System management device, system management method, and program

Abstract

To minimize a secured capacity of a GFM for providing a control amount and pseudo inertia by selecting and controlling an inverter power supply effective for improving system stability for each assumed system disturbance, and to reduce a calculation load for narrowing down the inverter power supply of a control candidate.SOLUTION: A system management device includes: an identification unit that identifies a power system in a supply area that is an outflow side of a power flow and a consumption area that is an inflow side of the power flow from the point of origin of disturbance based on power flow information; and a control unit for performing control so as to effectively increase an entire capacity of a GFM inverter power supply in the supply area when or before the disturbance occurs.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a system management device, a system management method, and a program.

Background Art

[0002] In recent years, the introduction of inverter power sources connected to the power grid through power conversion devices (inverter converters) such as solar power generation devices and storage batteries has been progressing.

[0003] A conventional Grid-Following (GFL) inverter power source as an inverter power source is controlled to follow a system mainly composed of synchronous generators and does not have inertia or synchronization power. Therefore, in a system where inverter power sources are the main power sources, there are concerns about a decrease in stability against system accidents and the like.

[0004] As a countermeasure, a Grid-Forming (GFM) inverter power source that mainly constitutes the system is expected. Furthermore, technological development is being carried out so that the same inverter power source can perform switching control between GFL and GFM.

[0005] On the other hand, in order for GFM to supply inertia, it is necessary to secure the charge-discharge capacity in the storage battery and suppress the output in the renewable energy power source. These lead to losses in charge-discharge and power generation output opportunities, which is a burden on the operator of the inverter power source. From the perspective of system stability, it is desirable to effectively select the control target so as to minimize the capacity for switching to GFM and minimize the above burden on the operator.

[0006] The technology described in Patent Document 1 proposes a method for determining the stability of a power system, calculating the necessary inertia and synchronization forces, and assigning them to a PCS (Power Conditioning Subsystem) with a pseudo-inertia function. This is performed for each branch of the power system, and pseudo-inertia is assigned until all faults converge to a stable state. By combining this with stability calculations, it is possible to output the minimum necessary pseudo-inertia to the PCS (Power Conditioning Subsystem).

[0007] In this case, the PCS to be allocated was determined solely based on whether or not it could output inertia from the predicted output of renewable energy sources. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-188595 [Overview of the project] [Problems that the invention aims to solve]

[0009] However, the target to which pseudo-inertia is effective in improving transient stability differs depending on the fault point, and depending on the arrangement of the fault point and the target PCS, the allocation of pseudo-inertia may increase the phase difference angle of the synchronous generator, leading to instability. As a result, there was a risk that the required pseudo-inertia was being overcalculated.

[0010] Furthermore, attempting to determine which PCS to stabilize by brute-force searching for all PCS to which pseudo-inertia should be assigned would increase the total number of PCS, potentially increasing the computational load.

[0011] The present invention has been made in view of the above, and provides a grid management device, grid management method, and program that, for each anticipated grid disturbance, selects and controls an inverter power supply that is effective in improving grid stability, thereby minimizing the required capacity of the GFM that provides the control amount and pseudo-inertia, and also reducing the computational load for narrowing down the candidate inverter power supplies for control. [Means for solving the problem]

[0012] The system management device of the embodiment includes an identification unit that identifies the power system as a supply area, which is the outflow side of the power flow, and a consumption area, which is the inflow side of the power flow, based on power flow information, and a control unit that controls the system to effectively increase the total capacity of the GFM inverter power supply in the supply area when the disturbance occurs. The identification unit, as the tidal current information, pre-divides the entire system into multiple areas and uses tidal current measurement values ​​from branches that represent the tidal currents between each area. . [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic block diagram of the system management device according to the first embodiment. [Figure 2] Figure 2 is an explanatory diagram illustrating an example of the general configuration of the systems managed by the system management device. [Figure 3] Figure 3 is an explanatory diagram of the first configuration example of an inverter power supply. [Figure 4] Figure 4 is an explanatory diagram of a second example configuration of the inverter power supply. [Figure 5] Figure 5 is an explanatory diagram of an example of an operation process flowchart in the first embodiment. [Figure 6] Figure 6 is a schematic block diagram of the system management device according to the second embodiment. [Figure 7] Figure 7 is a flowchart of the process for creating a control target list in the second embodiment. [Figure 8] Figure 8 is an explanatory diagram of an example of an operation process flowchart in the second embodiment. [Figure 9] Figure 9 is a block diagram illustrating the schematic configuration of the system management system according to the third embodiment. [Modes for carrying out the invention]

[0014] [1] First Embodiment Figure 1 is a schematic block diagram of the system management device according to the first embodiment. The system management device 10 includes a threshold setting unit 11 that sets criteria for determining system stability, a calculation unit 12 that performs power flow calculation and dynamic characteristic analysis, a control target selection unit 13 that selects and stores a control target machine from the inverter power supplies constituting the inverter power supply group 16, and a control unit 14 that outputs a control command to the selected control target machine.

[0015] In the above configuration, the system management device 10 functions as a system control device. Each inverter power supply constituting the inverter power supply group 16 is composed of a power supply and a power conversion device. Here, the power supply is composed of a renewable energy power supply such as a solar power generation facility or a wind power generation facility, or a power storage facility such as a storage battery or an EV.

[0016] The renewable energy power supply generates DC power and supplies it to the power conversion device. Also, the power storage facility supplies the stored power to the power conversion device. Furthermore, the power conversion device supplies the supplied power to the system as AC power having an arbitrary voltage and frequency within a range acceptable for system operation.

[0017] The system management device 10 can be configured as a single device or as separate devices for each function. It can also be configured as a monitoring and control system for a backbone system scale or as a system that monitors and controls a part of the power transmission and distribution system like an EMS (Energy Management System) in a microgrid. Also, instead of the calculation unit 12, it is possible to configure it as a calculation result input unit (calculation result input interface unit) that inputs the result calculated by an external device.

[0018] Figure 2 is an explanatory diagram of a schematic configuration example of a system that is the management target of the system management device. In Figure 2, the system 20 to be managed includes synchronous generators 21a and 21b, inverter power supplies 22a to 22c that constitute the inverter power supply group 16, step-up transformers 23a to 23b, step-up transformers 24a to 24c, nodes 25a to 25c, and branches 26a to 26c.

[0019] In the above configuration, the synchronous generator 21a is connected to node 25a via a step-up transformer 23a, and the power generated by the synchronous generator 21a is boosted and supplied to node 25a. Furthermore, the synchronous generator 21b is connected to node 25c via a step-up transformer 23b, and the power generated by the synchronous generator 21b is boosted and supplied to node 25c. The above description assumes that the synchronous generator is connected to the node with a single step-up transformer, but the voltage may be changed in stages using multiple transformers.

[0020] Here, we will explain the configuration of an inverter power supply. The inverter power supply 22a is connected to node 25a via a step-up transformer 24a, and the power supplied by the inverter power supply 22a is boosted and supplied to node 25a. The inverter power supply 22b is connected to node 25b via a step-up transformer 24b, and the power supplied by the inverter power supply 22b is boosted and supplied to node 25b. The inverter power supply 22c is connected to node 25c via a step-up transformer 24c, and the power supplied by the inverter power supply 22c is boosted and supplied to node 25c. In this case as well, although the description states that the inverter power supply is connected to the node with a single step-up transformer, the voltage may also be changed in stages using multiple transformers.

[0021] Here, we will explain inverter power supplies in more detail. Figure 3 is an explanatory diagram of the first configuration example of an inverter power supply. Figure 3 shows an example where the inverter power supply 22a is configured as a switchable inverter power supply that has both GFL control and GFM control functions and can switch between them. The control target selection unit 13 of the system management device 10 identifies whether, when a disturbance occurs, each inverter power supply is located on the supply area side, which is the outflow side of the tidal flow relative to the disturbance point, or on the consumption area side, which is the inflow side of the tidal flow relative to the disturbance point.

[0022] Then, based on the identification result, if the inverter power supply of the first configuration example, which is located on the supply area side and operating with GFL control, is identified as the target of control, the switchable inverter power supply will be switched to GFM control. Furthermore, inverter power supplies located on the consumption area side, which is the inflow side of the power flow, will not be subject to control.

[0023] Figure 4 is an explanatory diagram of a second example configuration of the inverter power supply. In Figure 4, the inverter power supply 22b is configured to include a first inverter power supply 22b-1, a second inverter power supply 22b-2, and a contactor 22b-3.

[0024] In this case, a second inverter power supply 22b-2, controlled by GFM, is connected in parallel to the first inverter power supply 22b-1, which is controlled by GFL control or GFM control, via a contactor 22b-3 in a disconnected state. Note that the parallel disconnection of the second inverter power supply 22b-2 is not limited to the contactor 22b-3; configurations using the gate control of circuit breakers or power converters are also conceivable.

[0025] In the example shown in Figure 4, the inverter power supply 22b is configured such that one GFM-controlled second inverter power supply 22b-2 is connected in parallel to the first inverter power supply 22b-1, which is GFL-controlled or GFM-controlled. However, it is also possible to configure the system to have multiple second inverter power supplies 22b-2. Furthermore, a configuration in which the first inverter power supply 22b-1 and the second inverter power supply 22b-2 are each connected to a node is also conceivable.

[0026] When the inverter power supply in the second configuration example becomes the control target, the control unit 14 of the grid management device 10 connects the GFM-controlled second inverter power supply 22b-2 in parallel to the grid. Specifically, in the example shown in Figure 4, when the inverter power supply 22b becomes the control target, the control unit 14 of the system management device 10 controls the contactor 22b-3 to be closed and controls the GFM-controlled second inverter power supply 22b-2, which is provided in a disconnected state, to be connected in parallel.

[0027] Let's return to Figure 2 and explain it again. Nodes 25a and 25b are connected by branch 26b, and node 25a is further connected to other branches by branch 26a. Nodes 25b and 25c are connected by branch 26c.

[0028] In this case, the tidal current is assumed to be flowing, for example, from node 25a towards nodes 25b and 25c. Furthermore, the system management device 10 is configured to control each inverter power supply 22a to 22c.

[0029] Next, the operation of the first embodiment will be described. Figure 5 is an explanatory diagram of an example of an operation process flowchart in the first embodiment. First, the threshold setting unit 11 of the system management device 10 sets acceptable threshold values ​​for system values ​​such as phase difference angle, voltage, and frequency of the synchronous generators for each synchronous generator 21a, 21b or node 25a~25c, branch 26a~26c (step S11).

[0030] The calculation unit 12 of the system management device 10 performs power flow calculations and calculates and stores the power flow and voltage phase angle of each branch (step S12). The calculation unit 12 performs dynamic characteristic analysis for each assumed disturbance, such as a system fault (step S13).

[0031] Next, the calculation unit 12 determines whether there was an unstable response, such as deviating from the acceptable threshold set by the threshold setting unit 11 or the synchronous generator losing synchronism (step S14). In this case, if a disturbance that deviates from the acceptable threshold is detected through analysis, it will be treated as the occurrence of a disturbance.

[0032] In the determination in step S14, if the acceptable threshold set by the threshold setting unit 11 is not deviated and no unstable response such as the synchronous generator losing synchronism occurs (step S14; No), then the dynamic characteristics analysis for the next disturbance is performed.

[0033] In the determination in step S14, if there is a disturbance that deviates from the acceptable threshold set by the threshold setting unit 11, or causes an unstable response such as the synchronous generator losing synchronism (step S14; Yes), it is set as a countermeasure event. For disturbances set as countermeasure events, the power flow direction or voltage phase angle is referenced from the power flow calculation results in the calculation unit 12, and the control target selection unit 13 sets the inverter power supply on the power flow supply side from the disturbance occurrence point as a control candidate (step S15).

[0034] For example, if the disturbance originates at branch 26b, the inverter power supply 22a, which is on the power supply side of the current flow relative to the disturbance origin, will be set as the control candidate. Next, the target machine that will actually output control commands is selected from among the candidate control machines (step S16).

[0035] In this case, the selection criteria are the inverter power supply near the node where the system value deviates most significantly from the acceptable threshold, but other options include the inverter power supply immediately adjacent to the disturbance source or the terminal inverter power supply.

[0036] The system is simulated assuming that the selected inverter power supply is controlled (for example, that a switchable inverter power supply has been switched to GFM control), and the dynamic characteristics analysis of the countermeasure event is performed again (step S17).

[0037] Next, the calculation unit 12 determines whether or not an unstable response occurs, such as deviating from the acceptable threshold set by the threshold setting unit 11, or the synchronous generator losing synchronism (step S18).

[0038] In the determination in step S18, if there is an unstable response such as deviating from the acceptable threshold set by the threshold setting unit 11 or the synchronous generator losing synchronism (step S18; Yes), that is, if the system still does not converge stably during the countermeasure event, the process returns to step S16, the next target machine is selected from the control candidate machines, and the above-described process is repeated.

[0039] In the judgment in step S18, if the system converges stably, the dynamic characteristics analysis for each disturbance is performed again while maintaining the controlled state of the simulated inverter power supply, and the above-described processing is carried out. If the acceptable threshold is not exceeded for all disturbances and no unstable response occurs, such as the synchronous generator losing synchronism, a control command is output from the control unit 14 to the inverter power supply set for the controlled machine (step S19), and the process is terminated. The above-described process is performed periodically to ensure stable operation of the system at all times.

[0040] Now, let's explain the operation in more detail. As mentioned above, the current is flowing from node 25a towards nodes 25b and 25c. For example, suppose that in step S13, a dynamic characteristics analysis was performed for a short-circuit fault at branch 26c, and the frequency and voltage at nodes 25a and 25b deviated from the acceptable thresholds set in step S11.

[0041] As a result, the control target selection unit of the system management device 10 functions as an identification unit and, when a disturbance occurs, identifies whether each inverter power supply is located on the supply area side, which is the outflow side of the tidal flow relative to the disturbance point, or on the consumption area side, which is the inflow side of the tidal flow relative to the disturbance point. Then, an inverter power supply located on the supply area side is set as the control candidate, and either the inverter power supply of the first configuration example or the inverter power supply of the second configuration example described above is set as the control candidate.

[0042] More specifically, since the power flow at branch 26c, the disturbance point (fault point), flows from node 25b to node 25c, in step S15, the inverter power supplies 22a and 22b, which are on the power supply side relative to the disturbance point, are set as control candidate units.

[0043] In step S16, if node 25a is the node where the frequency fluctuation is simulated to be the largest, the inverter power supply 22a connected to node 25a is set as the control target.

[0044] In step S17, the dynamic characteristics are simulated again when the control circuit is switched to a GFM or when a GFM power supply is connected in parallel to the grid. If the grid values ​​such as frequency and voltage fall within the acceptable thresholds for all branches, the dynamic characteristics analysis for all disturbances is performed again in step S13.

[0045] Then, when the system values ​​for all disturbances fall within the acceptable threshold, a control command is output to the inverter power supply 22a set for the controlled machine. Here, the condition for outputting the control command is that all disturbances converge stably, but it is also possible to set a threshold for the number of disturbances, output a control command when a certain number of disturbances or more converge stably, and consider stabilization control for the remaining disturbances through other measures.

[0046] Incidentally, in power grids where inverter power supplies have become the main force, stability against disturbances such as grid faults has decreased, and as a countermeasure, inverter power supplies with pseudo-inertia have been developed. However, if only the total amount of grid inertia is considered and inverter power supplies with inertia are installed, it may actually worsen grid stability or lead to the securing of excessive inertia.

[0047] In contrast, by applying the same method as in the first embodiment, the arrangement of inertia can be optimized, and system stability can be improved with the minimum amount of control and inertia required.

[0048] [2] Second embodiment Figure 6 is a schematic block diagram of the system management device according to the second embodiment. In Figure 6, the same reference numerals are used for parts that are the same as those in the first embodiment of Figure 1.

[0049] The grid management device 10A includes a threshold setting unit 11 for setting criteria for determining grid stability, a calculation unit 12A for performing power flow calculations and dynamic characteristic analysis, a control target selection unit 13 for selecting and storing control target units from among the inverter power supplies constituting the inverter power supply group 16, and a control unit 14 for outputting control commands to the selected control target units.

[0050] In the second embodiment, the basic configuration is the same as in the first embodiment, but multiple substations and switching stations are installed, with tidal current monitoring terminals 17-1 to 17-n (where n is a natural number of 2 or more) for monitoring tidal currents and disturbance detection terminals 18-1 to 18-m (where m is a natural number of 2 or more) for detecting disturbance location and disturbance content.

[0051] The tidal current monitoring terminals 17-1 to 17-n communicate with the control target selection unit 13, and the disturbance detection terminals 18-1 to 18-m communicate with the control unit 14.

[0052] In this case, the tidal current monitoring terminals 17-1 to 17-n and the disturbance detection terminals 18-1 to 18-m may have both functions in a single device, and the functions described in the system management device 10A may also be provided on the terminal side.

[0053] Figure 7 is a flowchart of the process for creating a control target list in the second embodiment. Figure 8 is an explanatory diagram of an example of an operation process flowchart in the second embodiment.

[0054] First, the threshold setting unit 11 of the system management device 10A sets acceptable threshold values ​​for system values ​​such as phase difference angle, voltage, and frequency of the synchronous generators for each synchronous generator 21a, 21b or node 25a~25c, branch 26a~26c (step S11).

[0055] The power flow monitoring terminals 17-1 to 17-n measure the power flow and voltage phase angle of each branch and periodically transmit this information to the system management device 10A (step S12A). The calculation unit 12A performs dynamic characteristic analysis for various assumed disturbances, such as system faults (step S13).

[0056] Next, the calculation unit 12A determines whether there was an unstable response, such as deviating from the acceptable threshold set by the threshold setting unit 11 or the synchronous generator losing synchronism (step S14).

[0057] In the determination in step S14, if the acceptable threshold set by the threshold setting unit 11 is not deviated and no unstable response such as the synchronous generator losing synchronism occurs (step S14; No), then the dynamic characteristics analysis for the next disturbance is performed.

[0058] In the determination in step S14, if the response deviates from the acceptable threshold set by the threshold setting unit 11, or if an unstable response occurs such as the synchronous generator losing synchronism (step S14; Yes), it is set as a countermeasure event. In the disturbance set as a countermeasure event, the control target selection unit 13 refers to the current direction or voltage phase angle from the current information measured by the current monitoring terminals 17-1 to 17-n, and sets the inverter power supply on the current supply side relative to the disturbance occurrence point as a control candidate (step S15).

[0059] For example, if the disturbance originates at branch 25b, the inverter power supply 22a, which is on the power supply side of the current flow relative to the disturbance origin, will be set as the control candidate. Next, the control unit 14 selects a target machine from the control candidate machines to which it will actually output a control command, adds it to the control target list, and updates the control target list. Furthermore, it removes the inverter power supply from the control candidate machines (step S16A).

[0060] In this case, the selection criteria are the inverter power supply near the node where the system value deviates most significantly from the acceptable threshold, but other options include the inverter power supply immediately adjacent to the disturbance source or the terminal inverter power supply.

[0061] The system is simulated assuming that the selected inverter power supply is controlled (for example, that a switchable inverter power supply has been switched to GFM control), and the dynamic characteristics analysis of the countermeasure event is performed again (step S17).

[0062] Next, the calculation unit 12 determines whether or not an unstable response occurs, such as deviating from the acceptable threshold set by the threshold setting unit 11, or the synchronous generator losing synchronism (step S18).

[0063] In the determination in step S18, if an unstable response occurs, such as deviating from the acceptable threshold set by the threshold setting unit 11 or the synchronous generator losing synchronism (step S18; Yes), that is, if the system still does not converge stably during the countermeasure event, the process returns to step S16A, the next target machine is selected from the control candidate machines, and the above-described process is repeated.

[0064] In the judgment in step S18, if a stable convergence is achieved, the dynamic characteristic analysis for each disturbance is performed again while retaining the controlled state of the simulated inverter power supply, and the above-described processing is carried out. If the acceptable threshold is not exceeded for all disturbances and no unstable response occurs, such as the synchronous generator losing synchronism, the process of updating the control target list is terminated. The process described above is performed periodically, ensuring that the list of controlled items is always updated to the latest state.

[0065] In parallel with the above processing, the control unit 14 communicates with the disturbance detection terminals 18-1 to 18-m to determine whether any of the disturbance detection terminals 18-1 to 18-m has detected that a system disturbance event X has occurred at any point in the system (step S21). In the determination in step S21, if none of the disturbance detection terminals 18-1 to 18-m have detected system disturbance event X (step S21; No), the system enters a standby state.

[0066] In the determination in step S21, if any of the disturbance detection terminals 18-1 to 18-m detect that a system disturbance event X has occurred (step S21; Yes), the control unit 14 refers to the control target list and outputs a control command to the inverter power supply of the control target corresponding to the system disturbance event X (step S22), and then terminates the process.

[0067] These processes are repeated sequentially to ensure stable operation of the system at all times.

[0068] In the above explanation, tidal currents were detected by collecting measurement data from tidal current monitoring terminals 17-1 to 17-n. However, considering that tidal currents follow patterns depending on the season, time of day, and weather, it may be possible to use multiple created tidal current patterns as tidal current information and omit the tidal current monitoring terminals.

[0069] In this case, calculations in steps S11 to S18 are performed in advance for each tidal current pattern to create and store a list of controllable machines. Based on the season, time, weather forecast, etc., the tidal current for the day is linked to the tidal current pattern, and the inverter power supply to be controlled in the event of a disturbance is scheduled.

[0070] According to this second embodiment, in the event of a grid fault, one of the inverter power supplies is set as the control target, similar to the first embodiment, and stored as a control target list. Then, when a system fault in a branch is detected by the disturbance detection terminals 18-1 to 18-m installed in nodes 25a to 25c, the control unit 14 retrieves the list of controlled devices stored in it and outputs a control command to the inverter power supply of the controlled device.

[0071] Therefore, compared to the first embodiment, according to this second embodiment, since a control command is output only when a disturbance occurs, the amount of control and the amount of inertia to be secured can be reduced further.

[0072] [3] Third embodiment Figure 9 is a block diagram illustrating the schematic configuration of the system management system according to the third embodiment. In Figure 9, the same reference numerals shall be used for parts that are the same as those in Figure 6. The difference between the system management system of this third embodiment and the embodiments described above is that it uses only power flow information and does not use dynamic characteristic analysis.

[0073] In this third embodiment, based on the power flow information from power flow monitoring terminals 17-1 to 17-n, the control target selection unit 13 selects an inverter power supply for a control target corresponding to an assumed disturbance such as a grid fault, and periodically transmits it to the disturbance detection terminals 18-1 to 18-m. The disturbance detection terminals 18-1 to 18-m store the control target list.

[0074] When a disturbance is detected by the disturbance detection terminals 18-1 to 18-m installed on site, a control command is output to the corresponding inverter power supply constituting the inverter power supply group 16 based on the stored control target list. In this third embodiment, the disturbance detection terminals 18-1 to 18-m are equipped with the functions of the control unit 14 in the first or second embodiment.

[0075] In this case, the tidal current monitoring terminals 17-1 to 17-n can be installed as representatives to monitor the tidal currents between several areas, which are separated from the system.

[0076] Furthermore, similar to the second embodiment, it is also possible to configure the system so that disturbance details and location are transmitted from disturbance detection terminals 18-1 to 18-m to the system management device 10B, and a control unit 14 provided in the system management device 10B outputs a control command to the corresponding inverter power supply, which is the control target constituting the inverter power supply group 16.

[0077] In this third embodiment, similar to the first embodiment, inverter power supplies that are candidates for control in response to grid disturbances are registered and stored in the control target list.

[0078] Then, when a system disturbance is detected at the disturbance detection terminals 18-1 to 18-m installed at nodes 25a to 25c, a control command is output to the corresponding inverter power supply based on the control target list stored in the disturbance detection terminals 18-1 to 18-m.

[0079] According to this third embodiment, in addition to the effects of the second embodiment, the uplink and downlink communication are reduced and local handling is possible, enabling faster control. Furthermore, since dynamic characteristic analysis is not used, the computational load can be reduced.

[0080] The system management device of this embodiment includes a control device such as a CPU, a storage device such as ROM (Read Only Memory) or RAM, an external storage device such as an HDD or CD drive, a display device such as a display device, and an input device such as a keyboard or mouse, and can be configured using hardware from a normal computer.

[0081] The program executed by the system management device of this embodiment is provided as an installable or executable file, recorded on a computer-readable recording medium such as a USB memory stick, an SSD (Solid State Drive), or a DVD (Digital Versatile Disk).

[0082] Furthermore, the program executed by the system management device of this embodiment may be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. Alternatively, the program executed by the system management device of this embodiment may be provided or distributed via a network such as the Internet.

[0083] Furthermore, the program for the system management device of this embodiment may be provided pre-installed in ROM or the like.

[0084] The program executed by the system management device of this embodiment has a modular configuration that includes the above-mentioned parts (threshold setting unit, calculation unit, control target selection unit, and control unit). In actual hardware, the CPU (processor) reads the program from the storage medium and executes it, loading the above-mentioned parts onto the main memory, and the threshold setting unit, calculation unit, control target selection unit, and control unit are generated on the main memory.

[0085] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0086] 10, 10A, 10B grid management device 11. Threshold setting section 12, 12A, 12B calculation section 13 Control Target Selection Unit 14 Control Unit 16 Inverter power supply group 17-1~17-n Tidal current monitoring terminal 18-1~18-m Disturbance Detection Terminal 20 lines 21a, 21b Synchronous generators 22A~22C Inverter Power Supply 22b-1 First Inverter Power Supply 22b-2 Second Inverter Power Supply 22b-3 Contactor 23a, 23b Step-up transformer 24a~24c Step-up transformer Nodes 25a~25c Branches 26a-26c

Claims

1. Based on tidal flow information, an identification unit identifies the power grid as a supply area (the outflow side of the tidal flow) and a consumption area (the inflow side of the tidal flow) from the point of origin of the disturbance. A control unit that controls the system to effectively increase the total capacity of the Grid-Forming (GFM) inverter power supply in the supply area when the aforementioned disturbance occurs, Equipped with, The identification unit, as the tidal current information, divides the entire system into multiple areas in advance and uses the tidal current measurement values ​​of branches that represent the tidal currents between each area. System management device.

2. The aforementioned power system has a switchable inverter power supply that has both Grid-Following (GFL) control and GFM control functions and can switch between them. The control unit, upon the occurrence of the disturbance, switches the switchable inverter power supply located on the supply area side and operating under GFL control to GFM control. The system management device according to claim 1.

3. The control unit, in the event of the disturbance, connects the GFM-controlled inverter power supply in parallel to the grid. The system management device according to claim 1.

4. The identification unit uses the measured power flow values ​​of the main power system as the power flow information. The system management device according to claim 1.

5. The identification unit uses power flow calculation results obtained by inputting grid information and predicted or historical values ​​of power demand and power generation output as power flow information. The system management device according to claim 1.

6. The identification unit uses, as the tidal current information, a plurality of tidal current patterns created in advance for each factor related to tidal currents, such as season, time of day, and weather. The system management device according to claim 1.

7. The control unit sets acceptable threshold values ​​in advance for system values ​​such as phase difference angle, voltage, and frequency of the synchronous generator, and when a disturbance that deviates from the acceptable threshold is detected from the results of simulating the dynamic characteristics, it treats this as the occurrence of the disturbance. The system management device according to claim 1.

8. An identification unit that, based on tidal flow information, identifies the power system as a supply area which is the outflow side of the tidal flow and a consumption area which is the inflow side of the tidal flow, with respect to the point of disturbance occurrence, A control unit that controls the system to effectively increase the total capacity of the Grid-Forming (GFM) inverter power supply in the supply area when the aforementioned disturbance occurs, Equipped with, The aforementioned power system has a switchable inverter power supply that has both Grid-Following (GFL) control and GFM control functions and can switch between them. The control unit, upon the occurrence of the disturbance, switches the switchable inverter power supply located on the supply area side and operating under GFL control to GFM control, selects one or more of the switchable inverter power supplies located on the power supply side relative to the disturbance point, selects a combination of the selected switchable inverter power supplies to be switched to GFM control, simulates the dynamic characteristics after control for each combination, and selects the switchable inverter power supply to actually switch to GFM control. System management device.

9. An identification unit that, based on tidal flow information, identifies the power system as a supply area which is the outflow side of the tidal flow and a consumption area which is the inflow side of the tidal flow, with respect to the point of disturbance occurrence, A control unit that controls the system to effectively increase the total capacity of the Grid-Forming (GFM) inverter power supply in the supply area when the aforementioned disturbance occurs, Equipped with, The control unit, upon the occurrence of the disturbance, connects a GFM-controlled inverter power supply in parallel to the grid, selects one or more disconnected GFM inverter power supplies located on the power supply side relative to the disturbance point, selects a combination of GFM inverter power supplies to be connected in parallel from the selected GFM inverter power supplies, simulates the dynamic characteristics after control for each combination, and selects the GFM inverter power supplies to actually connect in parallel. System management device.

10. A power system management method in a power system having a GFM inverter power supply or a switchable inverter power supply having both GFL control and GFM control functions and being switchable between them, Based on tidal flow information, the process of identifying the power grid as a supply area (the outflow side of the tidal flow) and a consumption area (the inflow side of the tidal flow) from the point of origin of the disturbance, A process for controlling the overall capacity of the GFM inverter power supply in the supply area to effectively increase when the aforementioned disturbance occurs, Equipped with, The process of controlling the GFM inverter power supply to effectively increase its overall capacity includes selecting a combination of GFM inverter power supplies to be newly connected in parallel or the switchable inverter power supplies to be switched to GFM control, simulating the dynamic characteristics after control for each combination, and then selecting the GFM inverter power supply to be actually connected in parallel or the switchable inverter power supply to be switched to GFM control. System management method.

11. The system includes a process for pre-setting acceptable thresholds for system values ​​such as phase difference angle, voltage, and frequency of a synchronous generator. The control process, when a disturbance that deviates from the acceptable threshold is detected from the results of simulating the dynamic characteristics, treats it as the occurrence of the disturbance. The system management method according to claim 10.

12. A program for controlling a power system management device by computer, which controls a power system having a GFM inverter power supply or a switchable inverter power supply that has both GFL control and GFM control functions and can switch between them, The aforementioned computer includes means for identifying the power system as a supply area, which is the outflow side of the tidal flow, and a consumption area, which is the inflow side of the tidal flow, based on tidal flow information, A means for controlling the overall capacity of the GFM inverter power supply in the supply area to be effectively increased when the aforementioned disturbance occurs, and make it work The aforementioned identification means divides the entire system into multiple areas in advance and uses the current measurement values ​​of branches that represent the currents between each area as the current information. program.

13. The system includes means for pre-setting acceptable thresholds for system values ​​such as phase difference angle, voltage, and frequency of a synchronous generator. The control means, when a disturbance that deviates from the acceptable threshold is detected from the results of simulating the dynamic characteristics, treats it as the occurrence of the disturbance. The program according to claim 12.

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