Power system management system and power system management method

Abstract

To suppress an occurrence of oscillation such as SSO while evaluating stability of a power line with instability of a power line due to an introduction and expansion of RES taken into account.SOLUTION: A power line management system includes: a storage unit that stores power load prediction information indicating prediction of a power load in a power line and power generation prediction information indicating prediction of power generation by a power plant in the power line; an index calculation unit that calculates stability index information indicating a stability index for evaluating stability of the power line on the basis of the power load prediction information and the power generation prediction information; a power information acquisition unit that acquires, from the power line via a communication network, power load information indicating an actual power load in the power line and power generation information indicating power actually generated by the power plant in the power line; and a stability evaluation unit that calculates a stability score relating to the power line on the basis of the power load information and the power generation information, and generates a stability evaluation result indicating the stability of the power line on the basis of the stability score and the stability index information.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power system management system and a power system management method. [Background technology]

[0002] In recent years, as demand for clean energy has increased, the introduction of renewable energy systems (RES) into power grids has expanded. However, the amount of electricity generated by RES fluctuates due to various factors, such as the amount of sunlight and wind direction, making the supply to the power grid prone to instability. For this reason, the widespread use of RES has raised concerns about the stability of the power grid.

[0003] Conventionally, proposals have been made for the purpose of monitoring the stability of power systems. For example, U.S. Patent No. 10,855,079 (Patent Document 1) discloses a technology in which "a method for operating a renewable energy power generation system connected to an electric power grid includes operating the renewable energy power generation system at one or more first operational settings. The method also includes monitoring the renewable energy power generation system for electrical oscillations due to faults in the electric power grid or system. If electrical oscillations exceeding a predetermined threshold are detected indicating that the one or more first operational settings are not suitable for the condition of the electric power grid, the method includes reducing the electrical oscillations of the renewable energy power generation system by changing the one or more first operational settings to one or more different second operational settings." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 10,855,079 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 describes a means for stabilizing the power system by monitoring oscillations in the power system, and when oscillations indicating that the current operating settings of the RES are not suitable for the state of the power system are detected, changing the operating settings of the RES to suppress the oscillations.

[0006] However, in the method described in Patent Document 1, the change in the operation settings of the RES to stabilize the power system is performed after oscillations such as SSO (Sub-synchronous Oscillation) are detected, that is, after the power system has already become unstable, and therefore there is a risk that equipment in the power system, such as transmission lines and transformers, may be damaged by the oscillations.

[0007] Considering the instability of the power system due to the expansion of the introduction of RES as mentioned above, there is a need for a means to evaluate the stability of the power system and suppress the occurrence of oscillations such as SSO.

[0008] Therefore, an object of the present disclosure is to provide a power system management means that can suppress the occurrence of oscillations such as SSO and ensure the stability of the power system by comparing, for each bus in the power system, a stability score calculated based on the power related to a power electronics system (PES) that leads to instability in the power system and the total power related to the bus with a predetermined stability index, evaluate the stability of the power system, and control the PES power as necessary. [Means for solving the problem]

[0009] In order to solve the above problems, a representative power system management system according to the present invention is system One of the present invention is a power system management system including a power system, a power system management device that manages the power system, and a communication network for communicating information between the power system and the power system management device, wherein the power system management device includes a processor and 、 Memory and a storage unit that stores power load forecast information indicating a forecast of a power load in the power system and power generation forecast information indicating a forecast of power generated by a power plant in the power system; wherein the memory ,beforeCalculating stability index information indicating a stability index for evaluating the stability of the power system based on the power load forecast information and the power generation forecast information. stability Index calculation part and 、 a power information acquisition unit that acquires, from the power system via the communication network, power load information indicating an actual power load in the power system and power generation information indicating power actually generated by power plants in the power system; and a stability evaluation unit that calculates a stability score for the power system based on the power load information and the power generation information, and generates a stability evaluation result indicating the stability of the power system based on the stability score and the stability index information. 、 and processing instructions for causing the processor to function as Includes. [Effects of the Invention]

[0010] According to the present disclosure, for each bus in a power system, a stability score calculated based on the power related to a power electronics system (PES) that leads to instability in the power system and the total power related to that bus is compared with a predetermined stability index to evaluate the stability of the power system, and by controlling the PES power as necessary, it is possible to provide a power system management means that can suppress the occurrence of oscillations such as SSO and ensure the stability of the power system. Problems, configurations, and effects other than those described above will become apparent from the following description of the preferred embodiment of the invention. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a computer system for implementing an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a power system management system according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a diagram illustrating an example of power load information according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram illustrating an example of power generation information according to an embodiment of the present disclosure. [Figure 5]FIG. 5 is a diagram showing an example of the flow of a power system stability evaluation process according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram illustrating an example of a logical configuration of a power system management system according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating an example of stability index information according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram showing an example of the flow of the stability index information generation process according to the embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram showing voltage waveforms indicating that the power system is stable as a result of a stability simulation according to an embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram illustrating voltage waveforms indicating that the power grid may become unstable as a result of a stability simulation according to an embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram showing an example of a stability evaluation result screen according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, in the description of the drawings, the same parts are designated by the same reference numerals.

[0013] Furthermore, although terms such as "first," "second," and "third" may be used to describe various elements or components in this disclosure, it will be understood that these elements or components should not be limited by these terms. These terms are used only to distinguish one element or component from another. Thus, a first element or component discussed below could also be referred to as a second element or component without departing from the teachings of the inventive concept.

[0014] (Summary of the Invention) As mentioned above, as demand for clean energy increases, the introduction of renewable energy systems (RES) into power grids is expanding. The amount of power generated by RES fluctuates due to various factors, such as sunshine hours and wind direction, making its supply to the power grid prone to instability. To control this unstable power supply, so-called power electronics systems (PES) are used. PES are equipment for power conversion and control, and include, for example, inverters, battery energy storage systems (BESS), static var compensators (STATCOM), series capacitors, and high-voltage direct current (HVDC) transmission lines.

[0015] However, when the density of PESs increases in a certain area, fluctuations in the grid impedance of the power system and interactions between PESs can cause oscillations in voltage, power, frequency, and current known as sub-synchronous oscillation (SSO). SSOs can damage power system equipment such as transmission lines and transformers, and can cause power outages, so it is desirable to suppress them.

[0016] Therefore, the present disclosure calculates, for each bus in a power system, the ratio of the power associated with the PES to the total power associated with that bus (i.e., the utilization rate of the PES power) as a stability score for the power system. The calculated stability score can then be compared with a stability index that defines the boundary between a "stable state" and an "unstable state" in the power system to evaluate the current stability of the power system. By performing this evaluation in real time, continuously, or periodically, it is possible to determine whether the power system may become unstable before oscillations such as SSO occur. Then, the utilization rate of the PES power can be controlled by transmitting a PES power generation reduction request requesting the reduction of PES power to, for example, a power plant that uses RES in the power system. In this way, the power system management means according to the embodiment of the present disclosure can suppress the occurrence of oscillations such as SSO and ensure the stability of the power system.

[0017] Next, referring to FIG. 1, a computer system 100 for implementing embodiments of the present disclosure will be described. The mechanisms and devices of various embodiments disclosed herein may be applied to any suitable computing system. The main components of the computer system 100 include one or more processors 102, memory 104, a terminal interface 112, a storage interface 113, an I / O (input / output) device interface 114, and a network interface 115. These components may be interconnected via a memory bus 106, an I / O bus 108, a bus interface unit 109, and an I / O bus interface unit 110.

[0018] Computer system 100 may include one or more general-purpose programmable central processing units (CPUs) 102A and 102B, collectively referred to as processors 102. In some embodiments, computer system 100 may include multiple processors, while in other embodiments, computer system 100 may be a single CPU system. Each processor 102 executes instructions stored in memory 104 and may include an on-board cache.

[0019] In some embodiments, memory 104 may include random-access semiconductor memory, storage devices, or storage media (either volatile or non-volatile) for storing data and programs. Memory 104 may store all or part of the programs, modules, and data structures that implement the functions described herein. For example, memory 104 may store a power system management application 150. In some embodiments, power system management application 150 may include instructions or descriptions that execute the functions described below on processor 102.

[0020] In some embodiments, power system management application 150 may be implemented in hardware via semiconductor devices, chips, logic gates, circuits, circuit cards, and / or other physical hardware devices instead of or in addition to a processor-based system. In some embodiments, power system management application 150 may include data other than instructions or descriptions. In some embodiments, cameras, sensors, or other data input devices (not shown) may be provided to communicate directly with bus interface unit 109, processor 102, or other hardware of computer system 100.

[0021] Computer system 100 may include a bus interface unit 109 that facilitates communication between processor 102, memory 104, display system 124, and I / O bus interface unit 110. I / O bus interface unit 110 may couple to an I / O bus 108 for transferring data to and from various I / O units. I / O bus interface unit 110 may communicate via I / O bus 108 with multiple I / O interface units 112, 113, 114, and 115, also known as I / O processors (IOPs) or I / O adapters (IOAs).

[0022] Display system 124 may include a display controller, a display memory, or both. The display controller may provide video, audio, or both data to display device 126. Computer system 100 may also include one or more sensors or other devices configured to collect data and provide the data to processor 102.

[0023] For example, computer system 100 may include environmental sensors that collect humidity data, temperature data, pressure data, etc. Other types of sensors may also be used. Display system 124 may be connected to a display device 126, such as a standalone display screen, a television, a tablet, or a handheld device.

[0024] The I / O interface unit provides functionality for communicating with various storage or I / O devices. For example, the terminal interface unit 112 may be attached to user I / O devices 116, such as user output devices such as a video display, a television with speakers, and user input devices such as a keyboard, a mouse, a keypad, a touchpad, a trackball, buttons, a light pen, or other pointing device. A user may use a user interface to enter input data or instructions into the user I / O devices 116 and the computer system 100, and receive output data from the computer system 100, by operating the user input devices. The user interface may be displayed on a display, played through speakers, or printed via a printer via the user I / O devices 116, for example.

[0025] Storage interface 113 allows attachment of one or more disk drives or direct access storage device 117 (typically a magnetic disk drive storage device, but may also be an array of disk drives or other storage devices configured to appear as a single disk drive). In some embodiments, storage device 117 may be implemented as any secondary storage device. The contents of memory 104 may be stored in storage device 117 and retrieved as needed from storage device 117. I / O device interface 114 may provide an interface to other I / O devices, such as printers, fax machines, etc. Network interface 115 may provide a communications path that allows computer system 100 and other devices to communicate with each other. This communications path may be, for example, network 130.

[0026] In some embodiments, computer system 100 may be a device that receives requests from other computer systems (clients) without a direct user interface, such as a multi-user mainframe computer system, a single-user system, or a server computer. In other embodiments, computer system 100 may be a desktop computer, a portable computer, a laptop, a tablet computer, a pocket computer, a telephone, a smartphone, or any other suitable electronic device.

[0027] Next, with reference to FIG. 2, a configuration of a power system management system according to an embodiment of the present disclosure will be described.

[0028] Fig. 2 is a diagram illustrating an example of the configuration of a power system management system 200 according to an embodiment of the present disclosure. The power system management system 200 is a system that ensures the stability of the power system by evaluating the stability of the power system and controlling power as necessary, and as shown in Fig. 2, is composed of a power system 220, a central load dispatching center 230, a communication network 235, and a power system management device 240. In the power system management system 200, the power system 220, the central load dispatching center 230, and the power system management device 240 are connected to each other so as to be able to communicate with each other via the communication network 235.

[0029] Power system 220 is a system that integrates power generation, transformation, transmission, and distribution for supplying power generated at a power plant to power receiving facilities of consumers. As shown in Fig. 2, power system 220 includes buses 201-205, renewable energy systems (RES) 206-208 that generate renewable energy, loads 209-212, a synchronous generator 213, and transmission lines 215-219. Power system 220 may also be connected to other power systems (not shown). Note that the power system 220 shown in FIG. 2 is an example of the configuration of a power system according to an embodiment of the present disclosure, and the present disclosure is not limited to the configuration of the power system 220 shown in FIG.

[0030] Bus 202, bus 203, bus 204, and bus 205 refer to junctions where power facilities such as generators, loads, and feeders are connected in power system 220. For example, power generated by RES 206-208 and power supplied to load 209 flow through bus 202, bus 203, bus 204, and bus 205, respectively. The power flowing through buses 201-205 includes, for example, PES power from RES 206-208 and other PESs that use PES, and power from non-PESs that are not PESs. As will be described later, in the power system management means according to an embodiment of the present disclosure, the PES power usage rate, which is the ratio of PES power to total power for each bus in the power system, is used to evaluate the stability of the power system.

[0031] The RESs 206, 207, and 208 are systems that generate renewable energy and supply it to the power grid 220, and include, for example, generators and power plants that generate electricity using wind power or solar power. As mentioned above, the amount of electricity generated by the RESs 206, 207, and 208 fluctuates due to various factors such as the hours of sunlight and wind direction. To control this unstable power supply, a so-called power electronics system (PES) is used. As shown in Fig. 2, the RES 206 is connected to a bus 202, the RES 207 is connected to a bus 205, and the RES 208 is connected to a bus 203. Note that, here, RES 206, 207, and 208 that use inverters to control the amount of power generated are shown as an example of equipment that uses a PES, but equipment that uses a PES is not limited to RES, and other equipment that uses a PES, such as a battery energy storage system (BESS), a static var compensator (STATCOM), a series capacitor, and a high-voltage direct current (HVDC) transmission line, may also be included in the power system 220.

[0032] The loads 209, 210, 211, and 212 include facilities and devices that receive and consume power generated by, for example, the RESs 206 to 208 via the buses 201 to 205. As shown in Fig. 2, the load 209 is connected to the bus 202, the load 210 is connected to the bus 204, the load 211 is connected to the bus 203, and the load 212 is connected to the bus 205.

[0033] The synchronous generator 213 (denoted as "SG1" in FIG. 2) is a generator that generates electric power synchronized with the rotation speed at which the magnetic field created by the field magnet crosses the armature winding, and supplies the electric power to the electric power grid 220. Unlike the RESs 206 to 208, the synchronous generator 213 may be a non-PES that does not use a PES.

[0034] The central load dispatching center 230 is an establishment that monitors the amount of power consumed by the loads 209-212 of the power system 220 and transmits commands to the power generation systems, such as the RES 206-208 and the synchronous generator 213, to adjust the amount of power generated by the power generation systems. In one embodiment, if it is determined that the PES power usage rate is high and there is a possibility that the power system 220 may become unstable, the central load dispatching center 230 may transmit a PES power generation suppression request from the power system management device 240 to the RES 206-208 and the synchronous generator 213.

[0035] Communications network 235 is a network for communicating information between power system 220, central dispatching center 230, and power system manager 240. Communications network 235 may include, for example, a wide area monitoring system (WAMS), a local area network (LAN), a wide area network (WAN), a satellite network, a cable network, a WiFi network, or any combination thereof. In one embodiment, communications network 235 may be used to obtain power load information 266 and power generation information 268, described below, from power system 220.

[0036] The power system management device 240 is a device for ensuring the stability of the power system by evaluating the stability of the power system and controlling power as necessary, and may be a computing device such as a server device. In one embodiment, the power system management device 240 may be implemented as the computer system 100 shown in FIG. 1 . As shown in FIG. 2, the power system management device 240 may include a memory 250, a storage unit 260, a processor 270, and an input / output unit 275.

[0037] The memory 250 may be a memory for storing a power system management application 150 for implementing the functions of the power system management means according to an embodiment of the present disclosure. The power system management application 150 may include processing instructions for implementing the functions of software modules such as a stability index calculation unit 252, a power information acquisition unit 254, and a stability evaluation unit 256, as shown in FIG.

[0038] The stability index calculation unit 252 is a functional unit for calculating stability index information indicating a stability index for evaluating the stability of the power system 220 based on power load prediction information 262 and power generation prediction information 264, which will be described later. The details of the processing by the stability index calculation unit 252 will be described later, and therefore will not be described here.

[0039] The power information acquisition unit 254 is a functional unit for acquiring power load information 266 and power generation information 268 from the power grid via the communication network 235 . The details of the processing by the power information acquisition unit 254 will be described later, and therefore will not be described here.

[0040] The stability evaluation unit 256 is a functional unit that calculates a stability score for the power system 220 based on the power load information 266 and the power generation information 268 acquired by the power information acquisition unit 254, and generates a stability evaluation result that indicates the stability of the power system 220 based on the stability score and the stability index information calculated by the stability index calculation unit 252. The details of the processing by the stability evaluation unit 256 will be described later, and therefore will not be described here.

[0041] The memory unit 260 is a memory area for storing various information related to an embodiment of the present disclosure, and may include power load forecast information 262, power generation forecast information 264, power load information 266, power generation information 268, and stability index information, as shown in FIG. 2 .

[0042] The power load prediction information 262 is information that indicates the predicted power load of the power grid 220 for a predetermined period of time. The power generation forecast information 264 is information that indicates the amount of power generation that is forecast to be supplied to the power grid 220 for a predetermined period of time. The power load prediction information 262 and the power generation prediction information 264 are generated in advance by, for example, a power company that manages the power system, and are stored in the storage unit 260 of the power system management device 240 .

[0043] The power load information 266 is information that indicates the actual power load in the power system 220 for a given period of time. The power generation information 268 is information indicating the amount of power actually supplied to the power grid 220 over a given period of time. The power load information 266 and the power generation information 268 are acquired by the power information acquisition unit 254 from the power system 220 via the communication network 235 and stored in the storage unit 260 of the power system management device 240 .

[0044] The stability index information 269 is information that defines the boundary between a "stable state" and an "unstable state" in the power system, and is used to evaluate the stability of the power system by comparing it with a stability score calculated for the power system. This stability index information 269 is generated by a stability index information generation process 800, which will be described later with reference to FIG. 8. The processor 270 is a processing unit for executing processing instructions stored by the memory 250 that define the functions of each functional unit of the power system management application 150 .

[0045] The input / output unit 275 is a functional unit for receiving information input to the power system management device 240 and outputting information such as stability evaluation results and PES power generation amount suppression requests generated by the power system management device 240. The input / output unit 275 may include, for example, a keyboard, a mouse, a display for displaying a GUI (Graphical User Interface), a communication function for transmitting and receiving information, and the like.

[0046] According to the power system management system 200 described above, it is possible to suppress the occurrence of oscillations such as SSO and ensure the stability of the power system.

[0047] Next, with reference to FIG. 3, the power load information according to the embodiment of the present disclosure will be described.

[0048] 3 is a diagram illustrating an example of the power load information 266 according to an embodiment of the present disclosure. As described above, the power load information 266 is information indicating the actual power load in the power grid 220 for a predetermined period of time, and is acquired by the power information acquisition unit 254 from the power grid 220 via the communication network 235.

[0049] More specifically, the power load information 266 includes, for a given time period, a total power load 310 for PES and non-PES, and a PES power load 320 for PES, for each bus in the power grid 220. Here, the expression "PES power load" means the power delivered from the power grid to the power consumer using the PES, and the expression "total power load" means the power delivered from the power grid to the power consumer using the PES and non-PES.

[0050] figure 3 As shown, total power load 310 may include time information 312, bus information 314, and total power load value 316. As an example, total power load 310 may indicate the total power load values ​​(50 MW, 55 MW, etc.) of buses 1, 2, and 3 in the power system for each 30-minute interval, such as 12:30, 13:00, and 13:30.

[0051] Also, Fig. 3 As shown, PES power load 320 may include time information 322, bus information 324, and PES power load values ​​326. As an example, PES power load 320 may indicate the PES power load values ​​(e.g., 35 MW, 45 MW, etc.) for each of buses 1, 2, and 3 in the power system for each 30-minute interval, e.g., 12:30, 13:00, and 13:30.

[0052] Next, power generation information according to an embodiment of the present disclosure will be described with reference to FIG.

[0053] 4 is a diagram illustrating an example of the power generation information 268 according to an embodiment of the present disclosure. As described above, the power generation information 268 is information indicating the amount of power actually supplied to the power grid 220 for a predetermined period, and is acquired by the power information acquisition unit 254 from the power grid 220 via the communication network 235.

[0054] More specifically, the generation information 268 includes, for a given time period, a total generation 410 for PES and non-PES, and a PES generation 420 for PES, for each bus in the power grid 220. Here, the expression "PES generation" refers to the power supplied to the power grid using the PES, and the expression "total generation" refers to the power supplied to the power grid using the PES and non-PES.

[0055] figure 4 As shown, total power generation 410 may include time information 412, bus information 414, and total power generation value 416. As an example, total power generation 410 may indicate the power generation values ​​(50 MW, 55 MW, etc.) of buses 1, 2, and 3 in the power system for each 30-minute interval, such as 12:30, 13:00, and 13:30.

[0056] Also, Fig. 4 As shown, PES power generation 420 may include time information 422, bus information 424, and PES power generation value 426. As an example, PES power generation 420 may indicate the PES power generation values ​​(e.g., 35 MW, 45 MW, etc.) of buses 1, 2, and 3 in the power system for each 30-minute interval, e.g., 12:30, 13:00, and 13:30.

[0057] As described above, by using the power load information 266 and the power generation information 268 described with reference to Figures 3 and 4, the PES power usage rate for each bus in the power system can be calculated as the stability score of the power system. Then, by comparing the stability score calculated in this way with a stability index that defines the boundary between a "stable state" and an "unstable state" in the power system, the current stability of the power system can be evaluated. The above-mentioned power load prediction information 262 and power generation prediction information 264 are substantially similar to the power load information 266 and power generation information 268 shown in FIGS. 3 and 4, except that they indicate predicted power loads and power generation amounts rather than actual power loads and actual power generation amounts, and therefore examples thereof will be omitted.

[0058] Next, the power system stability evaluation process according to the embodiment of the present disclosure will be described with reference to FIG.

[0059] 5 is a diagram showing an example of the flow of a power system stability evaluation process 500 according to an embodiment of the present disclosure. The power system stability evaluation process 500 shown in Fig. 5 is a process for determining whether the power system is stable or has the potential to become unstable using a stability score based on the PES power usage rate of each bus in the power system, and is executed by the power system management device 240 shown in Fig. 2.

[0060] First, in step S510, the power information acquisition unit 254 acquires power load information 266 and power generation information 268 for each bus (for example, bus 202, bus 203, bus 204, and bus 205 shown in FIG. 2) in a power system (for example, power system 220 shown in FIG. 2). Here, the power information acquisition unit 254 may transmit, for example, to each bus in the power system, a request to transfer the power load information 266 and power generation information 268 of that bus via the communication network 235.

[0061] Next, in step S520, the stability evaluation unit 256 calculates a stability score for the power system based on the power load information 266 and the power generation information 268 acquired in step S510. In one embodiment, the stability evaluation unit 256 may calculate the PES power usage rate for each bus in the power system, and use the average value of the PES power usage rates for each bus as the stability score. Here, "PES power" refers to power that is supplied, transmitted, received, distributed, transformed, controlled, or otherwise regulated by the PES in the power system. Furthermore, the expression "PES power usage rate" refers to the ratio of the PES power for each bus to the total power (i.e., the sum of the PES power and non-PES power for non-PES buses).

[0062] More specifically, the stability evaluation unit 256 may calculate the PES power utilization rate in the power system by dividing the sum of the PES power load (see PES power load 320 shown in FIG. 3 ) included in the power load information 266 and the PES power generation amount (see PES power generation amount 420 shown in FIG. 4 ) included in the power generation information 268 for each bus in the power system by the sum of the total power load (see total power load 310 shown in FIG. 3 ) included in the power load information 266 and the total power generation amount (see total power generation amount 410 shown in FIG. 4 ) included in the power generation information 268, and may use the average value of the PES power utilization rates of each bus as the stability score. This PES power usage rate can be calculated, for example, by the following equation 1.

number

[0063] where P PES (load) is the PES power load on a particular bus, and P PES (gen) is the PES power generation of the bus, and P total (load) is the total power load of the bus, and P total (gen) is the total power generation of the bus. The stability evaluation unit 256 may then calculate an average value of the PES power usage rates calculated for each bus and use this average value of the PES power usage rates as the stability score. In one embodiment, the stability evaluation unit 256 may set a weight for each bus based on the importance of the bus, etc., and calculate a weighted average value of the PES power usage rates based on these weights and the PES power usage rates calculated for each bus, and use this weighted average value of the power usage rates as the stability score.

[0064] Next, in step S530, the stability evaluation unit 256 evaluates the stability of the power system by comparing the stability score calculated in step S520 with pre-generated stability index information, and determines whether the power system is stable or has the potential to become unstable. More specifically, if the stability evaluation unit 256 compares the stability score calculated in step S520 with previously generated stability index information (for example, stability index information 269 shown in FIG. 7), and determines that the stability score corresponds to a stability index of "unstable" in the stability index information, the process proceeds to step S560.

[0065] On the other hand, if the stability evaluation unit 256 compares each stability score calculated in step S520 with pre-generated stability index information (for example, stability index information 269 shown in Figure 7) and determines that the stability score corresponds to a stability index of "stable" in the stability index information, the process proceeds to step S540. The expression that a stability score "corresponds to" a stability index means that the stability score is within a tolerance range established for a particular stability index. This tolerance range may be set arbitrarily, for example, ±5%, ±10%, or the like, of the stability index.

[0066] Next, in step S540, the stability evaluation unit 256 determines that the power system is stable because the stability score corresponds to the stability index of "stable" in the stability index information, the PES power usage rate in the power system is appropriate, and there is no risk of SSO occurring.

[0067] Next, in step S550, the stability evaluation unit 256 generates a stability evaluation result indicating that the power system is stable, and may output it via, for example, a stability evaluation result screen 1100 described below with reference to FIG. 11.

[0068] On the other hand, in step S560, the stability evaluation unit 256 determines that the power system may become unstable because the stability score corresponds to the stability index of "unstable" in the stability index information, and therefore the PES power usage rate in the power system is high and there is a risk of SSO occurring.

[0069] Next, in step S570, the stability evaluation unit 256 generates a stability evaluation result indicating that the power system may become unstable, and may output the result via, for example, a stability evaluation result screen 1100 described below with reference to Fig. 11, and may also transmit a request to reduce the PES power usage rate to power plants in the power system. As an example, the stability evaluation unit 256 may transmit a request to the central load dispatching center to transmit a PES power generation reduction request to reduce the PES power generation amount to power plants using RES in the power system.

[0070] According to the power system stability evaluation process 500 described above, it is possible to evaluate the stability of the power system based on, for example, the PES power usage rate of each bus in the power system. The above-described power system stability evaluation process 500 may be performed periodically or continuously. For example, by monitoring the power system in real time and continuously acquiring the power load information 266 and the power generation information 268, it is possible to evaluate the stability of the power system at any time.

[0071] Next, with reference to FIG. 6, a logical configuration of the power system management system according to an embodiment of the present disclosure will be described.

[0072] Fig. 6 is a diagram illustrating an example of a logical configuration of a power system management system 200 according to an embodiment of the present disclosure. As described above, the power system management system 200 according to an embodiment of the present disclosure is a system that ensures the stability of the power system by evaluating the stability of the power system and controlling power as necessary, and is configured with a power system 220, a central load dispatching center 230, a communication network 235, and a power system management device 240, as shown in Fig. 6.

[0073] In the power system management device 240, before performing the power system stability evaluation process 500 (see FIG. 5) for the power system 220, a stability index information generation process 800 (see FIG. 8) is performed to generate stability index information 269 to be used in the power system stability evaluation process 500.

[0074] More specifically, the stability index calculation unit 252 in the power system management device 240 receives as input power load prediction information 262 and power generation prediction information 264 obtained in advance from, for example, an electric power company. As described above, the power load prediction information 262 is information indicating the predicted power load of the power system 220 for a predetermined period, and the power generation prediction information 264 is information indicating the amount of power generation predicted to be supplied to the power system 220 for a predetermined period.

[0075] Next, the stability index calculation unit 252 generates a stability simulation model 605 based on the power load prediction information 262 and the power generation prediction information 264. The stability simulation model 605 is information that defines the configuration and state of the power system 220. In an embodiment, parameters of the load and power generation amount in the stability simulation model 605 may be set based on the power load prediction information 262 and the power generation prediction information 264.

[0076] Next, the stability index calculation unit 252 analyzes the stability simulation model 605 using a stability simulation program 610 to generate simulation results 615 that show the behavior of the power grid 220 for a number of different stability indexes. In one embodiment, the stability simulation program 610 may be a simulation program that generates predicted voltage waveforms in the power grid 220 for specific PES power utilization rates. In this case, the simulation results 615 may be information about voltage waveforms generated for different PES power utilization rates.

[0077] Next, the stability index calculation unit 252 analyzes the simulation results 615 generated by the stability simulation program 610, and determines whether each simulation result shows stable behavior (for example, a stable voltage waveform) or unstable behavior (for example, a voltage waveform with oscillations), and uses the PES power usage rate corresponding to each simulation result 615 as a stability index that defines the boundary between a ``stable state'' and an ``unstable state'' in the power system 220, and generates stability index information 269. The stability index information generation process 800 for generating the stability index information 269 will be described in detail later with reference to FIG. 8, and therefore will not be described here.

[0078] After the stability index information 269 is generated, the stability evaluation unit 256 evaluates the stability of the power system 220 by comparing a stability score calculated based on the power load information 266 and the power generation information 268 acquired from the power system 220 by the power information acquisition unit 254 via the communication network 235 with the stability index information 269. When it is determined that the power system 220 may become unstable, the power system management device 240 may transmit a PES power generation reduction request to a power plant in the power system 220 via, for example, the central load dispatching center 230 or the communication network 235, requesting reduction of PES power generation. The details of the power system stability evaluation process 500 for evaluating the stability of the power system 220 have been explained with reference to FIG. 5, and therefore will not be explained here.

[0079] Next, stability index information according to an embodiment of the present disclosure will be described with reference to FIG.

[0080] 7 is a diagram illustrating an example of the stability index information 269 according to an embodiment of the present disclosure. As described above, the stability index information 269 according to an embodiment of the present disclosure is information that defines the boundary between a "stable state" and an "unstable state" in a power system, and is used to evaluate the stability of the power system by being compared with a stability score calculated for the power system. The stability index information 269 shown in FIG. 7 may be generated in a stability index information generation process, which will be described later with reference to FIG.

[0081] As shown in FIG. 7, the stability index information 269 may include information on a stability index 710 and stability 720 . The stability index 710 is information indicating a value of a predetermined PES power usage rate. For example, the stability index 710 may be, for example, "10%," "30%," "50%," or the like. Stability 720 is information indicating whether the power system is stable or unstable for a particular stability index for each stability index 710. For example, stability 720 may indicate that a predetermined stability index "K1" (e.g., a PES power usage rate of 10%) is "stable" and that a stability index "K2" (e.g., a PES power usage rate of 60%) is "unstable."

[0082] As described above, after calculating a stability score for a power system, the stability score can be compared to the stability index information 269 shown in Figure 7 to determine whether the stability score corresponds to a stability index of "stable" or "unstable." Then, based on this determination, the PES power usage rate in the power system can be controlled to ensure the stability of the power system. The expression that a stability score "corresponds to" a stability index means that the stability score is within an acceptable range set for a particular stability index. This acceptable range may be set arbitrarily, for example, to ±5%, ±10%, or the like, of the stability index. For example, if the stability index is "50%, the stability score is "52%, and the acceptable range is "±10% of the stability index," it can be determined that the stability score of "52%" corresponds to the stability index of "50%."

[0083] Next, with reference to FIG. 8, a stability index information generation process according to an embodiment of the present disclosure will be described.

[0084] 8 is a diagram showing an example of the flow of stability index information generation processing 800 according to an embodiment of the present disclosure. The stability index information generation processing 800 is processing for defining the boundary between a "stable state" and an "unstable state" in a power system and generating stability index information used to evaluate the stability of the power system, and is performed by the stability index calculation unit 252 in the power system management device 240 shown in FIG.

[0085] First, in step S810, the stability index calculation unit 252 sets the stability index "k" to a predetermined initial value "k1." As described above, this stability index may be a predetermined PES power usage rate value. Here, the initial value k1 of the stability index may be set to any value.

[0086] Next, in step S815, the stability index calculation unit 252 generates a stability simulation model of the power system. This stability simulation model is information that defines the configuration and state of the power system 220. In one embodiment, the stability index calculation unit 252 may use an existing simulation model that simulates the voltage in the power system as the stability simulation model.

[0087] Next, in step S820, the stability index calculation unit 252 sets model parameters in the stability simulation model generated in step S815. More specifically, the stability index calculation unit 252 may set parameters of the load, power generation amount, and PES power usage rate in the stability simulation model based on the power load prediction information 262 and the power generation prediction information 264. This makes it possible to obtain realistic simulation results.

[0088] In an embodiment, the stability index calculation unit 252 may set a target range of the stability index to be analyzed in the simulation based on the power load prediction information 262 and the power generation prediction information 264. For example, using the above-described Equation 1, the stability index calculation unit 252 may set the minimum value of the PES power usage rate in the simulation (i.e., the lower limit of the stability index) to the PES usage rate calculated based on the minimum load and power generation amount values ​​in the power load prediction information 262 and the power generation prediction information 264, and set the maximum value of the PES power usage rate in the simulation (i.e., the upper limit kn of the stability index) to the PES usage rate calculated based on the maximum load and power generation amount in the power load prediction information 262 and the power generation prediction information 264.

[0089] Next, in step S825, the stability index calculation unit 252 can generate simulation results showing predicted behavior of the power system for a stability index (e.g., k1) indicating a specific PES power utilization rate by analyzing the stability simulation model generated in step S815 using a stability simulation program. In one embodiment, the stability simulation program may be a simulation program that generates predicted voltage waveforms in the power system for the specific PES power utilization rate. In this case, the simulation results may be information on voltage waveforms generated for the stability index representing the specific PES power utilization rate.

[0090] Next, in step S830, the stability index calculation unit 252 analyzes the voltage waveform shown in the simulation result generated in step S825. Here, the stability index calculation unit 252 may determine whether the fluctuation per unit time in the voltage waveform shown in the simulation result is equal to or greater than a predetermined fluctuation threshold. If it is determined that the voltage waveform has fluctuations equal to or greater than the predetermined fluctuation threshold, the process proceeds to step S835. On the other hand, if it is determined that the voltage waveform does not have fluctuations equal to or greater than the predetermined fluctuation threshold, the process proceeds to step S850.

[0091] Next, if it is determined in step S830 that fluctuations equal to or greater than a predetermined fluctuation threshold are present in the voltage waveform, then in step S835, the stability index calculation unit 252 determines that there is a risk of SSO (Sub-Synchronous Oscillation) occurring in the power system based on the stability index k1 indicating this PES power usage rate.

[0092] Next, in step S840, the stability index calculation unit 252 determines that the stability index k1 indicating the PES power usage rate indicates an "unstable" state because there is a risk that SSO may occur in the power system.

[0093] Next, in step S845, the stability index calculation unit 252 sets the stability index k1 to "unstable" in the above-mentioned stability index information 269. More specifically, the stability index calculation unit 252 may associate the stability index k1 with a label of "unstable" in the stability index information 269. Thereafter, the process proceeds to step S865.

[0094] On the other hand, in step S830, if a fluctuation equal to or greater than a predetermined fluctuation threshold is present in the voltage waveform, do not If it is determined that the stability index k1 indicates the PES power usage rate, then in step S850, the stability index calculation unit 252 determines that there is no risk of SSO (Sub-Synchronous Oscillation) occurring in the power system with the stability index k1 indicating this PES power usage rate.

[0095] Next, in step S855, the stability index calculation unit 252 determines that the stability index k1, which indicates the PES power usage rate, indicates a "stable" state because there is no risk of SSO occurring in the power system.

[0096] Next, in step S860, the stability index calculation unit 252 sets the stability index k1 to "stable" in the above-mentioned stability index information 269. More specifically, the stability index calculation unit 252 may associate the stability index k1 with a label of "stable" in the stability index information 269. Thereafter, the process proceeds to step S865.

[0097] Next, in step S865, the stability index calculation unit 252 determines whether the stability index k is equal to or less than the upper limit kn of the stability index. If the stability index k is equal to or less than the upper limit kn of the stability index, the process returns to step S820, and the stability index calculation unit 252 increments the stability index k. On the other hand, if the qualitative index k is equal to or greater than the upper limit kn of the stability index, the stability index calculation unit 252 determines that analysis of all stability indexes within the target range of the stability index has been completed, and the process ends.

[0098] The stability index information generation process 800 described above makes it possible to generate stability index information that indicates the PES power usage rate that defines the boundary between a "stable state" and an "unstable state" in a power system. In this way, by creating and storing stability index information in advance, it becomes possible to evaluate the stability of the power system at any time. The stability index information generation process 800 may be performed, for example, periodically (once a day, once a week), or may be performed whenever the configuration of the power system or the expected load and power generation amount changes.

[0099] As described above, in the stability index information generation process 800 according to an embodiment of the present disclosure, a stability simulation is performed to predict the behavior of the power system for each of a plurality of different PES power utilization rates. In one embodiment, a voltage waveform corresponding to a specific PES power utilization rate is used as the result of this stability simulation. Next, stability simulation results according to the embodiment of the present disclosure will be described with reference to FIGS.

[0100] 9 is a diagram illustrating a voltage waveform 900 indicating that the power grid is stable, as a result of a stability simulation according to an embodiment of the present disclosure. This voltage waveform 900 may be generated based on, for example, a predetermined PES power usage rate k1. As shown in FIG. 9, the horizontal axis of the voltage waveform 900 represents time, and the vertical axis represents voltage. 9, the voltage change per unit time 905 reaches a plateau and does not fluctuate significantly. Therefore, the fluctuation in the voltage change per unit time 905 is less than a predetermined fluctuation threshold value such as "0.25 MV / s," and therefore the stability index calculation unit 252 stores the PES power usage rate k1 corresponding to the voltage waveform 900 in the stability index information 269 as a "stable" stability index.

[0101] 10 is a diagram illustrating a voltage waveform 1000 indicating a potential instability of a power grid as a result of a stability simulation according to an embodiment of the present disclosure. The voltage waveform 1000 may be generated based on, for example, a predetermined PES power utilization rate k2. As shown in FIG. 10, the horizontal axis of the voltage waveform 1000 represents time, and the vertical axis represents voltage. 10 , oscillations (e.g., SSO) occur in the voltage transition per unit time 1005. Therefore, because the fluctuation in the voltage transition per unit time 1005 is equal to or greater than a predetermined fluctuation threshold value such as "0.25 MV / s," the stability index calculation unit 252 stores the PES power usage rate k2 corresponding to the voltage waveform 1000 in the stability index information 269 as a stability index of "unstable."

[0102] Next, with reference to FIG. 11, a stability evaluation result screen according to an embodiment of the present disclosure will be described.

[0103] Fig. 11 is a diagram showing an example of a stability evaluation result screen 1100 according to an embodiment of the present disclosure. The stability evaluation result screen 1100 shown in Fig. 11 is a screen showing a stability evaluation result generated by performing a stability evaluation on a power system. This stability evaluation result screen 1100 may be displayed on, for example, a terminal of a power company that manages the power system, a terminal of a central load dispatching center, or the like.

[0104] As shown in FIG. 11, a stability evaluation result screen 1100 may include a power system diagram 1105 , notation information 1110 , date and time information 1115 , a stability evaluation result 1120 , and an SSO waveform diagram 1125 .

[0105] The power system diagram 1105 is a diagram showing the configuration of the power system that is the subject of stability evaluation. The notation information 1110 indicates notations used to indicate equipment such as generators, RES, loads, transformers, buses, and transmission lines in the power system diagram 1105.

[0106] The date and time information 1115 is information indicating the date and time corresponding to the stability evaluation result. The stability evaluation result 1120 is generated by the power system stability evaluation process 500 according to an embodiment of the present disclosure, and is information indicating the stability of the power system. As shown in Fig. 11 , the stability evaluation result 1120 may include, for each of a plurality of areas (area 1, area 2, area 3) included in the power system, the PES power usage rate calculated for the buses in that area and the stability of that area (stable or unstable). This stability evaluation result 1120 information may be generated by the power system stability evaluation process 500 described above.

[0107] The SSO waveform diagram 1125 is a graph showing a waveform diagram of an SSO predicted to occur in an "unstable" area in the stability evaluation result 1120. This SSO waveform diagram 1125 may be generated, for example, by the simulation described above. By selecting a specific area or bus in the stability evaluation result 1120, the user of the stability evaluation result screen 1100 can check a waveform diagram of an SSO predicted to occur in that area or bus.

[0108] As described above, the power system management means according to the embodiment of the present disclosure calculates, for each bus in the power system, the ratio of the power related to the PES to the total power related to that bus (i.e., the PES power usage rate) as a stability score for the power system. The calculated stability score is then compared with a stability index that defines the boundary between a "stable state" and an "unstable state" in the power system, thereby making it possible to evaluate the current stability of the power system. In this way, by evaluating the stability of the power system based on the PES power utilization rate, it is possible to quantitatively evaluate, for example, fluctuations in grid impedance caused by an increase in PES density as RES deployment expands, and instability of the power system caused by interactions between PESs.

[0109] Furthermore, by performing this power system stability assessment in real time, continuously or periodically, it is possible to determine the possibility of the power system becoming unstable before oscillations such as SSO occur. Then, by sending a PES power generation reduction request requesting the reduction of PES power to, for example, a power plant that uses RES in the power system, the PES power usage rate can be controlled and SSO can be prevented. This makes it possible to avoid SSO damage to facilities in the power system, such as transmission lines and transformers.

[0110] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention.

[0111] As described above, the power system management means according to the embodiment of the present disclosure includes the following aspects.

[0112] (Aspect 1) The power system and a power system management device that manages the power system; A power system management system including a communication network for communicating information between the power system and the power system management device, The power system management device includes: a processor; Memory and a storage unit that stores power load prediction information indicating a prediction of a power load in the power system and power generation prediction information indicating a prediction of power generated by a power plant in the power system; The memory includes: a stability index calculation unit that calculates stability index information indicating a stability index for evaluating the stability of the power system based on the power load prediction information and the power generation prediction information; a power information acquisition unit that acquires, from the power system via the communication network, power load information indicating an actual power load in the power system and power generation information indicating power actually generated by a power plant in the power system; a stability evaluation unit that calculates a stability score for the power system based on the power load information and the power generation information, and generates a stability evaluation result indicating the stability of the power system based on the stability score and the stability index information; and a processing instruction for causing the processor to function as a power system management system.

[0113] (Aspect 2) The power system includes: A power electronics system (PES) and a plurality of buses connected to the non-PES, The power load information is for each bus in the power system, a PES power load associated with the PES and a total power load associated with the PES and the non-PES; The power generation information is For each bus in the power system, a PES power generation amount associated with the PES and a total power generation amount associated with the PES and the non-PES are included. 2. The power system management system according to aspect 1.

[0114] (Aspect 3) The stability evaluation unit Calculate a PES power utilization rate in the power system by dividing the sum of the PES power load and the PES power generation amount of each bus in the power system by the sum of the total power load and the total power generation amount of each bus in the power system based on the power load information and the power generation information, and set the PES power utilization rate as the stability score. 3. The power system management system according to aspect 2.

[0115] (Aspect 4) The stability index calculation unit determining a target range of a stability index based on the power load forecast information and the power generation forecast information; generating simulation results showing predicted voltages for each time period for a given bus in the power system for each stability index in the target range; designating a first stability index as stable when the time variation of the voltage in the simulation result is less than a predetermined variation threshold for the first stability index in the target range; generating the stability index information indicating whether each stability index in the target range is stable or unstable by designating the second stability index as unstable when the fluctuation per unit time of the voltage in the simulation result is equal to or greater than a predetermined fluctuation threshold value; 4. The power system management system according to any one of the first to third aspects.

[0116] (Aspect 5) The stability evaluation unit generating a stability evaluation result indicating that the power system is stable when the stability score is compared with the stability index information and it is determined that the stability score corresponds to the first stability index; generating a stability assessment result indicating that the power grid may become unstable when the stability score is compared with the stability index information and it is determined that the stability score corresponds to the second stability index; 5. The power system management system according to aspect 4.

[0117] (Aspect 6) The power system management device includes: When it is determined that there is a possibility that the power grid may become unstable, a PES power generation reduction request is transmitted to a power plant in the power grid, requesting reduction of a PES power generation amount. 6. The power system management system according to any one of the first to fifth aspects. [Explanation of symbols]

[0118] 150 Power System Management Applications 200 Power System Management System Buses 201, 202, 203, 204, and 205 206, 207, 208 RES 209, 210, 211, 212 Load 213 Synchronous Generator 215, 216, 217, 218, 219 Power lines 220 Power System 230 Central Power Supply Control Center 235 Communication Network 240 Power system management equipment 250 memory 252 Stability index calculation section 254 Power information acquisition section 256 Stability Evaluation Section 260 Storage section 262 Power Load Forecast Information 264 Power Generation Forecast Information 266 Power Load Information 268 Power Generation Information 269 ​​Stability index information 270 processor 275 Input / output section

Claims

1. The power system and a power system management device that manages the power system; A power system management system including a communication network for communicating information between the power system and the power system management device, The power system management device includes: a processor; Memory and a storage unit that stores power load prediction information indicating a prediction of a power load in the power system and power generation prediction information indicating a prediction of power generated by a power plant in the power system; The memory includes: a stability index calculation unit that calculates stability index information indicating a stability index for evaluating the stability of the power system based on the power load prediction information and the power generation prediction information; a power information acquisition unit that acquires, from the power system via the communication network, power load information indicating an actual power load in the power system and power generation information indicating power actually generated by a power plant in the power system; a stability evaluation unit that calculates a stability score for the power system based on the power load information and the power generation information, and generates a stability evaluation result indicating the stability of the power system based on the stability score and the stability index information; and processing instructions for causing the processor to function as The power system includes: a plurality of buses to which power electronic systems (PESs) and non-PESs are connected; The power load information is a PES power load associated with the PES and a total power load associated with the PES and the non-PES, for each bus in the power system; The power generation information is For each bus in the power system, a PES power generation amount related to the PES and a total power generation amount related to the PES and the non-PES are included, The stability evaluation unit a power system management system that calculates a PES power usage rate in the power system by dividing the sum of the PES power load and the PES power generation amount of each bus in the power system by the sum of the total power load and the total power generation amount of each bus in the power system based on the power load information and the power generation information, and sets the PES power usage rate as the stability score.

2. An electric power system; a power system management device that manages the power system; A power system management system including a communication network for communicating information between the power system and the power system management device, The power system management device includes: a processor; Memory and a storage unit that stores power load prediction information indicating a prediction of a power load in the power system and power generation prediction information indicating a prediction of power generated by a power plant in the power system; The memory includes: a stability index calculation unit that calculates stability index information indicating a stability index for evaluating the stability of the power system based on the power load prediction information and the power generation prediction information; a power information acquisition unit that acquires, from the power system via the communication network, power load information indicating an actual power load in the power system and power generation information indicating power actually generated by a power plant in the power system; a stability evaluation unit that calculates a stability score for the power system based on the power load information and the power generation information, and generates a stability evaluation result indicating the stability of the power system based on the stability score and the stability index information; and processing instructions for causing the processor to function as The stability index calculation unit determining a target range of a stability index based on the power load forecast information and the power generation forecast information; generating simulation results showing predicted voltages for each time period for a given bus in the power system for each stability index in the target range; designating a first stability index as stable if the time variation of the voltage in the simulation result is less than a predetermined variation threshold for the first stability index in the target range; and generating the stability index information indicating whether each stability index in the target range is stable or unstable by designating the second stability index as unstable when the fluctuation per unit time of the voltage in the simulation result is equal to or greater than a predetermined fluctuation threshold value for the second stability index in the target range.

3. The stability evaluation unit generating a stability evaluation result indicating that the power system is stable when the stability score is determined to correspond to the first stability index as a result of comparing the stability score with the stability index information; generating a stability assessment result indicating that the power grid may become unstable when the stability score is compared with the stability index information and it is determined that the stability score corresponds to the second stability index; 3. The power system management system according to claim 2.

4. a memory for storing processing instructions; a processor, The processing instructions stored in the memory include: obtaining power load forecast information indicating a forecast of a power load in a power grid and power generation forecast information indicating a forecast of power generated by a power plant in the power grid; determining a target range of a stability index for evaluating the stability of the power system based on the power load forecast information and the power generation forecast information; generating simulation results indicating predicted voltages for each time period for a given bus in the power system for each stability index in the target range; designating a first stability index as stable when the time variation of the voltage in the simulation result is less than a predetermined variation threshold for the first stability index in the target range; generating stability index information indicating whether each stability index in the target range is stable or unstable by designating the second stability index as unstable when the fluctuation per unit time of the voltage in the simulation result is equal to or greater than a predetermined fluctuation threshold; acquiring, from the power system, power load information including a PES power load related to a power electronics system (PES) and a total power load related to the PES and non-PES for each bus in the power system, and power generation information including a PES power generation amount related to the PES and a total power generation amount related to the PES and non-PES for each bus in the power system; calculating a PES power utilization rate as a stability score for the power system based on the power load information and the power generation information by dividing the sum of the PES power load and the PES power generation of each bus in the power system by the sum of the total power load and the total power generation of each bus in the power system; generating a stability evaluation result indicating that the power system is stable when the stability score is compared with the stability index information and it is determined that the stability score corresponds to the first stability index; generating a stability assessment result indicating that the power grid may become unstable when the stability score is determined to correspond to the second stability index as a result of comparing the stability score with the stability index information; transmitting a PES power generation amount suppression request to a power plant in the power system when it is determined that there is a possibility that the power system will become unstable, requesting suppression of a PES power generation amount; The power system management method is characterized by causing the processor to execute the above.

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