Light-storage-charging cooperative control and high-quality power supply method under limited measurement of power distribution network

Abstract

The invention provides a photovoltaic-storage-charging cooperative control and high-quality power supply method under limited measurement of a power distribution network. The method comprises the following steps: acquiring a system operation condition and aggregation power; judging whether to update the power regulation and control instruction or not based on the system operation condition; if yes, whether the current regulation and control level needs to be reset or not is judged based on the system operation condition; if not, updating the power regulation and control instruction based on the system operation condition, the aggregation power and the current regulation and control level; correcting the power regulation and control instruction to obtain a corrected power regulation and control instruction; distributing the corrected power regulation and control instruction, and carrying out corresponding regulation and control; judging whether the current regulation and control level reaches the maximum regulation and control level or not; and if yes, ending updating the power regulation and control instruction. According to the method provided by the invention, management and control of the voltage and the load rate of the power distribution network can be considered under the condition of limited measurement information through multi-stage regulation and control and feedback correction. Meanwhile, by setting the regulation and control priorities of photovoltaic, energy storage, charging piles and other resources, the photovoltaic utilization rate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power, in particular to a photovoltaic-storage-charging collaborative management and high-quality power supply method under limited measurement of a distribution network. BACKGROUND

[0002] In the direction of reducing energy consumption and greenhouse gas emissions, the penetration rate of distributed photovoltaic (PV) and electric vehicles (EV) in low-voltage distribution networks is rapidly increasing. The volatility of photovoltaic output, the spatio-temporal randomness of electric vehicle charging behavior, and the superimposition of load peaks and valleys lead to increasingly prominent problems of transformer (transformer) overload and node voltage out-of-limit in distribution areas, which seriously threaten the safe and economic operation of distribution networks. To alleviate these problems, the collaborative management of photovoltaic, energy storage (ESS), charging piles and other distributed resources (DER) has become a key means.

[0003] Existing research on photovoltaic-storage-charging collaborative management in low-voltage distribution networks mainly focuses on optimization modeling and data-driven methods. However, in low-voltage distribution networks with incomplete measurement information, existing collaborative management methods face fundamental bottlenecks. 1) Optimization strategies based on physical models (such as model predictive control) require accurate network parameters to construct power flow equations, but low-voltage distribution networks are complex and lack measurement, making it difficult to establish accurate mathematical models. 2) Artificial intelligence (AI) based control algorithms rely on massive historical data for training, but actual low-voltage distribution areas lack sufficient measurement devices and have frequent topology changes, resulting in a lack of training samples and poor model generalization ability. In addition, existing lightweight methods (such as rule-based control) reduce computational complexity, but fail to consider the dynamic coupling characteristics between resources, making it difficult to balance voltage safety and transformer load. SUMMARY

[0004] The present application provides a photovoltaic-storage-charging collaborative management and high-quality power supply method under limited measurement of a distribution network. To solve the above technical problems, the present application adopts the following technical methods: The present application provides a photovoltaic-storage-charging collaborative management and high-quality power supply method under limited measurement of a distribution network, comprising: Step S101: Obtain system operating conditions and aggregated power; Step S102: Determine whether to update power control instructions based on the system operating conditions; If yes, execute step S103; Step S103: Determine whether the current control level needs to be reset based on the system operating conditions; If no, execute step S104; Step S104: Update power control instructions based on the system operating conditions, the aggregated power, and the current control level; Step S105: correcting the power regulation instruction to obtain a corrected power regulation instruction; Step S106: distributing the corrected power regulation instruction to perform corresponding regulation; Step S107: determining whether the current regulation level reaches the maximum regulation level; If yes, ending the updating of the power regulation instruction; If no, increasing the current regulation level by 1 and executing step S101.

[0005] Optionally, the determination process of the aggregated power is: Collecting electrical information of limited monitoring points, the limited monitoring points including grid-connected nodes of photovoltaic, energy storage, charging pile and transformer; the electrical information including available power of photovoltaic, maximum charge-discharge power of energy storage and maximum adjustable power of charging pile; Aggregating the electrical information to obtain an aggregated power, the aggregated power including total available power of photovoltaic, total maximum charge-discharge power of energy storage and total maximum adjustable power of charging pile.

[0006] Optionally, the system operating conditions include voltage operating condition and transformer substation load operating condition, and the process of determining the system operating conditions is: Collecting operating condition judgment information of limited monitoring points, the operating condition judgment information including output power of transformer substation and voltage of photovoltaic grid-connected point; Based on the output power of transformer substation, determining transformer substation load operating conditions, the transformer substation load operating conditions including normal transformer substation load operating condition and abnormal transformer substation load operating condition; Based on the voltage of photovoltaic grid-connected point, determining voltage operating conditions, the voltage operating conditions including normal voltage operating condition and abnormal voltage operating condition.

[0007] Optionally, the process of determining whether to update the power regulation instruction based on the system operating conditions includes: Determining whether the system operating conditions are abnormal voltage operating condition or abnormal transformer substation load operating condition; If yes, updating the power regulation instruction and executing step S103; If no, maintaining the current output.

[0008] Optionally, the power regulation instruction includes voltage out-of-limit power regulation instruction and overload power regulation instruction, and the process of updating the power regulation instruction based on the system operating conditions, the aggregated power and the current regulation level includes: Step S201: determining whether the system operating conditions are abnormal voltage operating condition; If yes, executing step S202; If not, step S203 is performed; Step S202: updating the voltage out-of-limit power regulation instruction based on the voltage abnormal operating condition, the aggregated power and the current regulation level; Step S203: judging whether the system operating condition is a transformer and load abnormal operating condition; If yes, step S204 is performed; If not, step S105 is performed; Step S204: updating the heavy overload power regulation instruction based on the transformer and load abnormal operating condition, the aggregated power and the current regulation level; Step S205: covering the voltage out-of-limit power regulation instruction with the heavy overload power regulation instruction, and performing step S105.

[0009] Optionally, the voltage abnormal operating condition includes a node voltage lower limit exceeding and a node voltage upper limit exceeding, and the voltage out-of-limit power regulation instruction includes first active regulation instructions and first reactive regulation instructions in the voltage abnormal condition; the first active regulation instructions include first photovoltaic active regulation instructions, first energy storage active regulation instructions and first charging pile active regulation instructions, and the first reactive regulation instructions include first photovoltaic reactive regulation instructions and first energy storage reactive regulation instructions; the updating of the voltage out-of-limit power regulation instruction based on the voltage abnormal operating condition, the aggregated power and the current regulation level includes: Step S301: judging whether the voltage abnormal operating condition is a node voltage lower limit exceeding; If yes, step S302 is performed; Step S302: judging whether the current regulation level is less than 1; If yes, step S303 is performed; If not, step S304 is performed; Step S303: updating the first photovoltaic active regulation instruction based on the total available photovoltaic power; updating the first photovoltaic reactive regulation instruction based on the first photovoltaic active regulation instruction and the current regulation level; Step S304: judging whether the energy storage meets a discharging constraint; If yes, step S305 is performed; Step S305: judging whether the current regulation level reaches a first regulation level, the first regulation level being a maximum regulation level of a single type of resource set; If not, step S306 is performed; If yes, step S307 is performed; Step S306: updating the first energy storage active regulation instruction based on the current regulation level, the first regulation level and the total maximum chargeable and dischargeable power of the energy storage; updating the first energy storage reactive regulation instruction based on the first energy storage active regulation instruction and the current regulation level; Step S307: updating the first charging pile active regulation instruction based on the current regulation level, the maximum regulation level and the total maximum adjustable charging pile power.

[0010] Optionally, when the result of the step S304 is no, the following step S308 is performed: Step S308: updating the first charging pile active regulation instruction based on the current regulation level, the first regulation level and the total maximum adjustable charging pile power, and updating the first energy storage active regulation instruction to zero; updating the first energy storage reactive regulation instruction based on the first energy storage active regulation instruction of zero and the current regulation level.

[0011] Optionally, when the result of the step S301 is no, the following step is performed: Step S401: determining whether the current regulation level is less than 1; If yes, step S402 is performed; If no, step S403 is performed; Step S402: updating the first charging pile active regulation instruction based on the total maximum adjustable charging pile power; Step S403: determining whether the energy storage meets the charging constraint; If yes, step S404 is performed; If no, step S407 is performed; Step S404: determining whether the current regulation level reaches the first regulation level; If no, step S405 is performed; If yes, step S406 is performed; Step S405: updating the first energy storage active regulation instruction based on the current regulation level, the first regulation level and the total maximum charge-discharge power of the energy storage; updating the first energy storage reactive regulation instruction based on the first energy storage active regulation instruction and the current regulation level; Step S406: updating the first photovoltaic active regulation instruction based on the current regulation level, the maximum regulation level and the total available photovoltaic power; updating the first photovoltaic reactive regulation instruction based on the first photovoltaic active regulation instruction and the current regulation level; Step S407: updating the first photovoltaic active regulation instruction based on the current regulation level, the first regulation level and the total available photovoltaic power, and updating the first energy storage active regulation instruction to zero; updating the first photovoltaic reactive regulation instruction based on the first photovoltaic active regulation instruction and the current regulation level; updating the first energy storage reactive regulation instruction based on the first energy storage active regulation instruction being zero and the current regulation level.

[0012] Optionally, the abnormal operating condition of the transformer substation load includes forward heavy overload and reverse heavy overload, the heavy overload power regulation instruction includes second active regulation instruction and second reactive regulation instruction in the abnormal operating condition of the transformer substation load; the second active regulation instruction includes second photovoltaic active regulation instruction, second energy storage active regulation instruction and second charging pile active regulation instruction, and the second reactive regulation instruction includes second photovoltaic reactive regulation instruction and second energy storage reactive regulation instruction; the updating of the heavy overload power regulation instruction based on the abnormal operating condition of the transformer substation load, the aggregated power and the current regulation level includes: Step S501: determining whether the abnormal operating condition of the transformer substation load is forward heavy overload; If yes, executing step S502; Step S502: determining whether the current regulation level is less than 1; If yes, executing step S503; If no, executing step S504; Step S503: updating the second photovoltaic active regulation instruction based on the total available power generation of the photovoltaic power station; updating the second photovoltaic reactive regulation instruction based on the second photovoltaic active regulation instruction and the current regulation level; Step S504: determining whether the energy storage meets the discharging constraint; If yes, executing step S505; If no, executing step S508; Step S505: determining whether the current regulation level reaches the first regulation level; If no, executing step S506; If yes, executing step S507; Step S506: updating the second energy storage active regulation instruction based on the total maximum chargeable and dischargeable power of the energy storage; updating the second energy storage reactive regulation instruction based on the second energy storage active regulation instruction and the current regulation level; Step S507: updating the second charging pile active regulation instruction based on the total maximum adjustable power of the charging pile, the maximum regulation level and the current regulation level; Step S508: updating the second charging pile active regulation instruction based on the total maximum adjustable power of the charging pile, the current regulation level and the first regulation level, and updating the second energy storage active regulation instruction to zero; updating the second energy storage reactive regulation instruction based on the second energy storage active regulation instruction being zero.

[0013] Optionally, when the determination result of the step S501 is no, the following steps are performed: Step S601: determining whether the current regulation level is less than 1; If yes, step S602 is performed; If no, step S603 is performed; Step S602: updating the second charging pile active regulation instruction based on the total maximum adjustable power of the charging pile; Step S603: determining whether the energy storage satisfies the charging constraint; If yes, step S604 is performed; If no, step S607 is performed; Step S604: determining whether the current regulation level reaches the first regulation level; If no, step S605 is performed; If yes, step S606 is performed; Step S605: updating the second energy storage active regulation instruction based on the total maximum charge-discharge power of the energy storage, the current regulation level and the first regulation level; updating the second energy storage reactive regulation instruction based on the second energy storage active regulation instruction and the current regulation level; Step S606: updating the second photovoltaic active regulation instruction based on the total available generation power of the photovoltaic, the current regulation level and the maximum regulation level; updating the second photovoltaic reactive regulation instruction based on the second photovoltaic active regulation instruction and the current regulation level; Step S607: determining the second photovoltaic active regulation instruction based on the total available generation power of the photovoltaic, the current regulation level and the first regulation level, and updating the second energy storage active regulation instruction to zero; updating the second photovoltaic reactive regulation instruction based on the second photovoltaic active regulation instruction and the current regulation level; updating the second energy storage reactive regulation instruction based on the second energy storage active regulation instruction being zero and the current regulation level.

[0014] The application has the following beneficial effects: The method provided in the application can control and manage the voltage and load rate of the power distribution network under limited measurement information through multi-level regulation and feedback correction. At the same time, by setting the regulation priority of photovoltaic, energy storage and charging pile resources, the utilization rate of photovoltaic is improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a flowchart of the photovoltaic-energy storage-charging collaborative control and high-quality power supply method under limited measurement of the power distribution network provided by the embodiments of the application; Figure 2 is a flowchart of determining a specific updated power regulation instruction provided by the embodiments of the application; Figure 3 is a flowchart of updating the power regulation instruction when the node voltage of the power distribution network is lower than the lower limit provided by the embodiments of the application; Figure 4 is a flowchart of updating the power regulation instruction when the node voltage of the power distribution network is higher than the upper limit provided by the embodiments of the application; Figure 5 is a flowchart of updating the power regulation instruction when the power distribution network is forwardly overloaded provided by the embodiments of the application; Figure 6 is a flowchart of updating the power regulation instruction when the power distribution network is reversely overloaded provided by the embodiments of the application; Figure 7 is a waveform diagram of the load condition of the transformer area in the simulation stage provided by the embodiments of the application; Figure 8 is a waveform diagram of the predicted power of photovoltaic in the simulation stage provided by the embodiments of the application; Figure 9 is a waveform diagram of the charging load in the simulation stage provided by the embodiments of the application; Figure 10 is a comparison diagram of the 24-hour curve of the load rate before and after regulation in the simulation stage provided by the embodiments of the application; Figure 11 is a comparison diagram of the output of each resource before and after regulation in the simulation stage provided by the embodiments of the application; Figure 11 (a) is a comparison diagram of the output of photovoltaic, Figure 11 (b) is a comparison diagram of the output of energy storage, Figure 11 (c) is a comparison diagram of the output of charging pile; Figure 12 is a detail diagram of forward overload regulation in the simulation stage provided by the embodiments of the application; Figure 12 (a) is a detail diagram of load rate regulation, Figure 12 (b) is a detail diagram of energy storage charging and discharging regulation; Figure 13 is a detail diagram of reverse overload regulation in the simulation stage provided by the embodiments of the application;Figure 13 (a) is a load rate regulation detail map, Figure 13 (b) is a storage charging and discharging regulation detail map, Figure 13 (c) is a photovoltaic output regulation detail map. DETAILED DESCRIPTION

[0016] For the convenience of those skilled in the art, the present application will be further described below in conjunction with the embodiments and the accompanying drawings, and the content mentioned in the embodiments is not a limitation on the present application.

[0017] To solve the above technical problems, the present application provides a photovoltaic-storage-charging collaborative management and high-quality power supply method under limited measurement of power distribution network as shown in Figure 1 The method comprises the following steps: Step S101: acquiring system operation conditions and aggregated power; The system operation conditions in the present application include voltage operation conditions and transformer load operation conditions, and the corresponding determination processes are as follows: First, the condition judgment information of the limited monitoring points is collected. When installing photovoltaic, storage, and charging piles in low-voltage distribution networks, corresponding monitoring equipment (with data uploading and instruction receiving functions) is generally installed. Therefore, the limited monitoring points in the present application are the grid-connected nodes of photovoltaic, storage, and charging piles and transformers. The condition judgment information includes transformer output power and voltage of photovoltaic grid-connected points The transformer output power includes transformer output active power , transformer output reactive power .

[0018] According to the above condition judgment information, the system operation conditions can be determined, as follows: First, according to the transformer output power, the transformer load operation conditions can be determined. The transformer load operation conditions include normal transformer load operation conditions and abnormal transformer load operation conditions. The abnormal transformer load operation conditions include forward heavy overload and reverse heavy overload. According to the transformer output power, the transformer load rate can be determined, as shown in formula (1): (1) In the formula, is the transformer load rate, is the transformer port capacity; Further, according to the transformer load rate, the transformer load operation conditions can be determined, as shown in formula (2): (2) In the formula, and are the lower limit and upper limit of the transformer load rate, respectively; In addition, according to the voltage of the photovoltaic grid-connected points , to determine the voltage operating condition, the voltage operating condition including a voltage normal operating condition and a voltage abnormal operating condition, the voltage abnormal operating condition including a node voltage lower limit and a node voltage upper limit, the specific determination process being shown as formula (3): (3) In the formula, and are the lower limit and the upper limit of the voltage of the photovoltaic grid-connected point respectively.

[0019] The total power of the application includes the total available power of the photovoltaic , the total maximum charge-discharge power of the energy storage , and the total maximum adjustable power of the charging pile . The determination process is as follows: Get the electrical information of the limited monitoring points, including the available power of the photovoltaic , the maximum charge-discharge power of the energy storage , and the maximum adjustable power of the charging pile . Then, the electrical information of each monitoring point is summarized by type to obtain the total available power of the photovoltaic , the total maximum charge-discharge power of the energy storage , and the total maximum adjustable power of the charging pile . As shown in formula (4): (4) In the formula, , and are the number of photovoltaics, energy storages and charging piles in the transformer area respectively.

[0020] Step S102: based on the system operating condition, determine whether to update the power control instruction; If yes, execute step S103; Here, it needs to be decided whether to update the power control instruction according to whether the system operating condition is a voltage abnormal operating condition or a transformer load abnormal operating condition, that is, as long as the system operating condition is currently in one of the voltage abnormal operating condition or the transformer load abnormal operating condition, the power control instruction needs to be updated at this time, that is, step S103 is executed, if it is not in the above abnormal operating condition, it represents that the system is running stably, and the power control instruction does not need to be updated.

[0021] The power control instruction includes a voltage limit power control instruction and a heavy overload power control instruction. The abnormal operating condition of the application is different, and the updated power control instruction is also different. When the system operating condition is a voltage abnormal operating condition, the power control instruction is a voltage limit power control instruction, and when the system operating condition is a transformer load power control instruction, the power control instruction is a heavy overload power control instruction.

[0022] Step S103: judging whether the current regulation level needs to be reset based on the system operating condition; If no, then executing step S104; Setting G as the current regulation level, the initial value is 0. The algorithm gradually strengthens the regulation strength through multi-level feedback mechanism until the abnormal operating condition (voltage out-of-limit, heavy overload) is eliminated or the maximum regulation level 2N is reached, and the power regulation instruction is no longer updated. Since the corresponding updated regulation power instruction will change when the system operating condition changes, if the newly detected abnormal operating condition type is inconsistent with the last detected abnormal operating condition type, the current regulation level needs to be reset, as shown in the following formula: (5) In the formula, A is the reset identifier received by the algorithm, 1 represents reset, and 0 represents no reset. For the first time entering the system abnormal state category , the abnormal operating condition category 1 includes positive heavy overload and voltage lower limit, the abnormal operating condition category 2 includes negative heavy overload and voltage upper limit.

[0023] In addition to the reset determination condition of the above formula (5), the reset determination condition of the present application also includes receiving a reset signal based on a fixed time scale.

[0024] That is, as long as any of the above reset determination conditions is met, the reset operation is performed, that is, the current regulation level G is initialized, as shown in formula (6): (6) Step S104: updating the power regulation instruction based on the system operating condition, the aggregated power and the current regulation level; In combination with Figure 2 , the process of updating the power regulation instruction in this step is described in detail: Step S201: judging whether the system operating condition is a voltage abnormal operating condition; If yes, then executing step S202; If no, then executing step S203; ​Since the system operating condition may be voltage abnormal operating condition, voltage abnormal operating condition and transformer load abnormal operating condition exist at the same time, and only transformer load abnormal operating condition, the corresponding subsequent steps are different under different conditions, therefore, first determine whether the system operating condition is voltage abnormal operating condition, if yes, execute step S202, update the power control instruction under voltage abnormal condition. If not, execute step S203, determine whether the system operating condition is transformer load abnormal operating condition.

[0025] Step S202: update the voltage out-of-limit power control instruction based on the voltage abnormal operating condition, the aggregated power and the current control level. The voltage out-of-limit power control instruction includes first active control instruction and first reactive control instruction under voltage abnormal condition, the first active control instruction includes first photovoltaic active control instruction, first energy storage active control instruction and first charging pile active control instruction, and the first reactive control instruction includes first photovoltaic reactive control instruction and first energy storage reactive control instruction.

[0026] Since the update mode of the power control instruction is different due to the node voltage lower limit and the node voltage upper limit, the process of updating the power control instruction when the node voltage is lower limit is described in detail in combination with Figure 3 . Step S301: determine whether the system operating condition is node voltage lower limit; If yes, execute step S302; If not, execute step S401; According to formula (3), determine whether the system operating condition is node voltage lower limit, if the system operating condition is node voltage lower limit, execute step S302: if not, it means that the system operating condition is node voltage upper limit, at this time, execute step 401, enter the step of updating the power control instruction when the node voltage is upper limit.

[0027] Step S302: determine whether the current control level is less than 1; If yes, execute step S303; If not, execute step S304; Since the current control level is different, the update mode of the corresponding power control instruction is also different. If the current control level G is less than 1, it means that the corresponding control for node voltage lower limit condition is just started at this time, at this time, execute step S303, if the current control level G is greater than or equal to 1, it means that the node voltage lower limit has been controlled for multiple rounds, at this time, execute step S304.

[0028] Step S303: Update the first photovoltaic active power control command based on the total photovoltaic power generation capacity; Based on the first photovoltaic active power control instruction and the current control level, update the first photovoltaic reactive power control instruction; When initially regulating the node voltage below the lower limit, it is necessary to first remove the photovoltaic limitation to maintain full photovoltaic power generation. The specific process of updating the power regulation command is as follows: Update the first photovoltaic active power control instruction based on the total photovoltaic power generation capacity. As shown in equation (7): (7) After receiving the first photovoltaic active power control instruction, the first photovoltaic reactive power control instruction can be updated based on the first photovoltaic active power control instruction and the current control level G, specifically as follows: According to the first photovoltaic active power control instruction and the photovoltaic rated capacity Determine the current adjustable reactive power capacity of photovoltaic systems. As shown in equation (8): (8) Then, based on the current adjustable reactive power capacity of the photovoltaic system and the current control level, the first photovoltaic reactive power control instruction is determined. As shown in equation (9): (9) After determining the first photovoltaic active power control command and the first photovoltaic reactive power control command, step S105 can be executed.

[0029] Step S304: Determine whether the energy storage meets the discharge constraints; If so, proceed to step S305; When performing multiple rounds of regulation on node voltages below the lower limit, the energy storage is monitored. Subsequent operations are determined based on whether the energy storage meets the discharge constraint, as shown in the following equation: (10) That is, whether the state of charge (SOC) of the energy storage is greater than or equal to the lower threshold of the energy storage SOC. If SOC is greater than or equal to If the energy storage meets the discharge constraint, then the energy storage will be used first, i.e., step S305 will be executed.

[0030] If the energy storage does not meet the discharge constraint, then... In this case, the energy storage system neither charges nor discharges; instead, it directly controls the charging pile. Specifically, it updates the active power control command of the first charging pile based on the current control level G, the first control level N, and the total maximum adjustable power of the charging pile. and the first energy storage active power control command Update to zero, as shown in equation (11): (11) The first regulation level N is the maximum regulation level designed for a single type of resource.

[0031] Then, based on the zero-valued active power control command of the first energy storage system and the current control level, the reactive power control command of the first energy storage system can be updated, as follows: According to the first energy storage active power control command and the rated capacity of the energy storage Calculate the current adjustable reactive capacity of energy storage. As shown in the following formula: (12) Then, based on the current adjustable reactive power capacity of the energy storage and the current control level G, update the first energy storage reactive power control command. As shown in the following formula: (13) After updating the active power control command of the first charging pile, the active power control command of the first energy storage, and the reactive power control command of the first energy storage, step S105 can be executed.

[0032] Step S305: Determine whether the current control level is greater than the first control level, where the first control level is the maximum control level set for a single type of resource; If not, proceed to step S306; If so, proceed to step S307; However, to achieve better control effects, the current control level needs to be assessed again. Specifically, it needs to be determined whether the current control level G is greater than the first control level N. If the result is negative, it means that photovoltaic control cannot restore the node voltage to the normal range, and step S306 is executed. If it is greater than N, it means that after N control operations, the voltage still cannot reach the normal level, meaning that even with maximum energy storage discharge power, the control effect cannot be achieved. In this case, the control level continues to increase to begin controlling the charging pile, i.e., step S307 is executed.

[0033] Step S306: Update the first energy storage active power control command based on the current control level, the first control level, and the total maximum chargeable and dischargeable power of the energy storage. Based on the first energy storage active power control command and the current control level, update the first energy storage reactive power control command. At this point, energy storage is prioritized for regulation, and the discharge intensity is increased step by step according to the G / N ratio. That is, the first energy storage active power regulation command is updated based on the current regulation level G, the first regulation level N, and the total maximum chargeable and dischargeable power of the energy storage. As shown in the following formula: (14) After receiving the first active power control command for energy storage, the first active power control command can be updated according to the first active power control command and the current control level G, as shown in formulas (12)-(13). .

[0034] Step S307: Update the active power control command of the first charging pile based on the current control level, the maximum control level, and the total maximum adjustable power of the charging pile.

[0035] At this point, the charging pile reduces the charging load in stages according to the ratio of remaining power (2N-G) / N, until the voltage returns to the normal range or the charging load is completely reduced. This is based on the current control level G, the maximum control level 2N, and the total maximum adjustable power of the charging pile. Update the active power control command of the first charging pile. As shown in the following formula: (15) By updating the power control command as described above, when the node voltage falls below the lower limit, multiple levels of fine-grained adjustment can be performed, taking into account the priority of each resource control, so that the system operation condition can be restored to normal.

[0036] Combination Figure 4 The following is a detailed explanation of the process of updating the power regulation command when the node voltage exceeds the upper limit: Step S401: Determine whether the current control level is less than 1; If so, proceed to step S402; If not, proceed to step S403; When a node voltage exceeds its upper limit, fine-grained regulation is implemented according to three tiers: charging piles, energy storage, and photovoltaics. Therefore, the current regulation level G is first determined. If it is less than 1, the charging pile restriction is lifted, maintaining power supply without reduction, and step S402 is executed. If the determination result is negative, it indicates that energy storage or photovoltaic regulation will be implemented, and step S403 is executed.

[0037] Step S402: Update the active power control command of the first charging pile based on the maximum adjustable power of the charging pile; First, the charging station needs to be adjusted, that is, according to the maximum adjustable power of the charging station. To update the active power control instructions of the first charging pile. As shown in the following formula: (16) Step S403: Determine whether the energy storage meets the charging constraints; If so, proceed to step S404; If not, proceed to step S407; At this point, it is necessary to determine whether the energy storage meets the charging constraints. If the energy storage SOC meets the charging constraints, as shown in the following formula: (17) In the formula, If the threshold value is the upper limit of the energy storage state of charge (SOC), then step 404 is executed. If the energy storage SOC does not meet the charging constraints, then step S407 is executed.

[0038] Step S404: Determine whether the current control level is greater than the first control level; If not, proceed to step S405; If so, proceed to step S406; Different current control levels correspond to different power control command methods. If the judgment result is negative, energy storage is prioritized for control, i.e., step S405 is executed. If the judgment result is positive, it means that the energy storage has reached its maximum charging power and still cannot achieve the control effect, in which case step S406 is executed.

[0039] Step S405: Update the first energy storage active power control command based on the current control level, the first control level, and the total maximum chargeable and dischargeable power of the energy storage. Based on the first energy storage active power control command and the current control level, update the first energy storage reactive power control command. Prioritize the use of energy storage, and gradually increase the charging intensity according to the G / N ratio. That is, update the first energy storage active power control command based on the current control level G, the first control level N, and the total maximum chargeable and dischargeable power of the energy storage. As shown in the following formula: (18) After receiving the first active power control command for energy storage, the first reactive power control command for energy storage can be updated based on the first active power control command and the current control level G. The specific process is as follows: Using formula (12), the current reactive power adjustable capacity of energy storage can be calculated. Then, based on the adjustable reactive power capacity... Update the first energy storage reactive power control command according to the current control level. As shown in the following formula: (19) Step S406: Update the first photovoltaic active power control command based on the current control level, the maximum control level, and the total photovoltaic power generation capacity; updating the first photovoltaic reactive power regulation instruction based on the first photovoltaic active power regulation instruction and the current regulation level; At this time, the photovoltaic starts to be regulated, and the photovoltaic is reduced in output according to the proportion of the remaining power (2N-G) / N, until the voltage returns to the normal range or the photovoltaic output is reduced. That is, according to the current regulation level G, the maximum regulation level 2N and the total available photovoltaic power, the first photovoltaic active power regulation instruction is updated as shown in the following formula: (20) Further, the first photovoltaic reactive power regulation instruction is updated according to the first photovoltaic active power regulation instruction and the current regulation level G, and specifically: The current reactive power regulation capacity of the photovoltaic is calculated by formula (8) Then, the first photovoltaic reactive power regulation instruction is updated according to the reactive power regulation capacity and the current regulation level as shown in the following formula: (21) At this point, the updating of the power regulation instruction under different regulation levels when the energy storage meets the charging constraint is completed.

[0040] Step S407: updating the first photovoltaic active power regulation instruction based on the current regulation level, the first regulation level and the total available photovoltaic power, and updating the first energy storage active power regulation instruction to zero; updating the first photovoltaic reactive power regulation instruction based on the first photovoltaic active power regulation instruction and the current regulation level; updating the first energy storage reactive power regulation instruction based on the first energy storage active power regulation instruction of zero and the current regulation level.

[0041] If the SOC is insufficient, the energy storage neither charges nor discharges, and directly starts to regulate the photovoltaic according to the proportion of the remaining power (N-G) / N, until the voltage returns to the normal range or the photovoltaic output is reduced. That is, based on the current regulation level G, the first regulation level N and the total available photovoltaic power, the first photovoltaic active power regulation instruction is updated and the first energy storage active power regulation instruction is updated to zero, as shown in the following formula: (22) After obtaining the first photovoltaic active power regulation instruction, formula (8) and formula (20) are used to calculate the first photovoltaic reactive power regulation instruction. Formula (12) and (18) are used to calculate the first energy storage reactive power regulation instruction.

[0042] In addition, for equipment safety and to reflect the tiered control, the active power output commands of each resource (photovoltaic, energy storage, and charging) need to meet upper and lower power limits, as shown below: (twenty three) Based on the aforementioned steps, the specific methods for updating the power control command when the node voltage exceeds the lower limit and the node voltage exceeds the upper limit can be obtained.

[0043] Step S203: Determine whether the system is operating under abnormal transformer load conditions; If so, proceed to step S204; If not, proceed to step S105; At this point, if step S202 was not executed and step S203 was executed directly, it means that the abnormal operating condition of the system does not involve abnormal voltage operation, and voltage regulation only needs to maintain the current output. However, it is necessary to further determine whether the system operating condition is an abnormal transformer load operation. If so, step S204 is executed to calculate the update of the power regulation command under the abnormal transformer load operation condition. If not, the current processing continues, and step S105 is executed.

[0044] If step S202 has been executed, it indicates that there is an abnormal voltage operation in the system. However, to ensure that there is no abnormal transformer load operation, step S203 needs to be executed to determine whether there is such an operation. If so, step S204 is executed to calculate the update of the power control command under the abnormal transformer load operation. If not, the current processing continues, and step S105 is executed.

[0045] Step S204: Based on the abnormal operating conditions of the transformer load, the aggregated power, and the current control level, update the heavy overload power control command; The heavy overload power control command includes a second active power control command and a second reactive power control command under abnormal operating conditions of transformer load; the second active power control command includes a second photovoltaic active power control command, a second energy storage active power control command, and a second charging pile active power control command, and the reactive power control command includes a second photovoltaic reactive power control command and a second energy storage reactive power control command.

[0046] Because abnormal operating conditions of the transformer load include both forward heavy overload and reverse heavy overload, the corresponding power control command update methods differ under these two different conditions. (Combined with...) Figure 5 The update process of power control commands under positive heavy overload conditions is explained in detail, specifically as follows: Step S501: Determine whether the abnormal operating condition of the transformer load is a positive heavy overload; If so, proceed to step S502; Here, the abnormal operation condition of the table edge load needs to be judged. If it is a positive heavy overload, step S502 can be executed. If it is not a positive heavy overload, it is a reverse heavy overload, and step S601 can be executed.

[0047] Step S502: judge whether the current control level is less than 1; If yes, step S503 is executed; If no, step S504 is executed; First, the current control level G is judged. If the current control level is less than 1, it means that a positive heavy overload has just occurred. At this time, the operation of updating the power command in step S503 is executed. If the judgment result is no, the operation of updating the power command in step S504 is executed.

[0048] Step S503: update the second photovoltaic active control instruction based on the total photovoltaic available power; Update the second photovoltaic reactive control instruction based on the second photovoltaic active control instruction and the current control level; When a positive heavy overload just occurs, the photovoltaic restriction is removed, and the photovoltaic full-load state is maintained, that is, the second photovoltaic active control instruction is updated according to the total photovoltaic available power As shown in the following formula: (24) After obtaining the second photovoltaic active control instruction, the second photovoltaic reactive control instruction can be updated according to the second photovoltaic active control instruction and the current control level. The specific process is as follows: First, the reactive control capacity of the current photovoltaic is calculated according to the second photovoltaic active control instruction and the photovoltaic rated capacity As shown in the following formula: (25) Then, the second photovoltaic reactive control instruction is updated according to the reactive control capacity of the current photovoltaic and the current control level As shown in the following formula: (26) After obtaining the second photovoltaic active control instruction and the second photovoltaic reactive control instruction, step S105 of power control instruction correction can be directly entered.

[0049] Step S504: judge whether the energy storage satisfies the discharge constraint; If yes, step S905 is executed; If no, step S908 is executed; ​At this point, it means that other power control commands need to be updated to restore the system to normal. However, it is necessary to first determine whether the energy storage meets the discharge constraints, and then take the corresponding update method based on the result of the determination. If the determination result is yes, then the operation of prioritizing the use of energy storage in step S505 is executed; if the determination result is no, then the charging pile control in step S508 is executed.

[0050] Step S505: Determine whether the current control level is greater than the first control level; If not, proceed to step S506; If so, proceed to step S507; When performing energy storage regulation, the current regulation level needs to be judged again. If the current regulation level is higher than the first regulation level, it means that the energy storage has reached its maximum discharge power and still cannot achieve the regulation effect. In this case, the charging pile regulation in step S507 is executed. If the judgment result is negative, the energy storage regulation operation in step S506 is executed.

[0051] Step S506: Update the second energy storage active power control command based on the total maximum chargeable and dischargeable power of the energy storage. Based on the second energy storage active power control command and the current control level, update the second energy storage reactive power control command; At this point, energy storage is prioritized, and the discharge intensity is increased step by step according to the G / N ratio. That is, the second energy storage active power control command is updated based on the total maximum chargeable and dischargeable power of the energy storage. As shown in the following formula: (27) After receiving the second active power control command for energy storage, the second reactive power control command can be updated based on the second active power control command and the current control level, specifically as follows: According to the second energy storage active power control command and the rated capacity of energy storage Calculate the current adjustable reactive capacity of energy storage. As shown in the following formula: (28) Then, based on the current adjustable reactive power capacity of the energy storage and the current control level G, the reactive power control command of the second energy storage is updated. As shown in the following formula: (29) Then step S105 can be executed to modify the above-mentioned second energy storage active power control command and second energy storage reactive power control command.

[0052] Step S507: Update the active power control command of the second charging pile based on the total maximum adjustable power of the charging pile, the maximum control level, and the current control level; At present, the charging pile is regulated, at this time, the charging pile is graded according to the proportion of the remaining power (2N-G) / N to reduce the charging load, until the load rate returns to the normal range or the charging load is reduced, that is, the total maximum adjustable power of the charging pile, the maximum regulation level and the current regulation level, update the second charging pile active regulation instruction As shown in the following formula: (30) After obtaining the second charging pile active regulation instruction, step S105 is executed to update the second charging pile active regulation instruction.

[0053] Step S508: Based on the total maximum adjustable power of the charging pile, the current regulation level and the first regulation level, update the second charging pile active regulation instruction, and update the second energy storage active regulation instruction to zero; Based on the second energy storage active regulation instruction of zero, update the second energy storage reactive regulation instruction.

[0054] At this time, the energy storage SOC is insufficient, then the energy storage neither charges nor discharges, and directly starts to regulate from the charging pile. The charging pile is graded according to the proportion of the remaining power (N-G) / N to reduce the charging load, until the load rate returns to the normal range or the charging load is reduced, that is, according to the total maximum adjustable power of the charging pile, the current regulation level G and the first regulation level N, update the second charging pile active regulation instruction , and update the second energy storage active regulation instruction to zero, as shown in the following formula: (31) After obtaining the second energy storage active regulation instruction, the second energy storage reactive regulation instruction is calculated according to formula (28) and (29) in combination with the current regulation level G.

[0055] Step S105 is executed to correct the second charging pile active regulation instruction, the second energy storage active regulation instruction and the second energy storage reactive regulation instruction obtained at this time.

[0056] In combination with Figure 6 , the updating process of the power regulation instruction under the reverse heavy overload condition is described in detail, which is as follows: Step S601: Determine whether the current regulation level is less than 1; If yes, step S602 is executed; If no, step S603 is executed; At this time, the current regulation level also needs to be judged first, if the current regulation level is less than 1, it means that the reverse heavy overload just occurs, at this time, the charging pile regulation of step S602 is executed, if the judgment result is no, the regulation of step S603 is executed.

[0057] Step S602: updating the second charging pile active regulation instruction based on the total maximum adjustable power of the charging piles; At this time, the charging pile restriction is removed, and the charging pile load is not reduced, that is, the second charging pile active regulation instruction is updated according to the total maximum adjustable power of the charging piles As shown in the following formula: (32) Step S105 is performed to correct the second charging pile active regulation instruction. If the load rate returns to normal, the current power regulation instruction is maintained, and if it is still reverse overload, subsequent corresponding updating is performed.

[0058] Step S603: judging whether the energy storage meets the charging constraint; If yes, step S604 is performed; If no, step S607 is performed; At this time, the energy storage needs to be detected. If the energy storage SOC can meet the charging constraint, the updating operation of step S604 is performed, and if the energy storage cannot meet the charging constraint, the updating operation of step S607 is performed.

[0059] Step S604: judging whether the current regulation level is greater than the first regulation level; If no, step S605 is performed; If yes, step S606 is performed; When the energy storage meets the charging constraint, the different current regulation levels correspond to different power regulation instruction updating methods. If the judgment result of this step is no, it means that the updating operation of step S605 is performed to preferentially call the energy storage, and if the judgment result of this step is yes, it means that the energy storage reaches the maximum charging power but still cannot achieve the regulation effect, and the updating operation of step S606 is performed to call the photovoltaic.

[0060] Step S605: updating the second energy storage active regulation instruction based on the total maximum chargeable and dischargeable power of the energy storage, the current regulation level and the first regulation level; updating the second energy storage reactive regulation instruction based on the second energy storage active regulation instruction and the current regulation level; This step preferentially calls the energy storage to gradually increase the charging intensity according to the G / N ratio. If the load rate returns to the normal range, the regulation is ended, that is, the second energy storage active regulation instruction is updated according to the total maximum chargeable and dischargeable power of the energy storage, the current regulation level G and the first regulation level N As shown in the following formula: (33) Then, the second energy storage reactive regulation instruction is updated according to the second energy storage active regulation instruction and the current regulation level, specifically as follows: First, the second energy storage reactive regulation instruction is calculated by using formulas (28) and (29) according to the second energy storage active regulation instruction and the current regulation level G .

[0061] Then, the operation of step S105 is performed to correct the second energy storage active regulation instruction and the second energy storage reactive regulation instruction.

[0062] Step S606: The second photovoltaic active regulation instruction is updated based on the total photovoltaic available power, the current regulation level and the maximum regulation level. The second photovoltaic reactive regulation instruction is updated based on the second photovoltaic active regulation instruction and the current regulation level. At this time, the photovoltaic is proportionally reduced according to the remaining power (2N-G) / N, until the load rate returns to the normal range or the photovoltaic output is reduced. That is, the second photovoltaic active regulation instruction is updated according to the total photovoltaic available power, the current regulation level G and the maximum regulation level 2N , as shown in the following formula: (34) Then, the second photovoltaic reactive regulation instruction is updated according to the second photovoltaic active regulation instruction and the current regulation level G, specifically as follows: The second photovoltaic reactive regulation instruction is calculated by using formulas (25) and (26) according to the second photovoltaic active regulation instruction and the current regulation level G.

[0063] The operation of step S105 is performed to correct the second photovoltaic active regulation instruction and the second photovoltaic reactive regulation instruction.

[0064] Step S607: The second photovoltaic active regulation instruction is determined based on the total photovoltaic available power, the current regulation level and the first regulation level, and the second energy storage active regulation instruction is updated to zero. The second photovoltaic reactive regulation instruction is updated based on the second photovoltaic active regulation instruction and the current regulation level. The second energy storage reactive regulation instruction is updated based on the second energy storage active regulation instruction which is zero.

[0065] At this time, the energy storage SOC is insufficient, that is, the energy storage neither charges nor discharges, and directly starts to regulate from the photovoltaic, and is proportionally reduced according to the remaining power (N-G) / N, until the load rate returns to the normal range or the photovoltaic output is reduced. That is, the second photovoltaic active regulation instruction is determined according to the total photovoltaic available power, the current regulation level G and the first regulation level N and the second energy storage active regulation instruction to zero, as shown in the following formula: (35) Then, according to the second photovoltaic active regulation instruction and the current regulation level G, the second photovoltaic reactive regulation instruction is updated by using formulas (25) and (26); According to the second energy storage active regulation instruction and the current regulation level G, the second energy storage reactive regulation instruction is updated by using formulas (26) and (27).

[0066] Further, the regulation instruction updated in this step is subjected to the correction operation of step S105.

[0067] It should be noted that, under the abnormal operation condition of the transformer and the load, the obtained instruction also needs to meet the upper and lower power constraints: (36) Step S205: The voltage out-of-limit power regulation instruction is covered by the heavy overload power regulation instruction, and step S105 is executed.

[0068] Since the core logic of power regulation is to prioritize the safety of equipment and then pursue stable operation indicators, heavy overload directly threatens the physical safety of equipment, while voltage out-of-limit affects the operation quality more, and the priorities are different. Therefore, if the system simultaneously appears the voltage abnormal operation condition and the transformer and load abnormal operation condition, the regulation of heavy overload is prioritized, and the voltage regulation is not executed.

[0069] It should be noted that, under the voltage abnormal operation condition or the transformer and load abnormal operation condition, when updating a certain power regulation instruction, other regulation instructions are not updated at the same time, but the regulation instruction after the last update is maintained, and the power regulation instruction in the updating state is sent to step S105 for correction together.

[0070] Step S105: The power regulation instruction is corrected to obtain a corrected power regulation instruction; Based on the foregoing logical judgment, the corresponding power regulation instruction needs to be corrected, as follows: In the voltage abnormal operation condition or the transformer and load abnormal operation condition, the first energy storage active regulation instruction and the second energy storage active regulation instruction are corrected. The active regulation instruction of the energy storage needs to meet the current state of charge of the energy storage. If the energy storage SOC is lower than the threshold value and the regulation instruction is discharging, the energy storage regulation instruction is corrected to neither charge nor discharge. If the energy storage SOC is higher than the threshold value and the regulation instruction is charging, the energy storage regulation instruction is corrected to neither charge nor discharge, as shown in the following formula (37): (37) In the formula, the corrected energy storage active instruction, the uncorrected energy storage active instruction (first energy storage active regulation instruction or second energy storage active regulation instruction).

[0071] In addition, if the power regulation instruction of the energy storage is higher than the corresponding power maximum value, the regulation instruction of the corresponding type of equipment is corrected to the corresponding power maximum value. If the regulation instruction of the photovoltaic, energy storage and charging pile is lower than the corresponding power minimum value, the regulation instruction of the corresponding type of equipment is corrected to the corresponding power minimum value. The following formula is shown: (38) (39) (40) In the formula, , and are the corrected energy storage, photovoltaic and charging pile active regulation instructions, respectively.

[0072] In addition, the first reactive regulation instruction under the voltage abnormal operation condition is not corrected. The second reactive regulation instruction under the abnormal operation condition of the transformer substation load is corrected, After obtaining the photovoltaic and energy storage reactive regulation instructions, the instruction needs to be corrected according to the actual reactive load characteristics and size of the transformer substation to avoid overcompensation. In the forward heavy overload condition, if it is a capacitive load, the photovoltaic and energy storage are prohibited from issuing reactive power again; if it is an inductive load, the reactive power issued by the photovoltaic and energy storage is limited to not exceed the reactive load demand, avoiding overcompensation. While in the reverse heavy overload condition, if it is an inductive load, the photovoltaic and energy storage are prohibited from absorbing reactive power again; if it is a capacitive load, the reactive power absorbed by the photovoltaic and energy storage is limited to not exceed the reactive load demand, avoiding overcompensation. The correction instruction is shown in the following formula (41)-(42): (41) (42) Step S106: Distribute the corrected power regulation instruction and perform corresponding regulation; The corrected active / reactive instructions of the photovoltaic, energy storage and charging pile are distributed according to the equipment capacity proportion: (43) In the formula, and are the active and reactive regulation instructions of the first transformer photovoltaic, and are the active and reactive regulation instructions of the second Active and reactive power regulation instructions of the station energy storage, For the first Active power regulation instructions of the station charging pile.

[0073] Step S107: judge whether the current regulation level reaches the maximum regulation level; If yes, end the update of the power regulation instruction; If no, add 1 to the current regulation level, and execute step S101.

[0074] After each regulation, the current regulation level is judged. If the current regulation level G is greater than or equal to 2N, it means that even if the power regulation instruction is updated, the system operation condition does not recover to normal or changes. At this time, the operation of updating the power regulation instruction is ended. If the judgment result is no, it means that the next round of regulation can be carried out. At this time, the current regulation level is added by 1, so that when the next round of system operation condition and the current system operation condition are of the same type, the corresponding power regulation instruction is updated.

[0075] Simulation experiment The simulation model is verified based on the following facility parameters. The simulation parameters are shown in Table 1: ; The load, photovoltaic data and charging load data are shown in Figures 7-9 : (1) All-day regulation effect display The transformer load rate 24-hour curve comparison chart before and after regulation is shown in Figure 10 . After about 18 o'clock in the evening, the station area is prone to positive heavy overload condition because photovoltaic no longer generates power. In the noon period, photovoltaic generates more power due to high light intensity, which is prone to cause reverse heavy overload condition. After regulation, the heavy overload condition is obviously improved. In each regulation period (15 minutes), when the load rate exceeds the threshold value, the regulation measure is triggered to restore the load rate to the normal range, and the current instruction is maintained until the end of the regulation period, the reset is triggered, and the new regulation period is entered to re-judge the condition and regulate the operation. As can be seen from the figure, the logic control algorithm obviously shortens the time when the load rate exceeds the threshold value, and effectively improves the reliability of the distribution network.

[0076] The output comparison before and after regulation of each resource is shown in Figure 11 . In the positive heavy overload condition, the algorithm will first regulate the energy storage to gradually increase the discharge. When the energy storage SOC reaches the lower limit or has reached the maximum discharge power of the energy storage and still cannot solve the positive heavy overload, the charging load is gradually reduced. In the reverse heavy overload condition, the energy storage is first regulated to gradually increase the charging. When the energy storage SOCIf the upper limit is reached or the maximum charging power of the energy storage is reached and the reverse heavy overload cannot be solved, the photovoltaic is gradually reduced.

[0077] 2) Regulation details Each complete regulation cycle (i.e. reset interval) is 15 minutes, and the logic control algorithm runs ten rounds in each regulation cycle, i.e. one round of logic algorithm runs for 90 seconds. In the initial stage of the regulation cycle, the current cycle load, photovoltaic predicted output and charging load and other information collected are input to the algorithm, so as to perform logic judgment and regulation operation. In addition, in each regulation cycle, the transformer load rate, node voltage, energy storage state of charge and the like are updated in real time when the logic algorithm runs each round, so as to update the reasonable regulation operation according to the real-time state.

[0078] 1) Forward heavy overload The regulation details of the forward heavy overload in a typical representative regulation cycle from 20:00 to 20:15 are shown in FIG. 20, and the regulation details are as follows: Figure 12 At 20:00, the load rate is detected to be 0.93, which is higher than the threshold of 0.8, so the regulation is triggered. The energy storage discharging power is gradually increased in the proportions of 1 / 3, 2 / 3 and 3 / 3, until the load rate returns to normal, and the current reactive load is capacitive. In order to avoid overcompensation, the reactive output instructions of the energy storage and the photovoltaic are corrected to 0. As shown in FIG. 20(a) and (b), when the energy storage discharging power reaches 6.67 kW, the load rate is reduced to about 0.71, which returns to the normal range. Then the current instructions of each resource are maintained until 20:15, which enters a new regulation cycle, and the energy storage is reset. At the same time, the load, photovoltaic predicted output and charging load and other information in the new regulation cycle are input to the algorithm, so as to perform a new round of logic judgment and regulation operation. Figure 12 2) Reverse heavy overload The regulation details of the reverse heavy overload in a typical representative regulation cycle from 10:15 to 10:30 are shown in FIG. 21, and the regulation details are as follows:

[0079] At 10:15, the load rate is detected to be about -1.05, which is lower than the threshold of -0.8, so the regulation is triggered. The energy storage charging power is gradually increased in the proportions of 1 / 3, 2 / 3 and 3 / 3, until the load rate returns to the normal range. And the reactive load in the current regulation cycle is inductive. In order to avoid overcompensation, the reactive instructions of the photovoltaic and the energy storage are corrected to 0. As shown in FIG. 21(a) and (b), when the energy storage charging power reaches 10 kW, the load rate is increased to -0.71, which returns to the normal range. Then the current instructions of each resource are maintained. Figure 13 Figure 13 Figure 13

[0080] ​​​​​But at about 10:23, due to the previous regulation cycle charging operation, the energy storage SOC has reached the upper limit, so the energy storage stops charging, and the load rate is reduced to about -1.05 again. At this time, the energy storage has been unable to charge, so it directly starts to install the photovoltaic according to the proportion of 1 / 3, 2 / 3, and 3 / 3 to gradually reduce the photovoltaic. From Figure 13 (a) and (c), it can be seen that after the four photovoltaic outputs are reduced by 1 / 3, the load rate rises to about -0.52, and returns to the normal range. After that, the current resource output is maintained until 10:30, a new regulation cycle is entered, and the reset operation is performed. The photovoltaic is removed from the restriction, and the load condition, photovoltaic predicted output, and charging load of the new regulation cycle are input to the algorithm, so as to perform a new round of logical judgment and regulation operation.

[0081] In summary, the method proposed in the present application can control the voltage and load rate of the distribution network under limited measurement information through multi-level regulation and feedback correction. At the same time, by setting the regulation priority of photovoltaic, energy storage, charging pile and other resources, the utilization rate of photovoltaic is improved.

[0082] The above embodiment is a preferred implementation scheme of the present application, in addition to this, the present application can also be implemented in other ways, without departing from the technical scheme concept of the present application, any obvious replacement is within the protection scope of the present application.

[0083] In order to make those skilled in the art more easily understand the improvements of the present application over the prior art, some drawings and descriptions of the present application have been simplified, and some other elements have been omitted from the present application file for the sake of clarity. Those skilled in the art should realize that these omitted elements can also constitute the content of the present application.

Claims

1. A method for coordinated management and high-quality power supply of photovoltaic-storage-charging systems under limited measurement conditions in distribution networks, characterized in that: include: Step S101: Obtain system operating conditions and aggregated power; Step S102: Based on the system operating conditions, determine whether to update the power control command; If so, proceed to step S103; Step S103: Based on the system operating conditions, determine whether the current control level needs to be reset; If not, proceed to step S104; Step S104: Update the power control command based on the system operating conditions, the aggregated power, and the current control level; Step S105: Modify the power control command to obtain a modified power control command; Step S106: Assign the corrected power control command and perform corresponding control; Step S107: Determine whether the current control level has reached the maximum control level; If so, then end the update of the power control command; If not, increment the current control level by 1 and proceed to step S101.

2. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution networks according to claim 1, characterized in that, The process for determining the polymerization power is as follows: Electrical information is collected from a limited number of monitoring points, including grid-connected nodes of photovoltaic, energy storage, and charging piles, as well as transformers; the electrical information includes the power generation capacity of photovoltaic, the maximum charging and discharging power of energy storage, and the maximum adjustable power of charging piles. The electrical information is aggregated to obtain aggregated power, which includes the total photovoltaic power generation capacity, the total maximum chargeable and dischargeable power of energy storage, and the total maximum adjustable power of the charging pile.

3. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution networks according to claim 2, characterized in that, The system operating conditions include voltage operating conditions and transformer load operating conditions. The process for determining the system operating conditions is as follows: Collect operating condition assessment information from a limited number of monitoring points, including the output power of the transformer and the voltage at the photovoltaic grid connection point; Based on the output power of the transformer, the operating conditions of the transformer load are determined, including normal operating conditions and abnormal operating conditions. Based on the voltage at the photovoltaic grid connection point, the voltage operating conditions are determined, including normal voltage operating conditions and abnormal voltage operating conditions.

4. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution network as described in claim 3, characterized in that, The step of determining whether to update the power control command based on the system operating conditions includes: Determine whether the system is operating under abnormal voltage or abnormal transformer load conditions. If so, update the power control command and execute step S103; If not, maintain the current output.

5. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution network as described in claim 4, characterized in that, The power regulation commands include voltage over-limit power regulation commands and heavy overload power regulation commands. The step of updating the power regulation commands based on the system operating conditions, the aggregated power, and the current regulation level includes: Step S201: Determine whether the system is operating under abnormal voltage conditions; If so, proceed to step S202; If not, proceed to step S203; Step S202: Based on the abnormal voltage operation condition, the aggregated power, and the current control level, update the voltage over-limit power control command; Step S203: Determine whether the system is operating under abnormal transformer load conditions; If so, proceed to step S204; If not, proceed to step S105; Step S204: Based on the abnormal operating conditions of the transformer load, the aggregated power, and the current control level, update the heavy overload power control command; Step S205: Overwrite the voltage over-limit power control command with the heavy overload power control command, and execute step S105.

6. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution network as described in claim 5, is characterized in that, The abnormal voltage operating conditions include node voltage exceeding the lower limit and node voltage exceeding the upper limit. The voltage limit power control command includes a first active power control command and a first reactive power control command under the abnormal voltage operating conditions. The first active power control instruction includes the first photovoltaic active power control instruction, the first energy storage active power control instruction, and the first charging pile active power control instruction; the first reactive power control instruction includes the first photovoltaic reactive power control instruction and the first energy storage reactive power control instruction. The step of updating the voltage over-limit power control command based on the abnormal voltage operating condition, the aggregated power, and the current control level includes: Step S301: Determine whether the abnormal voltage operation condition is due to the node voltage falling below the lower limit; If so, proceed to step S302; Step S302: Determine whether the current control level is less than 1; If so, proceed to step S303; If not, proceed to step S304; Step S303: Update the first photovoltaic active power control command based on the total photovoltaic power generation capacity; Based on the first photovoltaic active power control instruction and the current control level, update the first photovoltaic reactive power control instruction; Step S304: Determine whether the energy storage meets the discharge constraints; If so, proceed to step S305; Step S305: Determine whether the current control level has reached the first control level, where the first control level is the maximum control level set for a single type of resource; If not, proceed to step S306; If so, proceed to step S307; Step S306: Update the first energy storage active power control command based on the current control level, the first control level, and the total maximum chargeable and dischargeable power of the energy storage. Based on the first energy storage active power control command and the current control level, update the first energy storage reactive power control command. Step S307: Update the active power control command of the first charging pile based on the current control level, the maximum control level, and the total maximum adjustable power of the charging pile.

7. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution network as described in claim 6, characterized in that, If the judgment result of step S304 is negative, then the following step S308 is executed: Step S308: Based on the current control level, the first control level, and the total maximum adjustable power of the charging pile, update the first charging pile active power control command and update the first energy storage active power control command to zero; Based on the first energy storage active power control command which is zero and the current control level, update the first energy storage reactive power control command.

8. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution network as described in claim 6, characterized in that, If the judgment result of step S301 is negative, then the following steps are executed: Step S401: Determine whether the current control level is less than 1; If so, proceed to step S402; If not, proceed to step S403; Step S402: Update the active power control command of the first charging pile based on the maximum adjustable power of the charging pile; Step S403: Determine whether the energy storage meets the charging constraints; If so, proceed to step S404; If not, proceed to step S407; Step S404: Determine whether the current control level has reached the first control level; If not, proceed to step S405; If so, proceed to step S406; Step S405: Update the first energy storage active power control command based on the current control level, the first control level, and the total maximum chargeable and dischargeable power of the energy storage. Based on the first energy storage active power control command and the current control level, update the first energy storage reactive power control command. Step S406: Update the first photovoltaic active power control command based on the current control level, the maximum control level, and the total photovoltaic power generation capacity; Based on the first photovoltaic active power control instruction and the current control level, update the first photovoltaic reactive power control instruction; Step S407: Based on the current control level, the first control level, and the total photovoltaic power generation, update the first photovoltaic active power control command and update the first energy storage active power control command to zero; Based on the first photovoltaic active power control instruction and the current control level, update the first photovoltaic reactive power control instruction; Based on the first energy storage active power control command which is zero and the current control level, update the first energy storage reactive power control command.

9. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution network as described in claim 5, characterized in that, The abnormal operating conditions of the transformer load include forward heavy overload and reverse heavy overload. The heavy overload power control command includes a second active power control command and a second reactive power control command under the abnormal operating conditions of the transformer load. The second active power control command includes the second photovoltaic active power control command, the second energy storage active power control command, and the second charging pile active power control command; the second reactive power control command includes the second photovoltaic reactive power control command and the second energy storage reactive power control command. The update of the heavy overload power control command based on the abnormal operating conditions of the transformer load, the aggregated power, and the current control level includes: Step S501: Determine whether the abnormal operating condition of the transformer load is a positive heavy overload; If so, proceed to step S502; Step S502: Determine whether the current control level is less than 1; If so, proceed to step S503; If not, proceed to step S504; Step S503: Update the second photovoltaic active power control command based on the total photovoltaic power generation capacity; Based on the second photovoltaic active power control instruction and the current control level, update the second photovoltaic reactive power control instruction; Step S504: Determine whether the energy storage meets the discharge constraint; If so, proceed to step S505; If not, proceed to step S508; Step S505: Determine whether the current control level has reached the first control level; If not, proceed to step S506; If so, proceed to step S507; Step S506: Update the second energy storage active power control command based on the total maximum chargeable and dischargeable power of the energy storage. Based on the second energy storage active power control command and the current control level, update the second energy storage reactive power control command; Step S507: Update the active power control command of the second charging pile based on the total maximum adjustable power of the charging pile, the maximum control level, and the current control level; Step S508: Based on the total maximum adjustable power of the charging pile, the current control level and the first control level, update the active power control command of the second charging pile and update the active power control command of the second energy storage to zero; Based on the second energy storage active power control command which is zero, update the second energy storage reactive power control command.

10. The method for coordinated control and high-quality power supply of photovoltaic-storage-charging under limited measurement of distribution networks according to claim 9, characterized in that, If the judgment result of step S501 is negative, then the following steps are executed: Step S601: Determine whether the current control level is less than 1; If so, proceed to step S602; If not, proceed to step S603; Step S602: Update the active power control command of the second charging pile based on the total maximum adjustable power of the charging pile; Step S603: Determine whether the energy storage meets the charging constraints; If so, proceed to step S604; If not, proceed to step S607; Step S604: Determine whether the current control level has reached the first control level; If not, proceed to step S605; If so, proceed to step S606; Step S605: Update the second energy storage active power control command based on the total maximum chargeable and dischargeable power of the energy storage, the current control level, and the first control level; Based on the second energy storage active power control command and the current control level, update the second energy storage reactive power control command; Step S606: Update the second photovoltaic active power control command based on the total photovoltaic power generation capacity, the current control level, and the maximum control level; Based on the second photovoltaic active power control instruction and the current control level, update the second photovoltaic reactive power control instruction; Step S607: Based on the total photovoltaic power generation capacity, the current control level, and the first control level, determine the second photovoltaic active power control command and update the second energy storage active power control command to zero; Based on the second photovoltaic active power control instruction and the current control level, update the second photovoltaic reactive power control instruction; Based on the second energy storage active power control command which is zero and the current control level, update the second energy storage reactive power control command.

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