A power distribution network overload control method and system

Abstract

This application discloses a method and system for managing heavy overload in a distribution network, belonging to the field of distribution network operation and control technology. The method for managing heavy overload in a distribution network provided in this application determines the real-time load rate of the corresponding phase based on the current active power, current apparent power, and rated capacity of each phase of the distribution transformer. Based on the real-time load rate of each phase, the current power data of the distribution transformer, the current operating data of the energy storage system, the current control mode of the distribution transformer for heavy overload management, and the planned curve control enable status, the actual power control command of each single phase of the energy storage system is determined. Furthermore, a safety constraint verification is performed through preset verification rules to determine the final power control command of each single phase of the energy storage system. This achieves precise phase-by-phase control of the heavy overload of the distribution transformer and improves the effect of heavy overload management.

Description

Technical Field

[0001] This application relates to the field of power distribution network operation control technology, and in particular to a method and system for managing heavy overload in power distribution networks. Background Technology

[0002] The power distribution network is a crucial link in the power system that directly faces users, undertaking the important functions of power distribution and voltage conversion. As the core equipment of the power distribution network, the operating status of the distribution transformer directly affects the reliability and quality of power supply.

[0003] With economic and social development and energy structure transformation, the operating environment of power distribution networks is becoming increasingly complex. On the one hand, electricity load continues to grow rapidly, especially during peak hours, which can easily lead to forward overload of distribution transformers (i.e., the power output of distribution transformers to the load side exceeds their long-term allowable operating power). On the other hand, with the large-scale integration of new energy sources such as distributed photovoltaics, power generation during periods of sufficient sunshine may far exceed local load, causing electricity to flow back to the grid, resulting in reverse overload (i.e., reverse power overload). Traditional solutions relying on grid expansion and renovation suffer from problems such as large investment, long cycles, and insufficient flexibility.

[0004] Energy storage systems are considered an effective means of mitigating heavy overloads in distribution transformers due to their flexible and rapid power regulation capabilities. However, existing energy storage-based mitigation technologies still have certain limitations: they mostly employ three-phase overall power control, which cannot provide differentiated and precise mitigation for single-phase unbalanced overloads commonly found in distribution networks, resulting in poor mitigation effects or waste of energy storage resources. Summary of the Invention

[0005] This paper provides a method and system for managing heavy overload in power distribution networks, which enables precise phase-by-phase control of heavy overload management and improves the effectiveness of heavy overload management.

[0006] Firstly, a method for mitigating heavy overload in a power distribution network is provided, wherein the power distribution network includes a distribution transformer and is connected to an energy storage system; the method includes: Receive current power data of the distribution transformer and current operating data of the energy storage system; wherein, the current power data includes the current active power and current apparent power of each phase of the distribution transformer; The real-time load rate of the target phase is determined based on the current active power, current apparent power, and rated capacity of the target phase of the distribution transformer. Determine the current control mode and planned curve control enable status for overload mitigation of distribution transformers; Based on the current control mode, planned curve control enable status, real-time load rate, current power data, and current operating data, determine the actual power control command for the target phase of the energy storage system. For the actual power control command, a safety constraint verification is performed according to the preset verification rules to determine the final power control command.

[0007] In some embodiments, the actual power control command is subjected to safety constraint verification according to a preset verification rule to determine the final power control command, including: When the actual power control command is greater than zero, the final power control command is determined based on the actual power control command, the total discharge power limit and rated power of the energy storage system. When the actual power control command is less than zero, the final power control command is determined based on the actual power control command, the total charging power limit and rated power of the energy storage system.

[0008] In some embodiments, the current operating data includes the current remaining power of the energy storage system and the real-time power of each phase; For the actual power control command, a safety constraint verification is performed according to preset verification rules to determine the final power control command, including: When the current remaining power is less than the first preset remaining power and the sum of the real-time power of each phase is greater than zero, the discharge power of each phase of the energy storage system is reduced once in each preset control cycle. That is, each time the current power control command of the target phase of the energy storage system is updated to the first preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle, until the real-time power of the target phase of the energy storage system meets the preset power judgment condition, the current power control command of the target phase of the energy storage system is set to zero. When the current remaining power is greater than the second preset remaining power and the sum of the real-time power of each phase is less than zero, the absolute value of the charging power of each phase of the energy storage system is reduced once in each preset control cycle. That is, each time the current power control command of the target phase of the energy storage system is updated to the second preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle, until the real-time power of the target phase of the energy storage system meets the preset power judgment condition, the current power control command of the target phase of the energy storage system is set to zero.

[0009] In some embodiments, when the current control mode is the first mode, the method for determining the actual power control command includes: When the real-time load rate of the target phase of the distribution transformer is greater than the preset threshold value for the positive heavy overload load rate, it is determined that the target phase of the distribution transformer has experienced a positive heavy overload. Based on the first target active power and the current active power of the positive heavy overload control of the target phase of the distribution transformer, as well as the total discharge power limit and rated power of the energy storage system, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is less than the first preset difference, and the current remaining power of the energy storage system is less than the preset reserved power threshold for positive heavy overload control, the active power replenishment strategy of the energy storage is triggered. Based on the second target active power and the current active power of the target phase of the distribution transformer for positive heavy overload control, as well as the total charging power limit and rated power of the energy storage system, the actual power control command is determined. When the current remaining power increases to the third preset remaining power, the power replenishment is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is less than the second preset difference, the active energy storage replenishment strategy is not triggered, and the planned curve control is enabled in the first enabled state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the second target active power of the positive heavy overload management of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power. If the active energy storage replenishment strategy is not triggered and the planned curve control is in the second enabled state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0010] In some embodiments, the actual power control command is determined based on the planned power for the current time period, the second target active power for positive heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power, including: If the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the total discharge power limit, and the rated power. When the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, the rated power, and the second target active power for the positive heavy overload control of the target phase of the distribution transformer.

[0011] In some embodiments, a method for determining the first target active power for positive heavy overload mitigation of a target phase of a distribution transformer includes: Based on the apparent power and current reactive power of the first target for positive heavy overload control of the target phase of the distribution transformer, determine the active power of the first target for positive heavy overload control of the target phase of the distribution transformer. Among them, the first target apparent power of the target phase of the distribution transformer for positive heavy overload control is determined based on the rated capacity of the target phase of the distribution transformer, the preset threshold value for the overload rate of positive heavy overload, and the preset threshold value for the first hysteresis of heavy overload control. Methods for determining the second target active power for positive heavy overload mitigation of the target phase of a distribution transformer include: Based on the second target apparent power and current reactive power of the target phase of the distribution transformer for positive heavy overload control, determine the second target active power of the target phase for positive heavy overload control. Among them, the second target apparent power for the positive heavy overload control of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset threshold value for the positive heavy overload load rate exceeding the limit, and the preset threshold value for the second hysteresis of the heavy overload control.

[0012] In some embodiments, when the current control mode is the second mode, the method for determining the actual power control command includes: When the real-time load rate of the target phase of the distribution transformer is less than the negative value of the preset reverse overload load rate threshold, it is determined that the target phase of the distribution transformer has reverse overload. Based on the first target active power and the current active power of the reverse overload control of the target phase of the distribution transformer, as well as the total charging power limit and rated power of the energy storage system, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is greater than the third preset difference, and the current remaining power of the energy storage system is greater than the preset reserved power threshold for reverse overload control, the active discharge strategy of the energy storage is triggered. Based on the second target active power and current active power of the reverse overload control of the target phase of the distribution transformer, as well as the total discharge power limit and rated power of the energy storage system, the actual power control command is determined. When the current remaining power is reduced to the fourth preset remaining power, the discharge is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference, the active discharge strategy of energy storage is not triggered, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the second target active power of the reverse heavy overload control of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power. If the active discharge strategy of energy storage is not triggered and the planned curve control enable state is the second enable state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0013] In some embodiments, the actual power control command is determined based on the planned power for the current time period, the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power, including: When the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the total discharge power limit, the rated power, and the second target active power for reverse heavy overload control of the target phase of the distribution transformer. If the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, and the rated power.

[0014] In some embodiments, a method for determining the first target active power for reverse heavy overload mitigation of a target phase of a distribution transformer includes: Based on the apparent power and current reactive power of the first target of reverse heavy overload control of the target phase of the distribution transformer, determine the active power of the first target of reverse heavy overload control of the target phase of the distribution transformer. Among them, the first target apparent power of the reverse heavy overload control of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset reverse heavy overload load rate limit threshold value, and the preset first hysteresis threshold value of the heavy overload control. Methods for determining the secondary target active power for reverse heavy overload mitigation of the target phase of a distribution transformer include: Based on the second target apparent power and current reactive power of the target phase of the distribution transformer for reverse heavy overload control, determine the second target active power of the target phase for reverse heavy overload control. The second target apparent power for reverse heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset reverse heavy overload load rate exceeding threshold value, and the preset second hysteresis threshold value for heavy overload mitigation.

[0015] In some embodiments, when the current control mode is the third mode, the method for determining the actual power control command includes: If the real-time load rate of any phase of the distribution transformer exceeds the preset threshold value for forward heavy overload, the planned curve control is interrupted, and the actual power control command is determined based on the first target active power and current active power of the target phase of the distribution transformer for forward heavy overload control, as well as the total discharge power limit and rated power of the energy storage system; or, if the real-time load rate of any phase of the distribution transformer is less than the negative value of the preset threshold value for reverse heavy overload, the planned curve control is interrupted, and the actual power control command is determined based on the first target active power and current active power of the target phase of the distribution transformer for reverse heavy overload control, as well as the total charging power limit and rated power of the energy storage system. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period. Based on the planned power of the current time period, the current active power, the total discharge power limit, the total charging power limit, the rated power, the second target active power of the forward heavy overload control of the target phase of the distribution transformer, and the second target active power of the reverse heavy overload control of the target phase of the distribution transformer, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the second enable state, the actual power control command is determined according to the preset overload power command reset strategy.

[0016] In some embodiments, the actual power control command is determined based on the planned power for the current time period, the total discharge power limit, the total charging power limit, the rated power, the second target active power for forward heavy overload mitigation of the target phase of the distribution transformer, and the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer, including: When the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the current active power, the total discharge power limit, the rated power, and the second target active power for reverse heavy overload control of the target phase of the distribution transformer. When the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the current active power, the total charging power limit, the rated power, and the second target active power for the positive heavy overload control of the target phase of the distribution transformer.

[0017] In some embodiments, the actual power control command is determined according to a preset overload power command reset strategy, including: The absolute value of the actual power control command of each phase of the energy storage system is gradually reduced according to the preset attenuation coefficient until the real-time power of each phase of the energy storage system meets the preset power conditions. Then, the actual power control command of each phase of the energy storage system is determined to be zero.

[0018] In some embodiments, when the current control mode is the fourth mode, the method for determining the actual power control command includes: When the planned curve control enable state is the first enable state, the planned curve control is traversed to match the planned power of the current period, and the actual power control command is determined based on the planned power of the current period, the total discharge power limit, the total charging power limit and the rated power of the energy storage system. When the planned curve control enable state is in the second enable state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0019] In some embodiments, the actual power control command is determined based on the planned power for the current time period, the total discharge power limit, the total charging power limit, and the rated power of the energy storage system, including: If the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the total discharge power limit, and the rated power. If the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, and the rated power.

[0020] Secondly, embodiments of this application also provide a power distribution network overload mitigation system, wherein the power distribution network includes a distribution transformer and an energy storage system is connected to the power distribution network; the system includes: The receiving module is used to receive the current power data of the distribution transformer and the current operating data of the energy storage system; wherein, the current power data includes the current active power and the current apparent power of each phase of the distribution transformer; The first determining module is used to determine the real-time load rate of the target phase based on the current active power, current apparent power and rated capacity of the target phase of the distribution transformer. The second determining module is used to determine the current control mode and the planned curve control enable status for the overload mitigation of the distribution transformer. The third determining module is used to determine the actual power control command of the target phase of the energy storage system based on the current control mode, the planned curve control enable status, the real-time load rate, the current power data and the current operating data. The fourth determination module is used to perform safety constraint verification on the actual power control command according to preset verification rules in order to determine the final power control command.

[0021] Beneficial Effects: This application provides a method and system for managing heavy overload in a power distribution network. The method includes: receiving current power data of a distribution transformer and current operating data of an energy storage system; wherein the current power data includes the current active power and current apparent power of each phase of the distribution transformer; determining the real-time load rate of the target phase based on the current active power, current apparent power, and rated capacity of the target phase of the distribution transformer; determining the current control mode and planned curve control enable state for managing the heavy overload of the distribution transformer; determining the actual power control command of the target phase of the energy storage system based on the current control mode, planned curve control enable state, real-time load rate, current power data, and current operating data; and performing safety constraint verification on the actual power control command according to preset verification rules to determine the final power control command. The distribution network overload mitigation method provided in this application determines the real-time load rate of each phase based on the current active power, current apparent power, and rated capacity of each phase of the distribution transformer. It then determines the actual power control command for each single phase of the energy storage system based on the real-time load rate of each phase, the current power data of the distribution transformer, the current operating data of the energy storage system, the current control mode of the distribution transformer overload mitigation, and the planned curve control enable status. Furthermore, it performs safety constraint verification through preset verification rules to determine the final power control command for each single phase of the energy storage system. This achieves precise phase-by-phase control of the distribution transformer's overload, improving the effectiveness of overload mitigation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0024] Figure 1 This is a schematic diagram of the power distribution network structure provided in the embodiments of this application; Figure 2 This is a flowchart of a method for mitigating heavy overload in a power distribution network, provided in an embodiment of this application. Figure 3 This is a schematic diagram of the overall process of a power distribution network overload mitigation method provided in the embodiments of this application; Figure 4 This is a schematic diagram of the principle structure of a power distribution network overload mitigation system provided in the embodiments of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0026] In the embodiments of this application, "at least one" refers to one or more; "multiple" refers to two or more. In the description of this application, the terms "first," "second," "third," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance, nor should they be construed as indicating or implying order.

[0027] References such as “one embodiment” or “some embodiments” as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the terms “comprising,” “including,” “having,” and variations thereof, as used in this specification, mean “including, but not limited to,” unless otherwise specifically emphasized.

[0028] It should be noted that in the embodiments of this application, "and / or" describes the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects before and after it are in an "or" relationship.

[0029] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0030] The applicant's research revealed that the power distribution network is a crucial link in the power system that directly faces users, undertaking the important functions of power distribution and voltage conversion. As the core equipment of the distribution network, the operating status of the distribution transformer directly affects the reliability and quality of power supply.

[0031] With economic and social development and energy structure transformation, the operating environment of power distribution networks is becoming increasingly complex. On the one hand, electricity load continues to grow rapidly, especially during peak hours, which can easily lead to forward overload of distribution transformers (i.e., load power exceeding rated capacity). On the other hand, with the large-scale integration of new energy sources such as distributed photovoltaics, power generation during periods of sufficient sunshine may far exceed local load, causing power to flow back to the grid and triggering reverse overload (i.e., reverse power overload). Traditional solutions that rely on grid expansion and renovation suffer from problems such as large investment, long cycles, and insufficient flexibility.

[0032] Energy storage systems are considered an effective means of mitigating heavy overloads in distribution transformers due to their flexible and rapid power regulation capabilities. However, existing energy storage-based mitigation technologies still have certain limitations: First, they mostly employ three-phase overall power control, which cannot provide differentiated and precise mitigation for single-phase unbalanced overloads commonly found in distribution networks, leading to poor mitigation results or wasted energy storage resources. Second, they lack coordinated control strategies for complex scenarios involving both forward and reverse overloads, and the priority of overload mitigation and other control functions such as planning curves is not clearly defined, easily causing command conflicts and control logic confusion. Third, the control strategies are not closely integrated with the energy storage's own state-of-charge safety and continuous power management, making it difficult to balance the effectiveness of overload mitigation with the long-term operational safety of energy storage.

[0033] Therefore, it is necessary to develop a method for managing the heavy overload of distribution transformers that can achieve precise phase control, multi-scenario adaptive coordination, and integrated intelligent power management, which has become an urgent need for the upgrading of distribution network technology.

[0034] In view of this, embodiments of this application provide a method and system for managing heavy overload in a distribution network. This embodiment determines the real-time load rate of each phase based on the current active power, apparent power, and rated capacity of each phase of the distribution transformer. It then determines the actual power control command for each single phase of the energy storage system based on the real-time load rate of each phase, the current power data of the distribution transformer, the current operating data of the energy storage system, the current control mode of the distribution transformer's heavy overload management, and the planned curve control enable status. Furthermore, it performs safety constraint verification through preset verification rules to determine the final power control command for each single phase of the energy storage system. This achieves precise phase-by-phase control of the distribution transformer's heavy overload, improving the effectiveness of heavy overload management.

[0035] Figure 1 This is a schematic diagram of the power distribution network structure provided in the embodiments of this application. For an example, please refer to [link to example diagram]. Figure 1This distribution network is a medium-voltage distribution network, which includes distribution transformers, each equipped with a power measurement unit. The network connects to an energy storage system, photovoltaic systems, and electrical loads. The energy storage system includes its own control equipment. The power measurement unit of the distribution transformer and the energy storage unit are connected to an energy storage management terminal. The power measurement unit, energy storage unit, and energy storage management terminal can be integrated into a single cabinet within a heavy overload mitigation system based on energy storage management and control.

[0036] The power distribution network overload mitigation method provided in this application is executed by an energy storage management terminal as the core control unit. This energy storage management terminal interacts with a power measurement unit installed on the low-voltage side of the distribution transformer and the energy storage unit's control equipment located within the energy storage system via a communication link.

[0037] The energy storage unit control equipment serves as the local controller for the energy storage system. It is responsible for receiving and executing power control commands issued by the energy storage energy management terminal, and for independently and precisely adjusting the A, B, and C phase power of the power conversion system (PCS). Simultaneously, it collects and reports real-time operating data of the energy storage unit, including three-phase power, remaining charge (SOC), charging power limits, and discharging power limits.

[0038] For example, the energy storage system controlled by the energy storage management terminal is a three-phase four-wire energy storage system, which includes an energy storage body control device, and the energy storage body control device supports independent control of the A, B, and C phase power of the energy storage converter.

[0039] The power measurement unit is installed on the low-voltage side of the distribution transformer, and its signal acquisition terminal is connected to a snap-fit ​​current transformer and a voltage acquisition terminal. The snap-fit ​​current transformer is a power-free installation structure that snaps directly onto the three-phase conductors on the low-voltage side of the distribution transformer; the voltage acquisition terminal draws power from the low-voltage side busbar of the distribution transformer to obtain the three-phase voltage signal.

[0040] Figure 2 This is a flowchart illustrating a method for mitigating heavy overload in a distribution network, as provided in an embodiment of this application. This embodiment provides a method for mitigating heavy overload in a distribution network, applicable to distribution network operation control systems, to achieve precise phase-by-phase control of heavy overload mitigation to improve its effectiveness. This method can be executed by a distribution network heavy overload mitigation system, which can be implemented in software and / or hardware, and can be configured in the processor or controller (e.g., an energy storage management terminal) of the distribution network operation control system. Please refer to... Figure 2 The method includes the following steps: Step 110: Receive the current power data of the distribution transformer and the current operating data of the energy storage system.

[0041] The current power data includes the current active power and the current apparent power of each phase of the distribution transformer.

[0042] The current power data of the distribution transformer can be obtained through the power measurement unit of the distribution transformer. For example, the current power data includes the current active power P_loadφ(t) (in kW), current reactive power Q_loadφ(t) (in kvar), and current apparent power S_loadφ(t) (in kVA) of each phase (or each single phase, e.g., phase A, phase B, and phase C) of the distribution transformer. Here, φ represents the target phase, which can be phase A, phase B, or phase C.

[0043] The current operating data of the energy storage system is transmitted in real time to the energy storage management terminal via a communication link. The current operating data includes the real-time power of each phase of the energy storage system (e.g., the power of the three phases A, B, and C, P_bessφ(t) (in kW, discharge is positive and charging is negative, i.e., the flow from the energy storage access point to the transformer is positive and the flow from the transformer to the energy storage access point is negative), the total charging power limit P_ch_total (absolute value, in kW), the total discharging power limit P_dis_total (absolute value, in kW), and the current remaining energy SOC(t) (percentage value).

[0044] Step 120: Determine the real-time load rate of the target phase based on the current active power, current apparent power, and rated capacity of the target phase of the distribution transformer.

[0045] Specifically, based on the real-time data received in step 110, the energy storage management terminal calculates the real-time load rate of the target phase φ of the distribution transformer. The formula for calculating the real-time load rate of the target phase φ is as follows: γ_φ(t)=[sign(P_loadφ(t))×(S_loadφ(t) / S_Nφ)]×100%; Wherein, γ_φ(t) represents the real-time load rate (in percentage form) of phase φ of the distribution transformer. The positive load rate indicates that the power is supplied from the distribution transformer to the low-voltage side of the distribution transformer in the forward direction, and the negative load rate indicates that the power is fed back from the low-voltage side of the distribution transformer to the distribution transformer in the reverse direction. Its absolute value characterizes the load level.

[0046] Wherein, sign(P_loadφ(t)) represents the active power sign function, which takes the value 1 when P_loadφ(t)>0, takes the value -1 when P_loadφ(t)<0, and takes the value 0 when P_loadφ(t)=0.

[0047] Where S_Nφ=S_N / 3, S_N is the total rated capacity of the distribution transformer (in kVA), which can be set in the energy storage management terminal, and S_Nφ is the single-phase rated capacity of the distribution transformer (in kVA).

[0048] The calculation of the forward and reverse overload mitigation targets for the distribution transformer includes: calculating the first target active power for forward overload mitigation of the target phase of the distribution transformer, calculating the first target apparent power for forward overload mitigation of the target phase of the distribution transformer, calculating the second target active power for forward overload mitigation of the target phase of the distribution transformer, calculating the second target apparent power for forward overload mitigation of the target phase of the distribution transformer, calculating the first target active power for reverse overload mitigation of the target phase of the distribution transformer, calculating the first target apparent power for reverse overload mitigation of the target phase of the distribution transformer, calculating the second target active power for reverse overload mitigation of the target phase of the distribution transformer, and calculating the second target apparent power for reverse overload mitigation of the target phase of the distribution transformer. The specific calculation process is as follows: In some embodiments, a method for determining the first target active power for positive heavy overload mitigation of a target phase of a distribution transformer includes: determining the first target active power for positive heavy overload mitigation of the target phase of the distribution transformer based on the first target apparent power for positive heavy overload mitigation of the target phase of the distribution transformer and the current reactive power; wherein the first target apparent power for positive heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, a preset threshold value for positive heavy overload load rate exceeding the limit, and a preset threshold value for the first hysteresis of heavy overload mitigation. A method for determining the second-level target active power for positive heavy overload mitigation of the target phase of a distribution transformer includes: determining the second-level target active power for positive heavy overload mitigation of the target phase of the distribution transformer based on the second-level target apparent power and the current reactive power; wherein, the second-level target apparent power for positive heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, a preset threshold value for positive heavy overload load rate exceeding the limit, and a preset threshold value for the second-level hysteresis of heavy overload mitigation.

[0049] Specifically, the formula for calculating the first target active power Ppos1_tarφ of the forward heavy overload mitigation phase φ of the distribution transformer in the energy storage energy management terminal is as follows: ; Wherein, Spos1_tarφ represents the first target apparent power of the target phase φ of the distribution transformer for positive heavy overload control; Q_loadφ(t) represents the current reactive power of the target phase φ.

[0050] The calculation formula for the first target apparent power Spos1_tarφ of the target phase φ of the distribution transformer for positive heavy overload mitigation is as follows: Spos1_tarφ=S_Nφ×(kpos-kdead1); Wherein, kpos represents the threshold value for the forward heavy overload rate of the distribution transformer; kdead1 represents the first hysteresis threshold value for heavy overload mitigation. Both kpos and kdead1 can be set in the energy storage energy management terminal.

[0051] Specifically, the formula for calculating the second target active power Ppos2_tarφ of the forward heavy overload mitigation phase φ of the distribution transformer in the energy storage energy management terminal is as follows: ; Wherein, Spos2_tarφ represents the second target apparent power of the target phase φ of the distribution transformer for positive heavy overload control.

[0052] The calculation formula for the second objective of positive heavy overload mitigation of the target phase φ of the distribution transformer, namely the apparent power Spos2_tarφ, is as follows: Spos2_tarφ=S_Nφ×(kpos-kdead2); Here, kdead2 represents the second hysteresis threshold value for heavy overload management, which can be set in the energy storage energy management terminal.

[0053] In some embodiments, a method for determining the first target active power for reverse heavy overload mitigation of a target phase of a distribution transformer includes: determining the first target active power for reverse heavy overload mitigation of the target phase of the distribution transformer based on the first target apparent power for reverse heavy overload mitigation of the target phase of the distribution transformer and the current reactive power; wherein the first target apparent power for reverse heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, a preset reverse heavy overload load rate exceeding threshold value, and a preset first hysteresis threshold value for heavy overload mitigation. A method for determining the second target active power for reverse heavy overload mitigation of a distribution transformer includes: determining the second target active power for reverse heavy overload mitigation of the distribution transformer based on the second target apparent power and the current reactive power of the target phase; wherein the second target apparent power for reverse heavy overload mitigation of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, a preset reverse heavy overload load rate exceeding threshold value, and a preset second hysteresis threshold value for heavy overload mitigation.

[0054] Specifically, the formula for calculating the first target active power Pneg1_tarφ of the reverse heavy overload mitigation phase φ of the distribution transformer in the energy storage energy management terminal is as follows: ; Wherein, Sneg1_tarφ represents the apparent power of the first target phase φ of the reverse heavy overload mitigation of the distribution transformer; The formula for calculating the apparent power Sneg1_tarφ of the first target phase in the reverse heavy overload mitigation of the distribution transformer is as follows: Sneg1_tarφ=S_Nφ×|(-kneg+kdead1)|; Here, "kneg" represents the threshold value for the reverse heavy overload rate of the distribution transformer, which can be set in the energy storage management terminal.

[0055] Specifically, the formula for calculating the second target active power Pneg2_tarφ of the reverse heavy overload mitigation phase φ of the distribution transformer in the energy storage energy management terminal is as follows: ; Wherein, Sneg2_tarφ represents the apparent power of the second target phase φ of the reverse heavy overload mitigation of the distribution transformer; The formula for calculating the apparent power Sneg2_tarφ of the second target phase in the reverse heavy overload mitigation of the distribution transformer is as follows: Sneg2_tarφ=S_Nφ×|(-kneg + kdead2)|; Step 130: Determine the current control mode and planned curve control enable status for the overload mitigation of the distribution transformer.

[0056] The current control mode is one of the following: Mode 1, Mode 2, Mode 3, and Mode 4. Specifically, the four modes are as follows: Mode 1 is characterized by the forward overload mitigation enabling state being in the first enabled state, and the reverse overload mitigation enabling state being in the second enabled state.

[0057] The first enable state is logic number 1, and the second enable state is logic number 0. When the forward overload management enable state is 1 and the reverse overload management enable state is 0, it indicates that the forward overload management is engaged and the reverse overload management is disengaged.

[0058] The second mode is as follows: the forward heavy overload management enable state is the second enable state, and the reverse heavy overload management enable state is the first enable state. Specifically, when the forward heavy overload management enable state is 0 and the reverse heavy overload management enable state is 1, it means that the forward heavy overload management is off and the reverse heavy overload management is on.

[0059] The third mode is: both the forward heavy overload management and reverse heavy overload management are enabled. Specifically, when both the forward heavy overload management and reverse heavy overload management are enabled (1), it means that both forward and reverse heavy overload management are in operation.

[0060] The fourth mode is: the forward heavy overload management enable state is the second enable state, and the reverse heavy overload management enable state is the second enable state. Specifically, when the forward heavy overload management enable state is 0 and the reverse heavy overload management enable state is 0, it means that both forward heavy overload management and reverse heavy overload management are exited.

[0061] The planned curve control enable state is either the first enable state (indicating that the planned curve control function is engaged) or the second enable state (indicating that the planned curve control function is disengaged).

[0062] It should be noted that the specific logical values ​​of the current control mode's enable status and the planned curve control enable status can be determined by the user in real time.

[0063] Specifically, the energy storage management terminal determines the control mode's activation status based on pre-set enable settings. It selects one of four modes to execute: Mode 1 (forward heavy overload mitigation enable setting 1, reverse heavy overload mitigation enable setting 0), Mode 2 (forward heavy overload mitigation enable setting 0, reverse heavy overload mitigation enable setting 1), Mode 3 (forward heavy overload mitigation enable setting 1, reverse heavy overload mitigation enable setting 1), and Mode 4 (forward heavy overload mitigation enable setting 0, reverse heavy overload mitigation enable setting 0). Simultaneously, it determines the planned curve control function's activation or deactivation status based on the planned curve control enable setting. Specifically, a planned curve control enable setting of 1 indicates that the planned curve control function is activated, while a set value of 0 indicates that the planned curve control function is deactivated. Planned curve control can coexist with all of the above control modes.

[0064] Step 140: Based on the current control mode, planned curve control enable status, real-time load rate, current power data, and current operating data, determine the actual power control command for the target phase of the energy storage system.

[0065] Specifically, the energy storage management terminal, based on the current overload control mode status and planned curve control enable status determined in step 130, combined with the real-time load rate calculated in step 120 and the real-time data received in step 110, executes the corresponding control mode strategy according to the preset control cycle T, and generates the target phase φ power control command P_outφ(t) for the energy storage system. Where P_outφ(t) > 0 indicates energy storage discharge, and P_outφ(t) < 0 indicates energy storage charging.

[0066] The specific value of the preset control period T is set by the energy storage management terminal.

[0067] It should be noted that the priority rule for control logic in each mode is as follows: overload management takes precedence over planning curve control. That is, when an overload condition exists, only the overload management instruction is executed; when there is no overload condition and planning curve control is enabled, the planning curve control instruction is executed.

[0068] The planned curve control can be implemented by setting parameters in the energy storage management terminal. These parameters include the start time T_began_m_plan of the planned curve control period m, the end time T_end_m_plan of the planned curve control period m, and the planned power P_m_plan (in kW) of the planned curve control period m. All of these parameters can be set in the energy storage management terminal. Here, m = 1~M, where M is the number of planned curve control periods. When the planned curve control enable state is 1, the energy storage management terminal iterates through the M set planned curve control periods. When its own time falls within the T_began_m_plan~T_end_m_plan interval of the planned curve control period m, the matched planned power P_m_plan for the current period is determined as the three-phase total command setting value required for the planned curve control at the current time.

[0069] In some embodiments, when the current control mode is the first mode, the method for determining the actual power control command includes: when the real-time load rate of the target phase of the distribution transformer is greater than the preset threshold value for the positive heavy overload load rate, determining that the target phase of the distribution transformer has a positive heavy overload, and determining the actual power control command based on the first target active power and the current active power of the positive heavy overload control of the target phase of the distribution transformer, as well as the total discharge power limit and rated power of the energy storage system; When the real-time load rate of all phases of the distribution transformer is less than the first preset difference, and the current remaining power of the energy storage system is less than the preset reserved power threshold for positive heavy overload control, the active power replenishment strategy of the energy storage is triggered. Based on the second target active power and the current active power of the target phase of the distribution transformer for positive heavy overload control, as well as the total charging power limit and rated power of the energy storage system, the actual power control command is determined. When the current remaining power increases to the third preset remaining power, the power replenishment is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is less than the second preset difference, the active energy storage replenishment strategy is not triggered, and the planned curve control is enabled in the first enabled state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the second target active power of the positive heavy overload management of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power. If the active energy storage replenishment strategy is not triggered and the planned curve control is in the second enabled state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0070] The first preset difference is: kpos-kdead2.

[0071] The second preset difference is: kpos-kdead1.

[0072] The third preset remaining power is: SOC_pos + SOC_dead; SOC_pos represents the threshold power reserved for positive heavy overload management, and SOC_dead represents the dead zone of SOC management and control. Both can be set in the energy storage energy management terminal.

[0073] Specifically, when the real-time load rate γ_φ(t) of the target phase φ of the distribution transformer is greater than the set positive overload load rate threshold value kpos, it is determined that the target phase φ of the distribution transformer has experienced a positive overload, and the actual power control command for the target phase φ of the energy storage system is generated as follows: P_outφ(t)=min(|Ppos1_tarφ-P_loadφ(t)|, P_dis_total / 3, Pbess_rate / 3); When the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are less than kpos-kdead2, and the current remaining energy SOC(t) of the energy storage system is less than the set threshold SOC_pos for the reserved energy for positive overload mitigation, the active energy storage replenishment strategy is triggered, and the target phase φ power control command of the energy storage system is generated as follows: P_outφ(t)=min{max[-|Ppos2_tarφ-P_loadφ(t)|, -P_ch_total / 3, -Pbess_rate / 3], 0}; Charging stops when the current remaining energy SOC(t) of the energy storage system increases to the level that SOC(t) > SOC_pos + SOC_dead, and P_outφ(t) = 0.

[0074] When the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are less than kpos-kdead1, the active energy storage replenishment strategy is not triggered, and the planned curve control enable status is 1 (planned curve control function is engaged), then M set time periods are traversed to match the planned power P_m_plan for the current time period. Then, based on the planned power for the current time period, the second target active power for positive heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power, the actual power control command is determined.

[0075] When the active energy storage replenishment strategy is not triggered and the planned curve control enable status is 0 (planned curve control function is off), the power control command P_outφ(t) of the target phase φ of the energy storage system is kept unchanged from the value of the previous preset control cycle.

[0076] In some embodiments, determining an actual power control command based on the planned power for the current time period, the second target active power for positive heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power includes: determining an actual power control command based on the planned power for the current time period, the total discharge power limit, and the rated power when the planned power for the current time period is greater than zero; and determining an actual power control command based on the planned power for the current time period, the total charging power limit, the rated power, and the second target active power for positive heavy overload mitigation of the target phase of the distribution transformer when the planned power for the current time period is less than zero.

[0077] Specifically, when the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are less than kpos-kdead1, the active energy storage replenishment strategy is not triggered, and the planned curve control enable status is 1 (planned curve control function is engaged), then the M set time periods are traversed to match the planned power P_m_plan for the current time period. If the planned power P_m_plan for the current time period is greater than zero (planned discharge), then an instruction is generated: P_outφ(t)=min(P_m_plan / 3, P_dis_total / 3, Pbess_rate / 3); If the planned power P_m_plan for the current time period is less than zero (planned charging), then an instruction is generated: P_outφ(t)=max (P_m_plan / 3,-||Ppos2_tarφ|-|P_loadφ(t)||,-P_ch_total / 3,-Pbess_rate / 3); In some embodiments, when the current control mode is the second mode, the method for determining the actual power control command includes: when the real-time load rate of the target phase of the distribution transformer is less than the negative value of the preset reverse overload load rate threshold, determining that the target phase of the distribution transformer has a reverse overload, and determining the actual power control command based on the first target active power and the current active power of the reverse overload control of the target phase of the distribution transformer, as well as the total charging power limit and rated power of the energy storage system; When the real-time load rate of all phases of the distribution transformer is greater than the third preset difference, and the current remaining power of the energy storage system is greater than the preset reserved power threshold for reverse overload control, the active discharge strategy of the energy storage is triggered. Based on the second target active power and current active power of the reverse overload control of the target phase of the distribution transformer, as well as the total discharge power limit and rated power of the energy storage system, the actual power control command is determined. When the current remaining power is reduced to the fourth preset remaining power, the discharge is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference, the active discharge strategy of energy storage is not triggered, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the second target active power of the reverse heavy overload control of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power. If the active discharge strategy of energy storage is not triggered and the planned curve control enable state is the second enable state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0078] The third preset difference is: -kneg+kdead2.

[0079] The fourth preset difference is: -kneg+kdead1.

[0080] The fourth preset remaining power is: SOC_neg-SOC_dead. SOC_neg represents the reserved power threshold for reverse overload management of energy storage, and SOC_dead represents the SOC management control dead zone (i.e., the power control dead zone value in the active power replenishment and active discharge strategies). Both can be set in the energy storage energy management terminal.

[0081] Specifically, when the real-time load rate γ_φ(t) of the target phase φ of the distribution transformer is less than the set reverse overload load rate threshold value kneg, it is determined that the target phase φ of the distribution transformer has experienced a reverse overload, and the actual power control command for the target phase φ of the energy storage system is generated as follows: P_outφ(t)=max(-|Pneg1_tarφ-P_loadφ(t)|,-P_ch_total / 3,-Pbess_rate / 3); When the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are greater than -kneg+kdead2, and the current remaining energy SOC(t) of the energy storage system is greater than the reserved energy threshold SOC_neg for reverse overload mitigation, the active discharge strategy of the energy storage system is triggered, and the power control command for the target phase φ of the energy storage system is generated as follows: P_outφ(t)=max{min[||Pneg2_tarφ|-|P_loadφ(t)||, P_dis_total / 3, Pbess_rate / 3], 0}; Discharge stops when the current remaining charge SOC(t) of the energy storage system decreases to the level that SOC(t) > SOC_neg - SOC_dead, and P_outφ(t) = 0.

[0082] When the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are greater than -kneg-kdead1, the active energy storage discharge strategy is not triggered, and the planned curve control enable status is 1 (planned curve control function is engaged), then the M set time periods are traversed to match the planned power P_m_plan for the current time period. Then, based on the planned power for the current time period, the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power, the actual power control command is determined.

[0083] When the active discharge strategy of energy storage is not triggered and the planned curve control enable status is 0 (planned curve control function is off), the power control command P_outφ(t) of the target phase φ of the energy storage system is kept unchanged from the value of the previous preset control cycle.

[0084] In some embodiments, determining an actual power control command based on the planned power for the current time period, the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power includes: determining an actual power control command based on the planned power for the current time period, the total discharge power limit, the rated power, and the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer when the planned power for the current time period is greater than zero; and determining an actual power control command based on the planned power for the current time period, the total charging power limit, and the rated power when the planned power for the current time period is less than zero.

[0085] Specifically, when the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are greater than -kneg-kdead1, the active energy storage discharge strategy is not triggered, and the planned curve control enable status is 1 (planned curve control function is engaged), then the M set time periods are traversed to match the planned power P_m_plan for the current time period. When the planned power P_m_plan for the current time period is greater than zero (planned discharge), then an instruction is generated: P_outφ(t)=min(P_m_plan / 3, ||Pneg2_tarφ|-|P_loadφ(t)||, P_dis_total / 3, Pbess_rate / 3); If the planned power P_m_plan for the current time period is less than zero (planned charging), then an instruction is generated: P_outφ(t)=max(P_m_plan / 3, -P_ch_total / 3, -Pbess_rate / 3); In some embodiments, when the current control mode is the third mode, the method for determining the actual power control command includes: interrupting the planned curve control when the real-time load rate of any phase of the distribution transformer is greater than a preset forward heavy overload load rate threshold value, and determining the actual power control command based on the first target active power and current active power of the forward heavy overload control of the target phase of the distribution transformer, as well as the total discharge power limit and rated power of the energy storage system; or, interrupting the planned curve control when the real-time load rate of any phase of the distribution transformer is less than a negative value of the preset reverse heavy overload load rate threshold value, and determining the actual power control command based on the first target active power and current active power of the reverse heavy overload control of the target phase of the distribution transformer, as well as the total charging power limit and rated power of the energy storage system. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period. Based on the planned power of the current time period, the current active power, the total discharge power limit, the total charging power limit, the rated power, the second target active power of the forward heavy overload control of the target phase of the distribution transformer, and the second target active power of the reverse heavy overload control of the target phase of the distribution transformer, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the second enable state, the actual power control command is determined according to the preset overload power command reset strategy.

[0086] Specifically, when any phase of the distribution transformer triggers a real-time load rate γ_φ(t) > kpos (indicating a positive heavy overload), the planned curve control is interrupted, and the power control command for the target phase φ of the energy storage system is issued according to the positive heavy overload management logic of the first mode. When any phase of the distribution transformer triggers a real-time load rate γ_φ(t) < -kneg (indicating a reverse heavy overload), the planned curve control is interrupted, and the power control command for the target phase φ of the energy storage system is issued according to the reverse heavy overload management logic of the second mode.

[0087] When the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are greater than -kneg+kdead1 and less than kpos-kdead1, and the planned curve control enable state is 1 (planned curve control function is engaged), then the M set time periods are traversed to match the planned power P_m_plan for the current time period. Then, based on the planned power for the current time period, the total discharge power limit, the total charging power limit, the rated power, the second target active power for the forward heavy overload mitigation of the target phase of the distribution transformer, and the second target active power for the reverse heavy overload mitigation of the target phase of the distribution transformer, the actual power control command is determined.

[0088] When the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are greater than -kneg+kdead1 and less than kpos-kdead1, and the planned curve control enable state is 0 (planned curve control function is off), then the overload power command reset strategy is executed.

[0089] In some embodiments, determining the actual power control command based on the planned power for the current time period, the total discharge power limit, the total charging power limit, the rated power, the second target active power for the forward heavy overload control of the target phase of the distribution transformer, and the second target active power for the reverse heavy overload control of the target phase of the distribution transformer includes: when the planned power for the current time period is greater than zero, determining the actual power control command based on the planned power for the current time period, the current active power, the total discharge power limit, the rated power, and the second target active power for the reverse heavy overload control of the target phase of the distribution transformer; and when the planned power for the current time period is less than zero, determining the actual power control command based on the planned power for the current time period, the current active power, the total charging power limit, the rated power, and the second target active power for the forward heavy overload control of the target phase of the distribution transformer.

[0090] Specifically, when the real-time load rates γ_A(t), γ_B(t), and γ_C(t) of all phases of the distribution transformer are all greater than -kneg + kdead1 and less than kpos - kdead1, and the planned curve control enabling state is 1 (the planned curve control function is enabled), then traverse the M set time periods to match the planned power P_m_plan of the current time period. When the planned power P_m_plan of the current time period is greater than zero (planned discharge), then generate an instruction: Then generate an instruction: P_outφ(t)=min(P_m_plan / 3, ||Pneg2_tarφ|-|P_loadφ(t)||, P_dis_total / 3, Pbess_rate / 3); When the planned power P_m_plan of the current time period is less than zero (planned charge), then generate an instruction: P_outφ(t)= max (P_m_plan / 3, -||Ppos2_tarφ|-|P_loadφ(t)||, -P_ch_total / 3, -Pbess_rate / 3); In some embodiments, determining the actual power control instruction according to a preset power instruction reset strategy after overload includes: gradually reducing the absolute value of the actual power control instruction of each phase of the energy storage system according to a preset attenuation coefficient until the real-time power of each phase of the energy storage system meets the preset power condition, and then determining that the actual power control instruction of each phase of the energy storage system is zero.

[0091] Wherein, the preset power condition is: kzero×(Pbess_rate / 3).

[0092] Specifically, the power instruction reset strategy after overload is: gradually reduce the absolute value of the power control instruction P_outφ(t) of each phase according to a preset attenuation coefficient k_decay (0 < k_decay < 1) until |P_bessφ(t) ≤ kzero×(Pbess_rate / 3), and then set P_outφ(t)=0.

[0093] In some embodiments, when the current control mode is the fourth mode, the method for determining the actual power control instruction includes: when the planned curve control enabling state is the first enabling state, traverse each time period of the planned curve control to match the planned power of the current time period, and determine the actual power control instruction according to the planned power of the current time period, as well as the total discharge power limit, total charge power limit, and rated power of the energy storage system; when the planned curve control enabling state is the second enabling state, keep the actual power control instruction of the previous preset control period.

[0094] Specifically, when neither forward nor reverse overload mitigation is activated, and the planned curve control enable is 1 (planned curve control function is activated), the system iterates through M set time periods to match the planned power P_m_plan for the current time period. Then, based on the planned power for the current time period, as well as the total discharge power limit, total charging power limit, and rated power of the energy storage system, the actual power control command is determined.

[0095] When the planned curve control enable is 0 (planned curve control function is off), the target phase φ phase power control command P_outφ(t) of the energy storage system is kept unchanged from the value of the previous control cycle.

[0096] In some embodiments, determining the actual power control command based on the planned power for the current time period, the total discharge power limit, the total charging power limit, and the rated power of the energy storage system includes: determining the actual power control command based on the planned power for the current time period, the total discharge power limit, and the rated power when the planned power for the current time period is greater than zero; and determining the actual power control command based on the planned power for the current time period, the total charging power limit, and the rated power when the planned power for the current time period is less than zero.

[0097] Specifically, when the planned curve control enable is 1 (planned curve control function is engaged), the system iterates through M set time periods and matches the planned power P_m_plan for the current time period. If the planned power P_m_plan for the current time period is greater than zero (planned discharge), then an instruction is generated: P_outφ(t)=min(P_m_plan / 3, P_dis_total / 3, Pbess_rate / 3); If the planned power P_m_plan for the current time period is less than zero (planned charging), then an instruction is generated: P_outφ(t)=max(P_m_plan / 3, -P_ch_total / 3, -Pbess_rate / 3); Step 150: Perform safety constraint verification on the actual power control command according to the preset verification rules to determine the final power control command.

[0098] Specifically, the target phase φ power control command P_outφ(t) of the energy storage system output in step 140 is subjected to a safety constraint verification strategy according to preset verification rules. If the verification passes, the final target phase φ power control command P_outφ(t) of the energy storage system is sent to the energy storage body control device. If the verification fails, the target phase φ power control command P_outφ(t) of the energy storage system is corrected according to the constraint rules and then sent to the energy storage body control device.

[0099] The preset verification rules include phase power constraints and extreme power adjustment constraints.

[0100] In some embodiments, the actual power control command is subjected to safety constraint verification according to a preset verification rule to determine the final power control command, including: when the actual power control command is greater than zero, determining the final power control command based on the actual power control command, the total discharge power limit and rated power of the energy storage system; when the actual power control command is less than zero, determining the final power control command based on the actual power control command, the total charging power limit and rated power of the energy storage system.

[0101] Specifically, the phase power constraint is as follows: when the target phase φ phase power control command P_outφ(t) generated in step 140 is greater than 0, then let: P_outφ(t)=min(P_outφ(t), P_dis_total / 3, Pbess_rate / 3); When the target phase φ phase power control command P_outφ(t) generated in step 140 is < 0, then let: P_outφ(t)=max(P_outφ(t),-P_ch_total / 3,-Pbess_rate / 3); In some embodiments, the current operating data includes the current remaining power of the energy storage system and the real-time power of each phase. For the actual power control command, a safety constraint verification is performed according to a preset verification rule to determine the final power control command. This includes: when the current remaining power is less than a first preset remaining power and the sum of the real-time power of each phase is greater than zero, reducing the discharge power of each phase of the energy storage system once in each preset control cycle, i.e., updating the current power control command of the target phase of the energy storage system to a first preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle each time, until the real-time power of the target phase of the energy storage system meets the preset power judgment condition, at which point the current power control command of the target phase of the energy storage system is set to zero; when the current remaining power is greater than a second preset remaining power and the sum of the real-time power of each phase is less than zero, reducing the absolute value of the charging power of each phase of the energy storage system once in each preset control cycle, i.e., updating the current power control command of the target phase of the energy storage system to a second preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle each time, until the real-time power of the target phase of the energy storage system meets the preset power judgment condition, at which point the current power control command of the target phase of the energy storage system is set to zero.

[0102] The first preset remaining power is the lower limit of the energy storage system's remaining power, SOC_min, and the second preset remaining power is the upper limit of the energy storage system's remaining power, SOC_max. The first and second preset multiples are the same, both being the power attenuation coefficient k_decay times, which can be set in the energy storage management terminal. Where 0... <k_decay<1。

[0103] The preset power determination condition is as follows: |P_bessφ(t)|≤kzero×(Pbess_rate / 3); Where P_bessφ(t) represents the real-time power of the target phase φ of the energy storage system; represents the low-power judgment coefficient of the energy storage system; and Pbess_rate represents the rated power of the energy storage system (in kW).

[0104] Specifically, the extreme power regulation constraint is as follows: when the current remaining energy SOC(t) of the energy storage system is less than SOC_min, and the sum of the real-time power of the three phases of the energy storage system P_bess_total(t) = P_bessA(t) + P_bessB(t) + P_bessC(t) > 0 (the energy storage system is in a discharging state), then the discharge power of each phase of the energy storage system is reduced once in each preset control cycle T. Each time, the power control command P_outφ(t) of the target phase φ of the energy storage system is updated to k_decay times the actual power P_outφ(t) of the target phase φ of the energy storage system in the previous preset control cycle, until |P_bessφ(t)| ≤ kzero × (Pbess_rate / 3), then P_outφ(t) is set to 0 to avoid SOC(t) from falling below SOC_min.

[0105] When the current remaining charge SOC(t) of the energy storage system is greater than SOC_max, and the sum of the real-time power of the three phases of the energy storage system P_bess_total(t) = P_bessA(t) + P_bessB(t) + P_bessC(t) < 0 (the energy storage system is in a charging state), the absolute value of the discharge power of each phase of the energy storage system is reduced once in each preset control cycle T. Each time, the power control command P_outφ(t) of the target phase φ of the energy storage system is updated to k_decay times the actual power P_outφ(t) of the target phase φ of the energy storage system in the previous preset control cycle, until |P_bessφ(t)| ≤ kzero × (Pbess_rate / 3), at which point P_outφ(t) is set to 0 to avoid SOC(t) being higher than SOC_max.

[0106] Among them, SOC_min, SOC_max, kzero, Pbess_rate, and k_decay can all be set in the energy storage management terminal.

[0107] It should be noted that various set values that can be set in the energy storage energy management terminal support local setting and modification on the terminal or setting and modification through remote communication. The setting ranges, recommended values, and association relationships of the set values that can be set are as follows: First, enable type set values, including forward heavy overload governance enable, reverse heavy overload governance enable, and planned curve control enable. Among them, forward heavy overload governance enable: can be set to 0 or 1. When set to 1, it means the forward heavy overload governance function is in the enabled state; when set to 2, it means the forward heavy overload governance function is in the disabled state. Among them, reverse heavy overload governance enable: can be set to 0 or 1. When set to 1, it means the reverse heavy overload governance function is in the enabled state; when set to 2, it means the reverse heavy overload governance function is in the disabled state. Among them, planned curve control enable: can be set to 0 or 1. When set to 1, it means the planned curve control function is in the enabled state; when set to 2, it means the planned curve control function is in the disabled state.

[0108] Second, energy storage power quantity type set values, including the allowable lower limit of the remaining energy storage power SOC_min, the allowable upper limit of the remaining energy storage power SOC_max, the reserved power threshold for forward heavy overload governance SOC_pos, the reserved energy storage power threshold for reverse heavy overload governance SOC_neg, and the SOC management control dead zone SOC_dead. Among them, the allowable lower limit of the remaining energy storage power SOC_min: the setting range is 0 - 100%, and it is recommended not to be greater than 30% in engineering applications. The allowable upper limit of the remaining energy storage power SOC_max: the setting range is 0 - 100%, and it is recommended not to be less than 70% in engineering applications. The reserved power threshold for forward heavy overload governance SOC_pos: the setting range is 0 - 100%, and the association relationship is SOC_pos < SOC_max - SOC_dead. The reserved energy storage power threshold for reverse heavy overload governance SOC_neg: the setting range is 0 - 100%, and the association relationship is SOC_neg > SOC_min + SOC_dead. The SOC management control dead zone SOC_dead: the setting range is 0 - 100%, and it is recommended to be set to 5% - 10% in engineering applications.

[0109] Thirdly, other auxiliary control settings. Total rated capacity of distribution transformer S_N: Set according to the actual rated capacity of the distribution transformer to be addressed; Small power judgment coefficient of energy storage kzero: Setting range 0-1, recommended to be less than 0.1 in engineering applications; Rated power of energy storage Pbess_rate: Set according to the actual rated power of the energy storage; Number of planned curve control periods M: In the development stage of the energy storage energy management terminal, M>1 is required; Start time of planned curve control period m T_began_m_plan: Setting range 00:00-23:59; Stop time of planned curve control period m T_end_m_plan: Setting range 00:00-23:59; When setting, it is necessary to ensure that the [start time, stop time] intervals of all periods do not overlap. The planned power P_m_plan for the planned curve control period m: the setting range is –Pbess_rate~Pbess_rate; the preset control period T: when setting, it must be greater than twice the “signal acquisition and power calculation time of the distribution transformer power measurement unit + data transmission time between the distribution transformer power measurement unit and the energy storage energy management terminal + logic judgment time of the energy storage energy management terminal + data transmission time between the energy storage energy management terminal and the energy storage body control equipment + maximum response time of the energy storage body to the power command”.

[0110] Furthermore, maintenance personnel can set and modify the parameters of the planned curve control locally or remotely at the energy storage energy management terminal based on the historical operating data of the distribution transformer area. This historical operating data includes historical load factor curves and historical photovoltaic power generation curves.

[0111] Among them, setting and modifying the planned curve control parameters locally or remotely is used for proactive power management of the energy storage system, including: setting a charging plan to increase the remaining power of the energy storage before the expected period of positive heavy overload; setting a discharging plan to decrease the remaining power of the energy storage before the expected period of reverse heavy overload; the power management is particularly suitable for the operation mode in which both positive and reverse heavy overload mitigation functions are engaged.

[0112] Among them, setting and modifying the control parameters of the planned curve locally or remotely is used to enable the energy storage system to charge and discharge at a predetermined power during a specified period, so as to achieve other specific operational objectives besides heavy overload management and the aforementioned forward-looking power management.

[0113] It is understood that the distribution network overload mitigation method provided in this application calculates the phase load rate of the distribution transformer in real time, and dynamically selects and executes four types of overload mitigation control modes and their coordinated control strategies with the planned curve based on preset enable settings, according to preset load rate over-limit thresholds, hysteresis thresholds, and the safe range of remaining energy storage capacity (SOC). This allows for independent adjustment of the charging and discharging power of each phase of energy storage, prioritizing the return of the overloaded phase load rate to the safe range, and achieving optimized energy storage capacity management and multi-strategy coordinated operation. The method provided in this application can solve the problems of forward and reverse overload caused by the coexistence of load growth and photovoltaic backfeed power in distribution transformers, while overcoming the technical problems of insufficient mitigation effect and energy storage capacity management in existing control methods, as well as the conflict of instructions between overload mitigation and planned control functions. Furthermore, the method provided in this application can achieve the following beneficial effects: First, the embodiments of this application overcome the shortcomings of related technologies that are based on the three-phase total capacity control method and have insufficient precision in heavy overload management by performing real-time calculation of phase load rate and independent phase power control of distribution transformers. This application can perform differentiated and precise management of common single-phase unbalanced overload conditions in distribution networks, which significantly improves the utilization efficiency and management effect of energy storage equipment.

[0114] Secondly, this application embodiment sets up four control modes: forward heavy overload management, reverse heavy overload management, mixed forward and reverse heavy overload management, and neither forward nor reverse heavy overload is activated. It also sets up a configurable control strategy that coordinates the control mode with the planned curve and clarifies the rigid priority rule that "overload management takes precedence over planned curve control". This completely solves the problem of instruction conflict and control disorder that may occur when multiple strategies are implemented in parallel from a logical level, ensuring that overload can be dealt with quickly in the first instance and guaranteeing the safe operation of the distribution network.

[0115] Third, the embodiments of this application establish a multi-dimensional energy storage power management system that includes SOC safety range, reserved threshold and control dead zone, and combine phase power constraints and extreme power adjustment constraints to perform command safety verification, thereby realizing dynamic balance and safety protection of energy storage under frequent charging and discharging operations, effectively preventing overcharging and over-discharging of energy storage, and extending the service life of equipment.

[0116] Fourth, the planned curve control function in this application supports localized independent parameter settings and commissioning / discharging. Operation and maintenance personnel can flexibly preset planned charging and discharging strategies based on the historical load and photovoltaic output curve of the transformer area, thereby actively managing the energy storage power during non-overload periods, reserving sufficient capacity to cope with expected positive or reverse heavy overloads, reducing dependence on the upper-level master station scheduling, and enhancing the flexibility and adaptability of field applications.

[0117] Fifth, the embodiments of this application introduce a scientific control cycle setting mechanism, requiring the control cycle to be greater than twice the total latency of the system's data acquisition, transmission, processing and execution, which effectively avoids control command delays or malfunctions caused by data latency, and greatly improves the reliability of the entire governance system.

[0118] Figure 3 This is a schematic diagram of the overall process of a power distribution network overload mitigation method provided in this application embodiment. For an example, please refer to [link to example]. Figure 3 The overall process of this distribution network overload mitigation method includes: Step S1, receiving real-time power data of the distribution transformer and energy storage operation data; Step S2, calculating the load rate of the distribution transformer and the forward and reverse overload mitigation targets; Step S3, determining the overload mitigation control mode status of the distribution transformer; Step S4, periodically executing the multi-mode overload mitigation strategy and generating phase-specific power commands for energy storage; Step S5, verifying and issuing the phase-specific power commands for energy storage based on safety constraints.

[0119] For example, the method for mitigating heavy overload in power distribution networks provided in the embodiments of this application is verified by simulation, as follows: according to Figure 1 The provided schematic diagram of the distribution network structure is used to build a simulation platform for managing forward and reverse overload of distribution transformers. The modeling objects include: medium-voltage distribution network, power lines, a 200kVA distribution transformer model, a distributed photovoltaic model, a residential / commercial composite load model, a three-phase four-wire energy storage system model with energy storage management terminals, and power measurement units and instrument transformer models. The parameter settings and simulation verification results are shown in Tables 1 and 2, respectively.

[0120] Table 1: Parameter Settings for Example

[0121] Table 2: Simulation Verification Results of the Examples

[0122] The following conclusions can be drawn from Table 2: First, in all overload control scenarios (including pure forward overload, pure reverse overload, and mixed forward and reverse overload), the load rate of the overloaded phase can be quickly stabilized within the set range of [corresponding overload threshold - first hysteresis threshold] (for example, 75% for forward and -75% for reverse in this embodiment), which fully conforms to the control logic of kpos=kneg=80%, verifying that the phase-independent control algorithm provided in this application embodiment has accurate and fast adjustment capabilities, and there is no overshoot or residual overload phenomenon.

[0123] Secondly, the phase-by-phase charging and discharging power of the energy storage system in each scenario never exceeded 20kW (i.e., 1 / 3 of the rated power of the energy storage system), and the remaining energy storage capacity (SOC) was maintained within the preset safe range of 20% to 80% throughout the process. This fully demonstrates the effectiveness of the phase-by-phase power constraint and extreme power regulation (including SOC over-limit protection) strategy provided in the embodiments of this application, ensuring the operational safety of the energy storage device itself.

[0124] Third, the verification through the "forward / reverse heavy overload and active power replenishment / discharge strategy" scenario shows that after the overload risk is eliminated, the system can automatically perform forward-looking power management based on the energy storage power status (replenishing when power is insufficient and discharging when power is sufficient), which reserves or frees up capacity to cope with possible subsequent overload events, and enhances the sustainability and initiative of governance.

[0125] Fourth, in the scenario of "power command reset after overload recovery", when the load rate returns to the safe range and there is no planned control, the system can smoothly reduce the power command to zero through the attenuation coefficient, which verifies the stability of the system exiting the governance state and avoids power impact on the distribution network.

[0126] Fifth, the results of "hybrid overload" and multiple collaborative control scenarios show that the method provided in this application can strictly execute the preset priority logic (overload governance > active power management > planned curve) among forward governance, reverse governance, planned curve control and various auxiliary strategies, and realize seamless coordination and conflict-free operation among multiple modes and multiple strategies.

[0127] In summary, under the parameter settings given in the embodiments of this application, the distribution network overload management method provided in the embodiments of this application can effectively cope with various complex operating conditions that may occur in the distribution transformer area, such as pure forward overload, pure reverse overload, and mixed forward and reverse overload. Through precise phase control, safe power constraints, intelligent power management and smooth state switching, it meets the needs of refined and intelligent overload management of 200kVA distribution transformers.

[0128] Figure 4 This is a schematic diagram of the principle structure of a distribution network overload mitigation system provided in the embodiments of this application. The embodiments of this application also provide a distribution network overload mitigation system, see below. Figure 4 The distribution network overload mitigation system 100 includes: a receiving module 101 for receiving current power data of the distribution transformer and current operating data of the energy storage system; wherein the current power data includes the current active power and current apparent power of each phase of the distribution transformer; a first determining module 102 for determining the real-time load rate of the target phase based on the current active power, current apparent power, and rated capacity of the target phase of the distribution transformer; a second determining module 103 for determining the current control mode and planned curve control enable status of the distribution transformer overload mitigation; a third determining module 104 for determining the actual power control command of the target phase of the energy storage system based on the current control mode, planned curve control enable status, real-time load rate, current power data, and current operating data; and a fourth determining module 105 for performing safety constraint verification on the actual power control command according to preset verification rules to determine the final power control command.

[0129] The technical solution of this application provides a power distribution network overload mitigation system. It determines the real-time load rate of each phase based on the current active power, apparent power, and rated capacity of each phase of the distribution transformer. Then, based on the real-time load rate of each phase, the current power data of the distribution transformer, the current operating data of the energy storage system, the current control mode of the distribution transformer overload mitigation, and the planned curve control enable status, it determines the actual power control command for each single phase of the energy storage system. Furthermore, it performs safety constraint verification through preset verification rules to determine the final power control command for each single phase of the energy storage system. This achieves precise phase-by-phase control of the distribution transformer's overload, improving the effectiveness of overload mitigation.

[0130] In some embodiments, the fourth determining module 105 is further configured to: When the actual power control command is greater than zero, the final power control command is determined based on the actual power control command, the total discharge power limit and rated power of the energy storage system. When the actual power control command is less than zero, the final power control command is determined based on the actual power control command, the total charging power limit and rated power of the energy storage system.

[0131] Current operating data includes the current remaining power of the energy storage system and the real-time power of each phase; In some embodiments, the fourth determining module 105 is further configured to: When the current remaining power is less than the first preset remaining power and the sum of the real-time power of each phase is greater than zero, the discharge power of each phase of the energy storage system is reduced once in each preset control cycle, and the current power control command of the target phase of the energy storage system is updated to the first preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle, until the real-time power of the target phase of the energy storage system meets the preset power judgment condition, and then the current power control command of the target phase of the energy storage system is set to zero. When the current remaining power is greater than the second preset remaining power and the sum of the real-time power of each phase is less than zero, the absolute value of the charging power of each phase of the energy storage system is reduced once in each preset control cycle. Each time, the current power control command of the target phase of the energy storage system is updated to the second preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle, until the real-time power of the target phase of the energy storage system meets the preset power judgment condition, at which point the current power control command of the target phase of the energy storage system is set to zero.

[0132] In some embodiments, when the current control mode is the first mode, the third determining module 104 is further configured to: When the real-time load rate of the target phase of the distribution transformer is greater than the preset threshold value for the positive heavy overload load rate, it is determined that the target phase of the distribution transformer has experienced a positive heavy overload. Based on the first target active power and the current active power of the positive heavy overload control of the target phase of the distribution transformer, as well as the total discharge power limit and rated power of the energy storage system, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is less than the first preset difference, and the current remaining power of the energy storage system is less than the preset reserved power threshold for positive heavy overload control, the active power replenishment strategy of the energy storage is triggered. Based on the second target active power and the current active power of the target phase of the distribution transformer for positive heavy overload control, as well as the total charging power limit and rated power of the energy storage system, the actual power control command is determined. When the current remaining power increases to the third preset remaining power, the power replenishment is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is less than the second preset difference, the active energy storage replenishment strategy is not triggered, and the planned curve control is enabled in the first enabled state, the various time periods of the planned curve control are traversed to match the planned power of the current time period. Based on the planned power of the current time period, the second target active power of the positive heavy overload management of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power, the actual power control command is determined. If the active energy storage replenishment strategy is not triggered and the planned curve control is in the second enabled state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0133] In some embodiments, the third determining module 104 is further configured to: If the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the total discharge power limit, and the rated power. When the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, the rated power, and the second target active power for the positive heavy overload control of the target phase of the distribution transformer.

[0134] In some embodiments, the system 100 further includes a fifth determining module, configured to: Based on the apparent power and current reactive power of the first target for positive heavy overload control of the target phase of the distribution transformer, determine the active power of the first target for positive heavy overload control of the target phase of the distribution transformer. Among them, the first target apparent power of the target phase of the distribution transformer for positive heavy overload control is determined based on the rated capacity of the target phase of the distribution transformer, the preset threshold value for the overload rate of positive heavy overload, and the preset threshold value for the first hysteresis of heavy overload control. The sixth module is used for: Based on the second target apparent power and current reactive power of the target phase of the distribution transformer for positive heavy overload control, determine the second target active power of the target phase for positive heavy overload control. Among them, the second target apparent power for the positive heavy overload control of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset threshold value for the positive heavy overload load rate exceeding the limit, and the preset threshold value for the second hysteresis of the heavy overload control.

[0135] In some embodiments, when the current control mode is the second mode, the third determining module 104 is further configured to: When the real-time load rate of the target phase of the distribution transformer is less than the negative value of the preset reverse overload load rate threshold, it is determined that the target phase of the distribution transformer has reverse overload. Based on the first target active power and the current active power of the reverse overload control of the target phase of the distribution transformer, as well as the total charging power limit and rated power of the energy storage system, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is greater than the third preset difference, and the current remaining power of the energy storage system is greater than the preset reserved power threshold for reverse overload control, the active discharge strategy of the energy storage is triggered. Based on the second target active power and the current active power of the reverse overload control of the target phase of the distribution transformer, as well as the total discharge power limit of the energy storage system and the rated power, the actual power control command is determined. When the current remaining power is reduced to the fourth preset remaining power, the discharge is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference, the active discharge strategy of energy storage is not triggered, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the second target active power of the reverse heavy overload control of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power. If the active discharge strategy of energy storage is not triggered and the planned curve control enable state is the second enable state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0136] In some embodiments, the third determining module 104 is further configured to: When the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the total discharge power limit, the rated power, and the second target active power for reverse heavy overload control of the target phase of the distribution transformer. If the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, and the rated power.

[0137] In some embodiments, the system 100 further includes a seventh determining module, configured to: Based on the apparent power and current reactive power of the first target of reverse heavy overload control of the target phase of the distribution transformer, determine the active power of the first target of reverse heavy overload control of the target phase of the distribution transformer. Among them, the first target apparent power of the reverse heavy overload control of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset reverse heavy overload load rate limit threshold value, and the preset first hysteresis threshold value of the heavy overload control. The eighth determining module is used for: Based on the second target apparent power and current reactive power of the target phase of the distribution transformer for reverse heavy overload control, determine the second target active power of the target phase for reverse heavy overload control. The second target apparent power for reverse heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset reverse heavy overload load rate exceeding threshold value, and the preset second hysteresis threshold value for heavy overload mitigation.

[0138] In some embodiments, when the current control mode is the third mode, the third determining module 104 is further configured to: If the real-time load rate of any phase of the distribution transformer exceeds the preset threshold value for forward heavy overload, the planned curve control is interrupted, and the actual power control command is determined based on the first target active power and current active power of the target phase of the distribution transformer for forward heavy overload control, as well as the total discharge power limit and rated power of the energy storage system; or, if the real-time load rate of any phase of the distribution transformer is less than the negative value of the preset threshold value for reverse heavy overload, the planned curve control is interrupted, and the actual power control command is determined based on the first target active power and current active power of the target phase of the distribution transformer for reverse heavy overload control, as well as the total charging power limit and rated power of the energy storage system. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period. Based on the planned power of the current time period, the current active power, the total discharge power limit, the total charging power limit, the rated power, the second target active power of the forward heavy overload control of the target phase of the distribution transformer, and the second target active power of the reverse heavy overload control of the target phase of the distribution transformer, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the second enable state, the actual power control command is determined according to the preset overload power command reset strategy.

[0139] In some embodiments, the third determining module 104 is further configured to: When the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the current active power, the total discharge power limit, the rated power, and the second target active power for reverse heavy overload control of the target phase of the distribution transformer. When the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the current active power, the total charging power limit, the rated power, and the second target active power for the positive heavy overload control of the target phase of the distribution transformer.

[0140] In some embodiments, the third determining module 104 is further configured to: The absolute value of the actual power control command of each phase of the energy storage system is gradually reduced according to the preset attenuation coefficient until the real-time power of each phase of the energy storage system meets the preset power conditions. Then, the actual power control command of each phase of the energy storage system is determined to be zero.

[0141] In some embodiments, when the current control mode is the fourth mode, the third determining module 104 is further configured to: When the planned curve control enable state is the first enable state, the planned curve control is traversed to match the planned power of the current period, and the actual power control command is determined based on the planned power of the current period, the total discharge power limit, the total charging power limit and the rated power of the energy storage system. When the planned curve control enable state is in the second enable state, the actual power control command will remain the actual power control command of the previous preset control cycle.

[0142] In some embodiments, the third determining module 104 is further configured to: If the planned power for the current period is greater than zero, the actual power control command is determined based on the planned power for the current period, the total discharge power limit, and the rated power. If the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, and the rated power.

[0143] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0144] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A method for mitigating heavy overload in a power distribution network, characterized in that, The distribution network includes a distribution transformer, and the distribution network is connected to an energy storage system; the method includes: Receive the current power data of the distribution transformer and the current operating data of the energy storage system; wherein, the current power data includes the current active power and current apparent power of each phase of the distribution transformer; The real-time load rate of the target phase is determined based on the current active power, the current apparent power, and the rated capacity of the target phase of the distribution transformer. Determine the current control mode and planned curve control enable status for the overload mitigation of the distribution transformer; Based on the current control mode, the planned curve control enable status, the real-time load rate, the current power data, and the current operating data, the actual power control command for the target phase of the energy storage system is determined; The actual power control command is subjected to safety constraint verification according to preset verification rules to determine the final power control command.

2. The method according to claim 1, characterized in that, The step of performing a safety constraint verification on the actual power control command according to a preset verification rule to determine the final power control command includes: When the actual power control command is greater than zero, the final power control command is determined based on the actual power control command, the total discharge power limit and the rated power of the energy storage system; If the actual power control command is less than zero, the final power control command is determined based on the actual power control command, the total charging power limit of the energy storage system, and the rated power.

3. The method according to claim 1, characterized in that, The current operating data includes the current remaining power of the energy storage system and the real-time power of each phase. The step of performing a safety constraint verification on the actual power control command according to a preset verification rule to determine the final power control command includes: When the current remaining power is less than the first preset remaining power and the sum of the real-time power of each phase is greater than zero, the discharge power of each phase of the energy storage system is reduced once in each preset control cycle. That is, each time the current power control command of the target phase of the energy storage system is updated to the first preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle, until the real-time power of the target phase of the energy storage system meets the preset power determination condition, the current power control command of the target phase of the energy storage system is set to zero. When the current remaining power is greater than the second preset remaining power and the sum of the real-time power of each phase is less than zero, the absolute value of the charging power of each phase of the energy storage system is reduced once in each preset control cycle. That is, each time the current power control command of the target phase of the energy storage system is updated to the second preset multiple of the actual power control command of the target phase of the energy storage system in the previous preset control cycle, until the real-time power of the target phase of the energy storage system meets the preset power determination condition, the current power control command of the target phase of the energy storage system is set to zero.

4. The method according to claim 1, characterized in that, When the current control mode is the first mode, the method for determining the actual power control command includes: If the real-time load rate of the target phase of the distribution transformer is greater than the preset threshold value for positive heavy overload load rate, it is determined that the target phase of the distribution transformer has experienced a positive heavy overload. Based on the first target active power of the positive heavy overload control of the target phase of the distribution transformer and the current active power, as well as the total discharge power limit and rated power of the energy storage system, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is less than the first preset difference, and the current remaining power of the energy storage system is less than the preset reserved power threshold for positive heavy overload control, the active power replenishment strategy of the energy storage is triggered. Based on the second target active power of the positive heavy overload control of the target phase of the distribution transformer and the current active power, as well as the total charging power limit and rated power of the energy storage system, the actual power control command is determined. When the current remaining power increases to the third preset remaining power, the power replenishment is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is less than the second preset difference, the active energy storage replenishment strategy is not triggered, and the planned curve control is enabled in the first enabled state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the second target active power of the positive heavy overload management of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power. If the active energy storage replenishment strategy is not triggered and the planned curve control is in the second enabled state, the actual power control command will remain the actual power control command of the previous preset control cycle.

5. The method according to claim 4, characterized in that, The determination of the actual power control command based on the planned power for the current time period, the second target active power for positive heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power includes: If the planned power for the current time period is greater than zero, the actual power control command is determined based on the planned power for the current time period, the total discharge power limit, and the rated power. When the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, the rated power, and the second target active power for the positive heavy overload mitigation of the target phase of the distribution transformer.

6. The method according to claim 4, characterized in that, A method for determining the first target active power for positive heavy overload mitigation of the target phase of the distribution transformer includes: Based on the first target apparent power and current reactive power of the target phase of the distribution transformer for positive heavy overload control, the first target active power of the target phase for positive heavy overload control is determined. The first target apparent power for the positive heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset threshold value for the positive heavy overload load rate exceeding the limit, and the preset threshold value for the first hysteresis of the heavy overload mitigation. A method for determining the second target active power for positive heavy overload mitigation of the target phase of the distribution transformer includes: Based on the second target apparent power and current reactive power of the target phase of the distribution transformer for positive heavy overload control, determine the second target active power of the target phase for positive heavy overload control. The second target apparent power for the positive heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset threshold value for the positive heavy overload load rate exceeding the limit, and the preset threshold value for the second hysteresis of the heavy overload mitigation.

7. The method according to claim 1, characterized in that, When the current control mode is the second mode, the method for determining the actual power control command includes: If the real-time load rate of the target phase of the distribution transformer is less than the negative value of the preset reverse overload load rate threshold, it is determined that the target phase of the distribution transformer has experienced reverse overload. Based on the first target active power of the reverse overload control of the target phase of the distribution transformer and the current active power, as well as the total charging power limit and rated power of the energy storage system, the actual power control command is determined. When the real-time load rate of all phases of the distribution transformer is greater than the third preset difference, and the current remaining power of the energy storage system is greater than the preset reserved power threshold for reverse overload control, the active discharge strategy of the energy storage is triggered. Based on the second target active power and the current active power of the target phase of the distribution transformer for reverse overload control, as well as the total discharge power limit and the rated power of the energy storage system, the actual power control command is determined. When the current remaining power is reduced to the fourth preset remaining power, the discharge is stopped, and the actual power control command is determined to be zero. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference, the active energy storage discharge strategy is not triggered, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the second target active power of the reverse heavy overload control of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power. If the active discharge strategy of energy storage is not triggered and the planned curve control enable state is the second enable state, the actual power control command will remain the actual power control command of the previous preset control cycle.

8. The method according to claim 7, characterized in that, The determination of the actual power control command based on the planned power for the current time period, the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer, the total discharge power limit, the total charging power limit, and the rated power includes: When the planned power for the current time period is greater than zero, the actual power control command is determined based on the planned power for the current time period, the total discharge power limit, the rated power, and the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer. If the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, and the rated power.

9. The method according to claim 7, characterized in that, A method for determining the first target active power for reverse heavy overload mitigation of the target phase of the distribution transformer includes: Based on the first target apparent power and current reactive power of the target phase of the distribution transformer for reverse heavy overload mitigation, determine the first target active power of the target phase for reverse heavy overload mitigation. The first target apparent power for reverse heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset reverse heavy overload load rate limit threshold, and the preset first hysteresis threshold for heavy overload mitigation. A method for determining the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer includes: Based on the second target apparent power and current reactive power of the target phase of the distribution transformer for reverse heavy overload mitigation, determine the second target active power of the target phase for reverse heavy overload mitigation. The second target apparent power for reverse heavy overload mitigation of the target phase of the distribution transformer is determined based on the rated capacity of the target phase of the distribution transformer, the preset reverse heavy overload load rate threshold value, and the preset second hysteresis threshold value for heavy overload mitigation.

10. The method according to claim 1, characterized in that, When the current control mode is the third mode, the method for determining the actual power control command includes: If the real-time load rate of any phase of the distribution transformer exceeds the preset threshold value for forward heavy overload, the planned curve control is interrupted, and the actual power control command is determined based on the first target active power and current active power of the target phase for forward heavy overload control of the distribution transformer, as well as the total discharge power limit and rated power of the energy storage system; or, if the real-time load rate of any phase of the distribution transformer is less than the negative value of the preset threshold value for reverse heavy overload, the planned curve control is interrupted, and the actual power control command is determined based on the first target active power and current active power of the target phase for reverse heavy overload control of the distribution transformer, as well as the total charging power limit and rated power of the energy storage system. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the first enable state, the various time periods of the planned curve control are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the current active power, the total discharge power limit, the total charging power limit, the rated power, the second target active power for the forward heavy overload control of the target phase of the distribution transformer, and the second target active power for the reverse heavy overload control of the target phase of the distribution transformer. When the real-time load rate of all phases of the distribution transformer is greater than the fourth preset difference and less than the second preset difference, and the planned curve control enable state is the second enable state, the actual power control command is determined according to the preset overload power command reset strategy.

11. The method according to claim 10, characterized in that, The step of determining the actual power control command based on the planned power for the current time period, the total discharge power limit, the total charging power limit, the rated power, the second target active power for forward heavy overload mitigation of the target phase of the distribution transformer, and the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer includes: When the planned power for the current time period is greater than zero, the actual power control command is determined based on the planned power for the current time period, the current active power, the total discharge power limit, the rated power, and the second target active power for reverse heavy overload mitigation of the target phase of the distribution transformer. When the planned power for the current time period is less than zero, the actual power control command is determined based on the planned power for the current time period, the current active power, the total charging power limit, the rated power, and the second target active power for the positive heavy overload mitigation of the target phase of the distribution transformer.

12. The method according to claim 10, characterized in that, The step of determining the actual power control command based on a preset overload power command reset strategy includes: The absolute value of the actual power control command of each phase of the energy storage system is gradually reduced according to the preset attenuation coefficient until the real-time power of each phase of the energy storage system meets the preset power condition, at which point the actual power control command of each phase of the energy storage system is determined to be zero.

13. The method according to claim 1, characterized in that, When the current control mode is the fourth mode, the method for determining the actual power control command includes: When the planned curve control enable state is the first enable state, the planned curve control time periods are traversed to match the planned power of the current time period, and the actual power control command is determined based on the planned power of the current time period, the total discharge power limit, the total charging power limit and the rated power of the energy storage system. When the planned curve control enable state is the second enable state, the actual power control command will remain the actual power control command of the previous preset control cycle.

14. The method according to claim 13, characterized in that, The step of determining the actual power control command based on the planned power for the current time period, the total discharge power limit, the total charging power limit, and the rated power of the energy storage system includes: If the planned power for the current time period is greater than zero, the actual power control command is determined based on the planned power for the current time period, the total discharge power limit, and the rated power. If the planned power for the current period is less than zero, the actual power control command is determined based on the planned power for the current period, the total charging power limit, and the rated power.

15. A power distribution network overload mitigation system, characterized in that, The distribution network includes a distribution transformer, and the distribution network is connected to an energy storage system; the system includes: The receiving module is used to receive the current power data of the distribution transformer and the current operating data of the energy storage system; wherein, the current power data includes the current active power and current apparent power of each phase of the distribution transformer; The first determining module is used to determine the real-time load rate of the target phase based on the current active power, the current apparent power, and the rated capacity of the target phase of the distribution transformer. The second determining module is used to determine the current control mode and the planned curve control enable state of the overload mitigation of the distribution transformer. The third determining module is used to determine the actual power control command of the target phase of the energy storage system based on the current control mode, the planned curve control enable state, the real-time load rate, the current power data, and the current operating data. The fourth determining module is used to perform safety constraint verification on the actual power control command according to preset verification rules in order to determine the final power control command.

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