Power outage risk assessment system and power outage risk assessment method

Abstract

To solve a problem that a reduction of power failure damage by a storage battery or a private power generation facility installed by a consumer is not considered, or even if being considered, it is evaluated based on a simple assumption that it will function without exception in an event of a disaster, and a risk of loss of a function of a power failure countermeasure itself is not considered.SOLUTION: A power failure risk evaluation system 1 includes a power failure probability evaluation unit 12 that analyses a power system with an event tree and evaluates a power failure probability of the power system, and a power failure risk evaluation unit 14 that evaluates a power failure risk of the power system based on the power failure probability. In this way, it is possible to contribute to consideration of a rational countermeasure for reducing the power failure risk.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to power outage risk assessment techniques. [Background technology]

[0002] Power system analysis is generally performed to analyze the entire power system, from the power plant where electricity is generated, through the transmission and distribution grid, and all the way to the consumer. This involves modeling power equipment in a simulator, and using the analysis results for facility planning or to investigate the causes of abnormal events. Power system analysis has traditionally been used with the goal of ensuring a stable supply of high-quality electricity. However, as a result of an abnormal event in the power system, power transmission or distribution becomes impossible, resulting in a power outage. There are multiple factors that cause power outages, but the impact of natural disasters has been widely studied, as it relates to the prediction of power outages and the restoration of power after a power outage.

[0003] For example, there is a known technology for predicting typhoon damage based on typhoon forecasts and past damage information. There is also a known technology for predicting the number of households that will experience power outages based on equipment resilience and weather forecast data. There is also a known technology for calculating the average power outage duration for consumers, the amount of power outage damage, and the cost-effectiveness of countermeasures based on data on past natural disasters and the number of power outages. There is also a known technology for modeling the target power distribution network, calculating the power distribution route and damage probability, and using an event tree to calculate the expected value of power demand or power supply for consumers, and calculating changes in the power supply rate over time. These technologies basically evaluate the impact of the presence or absence of a power distribution route on power outages based on the probability of physical damage to each component of the power distribution network. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5044243 [Patent Document 2] Patent No. 5931830 [Patent Document 3] Patent No. 5088628 [Non-patent literature]

[0005] [Non-Patent Document 1] Study on earthquake resilience evaluation method for power distribution networks with distributed generation systems Journal of the Japan Association for Earthquake Engineering Vol. 19, No. 7, 2019 Summary of the Invention [Problem to be solved by the invention]

[0006] Power outages are caused by natural disasters such as earthquakes, typhoons, lightning strikes, and floods, as well as other factors. If the risk of power outages due to various disasters can be quantitatively understood in advance, electricity consumers can take rational and effective measures based on that information. For example, as a measure to reduce the risk of power outages, power can be avoided by installing storage batteries, fuel cells, private power generation equipment, etc., and supplying power from these facilities when power supply from the power distribution grid is cut off. In addition, there are power distribution automation systems that monitor the power distribution grid or control system switching using various devices via a communication network, with the aim of maintaining and improving the power quality or supply reliability of the power distribution grid.

[0007] Figure 21 shows a schematic diagram of a conventional distribution automation system. This schematic diagram illustrates the restoration process performed by the distribution automation system when a fault occurs in the distribution network. For example, a distribution line extending from a substation is divided into multiple sections (1) to (6) by automatic switches. Under normal circumstances, power is transmitted through this distribution line. Now, assume that a fault affecting the distribution line occurs in a specific section (3). When the fault occurs, the automatic switch relay operates, and the automatic switch opens. Furthermore, the substation stops transmitting power. When the circuit is reclosed, power transmission from the substation resumes, and each automatic switch is closed in sequence, transmitting power to the fault point. At this time, the specific section (3) is identified as the fault section. The automatic switch on the power supply side of this fault section (3) is locked. Power is transmitted to sections (1) to (2) on the power supply side of the fault section (3). However, power is not transmitted to the fault section (3) because the automatic switch is locked. In this case, sections (4) to (6) on the load side of the fault section (3) will experience a power outage, even though no fault has occurred. These sections (4) to (6) are called healthy power outage sections. When a power outage occurs, the distribution automation system aims to minimize the scale of the outage by detecting the fault, identifying the fault section, and performing reverse power transfer. Here, reverse power transfer means supplying power from a different route to healthy power outage sections (4) to (6) on the load side of the fault section (3). This reverse power transfer can reduce the number of power outages.

[0008] In this way, when damage or a failure occurs at a specific point in the power distribution network, cutting off the power supply route, the point of the accident is identified, power is transmitted via an alternative route, and measures are taken to minimize the area affected by the outage. In order to take measures against outages in advance, it is necessary to evaluate the return on investment of the measures, such as whether the measures are effective for the investment. Because there are various disasters that can cause outages and the scale and form of outages, it is necessary to consider the components of the power system and their respective relationships and roles, quantitatively evaluate the outage risk, and then evaluate the risk reduction that can be achieved by implementing measures.

[0009] In the case of damage to a specific section of the power distribution network, a distribution automation system identifies that section and performs operations to transmit power via a detour route. However, even if a route for power transmission is secured, the functionality of the equipment necessary for this series of operations may be lost due to a disaster. Conventional technologies do not consider the impact of power outage damage on the system role of each device in the power distribution network. Furthermore, it is difficult to determine which functions of the power distribution network need to be strengthened to efficiently reduce the risk of power outages. Furthermore, the reduction of power outage damage caused by equipment installed by consumers is not considered, or even if it is, it is evaluated based on the simple assumption that the equipment will function without exception in the event of a disaster, without considering the risk of loss of functionality of the power outage countermeasures themselves. As a result, they are unable to contribute to the development of rational measures to reduce the risk of power outages.

[0010] The embodiment of the present invention has been made in consideration of these circumstances, and aims to provide a power outage risk assessment technology that can contribute to the consideration of rational measures to reduce the risk of power outages. [Means for solving the problem]

[0011] The power outage risk assessment system according to the embodiment of the present invention is a power system configuration or Connection The situation a disaster hazard database that stores information on natural disaster hazards and information on annual exceedance frequencies; an event tree creation unit that creates an event tree to be used for evaluating the power outage probability of the power system for the hazard to be evaluated from the information stored in the power system configuration database; a fault tree creation unit that uses the disaster hazard database to create a fault tree to be used for calculating the branching probability of the event tree; a power outage probability evaluation unit that analyzes the power system using the event tree and evaluates the power outage probability of the power system; and a power outage risk evaluation unit that evaluates the power outage risk of the power system based on the power outage probability. [Effects of the Invention]

[0012] According to an embodiment of the present invention, a power outage risk assessment technique is provided that can contribute to the consideration of rational measures for reducing the risk of power outages. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing a power outage risk assessment system. [Figure 2] FIG. 2 is a block diagram showing a main control unit. [Figure 3] FIG. 2 is a graphical representation showing the configuration of a power system stored in a power system configuration database. [Figure 4] FIG. 4 is an explanatory diagram showing a system configuration management table. [Figure 5] FIG. 4 is an explanatory diagram showing a consumer configuration management table. [Figure 6] FIG. 4 is an explanatory diagram showing a first device management table. [Figure 7] FIG. 10 is an explanatory diagram showing a second device management table. [Figure 8] This graph shows the relationship between the intensity of a disaster and the probability of equipment damage (equipment strength), in the case where the disaster is an earthquake. [Figure 9] FIG. 10 is an explanatory diagram showing a hazard management table. [Figure 10] This graph shows the relationship between disaster intensity and annual exceedance frequency (disaster hazard) when the disaster is an earthquake. [Figure 11] FIG. 1 is an image diagram showing a hazard map stored in a disaster hazard database. [Figure 12] FIG. 10 is an explanatory diagram showing an accident response and maintenance performance record table. [Figure 13] FIG. 4 is an explanatory diagram showing a material management table. [Figure 14] FIG. 4 is an explanatory diagram illustrating a resource management table. [Figure 15] FIG. 10 is an explanatory diagram showing an example of an event tree. [Figure 16] FIG. 10 is an explanatory diagram showing an example of a fault tree. [Figure 17] FIG. 10 is an explanatory diagram showing an example of a power outage risk curve. [Figure 18]FIG. 10 is an explanatory diagram showing an example of a customer countermeasure menu presentation. [Figure 19] A graph showing the relationship between time and electricity demand (changes in electricity demand). [Figure 20] 1 is a flowchart illustrating a method for assessing the risk of power outages. [Figure 21] FIG. 1 is an explanatory diagram showing a flow of restoration using a conventional power distribution automation system. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of a power outage risk assessment system and a power outage risk assessment method will be described in detail with reference to the drawings.

[0015] Reference numeral 1 in Fig. 1 denotes a power outage risk assessment system of this embodiment. This power outage risk assessment system 1 assesses the power outage risk of a power system. In this embodiment, an example of a mode used to calculate the power outage risk of a power system is illustrated.

[0016] An electric power system is a system that includes the generation of electricity (generation), the transportation of electricity (transmission and transformation), the supply of electricity (distribution), and the demand for electricity (consumption). This electric power system is a very large-scale system that includes everything from generation to consumption, and is highly controlled to keep the voltage and frequency within a certain range as a whole. The equipment that makes up this electric power system includes equipment installed by electric power companies and equipment installed by consumers.

[0017] In an electric power system, electricity generated at power plants is supplied to consumers (homes, factories, businesses, etc.) via a power transmission network and a power distribution network. This series of supply routes, from upstream to downstream, differs depending on the region. Power Outage Risk Assessment System 1 quantifies the risk of power outages in a region to accurately grasp that risk. This allows for more effective and necessary capital investments to be made. Power Outage Risk Assessment System 1 uses an event tree (Figure 15) and a fault tree (Figure 16) to assess the risk of power outages.

[0018] Here, an event tree (Fig. 15) is a tree diagram that systematically displays how an abnormal event that generally occurs in a plant or the like may spread depending on the system configuration and other conditions at the time. It is usually a logic diagram that branches sequentially depending on the success (branching upward in Fig. 15) or failure (branching downward in Fig. 15) of the operation of a component. If the branching probability of this event tree can be quantified, it is possible to estimate the probability of various consequences brought about by an abnormal event.

[0019] A fault tree (Figure 16) is a tree-like analysis method that places an undesirable event, such as a loss of functionality or failure to accomplish a mission in an engineering system, at the top, logically unfolds the factors that cause it, and traces it back to the underlying causes. Then, by providing the probability of occurrence of each underlying cause, the probability of occurrence of the underlying event is calculated. In this embodiment, the branching probability of the event tree is calculated using a fault tree, and the probability of various consequences caused by an abnormal event is estimated.

[0020] Next, the system configuration of the power outage risk assessment system 1 will be described with reference to the block diagrams shown in FIGS.

[0021] As shown in FIG. 1, the power outage risk assessment system 1 includes a main control unit 2, an input unit 3, an output unit 4, a storage unit 5, and a communication unit 6.

[0022] Furthermore, the power outage risk assessment system 1 includes a system configuration database 7, an equipment database 8, a disaster hazard database 9, an accident response and maintenance performance database 10, and a materials and resource database 11. These are collections of information stored in memory, a hard disk drive, or cloud storage capacity, and organized so that they can be searched or accumulated.

[0023] The power outage risk assessment system 1 of this embodiment is configured as a computer having hardware resources such as a CPU, ROM, RAM, and HDD, and in which software-based information processing is realized using the hardware resources by the CPU executing various programs. Furthermore, the power outage risk assessment method of this embodiment is realized by having the computer execute various programs.

[0024] Each component of the power outage risk assessment system 1 does not necessarily have to be installed on one computer. For example, one power outage risk assessment system 1 may be realized using multiple computers connected to each other via a network. For example, the various databases 7 to 11 may each be installed on a separate computer.

[0025] Predetermined information is input to the input unit 3 in response to operations by a user of the power outage risk assessment system 1. For example, various types of information are input to the input unit 3, such as the system configuration of the region or area where the power outage risk assessment is to be carried out, equipment fragility information, disaster hazard information, past accident response or maintenance information, and material or resource information.

[0026] The input unit 3 includes input devices such as a mouse or a keyboard. That is, predetermined information is input to the input unit 3 in response to the operation of these input devices. When inputting information, the user assigns a unique ID to each piece of information such as the system configuration and the equipment. An ID is identification information required to individually identify the corresponding information, and a unique ID is assigned in association with each piece of information.

[0027] The components (devices) of this embodiment include substations, distribution lines (transmission lines), distribution poles, and pole-mounted devices such as switches. They also include power-receiving devices of consumers who use the power system, or devices that may be introduced as a countermeasure against power outages. Specific examples include storage batteries, solar power generation systems, fuel cells, emergency diesel generators, and gas engines.

[0028] The output unit 4 outputs predetermined information. For example, the output unit 4 outputs the evaluation results of the main control unit 2 and information stored in the databases 7 to 11. The power outage risk assessment system 1 of this embodiment includes a device for displaying images, such as a display that outputs the analysis results. In other words, the output unit 4 controls the images displayed on the display. The display may be separate from the computer main body, or may be integrated with it.

[0029] The power outage risk assessment system 1 of this embodiment may also control images displayed on a display of another computer connected via a network. In this case, the output unit 4 of the other computer may control the output of the assessment results derived by the main control unit 2.

[0030] In this embodiment, a display is used as an example of a device for displaying images, but other modes may be used. For example, a projector may be used to display information. Furthermore, a printer that prints information on paper media may be used instead of a display. In other words, the objects controlled by the output unit 4 may include a projector or a printer.

[0031] The storage unit 5 stores various information required for evaluating the risk of a power outage based on the information stored in the databases 7 to 11.

[0032] The communication unit 6 communicates with other computers via a communication line such as the Internet. In this embodiment, the power outage risk assessment system 1 and the other computers are connected to each other via the Internet, but other modes are also possible. For example, they may be connected to each other via a LAN (Local Area Network), a WAN (Wide Area Network), or a mobile communication network.

[0033] The system configuration database 7 stores information indicating the configuration or connection status of the power system. This information includes geographical information about the power system, the relative positions of various pieces of equipment, and the distances between the various pieces of equipment. For example, the system configuration database 7 stores information indicating the configuration of the power system (FIG. 3), a system configuration management table (FIG. 4), and a consumer configuration management table (FIG. 5).

[0034] Figure 3 is an example of an image showing the configuration of a power system. Information showing the configuration of a power system can be displayed in two dimensions on a display or other device. This allows users to understand the relative positions and configuration of various pieces of equipment in the power system.

[0035] Furthermore, the power outage risk assessment system 1 has a function of showing the system configuration and displaying it by overlaying it on an actual map. Each system configuration is managed by a unique system configuration ID.

[0036] FIG. 4 is an example of a system configuration management table. Information on devices related to each system configuration is registered in this system configuration management table. Various information is registered in this system configuration management table using a system configuration ID as a primary key. For example, a device ID, a device detail ID, a device name, and coordinates and elevation are registered in association with the system configuration ID.

[0037] Here, the system configuration ID is identification information that can individually identify each system configuration. The device ID is identification information that can individually identify each device. The device detail ID is identification information that can individually identify each piece of data that records detailed information about the device. Based on this device detail ID, detailed data about the device stored in other areas of the system configuration database 7 can be read. The device name is a name that indicates the type of device. The coordinates and elevation are the coordinates and elevation of the location where the device is installed. These coordinates and elevation are specific information that can identify whether the device will lose its function due to a disaster.

[0038] FIG. 5 is an example of a consumer configuration management table. Information about consumers who receive power from each grid is registered in this consumer configuration management table. Various information is registered in this consumer configuration management table using a grid configuration ID as a primary key. For example, a consumer ID, coordinates and elevation, industry type, consumer name, contracted power capacity, normal power usage, emergency power demand, countermeasure equipment, and countermeasure equipment capacity are registered in association with the grid configuration ID.

[0039] Here, the customer ID is identification information that can individually identify each important customer. The coordinates and elevation are the coordinates and elevation of the customer's location. These coordinates and elevation are specific information that can identify whether or not equipment will lose function due to a disaster. The industry is the customer's industry. For example, this is the type of customer, such as a home, medical institution, office building, or government office. The customer name is a name that can identify the customer. The contracted power capacity is the power capacity that the power company has contracted with the customer.

[0040] Normal power usage is the power that a consumer uses during normal times. Emergency power demand is the power that a consumer needs during a power outage. Note that multiple patterns may be registered in the items for normal power usage and emergency power demand. The multiple patterns include, for example, summer and winter patterns, and day and night patterns.

[0041] Countermeasure equipment is equipment for continuing the supply of power during a power outage. For example, it is an emergency diesel generator. This countermeasure equipment includes equipment that supplies power not only during emergencies but also during normal times. Note that information indicating whether or not countermeasure equipment is available may be registered in the countermeasure equipment item. Countermeasure equipment capacity is the power capacity that can be supplied from the countermeasure equipment to consumers.

[0042] The equipment database 8 stores information indicating the strength information (fragility) or failure probability of the equipment that constitutes the power system. For example, the equipment database 8 stores a first equipment management table (FIG. 6), a second equipment management table (FIG. 7), and information indicating the relationship between earthquake acceleration as an example of disaster intensity and the probability of equipment damage (FIG. 8).

[0043] Fig. 6 is an example of a first equipment management table. This first equipment management table mainly stores information about equipment necessary for supplying power from the power plant. This first equipment management table stores various information using an equipment ID as a primary key. For example, the equipment use, equipment name, equipment proof strength, and design criteria are registered in association with the equipment ID.

[0044] 7 is an example of a second equipment management table. Information related to countermeasure facilities is mainly registered in this second equipment management table. Various information is registered in this second equipment management table using an equipment ID as a primary key. For example, an equipment name, an installed capacity, an equipment strength, and a design standard are registered in association with the equipment ID.

[0045] Here, equipment use is information indicating the use of the equipment. Equipment resistance is information indicating the durability of equipment against the intensity of the disaster. If the disaster is an earthquake, the intensity of the disaster is the seismic acceleration, and the equipment resistance is information indicating the durability of equipment against the seismic acceleration. If the disaster is a typhoon, the intensity of the disaster is the wind speed, and the equipment resistance is information indicating the durability of equipment against the wind speed. If the disaster is a lightning strike, the intensity of the disaster is the lightning current value, and the equipment resistance is information indicating the durability of equipment against the lightning current value. If the disaster is a flood, the intensity of the disaster is the flood depth, and the equipment resistance is information indicating the durability of equipment against the flood depth.

[0046] The design criteria is information indicating the design standard values that equipment can withstand against the intensity of the disaster. If the disaster is an earthquake, the intensity of the disaster is the seismic acceleration, and the design criteria is information indicating the design standard values that equipment can withstand against the seismic acceleration. If the disaster is a typhoon, the intensity of the disaster is the wind speed, and the design criteria is information indicating the design standard values that equipment can withstand against the wind speed. If the disaster is a lightning strike, the intensity of the disaster is the lightning current value, and the design criteria is information indicating the design standard values that equipment can withstand against the lightning current value. If the disaster is a flood, the intensity of the disaster is the flood depth, and the design criteria is information indicating the design standard values that equipment can withstand against the flood depth. These equipment strength and design criteria are specific information that can determine whether or not equipment will lose its functionality due to a disaster. Installed capacity is the amount of power that can be supplied from equipment to consumers.

[0047] The equipment strength is information that indicates the relationship between the intensity of a disaster and the probability of equipment damage. For example, the equipment strength may be shown as in the graph in Figure 8. As shown in this graph, if there are three types of equipment, the equipment strength will differ for each piece of equipment even if the design standards for each are the same.

[0048] The graph in Figure 8 shows the relationship between the severity of a disaster and the probability of equipment damage, taking the case of an earthquake as an example, with the severity of the disaster on the horizontal axis being earthquake acceleration. The severity of the disaster on the horizontal axis of the graph in Figure 8 is, for example, wind speed if the disaster is a typhoon, lightning current value if the disaster is a lightning strike, or flood depth if the disaster is flooding. For other disasters, the horizontal axis can also be the severity of the disaster, and the vertical axis can be the probability of equipment damage.

[0049] Information on the hazards of various natural disasters and information on the annual exceedance frequency is stored in the disaster hazard database 9. This information includes hazard maps published by the national government, local governments, and other organizations.

[0050] Furthermore, the power outage risk assessment system 1 can extract necessary points from the hazard map stored in the disaster hazard database 9. For example, the disaster hazard database 9 stores a hazard management table (FIG. 9), information showing the relationship between earthquake acceleration and annual exceedance frequency (disaster hazard) as an example of disaster intensity (FIG. 10), and information showing the hazard map stored in the disaster hazard database 9 (FIG. 11).

[0051] The graph in Figure 10 shows the relationship between disaster intensity and annual exceedance frequency (disaster hazard) for an earthquake disaster, with the horizontal axis representing the intensity of the disaster as earthquake acceleration. The horizontal axis of the graph in Figure 10 represents the intensity of the disaster, for example, if the disaster is a typhoon, the value of the lightning current if the disaster is a lightning strike, or the depth of flood water if the disaster is flooding. For other disasters, the horizontal axis can also represent the intensity of the disaster, and the vertical axis can represent the annual exceedance frequency.

[0052] 9 shows an example of a hazard management table. Information about various hazards is registered in this hazard management table using a hazard ID as a primary key. For example, the hazard type, disaster hazard, and reference source are registered in association with the hazard ID.

[0053] Here, the hazard ID is identification information that can individually identify each type of hazard. The hazard type is information that indicates the type of hazard. The hazard details are detailed information about each type of hazard. The reference source is information that indicates the reference source from which information about the hazard was obtained.

[0054] Hazard details are information that shows the relationship between the intensity of a disaster and the annual exceedance frequency. For example, hazard details may be shown as in the graph in Figure 10. As shown in this graph, if there are three locations, the annual exceedance frequency for each location will be different.

[0055] The graph in Figure 10 shows the relationship between disaster intensity and annual exceedance frequency (disaster hazard) for an earthquake, with the horizontal axis representing the intensity of the disaster as earthquake acceleration. The horizontal axis of the graph in Figure 10 represents the intensity of the disaster, for example, if the disaster is a typhoon, the value of the lightning current if the disaster is a lightning strike, or the depth of flood water if the disaster is flooding. For other disasters, the horizontal axis should also represent the intensity of the disaster, and the vertical axis should represent the annual exceedance frequency.

[0056] The hazard details may also include a hazard detail ID, which is identification information that can individually identify each piece of data that records information about the hazard details. Based on this hazard detail ID, detailed hazard data stored in other areas of the disaster hazard database 9 can be read. For example, the hazard map in Figure 11 may be linked to the hazard management table.

[0057] The accident response and maintenance record database 10 stores information on past power system accidents and the recovery time required to respond to them, etc. For example, the accident response and maintenance record database 10 stores an accident response and maintenance record record table (FIG. 12).

[0058] FIG. 12 is an example of an accident response and maintenance performance record table. In this accident response and maintenance performance record table, various information is registered using the equipment ID as the primary key. For example, the equipment detail ID, equipment use, equipment name, accident details, maintenance date and time, required time, required personnel, equipment used, and base distance are registered in association with the equipment ID. Note that the accident response and maintenance performance record table allows for the same equipment to be managed collectively using the equipment ID.

[0059] Here, the accident details are the type of accident. The maintenance date and time are the date and time when maintenance was performed. The required time is the time required to respond to the accident or for maintenance. The required personnel are the number of personnel required to respond to the accident or for maintenance. The equipment used is the equipment required for responding to the accident or for maintenance. The base distance is the distance from the office that serves as the base for accident response or maintenance to the work site.

[0060] The material and resource database 11 stores information such as spare part inventory status and resource information for maintenance and restoration personnel. For example, the material and resource database 11 stores a material management table (FIG. 13) and a resource management table (FIG. 14).

[0061] 13 is an example of a materials management table. This materials management table registers information about various materials, using the equipment ID of the equipment that serves as the material as a primary key. For example, the equipment use, equipment name, storage quantity, storage location, base ID, and supplier are registered in association with the equipment ID.

[0062] 14 is an example of a resource management table. In this resource management table, information about the resources of maintenance and restoration personnel is registered, using the base ID as the primary key. For example, the personnel ID, the work in charge, and the equipment in charge are registered in association with the base ID.

[0063] Here, the storage quantity is the number of materials stored. The storage location is the storage location of the materials. The base ID is identification information that can individually identify an accident response or maintenance base. The supplier is the supplier of the materials. The personnel ID is identification information that can individually identify each personnel. The assigned work is the type of work that the personnel can be responsible for. The assigned equipment is the equipment that the personnel can be responsible for. For example, the equipment ID is registered in this assigned equipment item.

[0064] As shown in Fig. 2, the main control unit 2 comprehensively controls the power outage risk assessment system 1. This main control unit 2 includes a power outage probability assessment unit 12, a restoration time assessment unit 13, and a power outage risk assessment unit 14. These are realized by the CPU executing programs stored in the memory or HDD.

[0065] The power outage probability evaluation unit 12 includes an event tree creation unit 15 and a fault tree creation unit 16. The power outage probability evaluation unit 12 analyzes the power system using an event tree and evaluates the power outage probability of the power system.

[0066] The power outage probability evaluation unit 12 calculates the branching probability of the event tree based on at least the fault tree related to the equipment required for power supply. In this way, the branching probability of the event tree can be quantitatively calculated using the fault tree.

[0067] The devices in this embodiment include those installed by consumers who receive power supply. The power outage probability evaluation unit 12 calculates the branching probability of the event tree based on the function loss probability of the devices installed by the consumers. In this way, the power outage probability can be calculated from the function loss probability of the devices installed by the consumers, and the expected damage can be evaluated based on this.

[0068] The event tree creation unit 15 creates an event tree (FIG. 15) used to evaluate the probability of power outage in the power system. The fault tree creation unit 16 creates a fault tree (FIG. 16) used to calculate the branching probability of the event tree.

[0069] Fig. 15 is an example of an event tree created by the event tree creation unit 15. First, attention is paid to the headings (events that set branches) at the top of the event tree. For example, 13 headings are set, from event A to event M. Note that the item for disaster occurrence is set as the root event at the left end of the event tree.

[0070] The distribution substation item is set for Event A. The nearby power transmission equipment item is set for Event B. The branching from Event A to Event B is set to evaluate whether or not power will be supplied from the distribution substation to the area being evaluated due to a failure in the distribution substation or an inability to transmit power to the distribution substation.

[0071] For event C, the items for main system, fault removal, and relay operation are set. For event D, the items for main system, fault spread prevention, and relay operation are set. For event E, the items for main system, backup protection, and relay operation are set. For event F, the items for main system and reclosing are set. These branches from event C to event F are set to evaluate whether or not it is possible to prevent the spread of an accident that occurs in the main system.

[0072] For event G, an item for FCB tripping is set. For event H, an item for reclosing and timed sequential transmission is set. For event I, an item for determining the faulted section is set. For event J, an item for creating a reverse transmission procedure is set. For event K, an item for automatically executing the reverse transmission procedure is set. For event L, an item for automatic switch and on / off operation is set. These branches from event G to event L are set to evaluate whether the faulted section can be determined by the power distribution automation system and whether the blackout section can be minimized by reverse transmission.

[0073] A countermeasure equipment item is set for event M. This branch for event M is set to evaluate whether or not the supply of power can be continued by using some kind of power generation equipment or power storage system in an emergency when commercial power from the power company cannot be received.

[0074] In this way, the branches of the event tree in this embodiment are composed of four elements: distribution substations, main grids, distribution automation systems, and countermeasure facilities. Note that the branches of the event tree may be set based on other elements. Furthermore, it is also possible to extract only events related to some of the four countermeasure facilities exemplified here (for example, only the distribution automation system) and evaluate the probability of function loss of the relevant components.

[0075] In this embodiment, the configurations of the distribution substation, the main grid, the distribution automation system, and the countermeasure equipment are set in this order in the branches from the root side at the left end of the event tree to the consequence side at the right end. In this way, by setting the configuration of the countermeasure equipment that has the greatest impact on consumers at the consequence side in the branches of the event tree, it is possible to contribute to a more detailed consideration of the installation of the countermeasure equipment.

[0076] By setting the branches of the event tree based on the configuration of countermeasure equipment to continue power supply during a power outage, the risk of power outage can be evaluated taking into account the countermeasure equipment installed by consumers.

[0077] By setting the branches of the event tree based on the configuration of a distribution automation system that monitors the power distribution network of the power system or controls system switching, it is possible to evaluate the risk of power outages taking into account the distribution automation system.

[0078] By setting the branches of the event tree based on the configuration of the distribution substations in the power system, it is possible to evaluate the risk of power outages taking the distribution substations into consideration.

[0079] By setting the branches of the event tree based on the configuration of the main system of the power distribution network of the power system, it is possible to evaluate the risk of power outages taking the main system into consideration.

[0080] Next, we focus on the consequent state at the right end of the event tree. In this embodiment, 27 patterns of power outage modes, P1 to P27, are set as consequent states of the event tree. These power outage modes indicate the state of the power system that occurs during a power outage. Note that the power outage modes include not only the state during a power outage, but also the state after recovery from a power outage.

[0081] Pattern P1 is a power outage mode in which there is no long-term power outage. This pattern P1 indicates that the distribution automation system has successfully performed reclosing and timed sequential transmission, and power transmission has resumed.

[0082] Pattern P2 is a power outage mode in which the fault section loses power. Note that this power outage area excludes areas capable of independent operation, which are capable of operating independently without receiving power from the power grid. Pattern P2 indicates that power was successfully supplied by the countermeasure equipment in event M.

[0083] Pattern P3 is a power outage mode in which only the faulted section is powered down. This pattern P3 indicates that the faulted section is identified by the power distribution automation system, reverse transmission is successful, and only the faulted section is powered down.

[0084] Patterns P4, P6, and P8 are set to power outage modes in which the load side of the fault point is powered down. Note that these power outage areas exclude areas where independent operation is possible. These patterns P4, P6, and P8 indicate that the countermeasure equipment was successful in supplying power in event M.

[0085] Patterns P5, P7, and P9 are set to a power outage mode in which the load side of the fault point experiences a power outage. These patterns P5, P7, and P9 indicate that the fault section was identified by the automated power distribution system, but reverse transmission failed, resulting in a power outage on the load side of the fault point.

[0086] For patterns P10, P12, P14, P16, P18, P20, P22, P24, and P26, a power outage mode is set in which only areas where autonomous operation is possible avoid power outages. These patterns P10, P12, P14, P16, P18, P20, P22, P24, and P26 indicate that the countermeasure equipment successfully supplied power during event M.

[0087] Patterns P11 and P13 are set to a power outage mode in which the entire feeder is powered down. These patterns P11 and P13 indicate that the entire target feeder is powered down due to failure to trip the FCB or failure to identify the fault section.

[0088] A power outage mode in which a wide area is affected is set for patterns P15, P19, P23, P25, and P27. These patterns P15, P19, P23, P25, and P27 indicate that a wide area connected to the main grid is affected by a power outage due to a failure in the main grid.

[0089] Patterns P17 and P21 are set to power outage modes in which a wide area below the distribution substation experiences a power outage. These patterns P17 and P21 indicate that the effects of an accident in the trunk grid spread to areas below the distribution substation, causing a power outage in a wide area below the distribution substation.

[0090] The power outage modes for patterns P2, P4, P6, P8, P10, P12, P14, P16, P18, P20, P22, P24, and P26 are the power outage modes when the power supply by the countermeasure equipment fails due to event M, minus the amount of power supplied by the countermeasure equipment.

[0091] In the event tree of this embodiment, the order of branches may be changed as necessary, and branches may be added or deleted.

[0092] The event tree creation unit 15 creates an event tree for the hazard to be evaluated from the system configuration to be evaluated stored in the system configuration database 7. Then, the power outage risk assessment unit 14 quantitatively evaluates the impact on the power system when the target hazard occurs at an occurrence frequency (annual exceedance frequency).

[0093] The branching probability of the event tree can be determined using the fault tree generated by the fault tree creation unit 16, or using one stored in advance in the equipment database 8. As a result of analyzing this event tree, the probability of power outage for each power outage mode that occurs due to differences in the progression of events in the event tree can be obtained.

[0094] 16 is an example of a fault tree created by the fault tree creation unit 16. In the fault tree of this embodiment, events that occur in equipment (substations, power transmission lines) are registered as lower-level items. Events include, for example, equipment failure (trouble), equipment shutdown, and equipment inspection. These lower-level items are associated with logic gates (AND gates, OR gates) to build a fault tree.

[0095] In addition, events that occur in relation to the occurrence of events in lower-level items are registered in the middle-level items in the fault tree, and events that occur in relation to the occurrence of events in middle-level items are registered in the upper-level items in the fault tree.

[0096] The fault tree is used to determine whether the occurrence of an event in a lower-level item will cause an event (fault mode) in a higher-level item. Alternatively, it is used to calculate the probability of an event in a higher-level item occurring. In this embodiment, the fault tree determination result includes the probability of equipment function loss. In this way, it is possible to perform a power outage risk assessment that includes the probability of function loss.

[0097] As shown in Fig. 2, the fault tree creation unit 16 creates a fault tree that takes into consideration the system configuration, system equipment configuration, and connection status, which are the targets for evaluating power outage risk, using the system configuration database 7, equipment database 8, and disaster hazard database 9. By inputting equipment resistance and disaster hazard into this fault tree, the equipment failure probability can be calculated.

[0098] In this embodiment, a power outage mode corresponding to the state of the power system that occurs during a power outage is set as a consequence state of the event tree. The power outage probability evaluation unit 12 can evaluate the power outage risk corresponding to various patterns of power outages by calculating the power outage probability of each power outage mode.

[0099] The restoration time evaluation unit 13 includes a target operation specification unit 17 and a restoration time calculation unit 18. The restoration time evaluation unit 13 evaluates the restoration time from a power outage in the power system. In this way, it is possible to evaluate restoration times corresponding to various patterns of power outages.

[0100] The target work identification unit 17 identifies the target work required to restore power in accordance with the power outage mode. The work required for restoration differs depending on the power outage mode. Therefore, the power outage mode is determined using the event tree created by the event tree creation unit 15. Then, the target work corresponding to the power outage mode is identified by referring to past cases in the accident response and maintenance performance database 10.

[0101] The restoration time calculation unit 18 calculates the time required for restoration based on the work identified by the target work identification unit 17. For example, it refers to the geographical distance of the system stored in the system configuration database 7, or to past accident response or maintenance performance values stored in the accident response and maintenance performance database 10, or to the inventory status of spare parts or resource information on maintenance and restoration personnel stored in the material and resource database 11. It calculates the time required for restoration by referring to this information.

[0102] The power outage risk assessment unit 14 includes a power outage risk curve creation unit 19 and a damage calculation unit 20. The power outage risk assessment unit 14 assesses the power outage risk of the power system based on the power outage probability determined by analysis using an event tree. This can contribute to the consideration of rational measures to reduce the power outage risk.

[0103] The power outage risk curve creation unit 19 creates a power outage risk curve. For example, it references the number of consumers (consumer IDs), contracted power capacity, normal power usage, and emergency power demand stored in the system configuration database 7. It references the power outage probability for each power outage mode calculated by the power outage probability evaluation unit 12. It also calculates the predetermined total power outage scale by summing the values obtained by multiplying the power outage probability by the restoration time calculated by the restoration time evaluation unit 13 and the number of consumers. Then, the annual exceedance frequency of the predetermined total power outage scale is obtained from the occurrence frequency (annual exceedance frequency) of the assumed hazard. A comprehensive power outage risk curve is created by referring to this information. Note that a comprehensive power outage risk curve may be created by assuming not only hazards with multiple annual exceedance frequencies, but also other types of natural disasters. The number of consumers may be replaced with the contracted power capacity or normal power usage to calculate the total power outage scale.

[0104] The damage calculation unit 20 calculates the amount of damage by multiplying the total power outage scale of the power outage risk curve created by the power outage risk curve creation unit 19 by the damage to be evaluated.

[0105] For example, when assessing damage to customers, the amount of damage to customers caused by the power outage can be calculated by multiplying the total scale of the power outage by the amount of direct or indirect damage per kWh calculated from external data such as statistical data or willingness to pay, depending on the customer's industry or business type.

[0106] In addition, when assessing damages suffered by businesses, the amount of loss in electricity revenues of power companies due to power outages and the annual frequency of such losses can be obtained by multiplying the total scale of power outages by the average electricity rate per kWh in the area being assessed.

[0107] In addition, by multiplying the hourly cost of business losses incurred by customers due to power outages by the expected hourly cost, it is possible to obtain the customer's losses due to power outages and the annual frequency of excess.

[0108] Figure 17 is an example of a power outage risk curve. As shown in this power outage risk curve, the curve for when customers do not have countermeasure equipment is depicted as exceeding the curve for when customers have countermeasure equipment. For example, when comparing the two at the point where the annual exceedance frequency is 0.01, when customers do not have countermeasure equipment, the total power outage scale is approximately 3,000. In contrast, when customers have countermeasure equipment, it is only approximately 2,000. In other words, it was evaluated that the countermeasure equipment can reduce the scale of power outages. The damage calculation unit 20 can convert the total power outage scale into a monetary value and compare the estimated damage amounts before and after the installation of countermeasure equipment.

[0109] It is necessary to collect and analyze various information and calculate the probability of power outages before calculating the estimated damage amount before and after the installation of countermeasure equipment.However, it is also possible to start the evaluation from the time a power outage occurs and confirm the estimated damage amount and the return on investment of countermeasure equipment.

[0110] For example, power outage duration can be assumed to be one hour, five hours, 24 hours, etc. In this case, the total power outage scale and estimated damage amount can be calculated as the minimum necessary evaluation of the failure probability of countermeasure equipment. In addition, by presenting a menu of additional countermeasures to customers and allowing them to select, it can be added to the existing evaluation process and the total power outage scale can be calculated.

[0111] It is necessary to create two types of event trees: one for when the consumer does not have countermeasure equipment and one for when it does. Here, some of the multiple branch probabilities set in the event tree can be set to 1 by accepting user input. For example, if there is no countermeasure equipment to continue the power supply during a power outage, the corresponding branch probability is set to 1, meaning that the equipment will definitely fail. On the other hand, if there is countermeasure equipment, the corresponding branch probability is set to an appropriate value. In this way, one event tree can be used by switching between the cases where there is no countermeasure equipment and the case where there is.

[0112] Figure 18 is an example of an additional countermeasure menu presentation. The customer ID, countermeasure equipment, countermeasure equipment capacity, and additional countermeasure menu are presented. Here, the additional countermeasure menu shows emergency diesel generators, hydrogen power generation, solar power generation, and storage batteries. This additional countermeasure menu automatically extracts equipment that can be used as countermeasure equipment from the equipment information stored in the equipment database 8. An event tree and fault tree are created using the equipment strength information linked to the equipment ID, and finally a power outage risk curve is created.

[0113] Furthermore, when considering an actual disaster, it is possible that the demand for electricity will differ from normal. For example, if a factory is affected by a disaster, operations will be halted. As a result, the factory's demand for electricity will drop significantly. An assessment that takes into account such changes in demand for electricity during a disaster is also required.

[0114] Figure 19 shows an example of the recovery of power demand after a disaster. The solid line shows a sudden drop in power demand followed by recovery over time. By changing the power demand value using the emergency power demand value stored in the system configuration database 7 or an arbitrarily set disaster impact, it is possible to evaluate the effectiveness of countermeasure equipment at a specified time.

[0115] Next, the power outage risk assessment method of this embodiment will be described using the flowchart of Figure 20. Note that the above-mentioned drawings will be referenced as appropriate. The following steps are at least some of the steps included in the power outage risk assessment method, and other steps may also be included in the power outage risk assessment method.

[0116] First, in step S1, the power outage probability evaluation unit 12 determines the evaluation range for power outage risk evaluation. The user specifies the evaluation range by inputting information. Based on this specification, the power outage probability evaluation unit 12 determines the evaluation range.

[0117] In the next step S2, the event tree creation unit 15 and the fault tree creation unit 16 of the power outage probability evaluation unit 12 create an event tree and a fault tree based on the system configuration of the evaluation target stored in the system configuration database 7. For example, for equipment failures, a fault tree is created as needed from the equipment data stored in the equipment database 8, and the failure probability is calculated. Note that the failure probability of some equipment may be determined by user input operations without using a fault tree.

[0118] In the next step S3 , the power outage probability evaluation unit 12 inputs the failure probability calculated by the fault tree created by the fault tree creation unit 16 into the event tree created by the event tree creation unit 15 .

[0119] In the next step S4, the power outage probability evaluation unit 12 analyzes the event tree to obtain the probability of a power outage mode as a consequent state of the event tree. That is, the power outage probability evaluation unit 12 analyzes the power system using the event tree and evaluates the power outage probability of the power system.

[0120] In the next step S5, the target task specifying unit 17 of the restoration time evaluation unit 13 specifies a target task required for restoration from the power outage in accordance with the power outage mode.

[0121] In the next step S6, the recovery time calculation unit 18 of the recovery time evaluation unit 13 calculates the time required for recovery based on the work identified by the target work identification unit 17.

[0122] In the next step S7, the power outage risk curve creation unit 19 of the power outage risk assessment unit 14 creates a power outage risk curve and calculates a predetermined total power outage scale.

[0123] In the next step S8, the damage calculation unit 20 of the power outage risk assessment unit 14 calculates the amount of damage by multiplying the damage to be assessed by the total power outage scale of the power outage risk curve created by the power outage risk curve creation unit 19. In other words, the power outage risk assessment unit 14 assesses the power outage risk of the power system based on the power outage probability calculated by the event tree.

[0124] In the next step S9, the output unit 4 outputs the evaluation result, and the power outage risk evaluation method is then terminated.

[0125] In the flowcharts of the above-described embodiments, steps are executed serially, but the order of steps is not necessarily fixed, and some steps may be executed in reverse order. Also, some steps may be executed in parallel with other steps.

[0126] The system of the above-described embodiment includes a control device with a highly integrated processor such as a dedicated chip, FPGA (Field Programmable Gate Array), GPU (Graphics Processing Unit), or CPU (Central Processing Unit), a storage device such as ROM (Read Only Memory) or RAM (Random Access Memory), an external storage device such as HDD (Hard Disk Drive) or SSD (Solid State Drive), a display device such as a monitor, an input device such as a mouse or keyboard, and a communication interface. This system can be realized with a hardware configuration using a normal computer.

[0127] The programs executed by the systems of the above-described embodiments are provided in advance in a ROM, etc. Alternatively, the programs may be provided in the form of installable or executable files stored on a computer-readable, non-transitory storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD).

[0128] The programs executed by this system may be stored on a computer connected to a network such as the Internet and provided by downloading them via the network. This system may also be configured by combining separate modules that independently perform the functions of the components and interconnect them via a network or dedicated lines.

[0129] Although the above embodiment illustrates a case where a power outage occurs due to an accident in the power distribution system of the power system, other cases are also possible. For example, the risk of a power outage caused by an accident in a higher-level system of the power system may be evaluated.

[0130] According to the embodiment described above, the power outage probability evaluation unit 12 that analyzes the power system using an event tree and evaluates the power outage probability of the power system is provided, which contributes to the consideration of rational measures to reduce the risk of power outages. Furthermore, it is possible to quantitatively calculate not only the failure probability of the components of the power system but also the probability of their function being lost, and evaluate the risk of power outages. It is also possible to evaluate the return on investment or validity of countermeasure equipment that consumers introduce to avoid damage caused by their own power outages.

[0131] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and modifications thereof are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0132] 1...power outage risk assessment system, 2...main control unit, 3...input unit, 4...output unit, 5...memory unit, 6...communication unit, 7...system configuration database, 8...equipment database, 9...disaster hazard database, 10...accident response and maintenance performance database, 11...materials and resource database, 12...power outage probability assessment unit, 13...restoration time assessment unit, 14...power outage risk assessment unit, 15...event tree creation unit, 16...fault tree creation unit, 17...target work identification unit, 18...restoration time calculation unit, 19...power outage risk curve creation unit, 20...damage calculation unit.

Claims

1. a system configuration database that stores information indicating the configuration or connection status of the power system; a disaster hazard database that stores information about natural disaster hazards and information about annual exceedance frequencies; an event tree creation unit that creates an event tree used to evaluate the power outage probability of the power system for a hazard to be evaluated from the information stored in the system configuration database; a fault tree creation unit that uses the disaster hazard database to create a fault tree used to calculate the branching probability of the event tree; a power outage probability evaluation unit that analyzes the power system using the event tree and evaluates the power outage probability of the power system; a power outage risk assessment unit that assesses a power outage risk of the power system based on the power outage probability; Equipped with Power outage risk assessment system.

2. The branches of the event tree are set based on the configuration of countermeasure facilities for continuing the supply of power during a power outage. The power outage risk assessment system according to claim 1 .

3. The branches of the event tree are set based on a configuration of a distribution automation system that monitors the power system or controls system switching. The power outage risk assessment system according to claim 1 or 2.

4. the branches of the event tree are set based on a configuration of distribution substations in the power system; The power outage risk assessment system according to any one of claims 1 to 3.

5. The branching of the event tree is set based on a configuration of a main grid of the power system. The power outage risk assessment system according to any one of claims 1 to 4.

6. a power outage mode corresponding to a state of the power system that occurs during a power outage is set as a consequent state of the event tree; The power outage probability evaluation unit calculates the power outage probability for each of the power outage modes. The power outage risk assessment system according to any one of claims 1 to 5.

7. a recovery time evaluation unit that identifies a target task required to restore power in accordance with the power outage mode and evaluates a recovery time from the power outage of the power system; The power outage risk assessment system according to claim 6.

8. The power outage probability evaluation unit calculates the branch probability of the event tree based on the fault tree related to at least equipment required for power supply, The power outage risk assessment system according to any one of claims 1 to 7.

9. The equipment includes equipment installed by a consumer receiving power supply, The power outage probability evaluation unit calculates the branch probability of the event tree based on a function loss probability of the equipment installed by the consumer. The power outage risk assessment system according to claim 8.

10. a database in which specific information is stored that can identify whether or not the function of the device will be lost due to a disaster by associating the device with an individually identifiable device ID; The power outage risk assessment system according to claim 8 or claim 9.

11. a step of storing information indicating a configuration or connection status of the power system in a power system configuration database; a disaster hazard database storing information about natural disaster hazards and information about annual exceedance frequencies; an event tree creation unit creating an event tree to be used for evaluating the probability of power outage in the power system for a hazard to be evaluated from information stored in the system configuration database; a step in which a fault tree creation unit uses the disaster hazard database to create a fault tree to be used for calculating the branching probability of the event tree; A power outage probability evaluation unit analyzes the power system using the event tree and evaluates the power outage probability of the power system; A step in which a power outage risk assessment unit assesses a power outage risk of the power system based on the power outage probability; Including, Power outage risk assessment methodology.

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