System monitoring and control device

Abstract

To provide a system monitoring control device which constitutes a single operation system of a sound zone by opening a circuit breaker of a prescribed place when a system accident occurs and can transmit a time that can maintain the signal operation system to a power generation company and users.SOLUTION: A system monitoring control device for forming a plurality of sections A1 to A5 between a system power source 40 and a distributed power source 10 through circuit breakers 21 to 26, and monitoring and controlling a power system having loads 31 to 35 connected to the sections A1 to A5 includes a function for monitoring a power generation amount of the distributed power source 10, a reception function of accident information, an opened / closed state monitoring function and an opening / closing control function of the circuit breakers, a function for monitoring load amounts of the loads, and a function for transmitting the constitution of a single operation system to the loads in a corresponding system and the distributed power source 10 when accident information is received, and controls the opening / closing of the circuit breakers 21 to 26 so as to constitute the single operation system on the basis of at least the power generation amount and the load amount of the distributed power source 10.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a system monitoring and control device that monitors the power generation amount, load amount, breaker state, etc. of distributed power sources connected to a power system, and based on the monitoring results, can configure a stand-alone operation system for a predetermined section by the distributed power source when an accident occurs in the power system.

Background Art

[0002] When an accident occurs in a power system to which a distributed power source is connected, a technique for adjusting the supply-demand balance of the stand-alone operation system to stabilize the system is disclosed in, for example, Patent Document 1. In this Patent Document 1, when a tie line is cut off due to the occurrence of a system accident and a plurality of generators are in a stand-alone operation state, the adjustment amount (the difference between the total power generation amount and the total load amount) required for system stabilization is calculated from the power flow immediately before the tie line. And when the deviation rate between the total power generation amount and the total load amount is greater than or equal to a predetermined value, if the total power generation amount exceeds the total load amount, the load with a higher cutoff target rank is cut off, and if the total power generation amount is less than or equal to the total load amount, the adjustment amount is distributed by the output of each generator to limit the output of each generator, enabling the stable maintenance of the stand-alone operation system while adjusting the supply-demand balance by simple processing.

[0003] Further, Patent Document 2 describes that in a power system in which a first generator and a second generator are connected in parallel to a commercial power source, power is selectively supplied to a plurality of each room within the total power generation amount by each generator during a power outage, and the selection criteria for each room consider the priority of the load and whether it is unnecessary or urgent.

[0004] Furthermore, Patent Document 3 describes that when a system accident occurs, a plurality of circuit breakers on the system side are opened and a plurality of unit generators are operated to shift to stand-alone operation in a substation, and the stand-alone operation that bears the common load of the minimum life consumption unit via the bus is continued until system restoration, and power supply to units other than the minimum life consumption unit is continued until a certain time limit elapses.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-5336 (

[0010] to

[0026] , Figures 1 to 3, etc.) [Patent Document 2] Japanese Patent Publication No. 6474174 (

[0038] to

[0061] , Figures 3, 4, etc.) [Patent Document 3] Japanese Patent Publication No. 63-138103 (Page 2, lower right column, line 4 to Page 3, upper left column, line 9, Figure 1, Figure 2, etc.) [Overview of the project] [Problems that the invention aims to solve]

[0006] The aforementioned Patent Documents 1 to 3 do not disclose any technology for stably maintaining islanding operation by calculating the time during which distributed power sources can maintain islanding operation in the event of a power grid accident, and transmitting this information to each facility (power generator, consumer) within the power grid. Therefore, for power generators and consumers, it was difficult to predict when to limit the amount of power generated or when to start load shedding, and depending on the configuration of the power grid, it was difficult to configure islanding systems.

[0007] Here, Figure 4 is a configuration diagram showing an example of a power system in which distributed power sources are interconnected, where 10 is a distributed power source equipped with a photovoltaic generator (PV) and a power conditioner system (PCS), 21-26 are circuit breakers installed in the power system, A1-A5 are sections partitioned by circuit breakers 21-26, and 31-35 are loads connected to sections A1-A5, respectively. Although not shown, the power conditioner system (PCS) is assumed to be equipped with an energy storage device such as a battery to serve as a power source when the output of the photovoltaic generator (PV) decreases.

[0008] If the amount of power generated by the distributed power source 10 is greater than the total load of all loads 31-35, then even if a fault occurs at a point within section A1-A5 (excluding the area between circuit breaker 21 and load 31), opening the circuit breaker between the fault point and the grid power source 40 will allow the distributed power source 10 to operate independently for one or more loads. For example, if a fault such as a ground fault occurs in section A4 (with F4 as the fault point), turning off circuit breakers 25 and 26 while keeping circuit breakers 21-24 on will create an independent operating system including loads 31-34, thereby maintaining power supply.

[0009] However, if the amount of power generated by the distributed power source 10 is greater than the total load of loads 31-33 but less than the total load of loads 31-34, then when a fault (fault point F3) occurs in section A3, it is possible to configure an islanding system including loads 31-33 by opening circuit breakers 24-26 and keeping circuit breakers 21-23 closed. However, when a fault (fault point F4) occurs in section A4, it becomes impossible to configure an islanding system including loads 31-34 because the amount of power generated by the distributed power source 10 is less than the total load of loads 31-34.

[0010] Furthermore, if an accident (accident point F5) occurs within section A5, the circuit breakers 25 and 26 will be opened, immediately causing a power outage for load 35. However, if the amount of power generated by the distributed power source 10 is less than the total load of loads 31-34, loads 31-34 will experience a power outage with a slight delay, and in any case, it will become impossible to maintain an isolated operation system including loads 31-34.

[0011] As described above, the relationship between the amount of power generated by the distributed power source 10 and the load amounts of loads 31-35 makes it impossible to operate the distributed power source 10 independently, or makes it impossible to predict the duration of power outages for the loads. These problems could not be solved by the aforementioned Patent Documents 1-3.

[0012] Therefore, the problem to be solved by the present invention is to provide a power system monitoring and control device that, when a fault occurs in a power system, controls a predetermined circuit breaker to be switched on and off to configure an islanding system to the extent possible, calculates the time for which the islanding state can be maintained, and transmits this calculation to each piece of equipment in the power system. [Means for solving the problem]

[0013] To solve the above problems, the present invention provides a power system monitoring and control device for monitoring and controlling a power system in which a plurality of sections are formed between a grid power source and a distributed power source via circuit breakers, and loads are connected to each of these plurality of sections, The system includes a function to monitor the amount of power generated by the distributed power source, a function to receive fault information in the power system, a function to monitor the open / closed state of the circuit breaker and a function to control the open / closed state, a function to monitor the load amount of the load, and a function to transmit to the loads in the islanding system and the distributed power source that the islanding system is configured with the distributed power source when the fault information is received. The circuit breaker is controlled to open and close so that the islanding system is configured based at least on the amount of power generated by the distributed power source and the load of the load.

[0014] Here, the scope of the isolated power system configured with distributed power sources in the event of an accident is: (1) Comparison of the amount of power generated by distributed power sources and the load on multiple consecutive sections. (2) Comparison of the sum of the amount of power generated by distributed power sources and the reserve capacity for adjusting the amount of power generated, and the load over multiple consecutive sections. (3) Comparison of the amount of power generated by distributed power sources and the difference between the load and load adjustment capacity of multiple consecutive sections. (4) Comparison of the sum of the amount of power generated by distributed power sources and the remaining capacity for power adjustment, and the difference between the load and the remaining capacity for load adjustment over multiple consecutive sections. The decision can be made based on the following criteria.

[0015] In addition, when an accident occurs in the power system, it is desirable to transmit to the loads and distributed power sources that constitute the islanding operation system that they are in the islanding operation state and the islanding operation system maintainable time calculated based on at least the time schedules of the power generation amount and the load amount. Also, during normal times before an accident occurs in the power system, the islanding operation system maintainable time for all assumed accident points may be calculated and stored in advance, and when an accident actually occurs, the islanding operation system maintainable time stored in advance may be transmitted to each facility.

Advantages of the Invention

[0016] According to the present invention, the power generation amount, load amount, state of circuit breakers, etc. of the distributed power sources are constantly monitored, and when an accident occurs in the power system, a predetermined circuit breaker is controlled to be turned on and off according to the above power generation amount, load amount, and accident point (interruption section), so that an islanding operation system can be configured and maintained as much as possible. In addition, by transmitting to the loads in the power system that they are in the islanding operation state and the time that the islanding operation can be maintained, unexpected power outages at the consumers can be prevented, and the operation plan of the loads can be achieved without problems.

Brief Description of the Drawings

[0017] [Figure 1] It is a configuration diagram of a power system to which an embodiment of the present invention is applied. [Figure 2] In an embodiment of the present invention, it is a flowchart showing a process of calculating and transmitting the time that the islanding operation system can be maintained. [Figure 3] In an embodiment of the present invention, it is a flowchart showing a process of calculating and transmitting the time that the islanding operation system can be maintained. [Figure 4] It is a configuration diagram of a power system for explaining the prior art.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a diagram of the power system configuration to which the system monitoring device 100 of this embodiment is applied. The power system, as in Figure 4, includes a distributed power source 10 having a photovoltaic power generation device (PV) and a power conditioner system (hereinafter abbreviated as PCS), circuit breakers 21 to 26, and loads 31 to 35 within sections A1 to A5.

[0019] Furthermore, the PCS within the distributed power source 10 is equipped with a battery or other energy storage device to serve as a power source when the output of the photovoltaic (PV) power generation system decreases. In addition, the power generation equipment may be a wind power generation system instead of a photovoltaic (PV) power generation system. In that case, the PCS can convert the AC output of the wind power generation system into DC power, and then convert it back into AC power for supply to the power grid.

[0020] The system monitoring device 100 receives information from the PCS of the distributed power source 10, such as the current power generation amount (including power generation amount based on the state of charge (SOC) of the battery, which is not shown), and the remaining capacity for power generation adjustment. It also receives fault information indicating that an accident such as a ground fault has occurred in any of sections A1 to A5, opening and closing information of circuit breakers 21 to 26, the current load amount of loads 31 to 35, and the remaining capacity for load adjustment. The device controls the output of the PCS and the opening and closing of circuit breakers 21 to 26. Furthermore, it has a function to transmit information to each facility in the power system (power generators with distributed power sources 10 and consumers with each load), aggregators, etc., regarding whether or not it is in an islanding state and the time that an islanding system can be maintained.

[0021] Next, the operation of this embodiment will be described. In Figure 1, with all circuit breakers 21-26 turned on and loads 31-35 supplied with power from the distributed power supply 10 or the grid power supply 40, if an accident such as a ground fault occurs in section A4 (let F4 be the fault location), the accident information is transmitted to the grid monitoring and control device 100. In this case, the system monitoring and control device 100 controls the on / off state of each circuit breaker 21 to 26 to configure an islanding system for loads included in the following ranges, based on the current power generation amount of the distributed power source 10, the power generation adjustment capacity, the current load amount of loads 31 to 35, the load adjustment capacity, etc.

[0022] (1) Range in which the current power generation amount of distributed power source 10 is greater than or equal to the current load amount For example, if an accident occurs in section A4, and the current power generation of distributed power source 10 is greater than or equal to the current total load of loads 31 to 33 in the consecutive sections A1 to A3, then power can be supplied from distributed power source 10 to loads 31 to 33, and an islanding system including these loads 31 to 33 can be configured. Therefore, the system monitoring and control device 100 sends a command to each circuit breaker to turn off the circuit breakers 24 and 25 on both sides of the load 34 (fault point F4) while keeping the other circuit breakers 21 to 23 and 26 on, thereby configuring an isolated operating system including loads 31 to 33.

[0023] Furthermore, if the current power generation of the distributed power source 10 is less than the current load amount of loads 31-33, but greater than or equal to the current load amount of loads 31 and 32, a command is sent to each circuit breaker to turn off circuit breakers 23-25 ​​and keep the other circuit breakers 21, 22, and 26 on, thereby forming an isolated operating system including loads 31 and 32 within sections A1 and A2. Furthermore, if the current power generation of distributed power source 10 is less than the current load of loads 31 and 32, but greater than or equal to the current load of load 31, a command is sent to turn off circuit breakers 22 to 25 and keep the other circuit breakers 21 and 26 on, thereby configuring an isolated operating system that includes only load 31 within section A1.

[0024] (2) Range in which (current power generation of distributed power source 10 + reserve capacity for power generation adjustment) ≥ current load If the distributed power source 10 is operating under output suppression, the maximum power that can be output after releasing this output suppression is (current power generation of the distributed power source 10 + remaining power generation adjustment capacity). In this case as well, a command is sent to each circuit breaker to turn off a predetermined circuit breaker and keep the remaining circuit breakers on, so that an isolated operation system is configured within the range where (current power generation of the distributed power source 10 + remaining power generation adjustment capacity) ≥ current load. In other words, the (current power generation amount of the distributed power source 10) in (1) above can be replaced with (current power generation amount of the distributed power source 10 + power generation adjustment capacity), the relationship with the load can be compared, and the on / off state of each circuit breaker can be controlled according to the result.

[0025] (3) Range in which the current power generation of distributed power sources 10 is greater than or equal to (current load - load adjustment capacity) If loads 31 to 35 are capable of performing demand response control, each load can reduce its current load amount by a predetermined amount, thereby reducing the overall load. This allows for the creation of an islanding system for a predetermined load based on the current power generation amount of the distributed power source 10. In this case, the current load amount in (1) above can be replaced with (current load amount - load adjustment capacity), and the relationship between this and the current power generation amount of the distributed power source 10 can be compared. The on / off state of each circuit breaker can then be controlled accordingly.

[0026] (4) Range where (current power generation of distributed power source 10 + power generation adjustment capacity) ≥ (current load - load adjustment capacity) This case is one in which both (2) and (3) above apply, where the distributed power supply 10 is operating in output suppression mode, and loads 31 to 35 are capable of demand response control. In this case, the (current power generation amount of the distributed power source 10) in (1) above is replaced with (current power generation amount of the distributed power source 10 + power generation adjustment capacity), and the current load is replaced with (current load - load adjustment capacity). The relationship between the two is then compared, and the on / off state of each circuit breaker is controlled according to the result.

[0027] In the cases (1) to (4) described above, if the minimum output of the distributed power source 10 is specified, the range in which an islanding system can be configured should be determined by comparing the amount of power generated at or above that minimum output with the load, etc. Furthermore, while the above explanation assumes an accident occurs in section A4, if an accident occurs in section A3 or A5 (at accident points F3 and F5, respectively), the on / off state of each circuit breaker can be controlled according to a similar principle.

[0028] Furthermore, in the cases (1) to (4) described above, the following can be considered as the surplus capacity for adjusting the amount of power generated by the distributed power source 10. (a) The reserve capacity for adjusting the amount of power generated by the distributed power source 10 shall be (rated output of the distributed power source 10 - current operating output). (b) The reserve capacity for adjusting the amount of power generated by the distributed power source 10 shall be (the maximum operational output of the distributed power source 10 - the current operating output). Here, if the distributed power source 10 has a photovoltaic (PV) power generation device, the maximum output will depend on the amount of solar radiation, and if it has a wind power generation device, the maximum output will depend on the wind speed and wind direction. (c) The reserve capacity for adjusting the amount of power generated by the distributed power source 10 shall be (the maximum output of the distributed power source 10 as applied for in advance - the current operating output). In other words, it shall be a value equivalent to the amount supplied in the supply and demand adjustment market. The reserve capacity for adjusting power generation described in (b) and (c) above may be information held by the power generation company, or information transmitted from an external source that monitors the power grid.

[0029] Furthermore, in the cases (1) to (4) described above, the following are possible as load adjustment margins. (i) The load adjustment surplus will be set as the supply and demand adjustment contract amount. (b) The load adjustment margin shall be the amount of demand response available as previously requested. Furthermore, if a minimum output of the distributed power source 10 is specified, the load adjustment margin includes not only the margin to decrease the load but also the margin to increase it.

[0030] As described above, according to this embodiment, the system monitoring and control device 100 can maintain an islanding system for the maximum possible section within the power system by identifying loads that can be supplied from the distributed power source 10 based on the current power generation amount and power generation adjustment capacity of the distributed power source 10, as well as the current load amount and load adjustment capacity, and controlling the on / off state of each circuit breaker.

[0031] Furthermore, in this embodiment, it is desirable that the system monitoring and control device 100 has a function to generate information on whether each load is operating independently and the time for which an independent system can be maintained, and to transmit this information to consumers with loads 31 to 35, power generators with distributed power sources 10, and aggregators, etc. Here, the time during which an isolated system can be maintained can be calculated and transmitted to each piece of equipment when a fault occurs in the power system, or it can be calculated in advance according to the fault section and stored, and this stored time can be transmitted to each piece of equipment when an actual fault occurs.

[0032] In other words, Figure 2 is a flowchart for calculating the time during which an islanding system can be maintained in the event of a fault in the power grid and transmitting this information to each piece of equipment. In Figure 2, the system monitoring and control device 100 identifies the section where the fault occurred and the section that was tripped based on the received fault information and the on / off status of the circuit breaker (step S1YES, S2), and calculates and stores the time for which island operation can be maintained for the load in the remaining section based on the time schedule of the power generation amount and load amount of the distributed power source 10 (including their predicted values), power generation adjustment margin, load adjustment margin, etc. (step S3). Then, information indicating that a predetermined load is operating independently, and the stored independent operation system maintenance time, are transmitted to the loads and equipment such as the distributed power supply 10 within the independent operation system (step S4).

[0033] This allows loads within the standalone system and distributed power sources 10 to confirm future supply and demand plans, adjust load levels (including shutting down non-essential loads), and prevent unexpected power outages for consumers, thereby ensuring smooth operation.

[0034] Figure 3 is a flowchart illustrating a scenario where, under normal circumstances, an accident occurs in a designated section of track, and the time required to maintain independent operation in that section is calculated and stored in advance. This stored time is then transmitted to each piece of equipment in the event of an actual accident. In Figure 3, the system monitoring and control device 100 pre-determines all points [i] within the section as fault points during normal operation. Then, in the event that a fault occurs and the system is shut off at point [i], the device calculates and stores the time for which island operation can be maintained for the load in the remaining section, based on the time schedule of the power generation amount and load amount of the distributed power source 10 (including their predicted values), the reserve capacity for power generation adjustment, the reserve capacity for load adjustment, etc. (step S12), and repeats this process for all points (steps S13, S11). Subsequently, if an accident actually occurs at point [i] (step S14YES), information indicating that a predetermined load is operating in an island state, and a pre-stored island operation system maintenance time are transmitted to the loads and equipment such as the distributed power supply 10 within the island operation system (step S15).

[0035] This allows for the rapid transmission of information indicating that an accident is occurring, as well as the remaining time the isolated operation system can be maintained, to each piece of equipment in the event of an actual accident, thereby contributing to a faster response at each piece of equipment. [Explanation of symbols]

[0036] A1~A5: Section PV: Photovoltaic power generation equipment PCS: Power Conditioner System F3,F4,F5: Accident point 10: Distributed power supply 21-26: Circuit breaker 31-35: Load 40: Grid power supply 100: System monitoring and control device

Claims

1. In a power system monitoring and control device for monitoring and controlling a power system in which multiple sections are formed between a grid power source and a distributed power source via circuit breakers, and loads are connected to each of these multiple sections, The system includes a function to monitor the amount of power generated by the distributed power source, a function to receive fault information in the power system, a function to monitor the open / closed state of the circuit breaker and a function to control the open / closed state, a function to monitor the load amount of the load, and a function to transmit to the loads in the islanding system and the distributed power source that the islanding system is configured with the distributed power source when the fault information is received. A system monitoring and control device characterized by controlling the opening and closing of the circuit breaker so that the islanding system is configured based at least on the amount of power generated by the distributed power source and the load amount of the load.

2. In the system monitoring and control device described in claim 1, A system monitoring and control device characterized by controlling the opening and closing of the circuit breaker so that when the amount of power generated by the distributed power source is greater than or equal to the load amount of the multiple consecutive sections, the multiple sections constitute an isolated operating system.

3. In the system monitoring and control device described in claim 1, A system monitoring and control device characterized by controlling the opening and closing of the circuit breaker so that the sum of the amount of power generated by the distributed power sources and the reserve capacity for adjusting the amount of power generated is greater than or equal to the load amount of the multiple consecutive sections, thereby forming an isolated operating system.

4. In the system monitoring and control device described in claim 1, A system monitoring and control device characterized by controlling the opening and closing of the circuit breaker so that when the amount of power generated by the distributed power sources is greater than or equal to the difference between the load amount and the load adjustment capacity of a plurality of consecutive sections, the plurality of sections constitute an isolated operating system.

5. In the system monitoring and control device described in claim 1, A system monitoring and control device characterized by controlling the opening and closing of the circuit breaker so that the sum of the amount of power generated by the distributed power sources and the remaining capacity for adjusting the amount of power generated is greater than or equal to the difference between the load amount and the remaining capacity for adjusting the load of a plurality of consecutive sections, thereby forming an isolated operating system.

6. In the system monitoring and control device described in claim 3 or 5, A grid monitoring and control device characterized in that the power generation adjustment margin is the difference between the rated output and the current operating output of the distributed power source.

7. In the system monitoring and control device described in claim 3 or 5, A grid monitoring and control device characterized in that the power generation adjustment margin is the difference between the maximum output of the distributed power source and the current operating output.

8. In the system monitoring and control device described in claim 4 or 5, The aforementioned load adjustment margin is A grid monitoring and control device characterized by being a predetermined supply and demand adjustment contract amount or a demand response available amount.

9. In the system monitoring and control device described in claim 1, With respect to the loads that constitute the aforementioned standalone operating system, The load is operating in an islanding state, and the islanding system can be maintained for at least the time calculated based on the time schedules of the power generation amount and the load amount. A system monitoring and control device characterized by its ability to transmit [data].

10. In the system monitoring and control device described in claim 1, For the aforementioned distributed power sources, A grid monitoring and control device capable of transmitting the time required to maintain an isolated grid, calculated based on at least the time schedules of the power generation amount and the load amount.

11. In the system monitoring and control device described in claim 9 or 10, A power system monitoring and control device characterized by calculating and transmitting the aforementioned islanding system maintenance time when an accident occurs in the power system.

12. In the system monitoring and control device described in claim 9 or 10, A power system monitoring and control device characterized by calculating and storing the time during which the islanding system can be maintained before an accident occurs in the power system, and transmitting the stored islanding system maintenance time when an accident actually occurs.

13. In a system monitoring and control device according to any one of claims 1 to 5, The grid monitoring and control device is characterized in that the amount of power generated includes the amount of power generated using the amount of energy stored by the energy storage device inside the distributed power source.

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