Power distribution network energy balance regulation method integrated with protection self-healing function

Abstract

The application discloses a kind of integrated protection self-healing function's power distribution network energy balance regulation and control method, comprising the following steps: S1, power distribution network system normal operation, energy manager acquires the data information of power distribution network system;S2, whether there is change in power distribution network system node load, if yes, enter step S3;If no, power distribution network system if fault enters step S4;If no fault, enter step S1;S3, whether there is fault in power distribution network system, if yes, enter step S4;If no, execute energy manager individual regulation strategy;S4, whether energy manager in power distribution network system adjusts switch position, if yes, adjust distributed power output, enter step S5;If no, carry out distributed protection self-healing system regulation;S5, power distribution network system restores balance.It is realized that energy balance regulation and control under normal operation condition of power distribution network system containing distributed power supply configuration and double-end power supply and self-healing system regulation and control under fault condition and energy regulation after fault self-healing.

Description

Technical Field

[0001] This invention relates to the field of energy regulation technology, and in particular to a distribution network energy balance regulation method with integrated protection and self-healing functions. Background Technology

[0002] Traditional 10kV distribution networks typically only have distribution terminals with three remote functions (telemetry, remote signaling, and remote control), lacking self-healing protection. In recent years, self-healing protection functions in distributed distribution network systems have been piloted and are now being widely adopted, but they are not integrated with energy balance regulation, making them unsuitable for distribution network systems with an increasing number of distributed power sources. Distribution area energy monitoring based on smart integrated terminals mainly focuses on monitoring and controlling distribution area equipment, with less emphasis on energy balance regulation and control. Microgrid energy management systems can regulate energy storage, charging piles, photovoltaic inverters, and other equipment within the system in real time, achieving energy balance regulation of the microgrid system. However, their adjustable range is limited, and in the event of a system fault, distributed power sources in non-faulty areas will lose their adjustability after being disconnected from the grid.

[0003] A patent document published in Chinese, titled "An Energy Management Controller for a Wind-Solar-Storage Microgrid System," with publication number CN104052159B, discloses an energy management controller for a wind-solar-storage microgrid system. This controller includes an energy management and monitoring system, a power generation and storage system, a plant load, a power distribution and protection system, a data acquisition system, and a remote dispatch and monitoring system. It enables the energy management system, remote clients, and the grid dispatch center to obtain real-time operating data of the wind, solar, and storage equipment within the microgrid system, as well as system power distribution parameters. This facilitates the consumption of the entire microgrid system's grid-connected output power by the plant load and allows for hierarchical allocation by the energy management system and the grid, reducing the plant's electricity costs while ensuring the long-term stable grid-connected operation of the wind-solar-storage microgrid system. However, it lacks a strategy for handling fault conditions. Summary of the Invention

[0004] This invention addresses the problem that current microgrid energy management systems have limited energy balance adjustment range and are prone to losing adjustability under fault conditions. It proposes a multi-factor temperature prediction method for primary equipment in substations, including an energy manager and a distributed protection self-healing system. This invention can realize real-time energy balance control under normal operation of a distribution network system with distributed power supply configuration and dual-end power supply, as well as self-healing system control under fault conditions and energy balance adjustment after fault self-healing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a distribution network energy balance regulation method integrating protection and self-healing functions, comprising the following steps:

[0006] S1, the power distribution network system is operating normally, and the energy manager collects real-time data information within the power distribution network system;

[0007] S2, determine whether there is a change in the load of any node in the distribution network system. If yes, proceed to step S3; if no, proceed to step S4 if a fault occurs in the distribution network system; if no fault occurs, proceed to step S1.

[0008] S3, determine whether a fault has occurred in the distribution network system. If yes, proceed to step S4; otherwise, execute the energy manager's individual control strategy.

[0009] S4. Determine whether the energy manager in the distribution network system has adjusted the switch position. If yes, adjust the output of the distributed power source and proceed to step S5; otherwise, perform distributed protection self-healing system control.

[0010] S5, the distribution network system restores balance. In this invention, the energy manager and the distributed protection self-healing system jointly regulate the distribution network system. The regulation process is mainly divided into normal operation and fault conditions of the distribution network system. Under normal operation, the energy manager acquires the position status of all switches in the system and real-time data information of distributed power sources. Under normal operation, the protection control terminals installed at each switch position in the system can receive control commands from the energy manager to realize the opening and closing control of the corresponding switches. At the same time, all protection control terminals realize the distributed protection self-healing function through information sharing. Under fault conditions, the energy manager works together with the distributed protection self-healing system to carry out targeted regulation.

[0011] Preferably, the individual control strategy of the energy manager specifically involves determining whether the load change value of any node in the distribution network system is greater than a preset change value. If so, the distributed power supply output is adjusted after adjusting the switch position; otherwise, the distributed power supply output is adjusted. In this invention, there is a preset change value within the system. If the change value is greater than the preset change value, it is determined that the node load change is large. In this case, the system will first calculate how to achieve energy balance in the region by adjusting the output of different distributed power supplies while keeping the switch positions unchanged. If adjusting the distributed power supply output cannot meet the energy balance of all nodes in the region, the energy balance control in the region is achieved by opening or closing the switches in the system and changing the position of the tie switches. If the change value is less than the preset change value, it is determined that the node load change is small, and the distributed power supply output can be adjusted.

[0012] Preferably, the regulation process of the distributed protection self-healing system includes the following steps:

[0013] S41, the distributed protection self-healing system performs self-healing logic charging;

[0014] S42, performs protective actions to isolate the fault after a fault occurs;

[0015] S43, perform self-healing action to restore power supply to non-faulty areas, adjust distributed power output, and restore system balance. In this invention, the self-healing logic is closely related to the tie switch. After the tie switch position changes, the self-healing logic needs to be recharged. The protection action is that when a fault occurs, the protection control terminal trips the switches on both sides of the fault point to isolate the fault. There are two power sources on both sides of the system, and a series of switches in the middle. One of these switches is open (the tie switch), and the rest are closed. In this way, the two power sources supply power to the loads on both sides of the tie switch. When a fault occurs on one side, the switches on both sides of the fault point trip to isolate the fault, but the load between the fault point and the tie switch is also de-energized. The self-healing action is to close the tie switch under these circumstances to restore power supply to this part of the load.

[0016] Preferably, after the self-healing action in step S43, the energy manager can only achieve maximum energy balance regulation within the system by adjusting the output of the distributed power supply, and at this time, the output adjustment of the distributed power supply does not consider the margin set under normal system operation. In this invention, in the event of a system fault, because the protection action and self-healing action clear the fault (trip the switches on both sides of the fault point) and self-heal (close the interconnection switch), the energy manager cannot arbitrarily open and close the switches to achieve system energy balance. It can only achieve system energy balance by adjusting the output of the distributed power supply. Since the switches cannot be arbitrarily opened and closed, the output power adjustment of the distributed power supply does not consider the margin.

[0017] Preferably, if a fault occurs when the energy manager is controlled independently, the process proceeds to step S3 for further handling. In this invention, the energy manager may also malfunction when controlled independently; the handling method varies depending on whether the energy manager's switch position has been adjusted.

[0018] Preferably, during the self-healing action in step S43, the energy manager cannot adjust the switch position. In this invention, the opening and closing operation of the energy manager is locked, and this lockout signal can only be released by manual reset after confirming that the system fault has been eliminated.

[0019] Preferably, in step S4, if a fault occurs immediately after the energy manager adjusts the switch position, the self-healing logic will not be triggered; after the system balance is restored and the self-healing logic is fully charged, the distributed protection self-healing system can be controlled if a fault occurs. In this invention, the self-healing logic also changes after the switch position is adjusted, and the original contact switch positions all change, so a certain amount of time is required for the self-healing logic to charge.

[0020] Preferably, the system includes a function to identify and remember situations where the load variation value of a node in the distribution network exceeds a preset value. For identified load variations, the system first checks if a feasible control strategy exists in the memory. If a feasible control strategy exists, the optimal strategy is selected for control. If no feasible control strategy exists, control is performed again and the result is stored in the memory corresponding to the load variation. In this invention, the function to identify large load variations refers to situations where the range of load variation is large or where adjusting the output of distributed power sources alone is insufficient to achieve system energy balance after a load variation. The function to remember large load variation refers to the control strategy adopted by the system after identifying large load variations.

[0021] The beneficial effects of this invention are:

[0022] 1. Realize real-time energy balance regulation of a power distribution network system with distributed power supply under normal operation, and achieve system energy balance by adjusting the output of each distributed power source and the position of the sectionalizing switch within the system;

[0023] 2. To enable automatic isolation of faulty areas and restoration of power supply to non-faulty areas in the event of a fault in a distribution network system with dual-end power supply configuration containing distributed power sources, while completing a new energy balance adjustment after self-healing. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of energy balance adjustment under normal operating conditions of the power distribution network system according to the present invention;

[0025] Figure 2 This is a schematic diagram of the adjustment of the distributed protection self-healing system under fault conditions in the power distribution network system of the present invention. Detailed Implementation

[0026] Example:

[0027] This embodiment proposes a distribution network energy balance control method with integrated protection and self-healing functions, referencing... Figure 1 and Figure 2 The process mainly includes the following steps: Step S1, the power distribution network system is operating normally, and the energy manager collects real-time data information within the power distribution network system; the real-time data information specifically includes the position status of all switches within the power distribution network system and the real-time data information of distributed power sources.

[0028] Step S2: Initially determine whether the load of any node in the distribution network system has changed. If yes, proceed to step S3; if no, proceed to step S4 if a fault occurs in the distribution network system; if no fault occurs, proceed to step S1. Specifically, a fault may occur even when the load of a node in the distribution network system has not changed. If no fault occurs, no further control steps are required.

[0029] Step S3: Determine whether a fault has occurred in the distribution network system. If yes, proceed to step S4; otherwise, execute the energy manager's individual control strategy. Specifically, in the absence of a fault, the energy manager performs individual control; if a fault occurs, subsequent steps for judgment and control are required.

[0030] The energy manager's individual control strategy specifically involves determining whether the load change value at any node in the distribution network system exceeds a preset change value. If so, the distributed power source output is adjusted after adjusting the switch position; otherwise, the distributed power source output is adjusted. In this embodiment, there is a preset change value within the system. If the change value exceeds the preset change value, it is determined that the node load change is large. In this case, the system will first calculate how to achieve energy balance within the region by adjusting the output of different distributed power sources while keeping all switch positions unchanged. If adjusting the distributed power source output cannot meet the energy balance of all nodes within the region, the system switches will be opened or closed, and the position of tie switches will be changed to achieve the purpose of energy balance control within the region. If the change value is less than the preset change value, it is determined that the node load change is small, and the distributed power source output can be adjusted. To ensure that the distributed power source output can be adjusted in real time and that there is still room for adjustment after a system failure, under normal operating conditions, the distributed power source output is set with a certain margin, and the output power does not exceed 70% of the maximum output power.

[0031] If a fault occurs when executing the individual control strategy of the energy manager, the process proceeds to step S3 for handling. In this embodiment, the energy manager may also malfunction when controlled individually, and the handling method varies depending on whether the switch position of the energy manager has been adjusted.

[0032] The system is equipped with a function to identify and remember situations where the load variation value of a node in the distribution network exceeds a preset variation value. For identified load variations, it first checks whether a feasible control strategy exists in the memory. If a feasible control strategy exists in the memory, the optimal strategy is selected for control. If no feasible control strategy exists in the memory, control is performed again and the result is stored in the memory of the corresponding load variation. In this embodiment, the function to identify large load variations refers to situations where the range of load variation is large or where it is difficult to achieve system energy balance by adjusting the output of distributed power sources alone after a load variation. The function to remember large load variations refers to the control strategy adopted by the system after identifying large load variations.

[0033] Step S4: Finally, determine whether the energy manager in the distribution network system has adjusted the switch position. If yes, adjust the output of the distributed power source and proceed to step S5; if no, perform distributed protection self-healing system control. Specifically, after the switch position has just been adjusted, the self-healing logic cannot perform self-healing actions during charging.

[0034] The process of regulating the distributed protection self-healing system includes the following steps: Step S41, firstly, the distributed protection self-healing system is charged with its self-healing logic; Step S42, secondly, after a fault occurs, a protection action is performed to isolate the fault; Step S43, finally, a self-healing action is performed to restore power supply to the non-faulty area, adjust the distributed power output, and restore system balance. In this embodiment, the self-healing logic is closely related to the tie switch. After the position of the tie switch changes, the self-healing logic needs to be recharged; the protection action is that when a fault occurs, the protection control terminal trips the switches on both sides of the fault point to isolate the fault. There are two power sources on both sides of the system, and a series of switches in the middle. One of these switches is open (the tie switch), and the rest are closed. In this way, the two power sources supply power to the loads on both sides of the tie switch respectively. When a fault occurs on one side, the switches on both sides of the fault point trip to isolate the fault, but the load between the fault point and the tie switch is also de-energized. The self-healing action is to close the tie switch under these circumstances to restore power supply to this part of the load.

[0035] In step S43, after the self-healing action, the energy manager can only achieve maximum energy balance regulation within the system by adjusting the output of the distributed power source. At this time, the output adjustment of the distributed power source does not consider the margin set under normal system operation. In this embodiment, in the event of a system fault, because the protection and self-healing actions clear the fault (trip the switches on both sides of the fault point) and self-heal (close the interconnection switch), the energy manager cannot arbitrarily open and close the switches to achieve system energy balance. It can only achieve system energy balance by adjusting the output of the distributed power source. Since the switches cannot be arbitrarily opened and closed, the output power regulation of the distributed power source does not consider the margin.

[0036] Furthermore, during the self-healing process in step S43, the energy manager cannot adjust its switch position. In this embodiment, the opening and closing operation of the energy manager is locked, and this lockout signal can only be released by manual reset after confirming that the system fault has been eliminated. After confirming that the system fault has been eliminated and manually resetting, the energy manager returns to normal operation.

[0037] Furthermore, in step S4, if a fault occurs immediately after the energy manager adjusts the switch position, the self-healing logic will not be triggered; after the system balance is restored and the self-healing logic is fully charged, the distributed protection self-healing system can be controlled if a fault occurs. In this invention, the self-healing logic also changes after the switch position is adjusted, and the original contact switch positions all change, so a certain amount of time is required for the self-healing logic to charge.

[0038] In step S5, the power distribution network system is finally restored to balance.

[0039] In this invention, the energy manager and the distributed protection self-healing system jointly regulate the power distribution network system. The regulation process is mainly divided into normal operation and fault conditions of the power distribution network system. Under normal operation, the energy manager acquires the position status of all switches in the system and real-time data information of distributed power sources. Under normal operation, the protection control terminals installed at each switch position in the system can receive control commands from the energy manager to realize the opening and closing control of the corresponding switches. At the same time, all protection control terminals realize the distributed protection self-healing function through information sharing. Under fault conditions, the energy manager works together with the distributed protection self-healing system to carry out targeted regulation.

[0040] In this invention, if the energy manager involves adjusting the opening and closing of a switch during the system energy balance adjustment process, the system self-healing function is temporarily locked during the switch opening and closing operation, that is, the self-healing action cannot be performed temporarily until the switch opening and closing operation is completed and the system self-healing function is reopened. The distributed protection self-healing system recharges the self-healing logic according to the switch position after the energy manager's action.

[0041] The above embodiments are further elaborations and descriptions of the present invention to facilitate understanding, and are not intended to limit the present invention in any way. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A power distribution network energy balance regulation method integrated with protection self-healing function, characterized in that, It comprises the following steps: S1, the power distribution network system is in normal operation, and the energy manager collects real-time data information in the power distribution network system; S2, it is judged whether the load of any node of the power distribution network system has changed, if yes, step S3 is entered; if no, if a fault occurs in the power distribution network system, step S4 is entered; if no fault occurs, step S1 is entered; S3, it is judged whether a fault occurs in the power distribution network system, if yes, step S4 is entered; if no, the energy manager independent control strategy is executed; S4, it is judged whether the energy manager adjusts the switch position in the power distribution network system, if yes, the output of the distributed power supply is adjusted, and step S5 is entered; if no, the distributed protection self-healing system control is performed; S5, the power distribution network system is restored to balance.

2. The power distribution network energy balance regulation method integrated with protection and self-healing functions according to claim 1, characterized in that, The energy manager independent control strategy specifically judges whether the load variation value of any node of the power distribution network system is greater than a preset variation value, if yes, the node load variation is large, at this time, the energy balance in the region is realized only by adjusting the output of different distributed power supplies under the condition that the switch positions are unchanged, in the case that the adjustment of the output of the distributed power supply cannot meet the energy balance of all nodes in the region, the switches in the system are opened or closed, and the position of the tie switch is changed; if no, the output of the distributed power supply is adjusted.

3. The power distribution network energy balance regulation method integrated with protection and self-healing functions according to claim 1, characterized in that, The process of the distributed protection self-healing system control comprises the following steps: S41, the distributed protection self-healing system performs self-healing logic charging; S42, after a fault occurs, a protection action is performed to isolate the fault; S43, a self-healing action is performed to restore power supply of a non-fault region, the output of the distributed power supply is adjusted, and the system balance is restored.

4. The power grid energy balance regulation method integrated with protection and self-healing functions according to claim 3, characterized in that, After the self-healing action in step S43 is performed, the energy manager can only realize the system energy balance adjustment to the maximum extent by adjusting the output of the distributed power supply, and at this time, the output adjustment of the distributed power supply does not consider the margin set under the condition that the system is in normal operation.

5. The power distribution network energy balance regulation method integrated with protection and self-healing functions according to claim 1 or 2, characterized in that, When the energy manager independent control strategy is executed, if a fault occurs, the process is transferred to step S3 for processing.

6. The power grid energy balance regulation method integrated with protection and self-healing functions according to claim 3, characterized in that, During the execution of the self-healing action in step S43, the energy manager cannot adjust the switch position.

7. The power grid energy balance regulation method integrated with protection and self-healing functions according to claim 1, characterized in that, In step S4, after the energy manager adjusts the switch position, if a fault occurs immediately, the self-healing logic will not be triggered; after the system balance is restored, if a fault occurs after the self-healing logic charging is completed, the distributed protection self-healing system control can be performed.

8. The power distribution network energy balance control method integrated with a protection self-healing function according to claim 2, characterized in that an identification and memory function is set for the case that the node load variation value of the power distribution network system is greater than a preset variation value, for the identified load variation, it is preferred to judge whether there is a feasible control strategy in the memory, if there is a feasible control strategy in the memory, the optimal strategy is selected for control; if there is no feasible control strategy in the memory, the control is re-performed and stored in the memory corresponding to the load variation.

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