the jurisdictional partial area AR2 given by the future power flow section calculation unit 61 and the operational limit value of the transmission line 3 given by the operational limit value calculation unit 62.

Specifically, the system equipment overload resolution calculation unit 63 calculates the difference between the operational limit value of the transmission line 3 and the predicted value of the tidal flow power of the supply and demand section of the transmission line 3 every 30 minutes as the predicted value of the available capacity of the transmission line 3, and judges whether the calculated predicted value of the available capacity is a positive value or not. The system equipment overload resolution calculation unit 63 then outputs the result of such judgment and the predicted value of the available capacity of the transmission line 3 for 24 hours every 30 minutes to the renewable energy output suppression amount calculation unit 64, and outputs the predicted value of the available capacity of the transmission line 3 to the operational limit value calculation unit 62.

The renewable energy output suppression amount calculation unit 64 is a functional unit embodied by the CPU 30 of the renewable energy system stabilization subsystem 10 executing the renewable energy output suppression amount calculation program stored in the main storage device. The renewable energy output suppression amount calculation unit 64 calculates the amount of suppression of renewable energy, such as the extent to which the output of which renewable energy device (here, wind power generation device 11) in the jurisdiction area AR2 should be suppressed in a certain time period when the predicted value of the flow power of the supply and demand cross section of the transmission line 3 in a certain time period exceeds the operation limit value of the transmission line 3, based on the predicted value of the flow power of the supply and demand cross section of the transmission line 3 for 24 hours every 30 minutes in the jurisdiction area AR2 given by the future flow cross section calculation unit 61, the judgment result of the overload judgment of the transmission line 3 for 24 hours every 30 minutes given by the system equipment overload resolution calculation unit 63, and the predicted value of the available capacity of the transmission line 3 for 24 hours every 30 minutes. The renewable energy output suppression amount calculation unit 64 then outputs the calculation result to the renewable energy grid stabilization system 9 as the renewable energy suppression amount.

Thus, the renewable energy grid stabilization system 9 corrects the operational limit values and renewable energy suppression amounts of the transmission lines 2 and 3 that it has calculated based on the new operational limit values and renewable energy suppression amounts of the transmission lines 3 provided by each renewable energy grid stabilization subsystem 10, and transmits them to the central load dispatching center system 8.

(1-5) Processing of the operational limit value calculation unit The predicted value of the available capacity of the transmission lines 2 and 3 can be obtained by calculating the expected flow power of the transmission lines 2 and 3 based on the demand forecast value, the renewable energy output forecast value, and the power generation plan within the entire area AR1 (Figure 1) as described above, and finding the difference between the calculated expected flow power and the operational limit value of the transmission lines 2 and 3.

Conventionally, the operational limits of transmission lines 2 and 3 are determined in advance at the planning stage using a transient stability calculation method that predicts the annual tidal power at various system cross sections and determines the oscillations of generators 5 and 6 (Figure 1) in the event of an N-1 accident such as a lightning strike. At this time, it is assumed that the number of inverter devices such as wind power generation equipment 11 (Figure 1) and solar power generation equipment 12 (Figure 1) introduced is small, and the operational limits are determined by performing a transient stability calculation on the premise that generators 5 and 6 are synchronous generators.

For this reason, as more inverter devices such as wind power generation devices 11 and solar power generation devices 12 are introduced, the pre-determined operational limit values become inaccurate, and the amount of non-farm-type connected power sources (wind power generation in this case) introduced will be underestimated with a margin, resulting in a reduction in the amount of power generated by the non-farm-type connected power sources.

Therefore, when the predicted value of the available capacity of the power transmission lines 2 and 3 falls below the available capacity threshold, the operational limit value calculation unit 52 of the renewable energy grid stabilization system 9 and the operational limit value calculation unit 62 of the renewable energy grid stabilization subsystem 10 calculate highly accurate operational limit values according to the processing procedure shown in FIG. 14 so as not to reduce the power generation amount of the non-farm type connected power source. Note that only the processing content of the operational limit value calculation unit 52 of the renewable energy grid stabilization system 9 will be described below, but the processing content of the operational limit value calculation unit 62 of the renewable energy grid stabilization subsystem 10 is almost the same.

In practice, the operational limit value calculation unit 52 first creates a power system configuration diagram for 24 hours (48 cross sections) every 30 minutes based on the information on the power system configuration diagram provided by the system configuration creation unit 50 (S20).

Then, the operational limit value calculation unit 52 selects one of the time periods for which the power system configuration diagram was created in step S20 and for which processing has not been completed after step S22 (S21), and calculates the expected value of the tidal flow power of each of the transmission lines 2 and 3 when each of the generators 5 and 6 is driven according to the power generation plan or the settings changed in step S29 (described later) during the selected time period (hereinafter, referred to as the selected time period in the description of FIG. 14) (S22).

Next, the operational limit value calculation unit 52 sets the occurrence of an accident such as a lightning strike expected during the selected time period for each of the necessary transmission lines 2 and 3 (S23), and then calculates the transient stability of the forward flow power flowing through each of the transmission lines 2 and 3 in a state in which an accident occurs on the transmission lines 2 and 3 (S24).

Next, based on the calculation results of step S24, the operational limit value calculation unit 52 sequentially determines whether the voltage fluctuation of the forward flow power flowing through each of the transmission lines 2, 3 is within a range preset for that transmission line 2, 3, whether each of the transmission lines 2, 3 is in an overload state, and whether the frequency fluctuation of the forward flow power flowing through each of the transmission lines 2, 3 is within a preset range (S25 to S27).

Furthermore, the operational limit calculation unit 52 determines whether a problem has occurred in either of the power transmission lines 2 and 3 in any of steps S25 to S27 (voltage fluctuation of the forward power is outside the specified range, an overload has occurred, and/or frequency fluctuation is outside the specified range) (S28).

If the operational limit value calculation unit 52 obtains a negative result in this determination, it changes the output settings of some or all of the generators 5, 6 within the entire area AR1 (Figure 1) in a predetermined pattern (S29), then returns to step S22, and repeats the processing of steps S22 to S29 until it obtains a positive result in step S28.

When the operational limit calculation unit 52 eventually obtains a positive result in step S28, it determines the values of the forward flow power of each of the power transmission lines 2 and 3 calculated in the previous step S22 as the operational limit values of these power transmission lines 2 and 3 (S30). The operational limit calculation unit 52 then determines whether or not the processing of steps S22 to S30 has been completed for all time periods of the 48 cross sections (S31).

If the operational limit calculation unit 52 obtains a negative result in this determination, it returns to step S21, and then repeats the processing of steps S21 to S31 while sequentially switching the time period selected in step S21 to other time periods that have not been processed in steps S22 and onward. Through this repeated processing, the operational limit values of each of the power transmission lines 2 and 3 in each time period are determined.

When the operational limit calculation unit 52 eventually obtains a positive result in step S31 by completing the calculation of the operational limit values of each of the power transmission lines 2 and 3 for all time periods, it ends the operational limit calculation process and transmits the calculated operational limit values of each of the power transmission lines 2 and 3 to the system equipment overload resolution calculation unit 53 (Figure 11) and the central load dispatching center system 8.

Note that calculating transient stability requires a lot of time. For this reason, for example, in FIG. 3, it is possible to perform transient stability calculations and correct the operational limit values of each transmission line 2 at the timing when the renewable energy grid stabilization system 9 calculates the power generation plan for the next day in the afternoon of the previous day (S1) or at the timing when the power generation plan is calculated several hours in advance (S6), but it is considered that there is insufficient time to perform the transient stability calculation one hour in advance (S11). Therefore, in such cases, it is considered to correct the operational limit values of each transmission line 2, 3 using the simplified calculation method described below.

Specifically, first, in FIG. 15(A) which shows the "Area A" portion of FIG. 1, the predicted solar power generation value for every moment for 24 hours, the power generation plan for wind power generation, and the power generation plan for generator 6 (6A) are calculated or obtained as shown in FIG. 15(B). The sum of the power generation amount of solar power generation device 12 (12A) and the power generation amount of wind power generation device 11 (11A) is regarded as the power generation amount of asynchronous power generation, and the power generation amount of generator 6 (6A), such as a thermal power generation device, is regarded as the power generation amount of synchronous power generation.

When the ratio of asynchronous power generation to synchronous power generation is taken as in Figure 15 (C), if this ratio is high (e.g., 40 to 60%), the inverter device (renewable energy device) will account for a large amount of operation, and generator 6 (6A) performing synchronous generation in the event of a grid accident will be prone to accelerated step-out. Therefore, the operating limit value can be quickly corrected by reducing the operating limit value by a margin (e.g., by reducing it by 20%).

In FIG. 15(A), when the synchronous generator 6 (6A) is disconnected from the grid, the power sources in area A are only the solar power generation device 12 (12A) and the wind power generation device 11 (11A), and the impedance on the grid side seen from the solar power generation device 12 (12A) and the wind power generation device 11 (11A) becomes large. Therefore, the voltage of the busbar to which the solar power generation device 12 (12A) and the wind power generation device 11 (11A) are connected fluctuates greatly with respect to the current supplied from the solar power generation device 12 (12A) and the wind power generation device 11 (11A), and a phenomenon that makes stable operation impossible may occur. In this case, it is necessary to increase the output suppression amount of the solar power generation device 12 (12A) or the wind power generation device 11 (11A). This stability index is known as the short circuit ratio (SCR). The renewable energy grid stabilization subsystem 10 (10A) in Figure 1 calculates the SCR for area A, and the renewable energy grid stabilization subsystem 10 (10B) calculates the SCR for area B. These indicators are shared with the renewable energy grid stabilization system 9 that manages the entire area, and the renewable energy grid stabilization system 9 calculates the weighted short circuit capacity ratio WSCR (Weighted Short Circuit Ratio) for the entire area, making it possible to manage appropriate renewable energy power generation.

In addition, during periods when the equipment's operational limit current is lowered due to work stoppages on power grid equipment, or when the output of renewable energy equipment is higher than planned, the amount of suppression of renewable energy can be reduced by charging the storage battery. Also, by using a pumped storage power generation device instead of a storage battery and replacing it with the potential energy of water, the amount of suppression of the output of the renewable energy device can be reduced.

(1-6) Processing of the renewable energy output suppression amount calculation unit Fig. 16(A) shows an example of the change in the forward flow power (P1+P2) of the utility grid 2 in Fig. 1 over two days, and Fig. 16(B) shows the change in the amount of change in the forward flow power (P1+P2) at that time. The amount of change in the forward flow power (P1+P2) is significantly affected by the photovoltaic power generation devices 12 (12A, 12B).

As shown in FIG. 16(A), there are time periods throughout the day when the flow of the tidal power (P1+P2) in the main grid 2 changes very little (nighttime periods surrounded by ellipse C1 in FIG. 16(A)) and time periods when the flow of the tidal power (P1+P2) changes significantly in a short period of time (morning periods surrounded by ellipse C2 in FIG. 16(A)). In addition to the rise in the flow due to the morning time period, the tidal power (P1+P2) in the main grid 2 increases rapidly when the solar power generation device 12 starts generating electricity, and in one time period the tidal power (P1+P2) increases by 1,800 MW in 30 minutes.

In this case, if the tidal power (P1 + P2) suddenly increases by 1,800 MW in 30 minutes while it is approaching the operational limit (13,500 MW in the example of Figure 16 (A)), depending on the situation, the tidal power (P1 + P2) may exceed the operational limit, which could cause a major problem.

Then, the renewable energy output suppression amount calculation unit 54 (Fig. 12) of the renewable energy grid stabilization system 9 (Fig. 1) executes a renewable energy output suppression amount calculation process to calculate the suppression amount of power generated by the wind power generation device 11 (Fig. 1) in each partial area AR2 (Fig. 1) based on the weather forecast for each partial area AR2 (Fig. 1), in accordance with the processing procedure shown in Fig. 17.

In practice, when the renewable energy output suppression amount calculation unit 54 is given the result of the overload determination for every 30 minutes for 24 hours and the available capacity of the main grid 2 for every 30 minutes from the grid equipment overload resolution calculation unit 53, it starts the renewable energy output suppression amount calculation process shown in FIG. 17 (hereinafter, this is referred to as the first renewable energy output suppression amount calculation process), and first obtains the predicted value of the available capacity for every 30 minutes for 24 hours of the main grid 2 given by the grid equipment overload resolution calculation unit 53 (S40).

Then, the renewable energy output suppression amount calculation unit 54 calculates the predicted amount of change in the tidal power of the main grid 2 in each supply and demand cross section for 24 hours every 30 minutes (hereinafter, this is called the tidal change predicted amount) (S41). Specifically, the renewable energy output suppression amount calculation unit 54 calculates the tidal change predicted amount based on the predicted value of the tidal power in each supply and demand cross section for 24 hours every 30 minutes of the main grid 2 provided by the future tidal flow cross section calculation unit 51.

Next, the renewable energy output suppression amount calculation unit 54 selects one of the time periods for each supply and demand cross section that has not been processed after step S43 (S42). The renewable energy output suppression amount calculation unit 54 also determines whether the predicted value of the available capacity of the main grid 2 acquired in step S40 in the time period selected in step S42 (hereinafter, in the explanation of FIG. 16, this will be referred to as the selected time period) is less than a first power threshold value (e.g., 1000 MW) that has been set in advance (S43).

If the renewable energy output suppression amount calculation unit 54 obtains a positive result in this judgment, it calculates a new suppression amount for wind power generation within the entire area AR1 (Figure 1) during the selected time period by increasing the renewable energy suppression amount that had been set up until that point by a uniform rate (S45), and then proceeds to step S51.

In contrast, if the renewable energy output suppression amount calculation unit 54 obtains a negative result in the judgment in step S43, it determines whether the predicted amount of power flow change in the selected time period of the main grid 2 calculated in step S41 is less than the first power threshold (S44).

Obtaining a negative result in this determination means that there is a risk that the tidal current power of the bulk grid 2 may exceed the operational limit value of the bulk grid 2 due to a tidal current change during the selected time period. Thus, at this time, the renewable energy output suppression amount calculation unit 54 executes step S45 in the same manner as described above, and then proceeds to step S51.

In contrast, obtaining a positive result in the judgment in step S44 means that there is no risk that the tidal current power of the main grid 2 will exceed the operational limit value of the main grid 2 due to a tidal current change during the selected time period. Thus, at this time, the renewable energy output suppression amount calculation unit 54 selects one of the partial areas AR2 (Figure 1) that has not been processed after step S47 (S46).

The renewable energy output suppression amount calculation unit 54 also determines whether the weather forecast for the selected time period of the selected partial area AR2 (hereinafter, this will be referred to as the selected partial area) is sunny (S47). If the renewable energy output suppression amount calculation unit 54 obtains a negative result in this determination, it proceeds to step S49.

In response to this, if the renewable energy output suppression amount calculation unit 54 obtains a positive result in the judgment of step S47, it predicts that the output of photovoltaic power generation in the selected partial area AR2 will increase sharply during the selected time period (S48), and then calculates the suppression amount of renewable energy in the selected partial area AR2 during the selected time period so that the amount of power generated by renewable energy in the selected partial area AR2 during the selected time period is equal to or less than the available capacity of the transmission line 3 in the selected partial area AR2 (S49).

Then, the renewable energy output suppression amount calculation unit 54 judges whether the processing of steps S47 to S49 has been completed for all partial areas AR2 (S50). If the renewable energy output suppression amount calculation unit 54 obtains a negative result in this judgment, it returns to step S46, and thereafter repeats the processing of steps S46 to S50 while sequentially switching the partial area AR2 selected in step S46 to other partial areas AR2 that have not been processed in steps S47 and after. Through this repeated processing, the renewable energy suppression amount for the selected time period in each partial area AR2 is calculated.

Then, when the renewable energy output suppression amount calculation unit 54 obtains a positive result in step S50 by completing calculation of the renewable energy suppression amount for all partial areas AR2 in the selected time period, it determines whether or not the processing from step S43 onwards has been executed for all time periods (S51).

If the renewable energy output suppression amount calculation unit 54 obtains a negative result in this determination, it returns to step S42, and then repeats the processing of steps S42 to S51 while sequentially switching the time period selected in step S42 to other time periods that have not been processed in steps S43 and after. Through this repeated processing, the suppression amount of renewable energy for all time periods in each partial area AR2 is calculated.

Then, when the renewable energy output suppression amount calculation unit 54 eventually completes the processing from step S43 onwards for all time periods and obtains a positive result in step S51, it ends this first renewable energy output suppression amount calculation process.

Incidentally, there are cases where it is not appropriate to change the amount of suppression of renewable energy in each partial area AR2 in accordance with the weather forecast for that partial area AR2, as in this first renewable energy suppression amount calculation process. For example, if the weather forecast for a certain partial area AR2 is sunny, the amount of solar radiation is likely to increase and the output of solar power generation is expected to increase. Therefore, it is necessary to increase the amount of suppression of wind power generation in that partial area AR2 so as not to exceed the operational limit value of the transmission line 3 in that partial area AR2 and also so as not to exceed the operational limit value of the main grid 2.

On the other hand, Figure 17 shows an example of a renewable energy suppression amount calculation process that takes into account the response speed of the power generation equipment to a command to change the output power for each partial area AR2.

As in the first renewable energy suppression amount calculation process described above with reference to FIG. 16, even if a uniform output change command (e.g., an output change command to suppress 10% of the current output or 10% of the rated output) is given to each power generation facility, if the response speed of each power generation facility differs, there is a risk that the operational limit value of the transmission line 3 in the partial area AR2 will be temporarily exceeded.

For example, in FIG. 1, the wind power generation device 11B in "area B" can reduce its output by 10% in one minute, but the wind power generation device 11A in "area A" takes 10 minutes to reduce its output by 10%. In such a case, it is necessary to give an output change command taking into account the response speed of the power generation equipment in each partial area AR2.

Figure 18 shows a renewable energy suppression amount calculation process that takes into account the response speed of the power generation equipment to the output change command for each partial area AR2 (hereinafter, this is referred to as the second renewable energy suppression amount calculation process). The renewable energy output suppression amount calculation unit 54 calculates the suppression amount of renewable energy (here, wind power generation) for each time period that takes into account the response speed of the power generation equipment to the output change command for each partial area AR2, according to the processing procedure shown in this Figure 17.

In practice, when the renewable energy output suppression amount calculation unit 54 is given the results of the overload judgment for every 30 minutes for the next 24 hours and the available capacity for every 30 minutes of each transmission line 2 from the system equipment overload resolution calculation unit 53, it starts the renewable energy output suppression amount calculation process shown in FIG. 18 (hereinafter, this will be referred to as the second renewable energy output suppression amount calculation process), and first, processes steps S60 and S61 in the same way as steps S40 and S41 of the first renewable energy output suppression amount calculation process described above with reference to FIG. 16.

Then, the renewable energy output suppression amount calculation unit 54 selects one of the time periods for each 30-minute supply and demand section for 24 hours that has not been processed after step S63 (S62). The renewable energy output suppression amount calculation unit 54 also determines whether the predicted value of the available capacity of the main grid 2 acquired in step S60 in the time period selected in step S62 (hereinafter, in the explanation of FIG. 18, this will be referred to as the selected time period) is less than a second voltage threshold (e.g., 1000 MW) set in advance (S63).

If the renewable energy output suppression amount calculation unit 54 obtains a negative result in this determination, it determines whether the predicted amount of power flow change in the selected time period of the main grid 2 calculated in step S61 is less than the second power threshold (S64).

Obtaining a negative result in this judgment means that there is a risk that the tidal power of the main grid 2 may exceed the operational limit value of the main grid 2 due to a change in tidal current during the selected time period. Thus, at this time, the renewable energy output suppression amount calculation unit 54 calculates new suppression amounts for each wind power generation device 11 (FIG. 1) within the entire area AR1 (FIG. 1) during the selected time period by increasing the suppression amounts set for each of these wind power generation devices 11 by a uniform rate (S67), and then proceeds to step S69.

In response to this, when the renewable energy output suppression amount calculation unit 54 obtains a positive result in the determination of step S63 or step S64, it determines whether the response speeds of the wind power generation devices 11 (FIG. 1) present in each partial area AR2 to the output change command are all faster than a predetermined response speed threshold (S65). Then, when the renewable energy output suppression amount calculation unit 54 obtains a positive result in this determination, it executes step S67 in the same manner as described above, and then proceeds to step S69.

If the renewable energy output suppression amount calculation unit 54 obtains a negative result in the determination in step S65, it determines whether the response speeds of all the wind power generation devices 11 (FIG. 1) present in each partial area AR2 to the output change command are slower than the above-mentioned response speed threshold (S66). If the renewable energy output suppression amount calculation unit 54 obtains a positive result in this determination, it executes step S67 in the same manner as described above, and then proceeds to step S69.

In response to this, when the renewable energy output suppression amount calculation unit 54 obtains a negative result in the judgment in step S66, it calculates a new suppression amount by reducing the current suppression amount for wind power generation by a predetermined amount for each partial area AR2 in which the response speed of the wind power generation device 11 (Figure 1) present therein to the output change command is slower than the above-mentioned response speed threshold. In addition, the renewable energy output suppression amount calculation unit 54 calculates a new suppression amount by increasing the current suppression amount for wind power generation by a predetermined amount for each partial area AR2 in which the response speed of the wind power generation device 11 (Figure 1) present therein to the output change command is faster than the above-mentioned response speed threshold (S68).

Then, the renewable energy output suppression amount calculation unit 54 judges whether or not the processing from step S63 onwards has been executed for all time periods (S69). If the renewable energy output suppression amount calculation unit 54 obtains a negative result in this judgment, it returns to step S62, and thereafter repeats the processing from step S62 to step S69 while sequentially switching the time period selected in step S62 to other time periods that have not been processed from step S63 onwards. Through this repeated processing, the suppression amount for all time periods of wind power generation in each partial area AR2 is calculated.

Then, when the renewable energy output suppression amount calculation unit 54 eventually completes the processing from step S63 onwards for all time periods and obtains a positive result in step S69, it ends this second renewable energy output suppression amount calculation process.

Incidentally, in the event that the tidal power flowing through the transmission line 3 in each partial area AR2 exceeds the operational limit value of the transmission line 3 despite the output suppression of each generator 5, 6 being implemented based on the processing results of the first renewable energy output suppression amount calculation process and the second renewable energy output suppression amount calculation process described above with reference to Figures 17 and 18, the central load dispatch center system 8 issues an alarm to the operator in the central load dispatch center based on information from the renewable energy grid stabilization system 9. Based on this alarm, the operator can re-issue an instruction to further suppress power generation of the generators 5, 6, etc., thereby eliminating the exceedance of the operational limit value in the transmission line 3.

(1-7) Effects of this embodiment As described above, in the power system management system 1 of this embodiment, each renewable energy system stabilization subsystem 10 calculates the operational limit values of the transmission lines 3 within its jurisdiction partial area AR2 and the suppression amount of renewable energy within the jurisdiction partial area AR2, and notifies the renewable energy system stabilization system 9 of the calculation results.

The renewable energy grid stabilization system 9 also corrects the operational limit values of each transmission line 2, 3 within the entire area AR1 that it has calculated, the amount of suppression of renewable energy within the entire area AR1, and the amount of power generated by the generators 5, 6 based on the amount of suppression of renewable energy notified from each renewable energy grid stabilization subsystem 10.

Therefore, according to the present power system management system 1, it is possible to calculate the operational limit values of each transmission line 2, 3 within the entire area AR1, the suppression amount of renewable energy, and the output adjustment amount of the generators 5, 6 more quickly than when the renewable energy system stabilization system 9 alone calculates these values.

If the operational limit values of each transmission line 2, 3 within the entire area AR1, the suppression amount of renewable energy, and the output adjustment amount of the generators 5, 6 can be calculated quickly in this way, it will be possible to calculate these values even later than one hour before the actual supply and demand cross section as in step S13 of Figure 4 (i.e., one hour is set with a margin of error due to the complexity of the calculations), and it will be possible to calculate the operational limit values of each transmission line 2, 3, the suppression amount of renewable energy, and the output adjustment amount of the generators 5, 6 based on information that is more in line with the actual situation and at a timing closer to the actual supply and demand cross section.

If it were possible to calculate the operational limit values of each transmission line 2, 3, the amount of suppression of renewable energy, and the amount of output adjustment of the generators 5, 6 based on information that is more in line with the actual situation, the margins of the operational limit values of each transmission line 2, 3 could be set small, making it possible to utilize the available capacity of the transmission lines 2, 3 allocated to renewable energy without waste.

As a result, the amount of suppression of non-farm-connected renewable energy can be reduced, the amount of output suppression of the renewable energy device can be minimized, and the amount of power generated by the renewable energy device can be maximized, promoting the effective use of renewable energy.

(2) Second embodiment In the first renewable energy suppression amount calculation process described above with reference to FIG. 17 and the second renewable energy suppression amount calculation process described above with reference to FIG. 18, the suppression amount of wind power generation in the entire area AR1 is increased at a uniform rate when the available capacity of the main grid 2 is insufficient (step S45 in FIG. 17, step S67 in FIG. 18). However, in addition to or instead of increasing the suppression amount of wind power generation, the suppression amount of wind power generation output can also be reduced by raising the operational limit value of the main grid 2.

This is because the operational limit values are calculated using methods called transient stability calculations and power flow calculations for typical operation patterns of the bulk grid 2 that are assumed in advance, and may not necessarily reflect the actual system state. In practice, for example, when the ambient temperature of the bulk grid 2 is low, even if the power flow of the bulk grid 2 is increased, the heat rise of the bulk grid 2 is low, making it possible to temporarily raise the operational limit value. This method is called DLR (Dynamic Line Rating).

Figure 19 shows the logical configuration of a renewable energy grid stabilization system 70 for increasing the amount of wind power suppression as well as reducing the amount of renewable energy (here, wind power) suppression by raising the operational limit value of the main grid 2.

This renewable energy system stabilization system 70 is a system applied to the power system management system 1 in place of the renewable energy system stabilization system 9 of the first embodiment, and differs from the renewable energy system stabilization system 9 of the first embodiment in that the operational limit value calculation unit 71 has a function to execute the operational limit value raising process shown in FIG. 20 in addition to the function of the operational limit value calculation unit 52 of the first embodiment, and that the future power flow cross section calculation unit 51 also outputs the calculated predicted value of the power flow power of the supply and demand cross section for 24 hours every 30 minutes for each transmission line 2, 3 to the operational limit value calculation unit 71.

Then, the operational limit value calculation unit 71 determines whether or not the operational limit value of the main grid 2 can be raised for each time period of each supply and demand cross section, according to the processing procedure shown in FIG. 20, based on the information on the configuration diagram of the power system within the entire area AR1 provided by the system configuration creation unit 50, the predicted values of power flow power in each supply and demand cross section for 24 hours every 30 minutes provided by the future power flow cross section calculation unit 51, and the available capacity for each time period of the main grid 2 provided by the grid equipment overload resolution calculation unit 53. If the operational limit value can be raised, the operational limit value of the main grid 2 is raised and notified to the grid equipment overload resolution calculation unit 53.

In practice, when the operational limit value calculation unit 71 starts the operational limit value raising process shown in FIG.
First, one unprocessed time period is selected from step S71 onwards (S70), and the result of the overload determination for the selected time period (hereinafter, in the explanation of Figure 20, this will be referred to as the selected time period) and a predicted value of the available capacity of the main system 2 are obtained based on the information provided from the system equipment overload resolution calculation unit 53 (S71).

Next, the operational limit value calculation unit 71 calculates the predicted amount of power flow change in the main grid 2 for the selected time period (S72). Specifically, the operational limit value calculation unit 71 calculates each of the predicted amounts of power flow change based on the power flow power of the supply and demand cross section for the selected time period of the main grid 2 provided by the future power flow cross section calculation unit 51.

Next, the operational limit calculation unit 71 determines whether the predicted value of the available capacity of the main grid 2 in the selected time period is less than a third power threshold (e.g., 1000 MW) that is set in advance (S73). If the operational limit calculation unit 71 obtains a positive result in this determination, it proceeds to step S76.

In contrast, if the operational limit value calculation unit 71 obtains a negative result in the judgment in step S73, it determines whether the predicted amount of power flow change in the selected time period of the main grid 2 calculated in step S72 is less than the third power threshold (S74).

Obtaining a negative result in this judgment means that there is a risk that the tidal flow power of the main grid 2 may exceed the operational limit value of the main grid 2 due to a change in tidal flow during the selected time period. Thus, at this time, the operational limit value calculation unit 71 calculates new suppression amounts for each wind power generation device 11 (FIG. 1) within the entire area AR1 (FIG. 1) during the selected time period by increasing the suppression amounts set for each of these wind power generation devices 11 by a uniform rate, notifies the central load dispatching center system 8 (S75), and then proceeds to step S80.

In response to this, if the operational limit value calculation unit 71 obtains a positive result in the judgment of step S74, it acquires the ambient temperature of the main grid 2 from the central load dispatching center system 8 and judges whether the acquired ambient temperature is equal to or lower than a preset threshold temperature (S76).

If the operational limit calculation unit 71 obtains a positive result in this determination, it temporarily raises the operational limit value of the main grid 2 for the selected time period notified to the grid equipment overload resolution calculation unit 53 (S78), and notifies the central load dispatching center system 8 of this (S79). The operational limit calculation unit then returns to step S71, and thereafter processes steps S71 and onward in the same manner as described above.

In contrast, if the operational limit calculation unit 71 obtains a negative result in the determination in step S76, it determines whether any problems will occur if the operational limit values of each of the power transmission lines 2 and 3 are raised during the selected time period (S77).

If the operational limit value calculation unit 71 obtains a negative result in the determination in step S77, it temporarily raises the operational limit value of the main grid 2 for the selected time period notified to the grid equipment overload resolution calculation unit 53 by a predetermined percentage (S78), and reports this to the central load dispatching center system 8 (S79). The operational limit value calculation unit 71 then returns to step S71 and executes the processes from step S71 onwards in the same manner as described above.

In response to this, if the operational limit calculation unit 71 obtains a positive result in the determination in step S77, it determines whether or not the processing from step S71 onwards has been completed for all time periods (S80). If the operational limit calculation unit 71 obtains a negative result in this determination, it returns to step S70, and thereafter repeats the processing from step S70 to step S80 while sequentially switching the time period selected in step S70 to other time periods that have not been processed from step S71 onwards.

Then, when the operational limit calculation unit 71 eventually completes the processing from step S71 onwards for all time periods and obtains a positive result in step S80, it ends the operational limit raising process.

As described above, in the power system management system of this embodiment, when the available capacity of the transmission line is less than the third power threshold, or when there is a risk that the tidal power of the main grid 2 will exceed the operational limit value of the main grid 2 due to a tidal change, and when the ambient temperature of the main grid 2 is equal to or lower than the threshold value, the operational limit value of the main grid 2 is increased to reduce the amount of suppression of renewable energy (wind-generated power in this case).

Therefore, according to this power system management system, it is possible to increase the available capacity of the main system 2 to be allocated to renewable energy, and to further reduce the amount of suppression of non-firm-type connected renewable energy compared to the power system management system 1 of the first embodiment. As a result, it is possible to minimize the amount of output suppression of the renewable energy device and maximize the amount of power generated by the renewable energy device, thereby further promoting the effective use of renewable energy.

(3) Other embodiments In the above-described first and second embodiments, the central load dispatching center system 8 discloses the amount of suppression of renewable energy on its own website on the Internet and requests renewable energy power generation companies to suppress power generation, thereby indirectly suppressing the power generation of renewable energy. However, the present invention is not limited to this, and the central load dispatching center system 8 may directly control renewable energy devices connected in a non-farm type to suppress the amount of power generation of renewable energy.

In the above-mentioned first and second embodiments, the central load control system 8 suppresses the power generation of the non-farm-connected renewable energy devices. However, the present invention is not limited to this, and the suppression may be performed by, for example, the renewable energy grid stabilization system 9.

The present invention can be widely applied to various types of power system management systems that perform control to stabilize a power system in which renewable energy devices that generate renewable energy are connected in a non-farm type manner.

1...power system management system, 2, 3, 3A, 3B...power transmission line, 4, 4A ₁ , 4A ₂ , 4B...transformer, 5, 5A to 5C, 6, 6A, 6B...generator, 8...central load dispatching center system, 9, 70...renewable energy system stabilization system, 10, 10A, 10B...renewable energy system stabilization subsystem, 11, 11A, 11B, 22...wind power generation device, 12, 12A, 12B...photovoltaic power generation device, 13, 13A, 13B, 14...system data storage database, 20...power generation company, 21...general power transmission and distribution company, 23...load, 30...CPU, 40...system configuration creation program, 41...future power flow interruption Area calculation program, 42...operational limit value calculation program, 43...system equipment overload resolution calculation program, 44...renewable energy output suppression amount calculation program, 45...generator output adjustment amount calculation program, 50, 60...system configuration creation unit, 51, 61...future power flow cross section calculation unit, 52, 62, 71...operational limit value calculation unit, 53, 63...system equipment overload resolution calculation unit, 54, 64...renewable energy output suppression amount calculation unit, 55...generator output adjustment amount calculation unit, AR1...entire area, AR2, AR2A, AR2B...partial area.

Claims (8)

In a power system management system that manages a power system in which a renewable energy device that generates renewable energy is connected in a non-farm type,
a first computer system that governs an entire area of the power grid;
a plurality of second computer systems each responsible for a non-overlapping partial area within the entire area;
and a third computer system that directly or indirectly controls the amount of power generated by the renewable energy device,
Each of the second computer systems is
sharing with the first computer system a power generation record within the partial area that is the partial area under the jurisdiction of the power generation system and an operational limit value of a power transmission line within the partial area;
Calculate a suppression amount of the renewable energy in the partial area under its jurisdiction based on a power generation record in the partial area and an operational limit value of the power transmission line in the partial area, and notify the first computer system of the calculated suppression amount of the renewable energy;
The first computer system
Calculate a suppression amount of the renewable energy generated by the non-farm type connected renewable energy device in the entire area based on the power generation record of the renewable energy in each of the partial areas and the operational limit value of the transmission line in each of the partial areas, and correct the calculated suppression amount of the renewable energy based on the suppression amount of the renewable energy notified from each of the second computer systems,
The third computer system is
a power system management system that controls an amount of power generation of the renewable energy device so as to suppress an amount of power generation of the renewable energy by the suppression amount calculated and corrected by the first computer system. The first computer system
2. The power system management system according to claim 1, further comprising: a power grid management system for managing a renewable energy consumption amount in a power grid that is ... The first computer system
The power system management system according to claim 1, characterized in that a suppression amount of the renewable energy in the entire area is calculated by calculating, for each partial area, a suppression amount of the renewable energy in consideration of a response speed of the renewable energy device in the partial area to an output change command. The first computer system
The power system management system according to claim 1 , wherein, when a free capacity of a transmission line of the power system to be allocated to the renewable energy device is insufficient, the operation limit value of the transmission line is increased. A power system management method executed in a power system management system that manages a power system in which a renewable energy device that generates renewable energy is connected in a non-farm type,
The power system management system includes:
a first computer system that governs an entire area of the power grid;
a plurality of second computer systems each responsible for a non-overlapping partial area within the entire area;
and a third computer system that directly or indirectly controls the amount of power generated by the renewable energy device;
a first step in which each of the second computer systems shares with the first computer system a power generation record in a partial area that is the partial area under its jurisdiction and an operational limit value of the transmission line in the partial area, calculates a suppression amount of the renewable energy in the partial area under its jurisdiction based on the power generation record in the partial area and the operational limit value of the transmission line in the partial area, and notifies the first computer system of the calculated suppression amount of the renewable energy;
A second step in which the first computer system corrects the suppression amount of the renewable energy generated by the non-farm type connected renewable energy device in the entire area, which is calculated based on the power generation record of the renewable energy in each of the partial areas and the operational limit value of the transmission line in each of the partial areas, based on the suppression amount of the renewable energy notified from each of the second computer systems;
and a third step of controlling, by the third computer system, the amount of power generation of the renewable energy device so as to suppress the amount of power generation of the renewable energy by the suppression amount calculated and corrected by the first computer system. The first computer system
Calculating the suppression amount of the renewable energy for each of the partial areas based on a weather forecast for each of the partial areas;
The power system management method according to claim 5, further comprising: calculating an amount of suppression of the renewable energy in the entire area based on a result of the calculation, thereby calculating an amount of suppression of the renewable energy in the entire area. The first computer system
The power system management method according to claim 5, further comprising: calculating, for each partial area, a suppression amount of the renewable energy in consideration of a response speed of the renewable energy device in the partial area to an output change command, thereby calculating the suppression amount of the renewable energy in the entire area. The first computer system
The power system management method according to claim 5, further comprising: increasing the operational limit value of a transmission line of the power system when the available capacity of the transmission line to be allocated to the renewable energy device is insufficient.

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