Grid stabilization system, power grid system, and grid stabilization method

Abstract

To obtain a power source limitation amount necessary for a power grid via an integration control system such as an aggregator while maintaining fairness even if a regeneration energy power source is included.SOLUTION: There is provided a system configured to: calculate a parallel-off amount of power source loads to be paralleled off in the event of an expected accident on the basis of configuration data on a power grid including a power source load group, demand prediction data on power source loads constituting the power source load group, and accident data expected in the power grid; receive, from a power source load control device for managing the power source load group, an allowable parallel-off amount and an allowable parallel-off cost of the power source loads for controlling the power source load group calculated on the basis of demands for power source loads, a parallel-off result of the power source load group, and a parallel-off cost corresponding to a parallel-off amount in paralleling off the power source load group; calculate a parallel-off amount for stable operation of the power source load group with a prescribed parallel-off index on the basis of the parallel-off amount of power source loads, the past parallel-off result, and the received allowable parallel-off amount and parallel-off cost; and calculate a set point for parallel-off of each of the power source loads on the basis of the calculated parallel-off amount for stable operation and demands of power source loads of the power source load group.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a power system stabilization system, a power system, and a power system stabilization method for maintaining the stability of a power system. [Background technology]

[0002] When a fault occurs in a power system due to a lightning strike or other cause, the output of some synchronous generators (SG) may become unstable. If effective measures are not taken to prevent this instability, the number of unstable synchronous generators will increase over time, and ultimately there is a risk of a major blackout.

[0003] In response to the above-mentioned problems, conventional power system stabilizers maintain the transient stability of a power system by isolating unstable synchronous generators from the power system in the event of a fault, i.e., limiting the power supply. For example, conventional power system stabilizers perform stabilization control by calculating in advance by numerical simulation which synchronous generators are to be limited in power supply in order to maintain transient stability in the event of a contingent fault in the power system, and limiting the power supply of the synchronous generators when the contingent fault actually occurs. This power system stabilizer aims to maintain transient stability by limiting the power supply from synchronous generators with a large internal phase difference angle in the event of a fault.

[0004] On the other hand, in recent years, in order to reduce CO2 emissions, the introduction of renewable energy sources such as solar power generation and wind power generation has been actively promoted as an alternative to synchronous generators such as thermal power generation, and the proportion of synchronous generators in the power system is on a downward trend. However, if the proportion of synchronous generators decreases, the inertia and voltage maintenance ability of the power system that they traditionally carried will decrease, and there is a risk that the system stability will decrease.

[0005] Furthermore, a reduction in synchronous generators means a reduction in the stabilization means in conventional power system stabilizers. This means that it may become difficult for conventional power system stabilizers to maintain transient stability, or that the amount of power supply restriction required to maintain system stability may not be secured. To address the above-mentioned issues, the possibility of maintaining transient stability will increase if renewable energy sources, which are expected to be introduced more in the future, are added to the list of candidates for power supply restriction.

[0006] In this regard, Patent Document 1 is known as an invention related to a power system stabilization device that includes renewable energy power sources as candidates for power source restriction. Patent Document 1 aims to provide a power system stabilization device that can efficiently ensure the stability of the power system by selecting a renewable energy power generation device to reduce or stop the output amount, and describes the power system stabilization device as "a power system stabilization device including a stability calculation unit 11 that calculates the stability regarding an assumed target failure case, an acceleration tendency synchronous generator extraction unit 12 that extracts one or more synchronous generators 4 with an acceleration tendency, a sensitivity calculation unit 13 that calculates the deceleration sensitivity of the acceleration tendency synchronous generator 6 when the output amount of the renewable energy power generation device 6 is reduced by a first reduction amount P1, a renewable energy reduction amount addition unit 14 that determines the total reduction amount P3 of the output amount of the extracted renewable energy power generation device 6 that is judged to be stable, and a reduction target determination unit 15 that determines the renewable energy power generation device 6 that reduces the output amount." [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2020-96472 A Summary of the Invention [Problem to be solved by the invention]

[0008] Patent Document 1 is based on the background that in a power system connected to many renewable energy power sources and with a small number of operating synchronous generators, if the power supply of a synchronous generator is limited in the event of a failure, the power system may become unstable. Based on this background, the stabilization effect of limiting the power supply of renewable energy power sources is expressed as sensitivity, and based on that sensitivity, the target of power supply limit for renewable energy power sources is selected in priority over synchronous generators, and the target of power supply limit for synchronous generators is selected when the power supply limit for renewable energy power sources alone is insufficient.

[0009] However, depending on the region where the failure occurs, it is possible that the proportion of renewable energy power sources in the power grid is low, or that there are few renewable energy power sources that have a high stabilizing effect due to power limiting. In such cases, the method of Patent Document 1, which selects renewable energy power sources to be subject to power limiting in preference to synchronous generators, may cause problems such as an increase in the total power limit required for stabilization (an increase in the cost required to recover from power limiting), a negative impact on the grid due to excessive power limiting, and an increase in the amount of calculation required to select renewable energy power sources to be subject to power limiting.

[0010] In addition, in recent years, the number of renewable energy sources has increased significantly, making it essential to develop a communication network in order to issue power limiting commands directly to each source. Also, aggregators that perform integrated control of multiple sources and loads have appeared, and there are systems that determine operation commands and power generation via aggregators. It is also desirable to ensure power limiting amounts via aggregators.

[0011] In addition, power sources that are subject to power supply restrictions will lose power generation opportunities and incur losses. If only certain power sources are subject to power supply restrictions, fairness cannot be ensured.

[0012] As described above, the conventional technology does not disclose how to ensure the necessary power supply limit amount in the power grid through an integrated control system such as an aggregator while ensuring fairness.

[0013] In view of the above, the problem that the present invention aims to solve is to ensure the necessary power supply limit amount in the power grid through an integrated control system such as an aggregator while ensuring fairness, even when renewable energy sources are included. [Means for solving the problem]

[0014] The power system stabilization system according to the present invention is a power system stabilization system that supports ensuring the amount of power supply loads that are disconnected in a power system by a computer having a processor and a memory, and the processor calculates the amount of disconnection of the power supply loads that should be disconnected in the event of the occurrence of the anticipated accident based on configuration data of the power system including a group of power supply loads, demand forecast data of the power supply loads that constitute the group of power supply loads, and accident data anticipated in the power system, and determines a disconnection amount according to the demand of the power supply loads, the disconnection record of the group of power supply loads, and the amount of disconnection when the group of power supply loads is disconnected. and receiving from a power source load group control device that manages the power source load group a disconnection capacity and a disconnection cost of the power source load that controls the power source load group, the disconnection capacity and the disconnection cost being calculated based on the disconnection capacity of the power source load, past disconnection records, and the received disconnection capacity and disconnection cost, calculating a disconnection capacity for stable operation of the power source load group according to a predetermined disconnection index for the power source load group based on the disconnection capacity of the power source load, past disconnection records, and the received disconnection capacity and disconnection cost, and calculating a setting value for disconnecting each power source load based on the calculated disconnection capacity for stable operation and the demand of the power source load of the power source load group. Effect of the Invention

[0015] According to the present invention, even when a renewable energy power source is included, it is possible to ensure fairness and ensure the required power supply limit amount in the power grid via an integrated control system such as an aggregator. [Brief description of the drawings]

[0016] [Figure 1A] 1 is a conceptual diagram of a configuration of a power system, a power source load group, and a power system stabilization system in a first embodiment. [Figure 1B]FIG. 4 is a conceptual diagram of another configuration of the power system, the power source load group, and the power system stabilization system in the first embodiment. [Figure 1C] Schematic diagram of a computer. [Diagram 2] FIG. 2 is an explanatory diagram of the functions and configuration of the power grid stabilization system in the present embodiment. [Diagram 3] An explanatory diagram of the power generation and demand forecast DB (DataBase). [Figure 4] An explanatory diagram of the lineage DB. [Diagram 5] An explanatory diagram of the anticipated accident database. [Figure 6] FIG. [Figure 7A] FIG. 11 is an explanatory diagram of data on parallel-off capacity and parallel-off cost. [Figure 7B] An explanatory diagram of data on parallel-off capacity and parallel-off cost (overall configuration). [Figure 8A] FIG. 11 is an explanatory diagram of data on parallel-off index and parallel-off amount. [Figure 8B] An explanatory diagram of the data on parallel-off index and parallel-off amount (overall configuration). [Figure 9] FIG. 2 is a diagram showing a control configuration of power supply load group control. [Figure 10] FIG. [Figure 11] FIG. 4 is an explanatory diagram of a calculation flow of a total disconnection amount calculation unit. [Figure 12] FIG. 11 is an explanatory diagram of a calculation flow of a parallel-off index and parallel-off amount calculation unit. [Figure 13] FIG. 4 is an explanatory diagram of the calculation flow of the parallel-off setting value calculation unit of each device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The examples are illustrative for explaining the present invention, and are omitted and simplified as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise limited, each component may be singular or plural. The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0018] As examples of various information, the various information may be described using expressions such as "table," "list," and "queue," but the various information may be expressed using data structures other than these. For example, various information such as "XX table," "XX list," and "XX queue" may be expressed as "XX information." When describing identification information, expressions such as "identification information," "identifier," "name," "ID," and "number" are used, but these are mutually interchangeable.

[0019] When there are multiple components having the same or similar functions, they may be described by using the same reference numerals with different subscripts, or when there is no need to distinguish between these multiple components, the subscripts may be omitted.

[0020] In the embodiments, a process performed by executing a program may be described. Here, a computer executes the program using a processor (e.g., CPU, GPU), and performs the process defined by the program while using a storage resource (e.g., memory) and an interface device (e.g., communication port), etc. Therefore, the subject of the process performed by executing the program may be the processor. Similarly, the subject of the process performed by executing the program may be a controller, device, system, computer, or node having a processor. The subject of the process performed by executing the program may be a calculation unit, and may include a dedicated circuit that performs specific processing. Here, the dedicated circuit is, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a CPLD (Complex Programmable Logic Device), etc.

[0021] The program may be installed in the computer from a program source. The program source may be, for example, a program distribution server or a computer-readable storage medium. When the program source is a program distribution server, the program distribution server may include a processor and a storage resource that stores the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. In addition, in the embodiment, two or more programs may be realized as one program, and one program may be realized as two or more programs.

[0022] First, a conceptual diagram of a power grid system in this embodiment will be described with reference to Fig. 1A. Fig. 1A illustrates devices and controls necessary for explaining the present invention, and other devices and controls may be included without departing from the spirit of the present invention. For ease of explanation, a case in which there are two power supply load groups is illustrated, but the present invention is also applicable to a case in which there are three or more power supply load groups.

[0023] 1A is a diagram showing an example of a power system 1000 having a power system 101, a power system stabilization system 102, a power source load group 103A, and a power source load group 103B. The power system 1000 is a system including power generation, power transformation, power transmission, and power distribution for supplying power to power receiving equipment of a consumer.

[0024] The power load group 103A has a power load group control device 104A, a power source 105A, and a load 106A. The power load group 103B has a power load group control device 104B, a power source 105B, and a load 106B. The power load group 103A and the power load group 103B may be simply referred to as the power load group 103. The power load group control device 104A and the power load group control device 104B, the power source 105A and the power source 105B, and the load 106A and the load 106B may be simply referred to as the power load group control device 104, the power source 105, and the load 106, respectively.

[0025] The power load group 103 is a collection of power sources and loads that are integrated and controlled by the power load group control device 104. For example, the power load group control device 104 may be an aggregator that fulfills that role, and the power load group 103 may be renewable energy power sources and loads managed by the aggregator, or power sources and loads from local power supply stations.

[0026] The power supply load includes a power supply load of a non-renewable energy power supply such as a synchronous generator, and a power supply load of a renewable energy power supply such as a solar power generator. The power supply limit includes not only a method of disconnecting an unstable power supply from the power system when the power system fails, but also a method of suppressing or stopping the output of the power supply. The load limit includes not only a method of disconnecting an unstable synchronous generator or solar power generator from the power system when the power system fails, but also a method of suppressing or stopping the input to the equipment or equipment. That is, the stabilization control of the power supply load includes not only the above-mentioned power supply limit, for example, a limit to disconnect an unstable synchronous generator or solar power generator from the power system when a failure occurs, but also a method to suppress or stop the output of these. Therefore, in the following, in addition to disconnecting them from the power system, output suppression and stop are also referred to as power supply limit, and such power supply limit and load limit are also referred to as disconnection. In addition, when performing stabilization control of the power supply load by disconnection, the above-mentioned control of the power supply load of the non-renewable energy power supply and the power supply load of the renewable energy power supply are included. The disconnection will be described later. In the following, a synchronous generator will be described as an example of a non-renewable energy power supply, and a solar power generator will be described as an example of a renewable energy power supply. Also, the facilities and equipment are just examples.

[0027] For ease of explanation, FIG. 1 illustrates one power source and one load for the power source load group; however, the present technology may be applicable to two or more power sources or loads, or to only power sources or only loads.

[0028] FIG. 1A illustrates an example in which there is one power system 101. However, as shown in FIG. 1B, for example, in a power system system 1000A having a plurality of (two in this example) power supply systems 101 (power systems 101a, 101b), when an aggregator (power source load group control device 104) of a certain power system is malfunctioning and cannot perform parallel-off processing due to equipment failure or the like (for example, when power interchange is required), one aggregator may request a parallel-off processing from an aggregator of another power system. In this way, even if an aggregator of a certain power system is malfunctioning, an aggregator of another power system can perform parallel-off processing on its behalf. In this case, information necessary for parallel-off processing and information for identifying the malfunctioning aggregator are transmitted to the aggregator of the other power system.

[0029] Furthermore, the power system stabilization system 102 and the power source load group control device 104 can be realized, for example, by a general server or computer 2001 equipped with a CPU 2002, a memory 2003, an external storage device 2004 such as an HDD (Hard Disk Drive), an external medium output device 2007 for reading and writing information to a portable storage medium such as a CD (Compact Disk) or a USB memory, an input device 2006 such as a keyboard or a mouse, an output device 2005 such as a display, and a network communication device 2008 such as a NIC (Network Interface Card) for connecting to a communication network, as shown in FIG. 1C (schematic computer diagram).

[0030] Various data stored in this system or used for processing can be realized by the CPU 2002 reading it out from the memory 2003 or the external storage device 2004. Each functional unit of the aggregator system 1000 (for example, a total parallel-off amount calculation unit 205, a parallel-off index and parallel-off amount calculation unit 206, a parallel-off setting value calculation unit 901, and a parallel-off possible amount / parallel-off cost calculation unit 902, which will be described later) can be realized by the CPU 2002 loading a predetermined program stored in the external storage device 2004 into the memory 2003 and executing it.

[0031] The above-mentioned predetermined program may be stored (downloaded) into the external storage device 2004 from a storage medium via the external medium output device 2007 or from a network via the network communication device 2008, and then loaded onto the memory 2003 and executed by the CPU 2002. Alternatively, the program may be directly loaded onto the memory 2003 from a storage medium via the external medium output device 2007 or from a network via the network communication device 2008, and executed by the CPU 2002.

[0032] Next, the term "parallelization off," "parallelization amount," "possible amount of parallelization off," "parallelization off cost," and "parallelization off index" used in this specification will be explained.

[0033] First, we will explain parallel-off. In this specification, parallel-off refers to electrically isolating a device from the power grid in order to maintain stable operation of the power grid when an accident occurs in the power grid or when a sudden imbalance between supply and demand occurs. As mentioned above, parallel-off described below includes both power source restriction and load restriction.

[0034] Next, the disconnection amount is the amount of power to be disconnected. For example, when the system frequency increases due to a sudden increase in renewable energy generation, it refers to the amount of renewable energy or power generated by the power generation facility to be disconnected.

[0035] Next, the disconnection possible amount is the amount of power that may be disconnected from the power source load group based on a command from the grid stabilization system 102 or a disconnection indicator.

[0036] The possible disconnection amount is calculated by the power load group control device 104 for each power load group.

[0037] Next, the disconnection cost is an expense associated with disconnection, and is calculated for each power source load group by the power source load group control device 104. The disconnection cost may be, for example, the cost of losing power generation opportunities or power selling opportunities associated with disconnection, or the cost of reconnecting to the power grid. As will be described later, the disconnection cost is calculated in the power source load group 103, and includes the cost of loss associated with disconnection of the power source load group 103.

[0038] Next, the parallel-off index is an index measured at the power supply load group or the power supply or the load, and is used to determine whether the power supply or the load should be paralleled off. Specifically, it includes the frequency and voltage measured at the connection point of the power supply or the load, as well as composite information thereof. In other words, the parallel-off index is information including the system voltage and system frequency measured at the power supply load group 103.

[0039] Next, the function and configuration of the power grid stabilization system in this embodiment will be described with reference to Figs. 2 to 8B.

[0040] Fig. 2 is a diagram showing an example of the configuration of the power grid stabilization system 102. As shown in Fig. 2, the power grid stabilization system 102 has a power generation / demand forecast DB (DataBase) 201, a power grid DB 202, a postulated accident DB 203, a parallel-off record DB 204, a total parallel-off amount calculation unit 205, and a parallel-off index / parallel-off amount calculation unit 206. The power grid stabilization system 102 receives a parallel-off possible amount / parallel-off cost 207 from the power source load group control device 104, and transmits a parallel-off index / parallel-off amount 208 to the power source load group control device 104.

[0041] The power generation / demand forecast DB 201 is a DB that predicts the power generation and demand of synchronous generators and solar power generators connected in the power grid 101, and can be calculated based on meteorological information, past records, and the like.

[0042] FIG. 3 shows an example of the configuration of the power generation / demand forecast DB 201. FIG. 3 is simply described for easy understanding, and the DB can be constructed arbitrarily without departing from the spirit of the present invention. FIG. 3 shows, for example, that at time "6:00", the predicted value of the power generation of the synchronous generator A is "100 MW", the predicted value of the power generation of the synchronous generator B is "50 MW", the predicted value of the demand A of a consumer which is one of the loads in the power system 101 is "90 MW", and the predicted value of the demand B of another consumer in the power system 101 is "40 MW". These contents can be predicted using various conventionally known techniques. The power generation / demand forecast DB 201 may be stored in units according to the environment to which the present system is applied, such as for each power source load group 103 or each power system 101.

[0043] The system DB 202 is a DB related to the configuration of the power system 101, and is a DB that contains information on the configuration of the power system including power loads under the control of the power system 101, such as buses, power plants, and substations, and on operational states such as power flow states and connection states.

[0044] Fig. 4 shows an example of the configuration of the system DB 202. Fig. 4 is a simplified diagram for ease of explanation, and the DB can be constructed arbitrarily without departing from the spirit of the present invention. In Fig. 4, for example, the configuration of elements constituting the power system 101, including power transmission lines (branches), synchronous generators, loads, and renewable energy power sources (e.g., solar power generators), is stored. The system DB 202 may be stored in units according to the environment to which the system is applied, such as for each power source load group 103 or for each power system 101.

[0045] The anticipated accident DB 203 is a DB of accidents anticipated in the power system 101, and is a DB that stores anticipated accidents such as ground faults in power transmission lines and breakdowns in power plants, and the associated effects on the power system 101.

[0046] Fig. 5 shows an example of the configuration of the assumed accident DB 203. Fig. 5 is a simplified diagram for ease of explanation, and the DB can be constructed arbitrarily without departing from the spirit of the present invention. Fig. 5 shows that, for example, when the internal phase difference angle is "100" (deg.) and the maximum value of the frequency fluctuation is "-30%, "the assumed fault of the power supply system 101 corresponds to "Fault A". The assumed accident DB 203 may be stored in units according to the environment to which the present system is applied, such as for each power supply load group 103 or each power supply system 101.

[0047] The parallel-off record DB 204 is a DB relating to the past records of parallel-off of power generation equipment and demand loads. FIG. 6 shows an example of the configuration of the parallel-off record DB 204. FIG. 6 is a simplified description for the sake of easy understanding, and the DB can be constructed arbitrarily without departing from the spirit of the present invention. FIG. 6 shows, for example, that a generator A (e.g., power source 105A) and a load A (e.g., load 106A) were parallel-off at "YY / MM / DD1 19:00". The parallel-off record DB 204 may be stored in units according to the environment to which the present system is applied, such as for each power source load group 103 or for each power system 101.

[0048] Next, the parallel-off possible amount / parallel-off cost 207 and the parallel-off index / parallel-off amount 208 will be described.

[0049] 7A and 7B are examples of data showing the disconnection capacity and disconnection cost 207 in this embodiment. The disconnection capacity and disconnection cost 207 are calculated in the power source load group 103 and transmitted to the power grid stabilization system 102. As shown in FIG. 7A, the disconnection capacity and disconnection cost 207 is data including the disconnection capacity and the disconnection cost. FIG. 7A shows, for example, that the cost incurred when disconnecting the disconnectable power generation capacity "+100 MW" is "XXX yen." In this way, the power source load group 103 determines the cost according to the power generation capacity and the load capacity. The disconnection capacity and disconnection cost 207 may be stored in units according to the environment to which this system is applied, such as for each power source load group 103 or each power grid 101.

[0050] 7B, the disconnection capacity and disconnection cost 207 are actually stored for each power supply load (for each power supply in this example), and the sum of these is stored as the disconnection capacity and disconnection cost 207 of the power supply load group 103. In Fig. 7B, for example, the sum of the costs of the power supply 105A_1 and the power supply 105_A2 is stored as the cost of the power supply load group 103A. The same is stored for the load 106.

[0051] 8A and 8B are examples of data showing the parallel-off index and parallel-off amount 208 in this embodiment. As shown in FIG. 8A, the parallel-off index and parallel-off amount 208 are calculated in the power grid stabilization system 102 and transmitted to each power source load group 103, and are data including the parallel-off index and the parallel-off amount. FIG. 8A shows an example of the frequency of the power grid as the parallel-off index (evaluation index), and when it exceeds 50.1 [Hz], for example, a command is issued to each power source load group 103 to parallel-off XXX [MW] of each power source load group 103. The parallel-off index and parallel-off amount 208 may be stored in units according to the environment in which this system is applied, such as for each power source load group 103 or for each power grid 101.

[0052] 8B, the disconnection index / disconnection amount 208 is actually stored for each power supply load, and their sum is stored as the disconnection index / disconnection amount 208 of the power supply load group 103, and further, the sum of the disconnection index / disconnection amount 208 of a plurality of power supply load groups 103 is stored as the disconnection index / disconnection amount 208 of the entire power system 101. In FIG. 8B, the sum of the disconnection amounts of the power supply 105A and the load 106A is stored as the disconnection amount of the power supply load group 103A, and further, the sum of the disconnection amounts of the power supply load group 103A, the power supply load group 103B, and other devices under the power system 101 other than these power supply load groups is stored as the disconnection amount of the entire power supply load group 101.

[0053] Next, the function of the power grid stabilization system 102 in this embodiment will be described.

[0054] First, the total disconnection amount calculation unit 205 calculates the impact of a predicted accident on system stability and the total amount of power sources and loads that should be disconnected, based on a power generation and demand forecast DB (DataBase) 201 (Figure 3), a system DB 202 (Figure 4), and a predicted accident DB 203 (Figure 5).

[0055] The calculation flow of the total parallel-off amount calculation unit 205 is shown in Fig. 9. This calculation flow is broadly composed of the steps of system stability calculation A11, parallel-off amount calculation for each assumed fault A12, and final total parallel-off amount calculation A13.

[0056] In the system stability calculation A11, a transient stability calculation of the power system is performed, and it is calculated whether stable operation is possible when each assumed fault occurs in the power system 101.

[0057] For example, the total parallel-off amount calculation unit 205 refers to the system DB 202 in Fig. 4 to read the type and configuration of each element of the power system 101. For example, the total parallel-off amount calculation unit 205 reads information such as the rated capacity and rated output of all synchronous generators (generators A, B, ...) included in the power system 101, and information such as the branch node number and resistance. Then, the total parallel-off amount calculation unit 205 determines whether or not power can be supplied even when a fault A occurs in which the internal phase difference angle threshold is less than "100 (deg.)" and the maximum frequency fluctuation value is "-30 (%)", as an accident in the assumed accident DB 203 shown in Fig. 5, based on the difference between the predicted value of power generation and the predicted value of demand for each time stored in the power generation / demand forecast DB 201 in Fig. 3. In this example, the threshold value of the internal phase difference angle is "100 (deg.)" to realize power transmission between points, so if there are two points that do not satisfy this value, it is determined that the power system 101 cannot operate stably due to the occurrence of the accident, that is, parallel-off is necessary. Here, synchronous generators (generators A, B, ...) have been explained, but the same can be said for photovoltaic generators.

[0058] In the calculation of the amount of parallel-off for each assumed fault A12, the total amount of parallel-off calculation unit 205 performs a transient stability calculation of the power system for the result that stable operation is not possible in the system stability calculation A11, and calculates the timing and amount of parallel-off required to enable stable operation.

[0059] For example, since the prediction in FIG. 3 is made in a time series, the total parallel-off amount calculation unit 205 further refers to the parallel-off index / parallel-off amount 208 shown in FIG. 8 and judges whether stable operation is possible for each time. That is, the total parallel-off amount calculation unit 205 judges whether each evaluation index in FIG. 8 is satisfied for each time in FIG. 3 at which it is judged that parallel-off is necessary. For example, if the evaluation index "50.1" (Hz) is not satisfied, the total parallel-off amount calculation unit 205 judges that a parallel-off amount of "XXX" is required for stable operation at that time. Also, if the evaluation index "50.1" (Hz) is satisfied but "50.2" (Hz) is not satisfied, it judges that a parallel-off amount of "YYY" is required.

[0060] In the calculation of the parallel-off index and the parallel-off amount A13, the total parallel-off amount calculation unit 205 calculates, based on the parallel-off amount obtained in the parallel-off amount calculation A12 for each assumed accident, a parallel-off index and a parallel-off amount required for stable operation of the power grid 101. For example, the total parallel-off amount calculation unit 205 calculates the sum of the parallel-off amount "XXX" required for one assumed accident and the parallel-off amount "YYY" required for another assumed accident.

[0061] Regarding the method of calculating the disconnection index and disconnection amount required for the stable operation of the power system 101, for example, a method of extracting the case of the assumed accident that has the most adverse effect on the system stability and calculating the amount of the power source and load that should be disconnected in that case is considered. In addition, a method of calculating the expected value of the adverse effect on the system stability using the occurrence probability of the assumed accident and calculating the amount of the power source and load that should be disconnected is also considered.

[0062] Next, a parallel-off index / parallel-off amount calculation unit 206 calculates a parallel-off index / parallel-off amount 208 for each power source load group from the parallel-off index / parallel-off amount required for stable operation of the power system 101 calculated by the total parallel-off amount calculation unit 205, the parallel-off record DB 204 ( FIG. 6 ), and the parallel-off possible amount / parallel-off cost 207 ( FIG. 7 ), and transmits the calculated parallel-off index / parallel-off amount 208 to each power source load group as the parallel-off index / parallel-off amount required for stable operation of the power system 101.

[0063] 10 is a calculation flow of the parallel-off index and parallel-off amount calculation unit, which includes a calculation A21 of a parallel-off index and a parallel-off amount to be instructed to each power source load group. In the calculation A21 of the parallel-off index and parallel-off amount, the parallel-off index and parallel-off amount calculation unit 206 calculates the parallel-off index and parallel-off amount to be allocated to the devices and power source load groups of the power source system 101 so as to minimize the parallel-off cost of the power source system 101, for example, based on the parallel-off index and parallel-off amount required for stable operation of the power source system 101 calculated by the total parallel-off amount calculation unit 205, the parallel-off record DB 204 (FIG. 6), and the parallel-off possible amount and parallel-off cost 207 (FIG. 7). For example, the parallel-off index and parallel-off amount calculation unit 206 refers to the parallel-off record DB 204 and specifies a combination of parallel-off devices that satisfies the parallel-off index and parallel-off amount required for stable operation of the power source system 101 calculated by the total parallel-off amount calculation unit 205. Furthermore, the parallel-off index and parallel-off amount calculation unit 206 refers to the parallel-off possible amount / parallel-off cost 207 and calculates the parallel-off cost corresponding to the parallel-off possible amount (power generation amount or demand amount) of the identified parallel-off device or combination of parallel-off devices. The parallel-off index and parallel-off amount calculation unit 206 finds, from the identified combinations of parallel-off devices, a combination of parallel-off devices that achieves the lowest parallel-off cost among the calculated parallel-off costs. The parallel-off index and parallel-off amount calculation unit 206 transmits the parallel-off index and parallel-off amount for the parallel-off device to each of the power supply load group 103 having the parallel-off device that achieves the found lowest parallel-off cost.

[0064] Next, the configuration for calculating the parallel-off setting values ​​of the power sources and loads in the power source load group in each power source load group and the calculation of the parallel-off capability and cost in each power source load group control device 104 will be described with reference to FIG.

[0065] FIG. 9 is a diagram showing the control configuration of the power supply load group control device, which has a calculation unit 901 for each device's parallel-off setting value, a calculation unit 902 for parallel-off capacity and parallel-off cost, a power generation and demand DB 903, a parallel-off record DB 904, a parallel-off cost DB 905, and parallel-off setting values ​​906 for each renewable energy source and load, a parallel-off index and parallel-off capacity 208, and a parallel-off capacity and cost 207.

[0066] The power generation / demand DB 903 is a DB about power generation facilities and demand in a power source load group, and is the same DB as in Fig. 3. Although explanation will be omitted below, the power generation / demand forecast DB 201 shown in Fig. 3 stores forecast values, while the power generation / demand DB 903 stores actual values ​​of power actually used and actual values ​​of demand.

[0067] The disconnection record DB 904 is a DB showing the disconnection records of the power generation facilities and the demands in the power source load group, and has the same configuration as in FIG. 6, so a description thereof will be omitted here.

[0068] The disconnection cost DB 905 is the cost incurred when disconnecting each power generation facility / demand in the power source load group, and has the same configuration as in FIG. 7, so a description thereof will be omitted here.

[0069] A calculation unit 901 for each device's parallel-off setting value sets a parallel-off setting value for each power generation facility and demand in the power source load group based on the power generation and demand DB 903 and the parallel-off index and parallel-off amount 208 .

[0070] A calculation flow diagram of the off-line setting value calculation unit 901 of each device is shown in FIG. 12. FIG. 12 mainly includes a off-line capacity calculation unit A31 of each device and a off-line setting value calculation unit A32 for each power source and load. The off-line capacity calculation unit A31 of each device refers to the power generation and demand DB 903 and reads the current power generation and power demand of each device. The off-line setting calculation unit 901 of each device calculates the difference between the current power generation and power demand of each device that has been read and the minimum power generation and power demand that should be left, and calculates the calculated difference as the off-line capacity of each device. The off-line setting calculation unit A32 of each power source and load determines the off-line index and off-line capacity to be finally given to each device based on the off-line capacity and off-line index of each device.

[0071] Regarding the determination of the parallel-off amount, for example, when the parallel-off index exceeds 50.1 [Hz] in the case of the system frequency, if a parallel-off index / parallel-off amount 208 is transmitted such that each power load group is parallel-off by XXX [MW], as described above, the parallel-off setting value of each power generation facility / demand in the power load group is determined so that the total value of the parallel-off amount of each power generation facility / demand in the power load group is XXX [MW]. Here, the system frequency is exemplified, but the parallel-off amount of each power load group can be determined in the same way when the system voltage exceeds a predetermined voltage. The parallel-off setting value in this specification refers to a setting value for operating an equipment to parallel-off when a certain setting value is exceeded, such as the frequency relay setting value of a frequency relay or the voltage setting value of a voltage relay.

[0072] A parallel-off capacity / parallel-off cost calculation unit 902 calculates the parallel-off capacity and the parallel-off cost of a power supply load group from a power generation / demand DB 903, a parallel-off record DB 904, and a parallel-off cost DB 905, and transmits the calculated capacity and the parallel-off cost to the grid stabilization system.

[0073] Regarding the method of calculating the disconnection cost, a method of calculating the loss of power generation opportunity in the case of participating in the disconnection, or the loss cost due to a power outage in the case of demand, as the disconnection cost can be considered. As for the disconnection capacity, for example, as described above, a method of calculating the difference between the minimum remaining power generation output and the demand load size from the current power generation power and power demand size of each device can be considered as the disconnection capacity of each device. Note that, although the example of disconnecting each power source and load based on the disconnection setting value has been described in this embodiment, it is also effective in the case of disconnecting power sources and loads collectively for each power line, for example. This concludes the description of the first embodiment of the present invention.

[0074] Next, a second embodiment of the present invention will be described with reference to FIG. 13. FIG. 13 is a conceptual diagram of the second embodiment of the present invention. In the first embodiment, the power source load group declares the disconnection possible amount and the disconnection cost, and the grid stabilization system calculates the disconnection index and the disconnection amount. In the second embodiment, the disconnection amount is traded with a trading market between the two. For example, the power source load group 103A provides the disconnection possible amount determined by the disconnection index and disconnection amount 208 and the disconnection cost determined by the disconnection possible amount and disconnection cost 207 to the trading market 1301 via an aggregator having a power source load group control device 104 that manages the power source load groups 103A and 103B. In return, the aggregator receives a disconnection incentive related to the disconnection. On the other hand, the operator of the power system 101 who manages the power system stabilization system 102 pays a fee to the trading market 1301 to purchase the necessary amount of parallel-off, thereby enabling the stable operation of the power system 101 under the operator's control to be maintained.

[0075] FIG. 13 illustrates a case where there is one grid operator and two renewable energy load groups, but there may be more grid operators and more renewable energy load groups without departing from the spirit of the present invention.

[0076] The second embodiment of the present invention can be realized by "calculating the disconnection possible amount and the disconnection cost in the power source load group, calculating the disconnection amount to be secured in the power grid stabilization system, and transmitting the disconnection index and the disconnection amount to each power source load group" in the present invention.

[0077] The above is the description of the second embodiment. Note that, although the second embodiment has been described with reference to an example in which the market is used, the present invention is also applicable to bilateral trading in which the aggregator and the operator of the power grid 101 trade directly with each other as a form of trading.

[0078] In this manner, in the above embodiment, as described with reference to FIGS. 1A, 2, 9, etc., in a system stabilization system 102 that supports ensuring the amount of disconnection of power supply loads in a power system by a computer having a processor and a memory, the processor calculates the amount of disconnection of the power supply loads that should be disconnected in the event of the occurrence of the anticipated accident based on configuration data of the power system including a group of power supply loads (e.g., system DB 202, FIG. 4), demand forecast data of the power supply loads that constitute the group of power supply loads (e.g., power generation demand forecast DB 201, FIG. 3), and accident data anticipated in the power system (e.g., anticipated accident DB 203, FIG. 5), and calculates the amount of disconnection of the group of power supply loads based on the demand of the power supply loads (e.g., power generation demand DB 903 having the same configuration as in FIG. 3), the disconnection record of the group of power supply loads (e.g., disconnection record DB 904 having the same configuration as in FIG. 6), and the disconnection of the group of power supply loads. The power supply load group control device receives from the power supply load group (e.g., the power supply load group control device 104, aggregator) managing the power supply load group a disconnection amount and a disconnection cost (e.g., the disconnection amount and the disconnection cost 207, FIG. 7) of the power supply load controlling the power supply load group, which are calculated based on a disconnection cost according to the disconnection amount obtained by the power supply load control device and a disconnection cost (a disconnection cost DB 905 having the same configuration as in FIG. 7) according to the disconnection amount obtained by the power supply load control device and a disconnection amount (e.g., the disconnection index and the disconnection amount 208, FIG. 8) for stable operation of the power supply load group according to a predetermined disconnection index (evaluation index) based on the disconnection amount of the power supply load, past disconnection records (e.g., the disconnection record DB 204, FIG. 6), and the received disconnection amount and disconnection cost, and calculates a setting value for disconnecting each power supply load based on the calculated disconnection amount for stable operation and the demand of the power supply load of the power supply load group (e.g., the power generation demand DB 903). This makes it possible to ensure fairness even when renewable energy sources are included, and to secure the necessary power supply limit for the power grid through an integrated control system such as an aggregator. As a result, in the event of an accident in the power grid, it becomes possible to secure in advance the amount of power sources and loads that should be disconnected to ensure stable operation of the power grid.

[0079] In addition, by having the grid stabilization system calculate the amount of parallel-off based on the parallel-off cost, power source loads with a low parallel-off cost set can receive an incentive from the grid stabilization system for cooperating with the parallel-off, while power source loads with a high parallel-off cost can refuse to parallel-off. This allows the power source loads to declare whether or not they will cooperate with the parallel-off, making it easier to ensure fairness than if the grid stabilization system were to simply issue a parallel-off command.

[0080] In addition, in a power system system 1000 that supports ensuring the amount of disconnection of power supply loads in a power system by a computer having a processor and a memory, the power system system 1000 includes a power supply load group 103 including power supply loads 105 and 106 connected to the power system and a power supply load group control device 104 that manages the power supply loads, which is configured with the computer, and a power system stabilization system 102 that calculates the amount of disconnection of the power supply load group 103, and the power system stabilization system calculates the amount of disconnection of the power supply loads to be disconnected when the anticipated accident occurs based on configuration data of the power system including the power supply load group (e.g., a power system DB 202, FIG. 4), demand forecast data of the power supply loads that constitute the power supply load group (e.g., a power generation demand forecast DB 201, FIG. 3), and accident data anticipated in the power system (e.g., an anticipated accident DB 203, FIG. 5), and controls the power supply load group control device (e.g., a power supply load group control device) that manages the power supply load group. The group control device 104, aggregator) calculates the disconnection capacity and disconnection cost (for example, disconnection capacity and disconnection cost 207, FIG. 7 ) of the power supply load controlling the power supply load group based on the demand of the power supply load (for example, power generation demand DB 903), the disconnection record of the power supply load group (for example, disconnection record DB 904), and the disconnection cost according to the disconnection capacity when the power supply load group is disconnected (for example, disconnection cost DB 905). Based on the past parallel-off records (e.g., parallel-off record DB, FIG. 6) and the received parallel-off possible amount and parallel-off cost, the power source load group control device calculates a parallel-off amount (parallel-off index / parallel-off amount 208, FIG. 8) for stable operation with a predetermined parallel-off index (evaluation index) for the power source load group, and the power source load group control device calculates a setting value for parallel-off of each power source load based on the calculated parallel-off amount for stable operation and the demand of the power source load of the power source load group (e.g., power generation demand DB 903). In this way, the power grid stabilization system 102 transmits the parallel-off amount to each power source load group, allowing the power source load group side to select which device to parallel-off. Therefore, in addition to the above-mentioned effects, the communication burden can be reduced compared to issuing a parallel-off command to each device individually from the power grid stabilization system.

[0081] In this way, by leaving the decision of the protective relay setting value of each power load in the aggregator to the aggregator, it becomes possible to control the power load including a huge power load, and it becomes unnecessary to send the above control command to the power load quickly after an accident, and the communication load can be reduced. Also, it becomes possible to secure the power supply limit amount in the future in a form similar to market procurement. The aggregator monitors the power load in its jurisdiction, transmits the controllable amount of the power load and the cost table for controlling the power load to the grid stabilization system, and the aggregator calculates the costs related to these controls, thereby ensuring fairness. For example, if it is undesirable to lose power generation opportunities, it can be managed not to be subject to such control as being high cost. [Explanation of symbols]

[0082] 101: Power system 102: Power grid stabilization system 103A: Power supply load group A 103B: Power supply load group B 104A: Power load group control device A 104B: Power supply load group control device B 105A: Power supply A 105B: Power supply B 106A: Load A 106B: Load B 201: Power generation and demand forecast DB 202: Lineage DB 203: Expected accident DB 204: Disconnection record DB 205: Total off-line amount calculation unit 206: Solution sequence index solution sequence amount calculation part 207: Disconnection capacity and disconnection cost 208:Sequence index / Sequence amount 901: Parallel off setting value calculation section 902: Parallel-off possibility amount / parallel-off cost calculation unit 903: Power generation and demand database 904: Disconnection record DB 905: Disconnection cost DB 906: Off-parallel setting value for each power source and load

Claims

1. A power system stabilization system that supports securing an amount of power source load disconnection in a power system by a computer having a processor and a memory, The processor, Calculating an amount of disconnection of the power supply loads to be disconnected when the anticipated accident occurs, based on configuration data of a power system including a power supply load group, demand forecast data of the power supply loads constituting the power supply load group, and anticipated accident data in the power system; receiving, from a power source load group control device that manages the power source load group, a disconnection possible amount and a disconnection cost of a power source load that controls the power source load group, the amount being calculated based on a demand for the power source load, a disconnection record of the power source load group, and a disconnection cost according to the amount of disconnection when the power source load group is disconnected; calculating a disconnection amount for stable operation of the power source load group according to a predetermined disconnection index based on the disconnection amount of the power source load, past disconnection records, and the received disconnection possible amount and disconnection cost; Calculating a setting value for paralleling off each power supply load based on the calculated paralleling off amount for stable operation and the demand of the power supply load of the power supply load group. A power grid stabilization system comprising:

2. The power grid stabilization system according to claim 1, The power grid stabilization system, wherein the disconnection cost is calculated in the power source load group and includes a loss cost associated with the disconnection of the power source load group.

3. The power grid stabilization system according to claim 1, The disconnection indicator is information including a system voltage and a system frequency measured at the power supply load group. A power grid stabilization system comprising:

4. A power system system that supports securing an amount of disconnection of a power source load in a power system by a computer having a processor and a memory, The power grid system includes a power load group including a power load connected to the power grid and a power load group control device that manages the power load, the power load group being configured to include the computer, and a power grid stabilization system that calculates a disconnection amount of the power load group, The power grid stabilization system includes: Calculating an amount of disconnection of the power supply loads to be disconnected when the anticipated accident occurs, based on configuration data of a power system including a power supply load group, demand forecast data of the power supply loads constituting the power supply load group, and anticipated accident data in the power system; A power source load group control device for managing the power source load group, calculating a disconnection capacity and a disconnection cost of a power supply load that controls the power supply load group based on a demand of the power supply load, a disconnection record of the power supply load group, and a disconnection cost according to a disconnection capacity when the power supply load group is disconnected; The power grid stabilization system includes: calculating a disconnection amount for stable operation of the power source load group according to a predetermined disconnection index based on the disconnection amount of the power source load, past disconnection records, and the received disconnection possible amount and disconnection cost; The power source load group control device comprises: Calculating a setting value for paralleling off each power supply load based on the calculated paralleling off amount for stable operation and the demand of the power supply load of the power supply load group. The power grid system according to the present invention is characterized in that:

5. A system stabilization method for supporting securing an amount of disconnection of a power source load in a power system by a computer having a processor and a memory, comprising: Calculating an amount of disconnection of the power supply loads to be disconnected when the anticipated accident occurs, based on configuration data of a power system including a power supply load group, demand forecast data of the power supply loads constituting the power supply load group, and anticipated accident data in the power system; receiving, from a power source load group control device that manages the power source load group, a disconnection possible amount and a disconnection cost of a power source load that controls the power source load group, the amount being calculated based on a demand for the power source load, a disconnection record of the power source load group, and a disconnection cost according to the amount of disconnection when the power source load group is disconnected; calculating a disconnection amount for stable operation of the power source load group according to a predetermined disconnection index based on the disconnection amount of the power source load, past disconnection records, and the received disconnection possible amount and disconnection cost; Calculating a setting value for paralleling off each power supply load based on the calculated paralleling off amount for stable operation and the demand of the power supply load of the power supply load group. A system stabilization method comprising:

6. The method for stabilizing a power system according to claim 5, The disconnection cost includes a loss cost associated with disconnection of the power source load group and is calculated in the power source load group. A system stabilization method comprising:

7. The method for stabilizing a power system according to claim 5, The disconnection indicator is information including a system voltage and a system frequency, and is measured at the power source load group. A system stabilization method comprising:

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