Overload management method and device based on micro-grid light storage and charging station

Abstract

The present application relates to the technical field of power system, specifically relates to overload management method and device based on micro-grid light storage and filling station, the method comprises: according to the active power of the gateway electric meter and the rated power of transformer, the overload power of the transformer is calculated;Wherein the gateway electric meter is arranged at the low-voltage side total incoming line of the transformer;According to the positive and negative of transformer overload power, the overload state is judged, and the corresponding power control operation is executed to each system participating in regulation according to the preset priority.

Description

Technical Field

[0001] This invention relates to the field of power system technology, specifically to overload mitigation methods and devices based on microgrid photovoltaic-storage-charging stations. Background Technology

[0002] Because transformer capacity is limited, while the load on charging stations far exceeds the transformer's capacity, and charging piles are the largest load on the station, when the load power of the charging station exceeds a certain value of the transformer's rated power, the transformer will trip due to overcurrent, causing a power outage for the entire station. In recent years, obtaining transformer permits has become increasingly difficult, and the cost of station renovation is also very high. In addition, transformer overload can cause power system instability and induce safety accidents. Summary of the Invention

[0003] The purpose of this invention is to provide an overload management method and apparatus for microgrid photovoltaic-storage-charging stations, which can solve or at least partially solve the above-mentioned defects of the prior art.

[0004] To achieve the above objectives, the first aspect of this invention discloses an overload mitigation method based on a microgrid photovoltaic-storage-charging station, the method comprising: The overload power of the transformer is calculated based on the active power measured by the gate meter and the rated power of the transformer; wherein the gate meter is installed at the low-voltage side main incoming line of the transformer. Determine whether the photovoltaic system, energy storage system, and charging pile participate in power regulation respectively; When the overload power of the transformer is greater than 0, the transformer is determined to be overloaded, and corresponding power regulation operations are performed on each system participating in power regulation according to a preset priority order, including: The power output of the photovoltaic system is increased, the power output of the energy storage system is increased, and the power output of the charging pile is decreased; and When the overload power of the transformer is less than or equal to 0, it is determined that the transformer is not overloaded. The corresponding power regulation operations are then performed on each system participating in the power regulation according to a preset priority order, including: For the photovoltaic system, the power generation is adjusted to the sum of the current power generation and the active power measured by the gate meter, but not exceeding the rated power of the photovoltaic system; For the energy storage system, during the discharge phase, the system discharges according to the active power measured by the gate meter, and during the charging phase, it charges according to the difference between the rated power of the transformer and the active power measured by the gate meter. For the charging pile, the total charging power is adjusted according to the charging pile's required power and rated power.

[0005] Preferably, the power increase for the photovoltaic system includes: Based on the current power generation of the photovoltaic system. The total controlled photovoltaic power in the last adjustment and rated power Preset threshold The current overload power of the transformer And the following formula is used to calculate the total controlled photovoltaic power of the photovoltaic system. : like ,but ;otherwise ; The total photovoltaic control power The photovoltaic capacity is allocated to each photovoltaic inverter according to the photovoltaic capacity ratio. Preferably, the step of increasing the power of the energy storage system includes: If the transformer is still overloaded, the current discharge power corresponding to the energy storage system will be used. and rated power The current remaining overload power of the transformer And the following formula is used to calculate the total discharge power corresponding to the energy storage system. : ; The total discharge power The energy storage units are allocated to each energy storage unit according to their SOC ratio.

[0006] Preferably, the reduction of power for the charging pile includes: If the transformer is still overloaded, the current total charging power corresponding to the charging pile will be used as a reference. and rated power The current remaining overload power of the transformer The total charging power of the charging pile is calculated using the following formula. : ; The total charging power The allocation will be carried out according to the power demand ratio of each charging station.

[0007] Preferably, for the photovoltaic system, adjusting the power generation to the sum of the current power generation and the active power measured by the gate meter, but not exceeding the rated power of the photovoltaic system, includes: Based on the current power generation of the photovoltaic system and rated power The active power measured by the aforementioned gate meter And the following formula is used to calculate the total control power of the photovoltaic system. : The total control power The photovoltaic capacity is allocated to each photovoltaic inverter according to the photovoltaic capacity ratio. Preferably, for the energy storage system, discharging according to the active power measured by the gate meter during the discharge phase, and charging according to the difference between the transformer's rated power and the active power measured by the gate meter during the charging phase, includes: When the energy storage system enters the discharge phase: based on the active power measured by the gate meter... The rated power of the energy storage system The total discharge power of the energy storage system is calculated using the following formula. : ; The total discharge power The energy storage units are allocated to each energy storage unit according to their SOC ratio for execution. When the energy storage system enters the charging phase: based on the active power measured by the gate meter. The rated power of the energy storage system The rated power of the transformer And the following formula is used to calculate the total charging power of the energy storage system. : ; The total charging power The energy storage units are allocated to each energy storage unit according to their SOC ratio.

[0008] Preferably, adjusting the charging power according to the charging pile's required power and rated power includes: According to the required power of the charging pile and rated power The total charging power of the charging pile is calculated using the following formula. : ; The total charging power The allocation will be carried out according to the power demand ratio of each charging station. A second aspect of the present invention discloses an overload management device for a microgrid-based photovoltaic-storage-charging station, comprising: a memory configured to store instructions; and a processor configured to retrieve the instructions from the memory and, when executing the instructions, to implement the overload management method for the microgrid-based photovoltaic-storage-charging station.

[0009] A third aspect of the present invention discloses a machine-readable storage medium storing instructions for causing a machine to execute the overload management method based on a microgrid photovoltaic-storage-charging station.

[0010] The overload management method for microgrid-based photovoltaic-storage-charging stations provided in this invention monitors the overload status of transformers in real time and performs differentiated power regulation according to the fixed priority order of photovoltaic, energy storage, and charging piles. This effectively avoids transformer overload tripping and ensures the continuity of power supply to the station. At the same time, it optimizes the power allocation of each system under non-overload conditions, improves the photovoltaic absorption rate and energy storage utilization efficiency, and achieves economical and stable operation of the station. Attached Figure Description

[0011] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 A schematic diagram of a photovoltaic energy storage and charging station in the prior art is shown; Figure 2 A flowchart illustrating the overload mitigation method for microgrid-based photovoltaic-storage-charging stations provided by the present invention is shown. Figure 3 A schematic diagram showing the installation location of the overload mitigation device based on microgrid photovoltaic energy storage and charging stations provided by the present invention is shown. Detailed Implementation

[0012] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0013] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0014] Figure 1 A schematic diagram of a photovoltaic energy storage and charging station in the prior art is shown, such as... Figure 1 As shown, the energy storage system, photovoltaic system, and charging piles are all connected to the low-voltage side of the transformer. When the power consumption of the power station exceeds the sum of the photovoltaic power generation, the energy storage system discharge power, and the transformer's rated power, the transformer will overload and trip due to overcurrent protection, resulting in a power outage for the entire power station.

[0015] To address the transformer overload tripping problem in existing technologies, this invention proposes an overload mitigation method for microgrid photovoltaic-storage-charging stations. This method uses data collected from the active power measured by the meter at the gateway, the power generation of the photovoltaic system, the operating parameters of the energy storage system, and the power data of the charging piles to determine in real time whether the transformer is overloaded. When an overload occurs, the power of each system is adjusted sequentially according to a fixed priority order: first the photovoltaic system, then the energy storage system, and finally the charging piles, until the transformer overload is eliminated. This prevents the transformer from tripping due to overcurrent, thus ensuring a continuous and stable power supply to the station.

[0016] Figure 2 This diagram illustrates the overload mitigation method for a microgrid-based photovoltaic-storage-charging station provided by the present invention. In this photovoltaic-storage-charging station, the photovoltaic system, energy storage system, and charging piles all participate in power regulation. Figure 2 The method may include the following steps S100~S104: S100, collecting active power measured by the meter at the collection point, power generation of the photovoltaic system, actual charging and discharging power, SOC value, maximum charging power and maximum discharging power of the energy storage system, and charging power and demand power of the charging pile.

[0017] S101. Calculate the overload power of the transformer based on the active power measured by the meter at the gate and the rated power of the transformer. The gate meter is installed at the low-voltage side main incoming line of the transformer. The active power measured by the gate meter represents the power output by the transformer to the station bus.

[0018] In one embodiment of the present invention, the active power measured by the gate meter is used. Rated power of transformer And the following formula is used to calculate the overload power of the transformer. : .

[0019] S102. Determine whether the photovoltaic system, energy storage system, and charging pile participate in power regulation respectively; The power regulation priority for each system is as follows: first, power regulation is performed on the photovoltaic system; then, power regulation is performed on the energy storage system; and finally, power regulation is performed on the charging pile.

[0020] S103. When the overload power of the transformer is greater than 0, the transformer is determined to be overloaded, and corresponding power regulation operations are performed on each system participating in power regulation according to a preset priority order, including: S201. Increase the power of the photovoltaic system; In one embodiment of the present invention, the step of increasing the power of the photovoltaic system includes: First, based on the current power generation of the photovoltaic system. The total controlled photovoltaic power in the last adjustment and rated power Preset threshold The current overload power of the transformer And the following formula is used to calculate the total controlled photovoltaic power of the photovoltaic system. : like ,but ;otherwise ; in, It means that when season .

[0021] Then, using the calculated total photovoltaic control power Update the total controlled photovoltaic power of the last adjustment. This is used for the next iteration calculation.

[0022] Next, the total photovoltaic control power is... The photovoltaic capacity is allocated to each photovoltaic inverter according to the photovoltaic capacity ratio.

[0023] Specifically, ; .

[0024] Finally, the overload power of the transformer is initially calculated using step S101. And the total photovoltaic control power calculated in step S201 The difference is used to determine the current remaining overload power of the transformer. ,like If the condition is met, the overload management process ends and the entire management procedure is interrupted; otherwise, the transformer is determined to be still overloaded.

[0025] S202, Increase the power of the energy storage system; In one embodiment of the present invention, if the transformer is still overloaded after the power of the photovoltaic system is increased, the current discharge power of the energy storage system is first determined. and rated power The current remaining overload power of the transformer And the following formula is used to calculate the total discharge power corresponding to the energy storage system. : ; in, It means that when season = ; Then, the total discharge power The energy storage units are allocated to each energy storage unit according to their SOC ratio.

[0026] Specifically, ; ; Finally, using the current remaining overload power of the transformer after executing step S201... The total discharge power of the energy storage system calculated in step S202 The difference is used to iteratively update the current remaining overload power of the transformer. ,like If the condition is met, the overload management process ends and the entire management procedure is interrupted; otherwise, the transformer is determined to be still overloaded.

[0027] S203. Reduce the power of the charging pile; In one embodiment of the present invention, if the transformer is still overloaded after the power of the energy storage system is increased, firstly, based on the current total charging power corresponding to the charging pile... and rated power The current remaining overload power of the transformer The total charging power of the charging pile is calculated using the following formula. : ; in, Indicates when season .

[0028] Then, the total charging power The allocation will be based on the power demand ratio of each charging station.

[0029] Specifically, ; .

[0030] S104. When the overload power of the transformer is less than or equal to 0, it is determined that the transformer is not overloaded, and corresponding power regulation operations are performed on each system participating in power regulation according to a preset priority order, including: S301. For the photovoltaic system, the power generation is adjusted to the sum of the current power generation and the active power measured by the gate meter, but not exceeding the rated power of the photovoltaic system. In one embodiment of the present invention, adjusting the power generation of the photovoltaic system to the sum of the current power generation and the active power measured by the gate meter, but not exceeding the rated power of the photovoltaic system, includes: First, based on the current power generation of the photovoltaic system and rated power The active power measured by the aforementioned gate meter And the following formula is used to calculate the total control power of the photovoltaic system. : in, express ， when > hour ， make .

[0031] Then, the total control power The photovoltaic capacity is allocated to each photovoltaic inverter according to the photovoltaic capacity ratio.

[0032] S302. For the energy storage system, during the discharge phase, the system discharges according to the active power measured by the gate meter, and during the charging phase, the system charges according to the difference between the rated power of the transformer and the active power measured by the gate meter. In one embodiment of the present invention, when the energy storage system enters the discharge phase: based on the active power measured by the gate meter... The rated power of the energy storage system The total discharge power of the energy storage system is calculated using the following formula. : ; The total discharge power The energy storage units are allocated to each energy storage unit according to their SOC ratio for execution. When the energy storage system enters the charging phase: based on the active power measured by the gate meter. The rated power of the energy storage system The rated power of the transformer And the following formula is used to calculate the total charging power of the energy storage system. : ; min The function represents the minimum value among two numbers.

[0033] The total charging power The energy storage system is allocated to each energy storage unit according to its SOC ratio. ; ; .

[0034] S303. For the charging pile, adjust the charging power according to the charging pile's required power and rated power.

[0035] In one embodiment of the present invention, The step of adjusting the charging power according to the charging pile's required power and rated power includes: According to the required power of the charging pile and rated power The total charging power of the charging pile is calculated using the following formula. : ; , . min The function represents the minimum value among two numbers.

[0036] The total charging power The allocation will be based on the power demand ratio of each charging station. This invention provides an overload mitigation device for a microgrid-based photovoltaic-storage-charging station, comprising: a memory configured to store instructions; and a processor configured to retrieve the instructions from the memory and, when executing the instructions, to implement the overload mitigation method for the microgrid-based photovoltaic-storage-charging station. Figure 3 A schematic diagram showing the installation location of the overload mitigation device based on a microgrid photovoltaic-storage-charging station provided by the present invention is shown. (Refer to...) Figure 3 The meter A and the photovoltaic system are connected to the overload mitigation device of the microgrid-based photovoltaic-storage-charging station via a 485 serial port; the energy storage system and the charging pile are connected to the overload mitigation device B of the microgrid-based photovoltaic-storage-charging station via a network cable.

[0037] The overload mitigation device B, based on a microgrid photovoltaic-storage-charging station, collects the following data: the active power of the meter at the gateway, the power generation of the photovoltaic system, the operating power and SOC value of the energy storage system, the maximum charging / discharging power of the energy storage system, and the charging power and demand power of the charging piles. It then analyzes the collected data to calculate whether the transformer is overloaded. If the transformer is overloaded, the overload problem is mitigated by controlling the photovoltaic power generation, the energy storage system discharge power, and the charging pile charging power.

[0038] This invention provides a machine-readable storage medium storing instructions that cause a machine to execute the overload mitigation method based on a microgrid photovoltaic-storage-charging station.

[0039] The overload management method for microgrid-based photovoltaic-storage-charging stations provided in this invention monitors the overload status of transformers in real time and performs differentiated power regulation according to the fixed priority order of photovoltaic, energy storage, and charging piles. This effectively avoids transformer overload tripping and ensures the continuity of power supply to the station. At the same time, it optimizes the power allocation of each system under non-overload conditions, improves the photovoltaic absorption rate and energy storage utilization efficiency, and achieves economical and stable operation of the station.

[0040] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0041] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0042] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes: a USB flash drive, a portable hard drive, and a read-only memory (ROM). Various media that can store program code, such as only memory, random access memory (RAM), magnetic disks or optical disks.

[0043] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. An overload mitigation method based on microgrid photovoltaic-storage-charging stations, characterized in that, The method includes: The overload power of the transformer is calculated based on the active power measured by the gate meter and the rated power of the transformer; wherein the gate meter is installed at the low-voltage side main incoming line of the transformer. Determine whether the photovoltaic system, energy storage system, and charging pile participate in power regulation respectively; When the overload power of the transformer is greater than 0, the transformer is determined to be overloaded, and corresponding power regulation operations are performed on each system participating in power regulation according to a preset priority order, including: The power output of the photovoltaic system is increased, the power output of the energy storage system is increased, and the power output of the charging pile is decreased; and When the overload power of the transformer is less than or equal to 0, it is determined that the transformer is not overloaded. The corresponding power regulation operations are then performed on each system participating in the power regulation according to a preset priority order, including: For the photovoltaic system, the power generation is adjusted to the sum of the current power generation and the active power measured by the gate meter, but not exceeding the rated power of the photovoltaic system; For the energy storage system, during the discharge phase, the system discharges according to the active power measured by the gate meter, and during the charging phase, it charges according to the difference between the rated power of the transformer and the active power measured by the gate meter. For the charging pile, the total charging power is adjusted according to the charging pile's required power and rated power.

2. The method according to claim 1, characterized in that, The power increase for the photovoltaic system includes: Based on the current power generation of the photovoltaic system. The total controlled photovoltaic power in the last adjustment and rated power Preset threshold The current overload power of the transformer And the following formula is used to calculate the total controlled photovoltaic power of the photovoltaic system. : like ,but ;otherwise ; The total photovoltaic control power The photovoltaic capacity is allocated to each photovoltaic inverter according to the photovoltaic capacity ratio.

3. The method according to claim 1, characterized in that, The power increase for the energy storage system includes: If the transformer is still overloaded, the current discharge power corresponding to the energy storage system will be used. and rated power The current remaining overload power of the transformer And the following formula is used to calculate the total discharge power corresponding to the energy storage system. : ； The total discharge power The energy storage units are allocated to each energy storage unit according to their SOC ratio.

4. The method according to claim 1, characterized in that, The reduction of power for the charging pile includes: If the transformer is still overloaded, the current total charging power corresponding to the charging pile will be used as a reference. and rated power The current remaining overload power of the transformer The total charging power of the charging pile is calculated using the following formula. : ； The total charging power The allocation will be carried out according to the power demand ratio of each charging station.

5. The method according to claim 1, characterized in that, For the photovoltaic system, adjusting the power generation to the sum of the current power generation and the active power measured by the gate meter, but not exceeding the rated power of the photovoltaic system, includes: Based on the current power generation of the photovoltaic system and rated power The active power measured by the aforementioned gate meter And the following formula is used to calculate the total control power of the photovoltaic system. : The total control power The photovoltaic capacity is allocated to each photovoltaic inverter according to the photovoltaic capacity ratio.

6. The method according to claim 1, characterized in that, For the energy storage system, discharging during the discharge phase according to the active power measured by the gate meter, and charging during the charging phase according to the difference between the transformer's rated power and the active power measured by the gate meter include: When the energy storage system enters the discharge phase: based on the active power measured by the gate meter... The rated power of the energy storage system The total discharge power of the energy storage system is calculated using the following formula. : ； The total discharge power The energy storage units are allocated to each energy storage unit according to their SOC ratio for execution. When the energy storage system enters the charging phase: based on the active power measured by the gate meter. The rated power of the energy storage system The rated power of the transformer And the following formula is used to calculate the total charging power of the energy storage system. : ； The total charging power The energy storage units are allocated to each energy storage unit according to their SOC ratio.

7. The method according to claim 1, characterized in that, The step of adjusting the charging power according to the charging pile's required power and rated power includes: According to the required power of the charging pile and rated power The total charging power of the charging pile is calculated using the following formula. : ； The total charging power The allocation will be based on the power demand ratio of each charging station.

8. An overload mitigation device based on a microgrid photovoltaic-storage-charging station, characterized in that, include: The memory is configured to store instructions; The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the overload mitigation method for microgrid-based photovoltaic-storage-charging stations according to any one of claims 1 to 7.

9. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions for causing the machine to execute the overload mitigation method for microgrid-based photovoltaic-storage-charging stations according to any one of claims 1 to 7.

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