Power system
The power system optimizes generator capacity coordination to provide stable power supply during grid abnormalities, reducing costs by efficiently managing generator output in facilities like evacuation shelters.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- DAIHEN CORP
- Filing Date
- 2024-11-08
- Publication Date
- 2026-05-20
AI Technical Summary
Facilities like evacuation shelters and disaster prevention bases face the challenge of providing stable power supply during grid abnormalities while minimizing the cost burden of generators.
A power system comprising a power demand facility with generators, an emergency power supply facility, a processing device for calculating induction command values, and an equipment control device to manage generator output, ensuring stable power distribution by coordinating generator capacities.
Enables stable power supply to power loads without requiring excessive generators, optimizing generator usage, and reducing cost burdens.
Smart Images
Figure 2026083729000001_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a power system.
Background Art
[0002] Conventionally, there is a power system that is connected to a power grid and supplies power from the power grid to a power load. In addition, some power systems are configured to disconnect from the power grid and operate independently in the event of an abnormality in the power grid (e.g., a power outage). A power system that operates independently includes a distributed power source and, during independent operation, supplies power obtained from the distributed power source to the power load without receiving power from the power grid. This enables power to be supplied to the load even during an abnormality in the power grid. For example, Patent Document 1 discloses a power system that operates independently. The power system described in Patent Document 1 includes a home power generation facility as a distributed power source and, during independent operation, supplies power generated by the home power generation facility to the power load. The home power generation facility generates power by driving a prime mover such as a gas engine, a gas turbine engine, or a diesel engine.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0004] For example, in facilities such as evacuation shelters and disaster prevention bases, it is necessary to continue to supply stable power to the power load of the facility even during an abnormality in the power grid. On the other hand, although it is possible to increase the number of generators (home power generation facilities) to provide redundancy, providing more generators than the required power increases costs. In this case, the cost burden on the facility equipped with the generators increases.
[0005] This disclosure was conceived in view of the above circumstances, and its purpose is to provide a power system that can provide a stable power supply to the power load even during independent operation, while reducing the cost burden on facilities equipped with generators. [Means for solving the problem]
[0006] The power system provided by this disclosure comprises: a power demand facility having at least one first generator, a generator control unit for controlling the at least one first generator, and at least one power load; an emergency power supply facility having at least one second generator for supplying power to the power demand facility from the at least one second generator when the power demand facility is disconnected from the power grid; an equipment control device for controlling the power received by the power demand facility from the emergency power supply facility; and a processing device for calculating an induction command value corresponding to the output power of the emergency power supply facility. The processing device transmits the induction command value to the equipment control device, the equipment control device includes a first power sensor for detecting the power received by the power demand facility, and receives the induction command value, calculates a target power received value which is the target power received using the received induction command value, and transmits the difference between the value detected by the first power sensor and the target power received value to the generator control unit, and the generator control unit controls the output power from the at least one first generator such that the power generated by the at least one first generator becomes a value that makes the difference value zero.
[0007] In a preferred embodiment of the power system, a second power sensor is further provided for detecting power in a power line connecting the power demand equipment and the emergency power supply equipment, and the processing device changes the induction command value to increase the received power when the output power of the emergency power supply equipment falls below a preset target value for the supply equipment.
[0008] In a preferred embodiment of the power system, the power demand equipment is designated as a first power demand equipment, and further comprising a second power demand equipment that is equipped with a power load but does not have a generator, and the output power of the emergency power supply equipment is divided into a first received power supplied to the first power demand equipment and a second received power supplied to the second power demand equipment. [Effects of the Invention]
[0009] The power system disclosed herein includes an emergency power supply system that supplies power to a power demand facility equipped with a power load and a generator (first generator) when the facility is disconnected from the power grid. This allows for power supply from the emergency power supply system when the power demand facility operates independently, enabling a stable power supply to the power load of the power demand facility even without many generators installed at the facility. Furthermore, in the power system disclosed herein, the equipment control device receives an induction command value corresponding to the output power of the emergency power supply system and uses the received induction command value to control the output power from the generator (first generator) of the power demand facility. This allows for coordinated power control between the generator (first generator) of the power demand facility and the generator (second generator) of the emergency power supply system, thus enabling optimization of the capacities of the first and second generators. In other words, the power system disclosed herein reduces the cost burden on the facility (power demand facility) equipped with the generator (first generator) while enabling a stable power supply to the power load even during independent operation.
[0010] Other features and advantages of this disclosure will become more apparent from the detailed description below, based on the accompanying drawings. [Brief explanation of the drawing]
[0011] [Figure 1] This is a functional block diagram showing a power system according to one embodiment. [Figure 2] This figure shows the correlation between the induction command value, the target power received value, and the generated power in a power system according to one embodiment. [Figure 3]This is a simulation result of power control of a power system according to one embodiment. [Modes for carrying out the invention]
[0012] Preferred embodiments of the power system of this disclosure are described below with reference to the drawings. Hereafter, identical or similar components are denoted by the same reference numerals, and redundant descriptions are omitted.
[0013] Figure 1 shows a power system S1 according to one embodiment of the present disclosure. The power system S1 comprises an emergency power supply facility A1, two power demand facilities B1 and B2, a processing unit C1, and a facility control device D1. In the power system S1, the processing unit C1 and the facility control device D1 may be installed in the emergency power supply facility A1, or in either of the two power demand facilities B1 and B2. In the power system S1, the processing unit C1 and the facility control device D1 may be a single device or different devices.
[0014] In power system S1, each of the two power demand facilities B1 and B2 can be connected to a power grid (not shown), and when connected, power is supplied from the power grid. As shown in Figure 1, each of the two power demand facilities B1 and B2 is connected to the emergency power supply facility A1 by a power line. When each of the two power demand facilities B1 and B2 is disconnected from the power grid, power is supplied from the emergency power supply facility A1. Although not shown in the diagram, power system S1 is equipped with a switching device that, when connected, connects each of the two power demand facilities B1 and B2 to the power grid, and when disconnected, connects each of the two power demand facilities B1 and B2 to the emergency power supply facility A1.
[0015] Emergency power supply equipment A1 is located in a different location from, for example, the two power demand facilities B1 and B2. Unlike this example, emergency power supply equipment A1 may be located in the same location as either of the two power demand facilities B1 or B2. Emergency power supply equipment A1 includes at least one generator 11. In the illustrated example, emergency power supply equipment A1 includes two generators 11. The number of generators 11 is not limited to two; it may be one or three or more. Emergency power supply equipment A1 supplies power generated by each generator 11 to each power demand facility B1 and B2 when each of the two power demand facilities B1 and B2 is disconnected from the power grid. Each generator 11 converts the thermal energy generated when a fuel such as oil, coal, or gas is burned into mechanical energy, and generates electricity using this mechanical energy. Each generator 11 may be a power generation device that utilizes renewable energy (e.g., solar, wind, hydro, biomass, geothermal, etc.). However, each generator 11 should preferably be capable of stable power generation.
[0016] The processing unit C1 calculates an induction command value for controlling the output power of the emergency power supply equipment A1. The processing unit C1 transmits the calculated induction command value to the equipment control device D1. The processing unit C1 is equipped with a power sensor 31. The power sensor 31 is installed on the power lines connecting each power demand equipment B1, B2 and the emergency power supply equipment A1, and detects the output power of the emergency power supply equipment A1. The processing unit C1 calculates an induction command value based on the value detected by the power sensor 31.
[0017] The induction command value is calculated, for example, in the same manner as in Patent Document 2. In this embodiment, it is calculated using the difference between the output power of the emergency power supply equipment A1 (the value detected by the power sensor 31) and the target value of the output power of the emergency power supply equipment A1 (the target value of the supply equipment). In this embodiment, the output power of the emergency power supply equipment A1 is defined as a positive value when power is supplied to the emergency power supply equipment A1 from each power demand equipment B1 and B2. The aforementioned difference is the value obtained by subtracting the output power of the emergency power supply equipment A1 (the value detected by the power sensor 31) from the target value of the supply equipment A1. Note that the direction of the output power, indicated by the positive and negative values, may be reversed. This state equation and the target value of the supply equipment are set in the processing unit C1. The processing unit C1 calculates the induction command value at predetermined intervals.
[0018] In this embodiment, if the detected value of the power sensor 31 (i.e., the output power of the emergency power supply equipment A1) is greater than the supply equipment target value, the processing unit C1 updates the guidance command value in a direction that decreases the output power of the emergency power supply equipment A1 (i.e., in a direction that increases the power generated by the generator 22 in the power demand equipment B1). On the other hand, if the detected value of the power sensor 31 (i.e., the output power of the emergency power supply equipment A1) is less than the supply equipment target value, the processing unit C1 updates the guidance command value in a direction that increases the output power of the emergency power supply equipment A1 (i.e., in a direction that decreases the power generated by the generator 22 in the power demand equipment B1).
[0019] The equipment control device D1 receives an induction command value from the processing device C1 and uses the received induction command value to calculate a target value for the power received by the power demand equipment B1. Hereinafter, this target value will be referred to as the target power received value. For example, the equipment control device D1 calculates the target power received value based on an optimization problem using the induction command value. This optimization problem includes an evaluation function and constraints. The evaluation function and constraints are the same as those described in, for example, Patent Document 2. In other words, the equipment control device D1 calculates the target power received value in the same manner as described in Patent Document 2. The correlation between the induction command value and the calculated target power received value will be described later (see Figure 2(a)).
[0020] The equipment control device D1 includes a power sensor 41. The power sensor 41 detects the received power of the power demand equipment B1. The equipment control device D1 outputs a power generation command to the power demand equipment B1 (the generator control unit 23 described later) so that the detected value of the received power detected by the power sensor 41 becomes the calculated received power target value. The power generation command is, for example, the difference value between the detected value of the received power and the received power target value.
[0021] The two power demand equipments B1 and B2 each receive power from the power grid during connection. Also, the two power demand equipments B1 and B2 each receive power supplied from the emergency power supply equipment A1 during disconnection. The sum of the received powers of the two power demand equipments B1 and B2 corresponds to the output power of the emergency power supply equipment A1.
[0022] The two power demand equipments B1 and B2 each include at least one power load 21. In the illustrated example, the two power demand equipments B1 and B2 each include one power load 21. Note that the number of power loads 21 may be two or more. The power loads 21 of each power demand equipment B1 and B2 consume the power supplied from the power grid during grid connection. Also, the power loads 21 of each power demand equipment B1 and B2 consume the power supplied from the emergency power supply equipment A1 during disconnection.
[0023] In addition to the power load 21, the power demand equipment B1 includes at least one generator 22 and at least one generator control unit 23. In the illustrated example, the power demand equipment B1 includes one generator 22 and one generator control unit 23. Note that the number of generators 22 may be two or more. On the other hand, as shown in FIG. 1, unlike the power demand equipment B1, the power demand equipment B2 does not include a generator 22 (and a generator control unit 23 that controls the generator 22).
[0024] The generator 22 converts the thermal energy generated when a fuel such as oil, coal, or gas is burned into mechanical energy, and generates electricity using this mechanical energy. Note that the generator 22 is not limited to one that converts thermal energy into mechanical energy; it may also be a generator using renewable energy. When connected to the grid, the power load 21 of the power demand facility B1 can receive power from the power grid as well as from the generator 22. Therefore, when connected to the grid, while power is being supplied from the generator 22, the power supplied from the power grid is suppressed. Furthermore, when disconnected, the power load 21 of the power demand facility B1 can receive power from the emergency power supply facility A1 as well as from the generator 22. Therefore, when disconnected, while power is being supplied from the generator 22, the power supplied from the emergency power supply facility A1 is suppressed.
[0025] The generator control unit 23 controls the power generation of the generator 22. The generator control unit 23 includes, for example, a governor that controls the frequency of the generated power and an automatic voltage regulator that controls the voltage of the generated power. Each generator control unit 23 receives a power generation command for the generator 22 from the equipment control device D1 and controls the power generated by the generator 22. If the power generation command is the difference between the detected value of the received power and the target value of the received power, the generator control unit 23 controls the generator 22 so that the power generated by the generator 22 (output power) becomes a value that makes the difference value zero. If the power demand equipment B1 has two or more generators 22, a separate generator control unit 23 is provided for each of the two or more generators 22. Alternatively, fewer generator control units 23 than the number of generators 22 may be provided for two or more generators 22. In this case, two or more generators 22 are controlled by one generator control unit 23.
[0026] In the power control of the power system S1, the processing unit C1 calculates an induction command value corresponding to the output power of the emergency power supply equipment A1 (the value detected by the power sensor 31). The calculated induction command value is then transmitted to the equipment control unit D1. The equipment control unit D1 receives the induction command value and calculates the target power received value for the power demand equipment B1. The equipment control unit D1 then transmits a power generation command to the power demand equipment B1 corresponding to the calculated target power received value and the power received by the power demand equipment B1 (the value detected by the power sensor 41). The power demand equipment B1 receives the power generation command and controls the power generated by the generator 22 according to the received power generation command. If the power demand equipment B1 is equipped with multiple generators 22, the power demand equipment B1 controls the power generated by the multiple generators 22 based on the power generation command.
[0027] In the power control of this power system S1, in this embodiment, the correlation between the induction command value and the target value of the power received by the power demand equipment B1 is configured as shown in Figure 2(a), and the correlation between the induction command value and the power generated by the generator 22 of the power demand equipment B1 is configured as shown in Figure 2(b). Specifically, when the induction command value is less than the value pr1, the target value of the power received remains constant as shown in Figure 2(a). During this period when the value is less than pr1, in order to keep the target value of the power received at a relatively low level, the power generated by the generator 22 is kept constant at a high level (for example, the rated output of the generator 22), as shown in Figure 2(b). This makes it possible to keep the output power of the emergency power supply equipment A1 constant at a relatively low level. On the other hand, during the period when the induction command value is pr1 or greater, the target value of the power received gradually increases as the induction command value rises, as shown in Figure 2(a). During this period when the value is pr1 or greater, in order to gradually increase the target value of the power received as the induction command value rises, the power generated by the generator 22 is gradually reduced, as shown in Figure 2(b). This allows the output power of the emergency power supply equipment A1 to be gradually increased as the induction command value rises. The above value pr1 is, for example, 0, and in this example, the correlation between the induction command value and the power generated by the generator 22 of the power demand equipment B1 (Figure 2(b)) is equivalent to the correlation between the induction command value and the output target value in the generator control device described in Patent Document 2 (see Figure 5 of Patent Document 2).
[0028] In this configuration, when the output power of the emergency power supply equipment A1 falls below the supply equipment target value, the power system S1 increases the induction command value to increase the power received target value of the power demand equipment B1. This increases the power received by the power demand equipment B1, thereby reducing the power generated by the generator 22 of the power demand equipment B1. Therefore, a situation can be avoided where the output power of the emergency power supply equipment A1 rises and power is supplied to the emergency power supply equipment A1 from the two power demand equipment B1 and B2. On the other hand, when the output power of the emergency power supply equipment A1 falls above the supply equipment target value, the power system S1 decreases the induction command value to decrease the power received target value of the power demand equipment B1. This increases the power generated by the generator 22 of the power demand equipment B1 in order to reduce the power received by the power demand equipment B1. Therefore, the output power of the emergency power supply equipment A1 decreases, thereby suppressing the power supplied from the emergency power supply equipment A1 to the two power demand equipment B1 and B2. As described above, in the power system S1, the output power of the emergency power supply equipment A1 is controlled to reach the target value of the supply equipment, thereby stabilizing the output power of the emergency power supply equipment A1. In other words, the emergency power supply equipment A1 can continue to supply power stably.
[0029] Next, power control in the power system S1 will be explained with reference to Figure 3. Figure 3 shows the simulation results for this power control. Figure 3(a) shows the total power generated by each generator 11 of the emergency power supply equipment A1 (solid line) and the power consumption of the power load 21 of the power demand equipment B2 (dashed line). Figure 3(b) shows the power generated by the generator 22 of the power demand equipment B1 (solid line) and the power consumption of the power load 21 of the power demand equipment B1 (dashed line). Figure 3(c) shows the target power received by the power demand equipment B1 and the power received by the power demand equipment B1 (detection value of the power sensor 41). In Figures 3(a) to (c), the horizontal axis represents time [s] and the vertical axis represents power value [MW]. Figure 3 shows the results of a simulation of the changes in each power value when the power consumption of power load 21 of power demand facility B2 is changed from 2MW to 1MW at time t1 (approximately 20 sec), as indicated by the dashed line in Figure 3(a). In this simulation, the target value of the supply facility is set to 2MW.
[0030] As shown in Figure 3(a), when the power load 21 of power demand facility B2 decreases from 2MW to 1MW at time t1, the power generated by emergency power supply facility A1 (the sum of the power generated by each generator 11) also decreases accordingly. Due to this decrease in the power generated by emergency power supply facility A1, the output power of emergency power supply facility A1 decreases, and the processing unit C1 updates the induction command value. As the induction command value is updated, the target value of received power gradually increases, as shown in Figure 3(c). Due to this increase in the target value of received power, the power generated by generator 22 of power demand facility B1 decreases, as shown in Figure 3(b), and the received power of power demand facility B1 (the value detected by power sensor 41) increases, as shown in Figure 3(c). Therefore, as shown in Figure 3(a), the power generated by emergency power supply facility A1 gradually increases from the value that decreased at time t1 and converges to 2MW so that the output power of emergency power supply facility A1 (the value detected by power sensor 31) becomes the supply facility target value. In other words, as can be seen from the simulation results shown in Figure 3, the power control of the power system S1 can avoid reverse power flow from each power demand facility B1 and B2 to the emergency power supply facility A1, which may occur when the power generated by the emergency power supply facility A1 decreases.
[0031] The power system S1 configured as described above includes an emergency power supply facility A1 equipped with a generator 11. The emergency power supply facility A1 supplies power to the power demand facility B1, which is equipped with a power load 21 and a generator 22 (first generator), when the facility is disconnected from the power grid. As a result, when the power demand facility B1 operates independently, it is possible to supply power from the emergency power supply facility A1, so that the power load 21 of the power demand facility B1 can be stably supplied with power even if the power demand facility B1 is not equipped with many generators 22. In other words, the power system S1 reduces the cost burden on the power demand facility B1 and enables a stable power supply to the power load 21 even when it is operating independently.
[0032] In power system S1, emergency power supply equipment A1 supplies power to power demand equipment B1 when B1 is disconnected from the power grid. In power system S1 with this configuration, complex power control of both emergency power supply equipment A1 and power demand equipment B1 is required. Therefore, power system S1 includes a processing device C1 that calculates an induction command value according to the output power of emergency power supply equipment A1, and an equipment control device D1 that receives the induction command value and uses the received induction command value to control the output power from the generator 22 of power demand equipment B1 (the power generated by the generator 22). In this embodiment, the equipment control device D1 calculates a target received power value, which is the target value of the received power of power demand equipment B1, from the induction command value, and controls the output power of the generator 22 so that the received power becomes the target received power value. This makes it possible to control the output power from the generator 22 of power demand equipment B1 (the power generated by the generator 22) according to the output power of emergency power supply equipment A1. In other words, the power system S1 can perform combined power control of the emergency power supply equipment A1 and the power demand equipment B1.
[0033] For example, in power system S1, if the output power of emergency power supply equipment A1 falls below a preset target value for the supply equipment, the induction command value is changed to increase the power received by power demand equipment B1. In power system S1, the power received by power demand equipment B1 is increased by reducing the power generated by the generator 22 of power demand equipment B1. As a result, power system S1 can prevent the output power of emergency power supply equipment A1 from falling below the target value for the supply equipment, thus avoiding reverse power flow from power demand equipment B1 to emergency power supply equipment A1.
[0034] Furthermore, in power system S1, if the output power of emergency power supply equipment A1 exceeds a preset target value for the supply equipment, the induction command value is changed to increase the power generated by the generator 22 of power demand equipment B1 and decrease the power received by power demand equipment B1. In power system S1, increasing the power generated by the generator 22 of power demand equipment B1 reduces the power received by power demand equipment B1. As a result, power system S1 can suppress the output power from exceeding the target value for the supply equipment, thereby reducing the burden on emergency power supply equipment A1.
[0035] The power system S1 includes a power demand facility B2. The power demand facility B2 includes a power load 21 but does not have a generator 22. Even in this configuration, by controlling the output power from the generator 22 of the power demand facility B1 (the power generated by the generator 22) in accordance with the output power of the emergency power supply facility A1, it is possible to avoid reverse power flow from the power demand facility B1 to the emergency power supply facility A1 or to reduce the burden on the emergency power supply facility A1. In the configuration that includes the power demand facility B2, if the power consumption of the power load 21 of the power demand facility B2 fluctuates, the output power of the emergency power supply facility A1 will change, and the induction command value calculated by the processing unit C1 may change. Therefore, if the equipment control unit D1 controls the power received by the power demand facility B1 which is equipped with a generator 22, it is possible to achieve complex power control between the emergency power supply facility A1 and the two power demand facilities B1 and B2.
[0036] In an example different from the above embodiment, the power system of this disclosure may not include power demand equipment B2. Furthermore, the power system of this disclosure may include multiple power demand equipment B2, or multiple power demand equipment B1. In a power system with multiple power demand equipment B1, the equipment control device D1 calculates a target power received value for each of the multiple power demand equipment B1 from the received induction command value and transmits it to the corresponding power demand equipment B1.
[0037] The power system relating to this disclosure is not limited to the embodiments described above. The specific configuration of each part of the power system relating to this disclosure can be modified in various ways. [Explanation of Symbols]
[0038] S1: Power system, A1: Emergency power supply equipment, B1, B2: Power demand equipment, C1: Processing unit, D1: Equipment control unit, 11: Generator, 21: Power load, 22: Generator, 23: Generator control unit, 31: Power sensor
Claims
1. A power demand facility comprising at least one first generator, a generator control unit for controlling the at least one first generator, and at least one power load, An emergency power supply system comprising at least one second generator, which supplies power from the at least one second generator to the power demand equipment when the power demand equipment is disconnected from the power grid, A device control system that controls the power received by the power demand equipment from the emergency power supply equipment, A processing device that calculates an induction command value corresponding to the output power of the emergency power supply equipment, Equipped with, The processing unit transmits the induction command value to the equipment control device, The equipment control device includes a first power sensor that detects the power received by the power demand equipment, and receives the induction command value, calculates a target power received value which is the target power received using the received induction command value, and transmits the difference between the value detected by the first power sensor and the target power received value to the generator control unit. A power system comprising a generator control unit that controls the output power from the at least one first generator such that the power generated by the at least one first generator becomes a value that makes the difference value zero.
2. The system further includes a second power sensor for detecting power in a power line connecting the aforementioned power demand equipment and the aforementioned emergency power supply equipment. The power system according to claim 1, wherein the processing device changes the induction command value to increase the received power when the output power of the emergency power supply equipment falls below a preset target value for the supply equipment.
3. The aforementioned power demand facility is designated as the first power demand facility, and a second power demand facility is further provided which is equipped with a power load but does not have a generator. The power system according to claim 1 or claim 2, wherein the output power of the emergency power supply equipment is divided into a first received power supplied to the first power demand equipment and a second received power supplied to the second power demand equipment.