Low-voltage treatment method and system based on power distribution energy storage

Abstract

The invention discloses a low-voltage treatment method and system based on power distribution energy storage, and belongs to the technical field of power grid governance, the system is a system for realizing the method, and the method comprises the steps: predicting the load or voltage change trend of a transformer area based on historical load data of the transformer area, obtaining a risk time period, and obtaining the risk time period of the transformer area; the compensation power and the total compensation electric quantity required by low-voltage treatment in the risk period are obtained; collecting the current energy storage state of the energy storage unit and the charging and discharging power of the energy storage unit; defining an energy storage subunit for low-voltage treatment in the risk period from the energy storage unit; according to the total compensation electric quantity and the charge state range, making a charging plan for the energy storage subunits in an energy complementing period, and charging the energy storage subunits in the energy complementing period; and in the low-voltage treatment process, the discharge parameters of the energy storage subunits are dynamically matched. According to the scheme, prospective low-voltage treatment is realized, the sustainability of low-voltage treatment is ensured, and long-term reliable operation of energy storage equipment is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power grid management, in particular to a low-voltage management method and system based on distribution energy storage. BACKGROUND

[0002] Low voltage refers to the phenomenon that the user end voltage is lower than the lower limit of the rated voltage. The most common cause of low voltage is that the current in the line increases due to the sharp increase in user power consumption, resulting in a significant increase in voltage loss on the line, and ultimately leading to a voltage lower than the rated voltage level at the user side. The low voltage phenomenon at the user side of the power grid not only directly affects the normal power consumption of the user and the service life of the power consumption equipment, but also significantly increases the line loss of the power grid and brings challenges to the stability of the power grid operation.

[0003] In the prior art, to improve user power consumption satisfaction, ensure power grid power supply efficiency and power grid stability, common low voltage management methods include line reconstruction, transformer on-load voltage regulation, reactive power compensation and multi-source power supply. In recent years, with the further development of energy storage technology, low voltage management schemes based on battery energy storage systems have been widely used in short-term periodic low voltage management, high proportion step-by-step photovoltaic application areas, and users with high requirements for power supply quality due to their fast response speed, high flexibility, and flexible capacity adjustment. In particular, in the prior art, such as the patent application number CN202410191678.6, the invention name is a low-voltage power grid end voltage management method and energy storage device, which provides an energy storage device, which includes a controller, an energy storage converter and a battery management system. The specific working method is as follows: the energy storage converter is directly connected to the power grid to collect the grid-connected point voltage at the position where the energy storage device is connected to the power grid; the controller collects the information of the area meter and obtains the grid-connected point voltage and the device operating state information from the energy storage converter and the battery management system, determines the power grid state according to the area meter information, the grid-connected point voltage and the device operating state information, and compensates the power grid according to the power grid state.

[0004] Generally, the existing low-voltage management scheme based on distribution energy storage triggers the distribution energy storage to compensate for the low voltage of the power grid based on the collection of current parameters of the power grid and the judgment of the collection results. Such an implementation method is a real-time response method for low-voltage management. In order to further improve the intelligent management level of the energy storage device and promote the further development of power grid management technology, it is necessary to further optimize the related low-voltage management method. SUMMARY

[0005] In view of the problem of further optimizing the low-voltage treatment method proposed above, the application provides a low-voltage treatment method and system based on power distribution energy storage, which aims to realize prospective low-voltage treatment, ensure the sustainability of low-voltage treatment, and ensure the long-term reliable operation of the energy storage device.

[0006] The application mainly realizes the purpose by the following technical scheme: a low-voltage treatment method based on power distribution energy storage, which discharges the energy storage unit to the transformer area to realize low-voltage treatment of the transformer area, wherein, based on historical load data of the transformer area, the load or voltage change trend of the transformer area in a future set time period is predicted, a risk period of line low voltage occurring in the future set time period is obtained, and the required compensation power and total compensation power of the risk period low-voltage treatment are obtained.

[0007] The current energy storage state of the energy storage unit and the charging and discharging power of the energy storage unit are collected.

[0008] According to the compensation power, the total compensation power, the discharging power and capacity of the energy storage unit, and the set state of charge range of the battery in the energy storage unit, an energy storage subunit for low-voltage treatment of the risk period is demarcated from the energy storage unit.

[0009] The time between the current time and the risk period is set as the compensation period of the energy storage subunit, a charging plan of the energy storage subunit in the compensation period is formulated according to the total compensation power and the state of charge range, and the energy storage subunit is charged in the compensation period, and after the charging is completed and the low-voltage treatment is completed, the state of charge of the battery in the energy storage subunit is within the state of charge range.

[0010] In the low-voltage treatment process, the discharging parameters of the energy storage subunit are dynamically matched according to the real-time monitored transformer area line voltage.

[0011] The present application is a kind of based on energy storage device realizes transformer area low-voltage treatment, to realize through load or voltage prediction, realize the treatment mode from traditional passive response changes to active defense, provide can realize prospective treatment scheme;Meanwhile, the present application determines the energy storage subunit and pre-charges before the risk period through prospective prediction, realizes guaranteeing available treatment resources in the risk period, provides the scheme for ensuring the sustainability of risk period treatment;Meanwhile, the present application sets the state of charge range in the way of optimizing the charging and discharging strategy to avoid damaging the battery health in the low-voltage treatment process, improves the whole life cycle of the energy storage unit, and provides a technical scheme capable of ensuring the long-term reliable operation of the low-voltage treatment system;Meanwhile, in the discharging process of the energy storage unit, the present application dynamically matches the discharging parameters to provide a technical scheme for ensuring the voltage quality of the transformer area and guaranteeing the user's power consumption satisfaction.

[0012] Specifically: the energy storage unit is charged before the risk period, and the stored electric energy is used as an available management resource during the risk period. In the specific process, a future setting time period can be set as a day, and the setting time period can be 24 hours in the future. The load or voltage change trend is preferably predicted based on historical load data of the transformer area, weather type, work or holiday type, and season. The specific trend can be based on the time sequence curve of the associated load or voltage predicted by the neural network model. After the time sequence curve is predicted, it is preferably manually adjusted according to experience to better include variables such as body temperature, local traditional festivals, and other difficult-to-quantify variables in the consideration range. The risk period is the period during which the line low-voltage event occurs in the setting time period. The compensation power is the line compensation power required to realize the low-voltage management of the risk period. The total compensation electric quantity is the total compensation electric quantity provided by the energy storage unit for the line during the risk period. The compensation power, total compensation electric quantity, discharge power and capacity, state of charge range, i.e., used to demarcate the energy storage subunit that meets the low-voltage management demand from the energy storage unit, to avoid all batteries in the energy storage unit participating in charging and discharging every time. The state range is used to limit the depth of charge and discharge, optimize the influence of battery cycle on the service life of the energy storage unit, the current energy storage state, and the charging power of the energy storage unit, the compensation period length, the total compensation electric quantity, and the current energy storage state, i.e., to determine the charging plan formulation, to ensure that the risk period has available management resources. The dynamic matching of the energy storage subunit discharge parameters is used to ensure the voltage quality of the transformer area and the user's power utilization satisfaction.

[0013] More specifically, in one specific embodiment, the electricity price valley period is generally from night to early morning of the next day, such as from 11 o'clock at night to 7 o'clock in the morning, and the low voltage risk period of the residential transformer area is mostly concentrated in the summer night from 6 o'clock to 9 o'clock. In order to extend the length of the energy supplement period, optimize the battery charging power and cost, and reduce the impact of charging on line load, the change trend prediction is set to be performed at 11 o'clock at night after the risk period is obtained, and the charging is started immediately after the charging plan is developed. For the power distribution energy storage system serving a single line, a battery cluster with multiple battery groups is configured, so that different battery groups can be used alternately as the power storage modules of different energy storage sub-units in each low voltage management process. For example, based on the state of charge, the battery groups with high state of charge are divided into energy storage sub-units to reduce the number of charging and discharging cycles of the battery groups in the low voltage management process, or according to the cumulative charging and discharging cycles of each battery group, the battery groups with fewer charging and discharging cycles are included in the energy storage sub-units to extend the overall life of the battery cluster and increase the utilization rate of the battery cluster. The state of charge range of each battery group is dynamically adjusted according to the total compensation power, the battery group health parameters, etc. For example, to meet the low voltage management demand and slow down the performance degradation rate of the energy storage unit, the upper limit value of the state of charge range of the battery group is increased with the increase of the total compensation power in the risk period, the lower limit value is decreased with the increase of the predicted load of the transformer area, the upper limit value is decreased with the deterioration of the battery health state, and the lower limit value is increased with the deterioration of the battery health state. In the process of determining the upper limit value and the lower limit value of the state of charge range, the battery groups with different battery health states have differentiated upper limit values and lower limit values of the state of charge range, for example, the upper limit value of the battery with good health state is set to 95%, the lower limit value is set to 15%, the upper limit value of the battery with general health state is set to 90%, the lower limit value is set to 20%, the upper limit value of the battery with poor health state is set to 80%, and the lower limit value is set to 30%. In the low voltage management process, if the line voltage drops more than a set threshold due to sudden high-power consumption of multiple users, the discharge parameter adjustment is performed to ensure the quality of user power consumption.

[0014] As a further technical solution of the low voltage management method based on power distribution energy storage:

[0015] The number of energy storage sub-units for low voltage management in the current risk period is multiple, and the energy storage sub-units for low voltage management in the current risk period form an energy storage sub-unit set.

[0016] In the process of dividing the energy storage sub-units, the multiple energy storage sub-units with high state of charge in the high-low order are divided into the energy storage sub-unit set for low voltage management in the current risk period according to the high-low order of the state of charge of each energy storage sub-unit in the energy storage unit.

[0017] Alternatively, based on the historical cumulative charge-discharge cycle count of each energy storage sub-unit in the energy storage unit, the energy storage sub-units with the fewest historical cumulative charge-discharge cycle counts in the ranking can be designated as the set of energy storage sub-units for low voltage management during this risk period.

[0018] This solution aims to provide a specific implementation form of energy storage unit and energy storage sub-unit. Specifically, the energy storage unit includes multiple energy storage sub-units that can independently discharge for the transformer area. When performing low voltage management during risk periods, a portion of the energy storage sub-units are selected as the set of energy storage sub-units for low voltage management during this risk period. By using the energy storage sub-units to work in turn and the low voltage management resource system to integrate, the robustness and lifespan of the system in response to different low voltage management needs are improved. Furthermore, energy storage sub-units are categorized based on their state of charge (SOC). Sub-units selected for inclusion in the energy storage sub-unit cluster have a higher initial SOC. This approach not only ensures that sub-units have sufficient charge before charging during low-voltage management, guaranteeing the reliability of low-voltage management, but also narrows the SOC range during charging, minimizing the impact of charging plans on battery lifespan. Alternatively, energy storage sub-units can be categorized based on their historical cumulative charge-discharge cycle count. Specifically, batteries with fewer cycles are prioritized to balance losses across the entire energy storage sub-unit cluster and maximize the system's lifespan value.

[0019] During the charging process of the energy storage sub-units during the replenishment period, based on the grid time-of-use electricity price information, the charging power of the energy storage sub-units, and the historical load of the replenishment period, a charging volume plan for the energy storage sub-units is set for the off-peak electricity price period, the normal electricity price period, and the peak electricity price period. The charging volume plan includes:

[0020] Plan 1: When the charging power of the energy storage sub-unit and the available charging capacity of the line during off-peak electricity price periods meet the charging power demand of the energy storage sub-unit, the charging of the energy storage sub-unit will be completed during off-peak electricity price periods.

[0021] Plan 2: When the energy storage sub-unit is fully charged during the off-peak electricity price period based on the charging power of the energy storage sub-unit and the available charging capacity of the line during the normal electricity price period, and the charging power of the energy storage sub-unit and the available charging capacity of the line during the normal electricity price period meet the charging power gap of the energy storage sub-unit, the charging of the energy storage sub-unit is completed during the normal electricity price period.

[0022] Plan 3: Based on the charging power of the energy storage sub-unit and the available charging capacity of the line during off-peak and normal electricity price periods, the energy storage sub-unit will be fully charged during off-peak and normal electricity price periods, and then the charging of the energy storage sub-unit will be completed during peak electricity price periods.

[0023] The above scheme provides a specific method for implementing a charging plan, aiming to provide a technical solution for economical charging as much as possible when charging conditions permit. Specifically: This scheme is based on the grid time-of-use pricing rules. When the charging capacity of the energy storage sub-unit and the charging capacity of the line meet the charging requirements during off-peak hours, the energy storage sub-unit is charged during off-peak hours. Otherwise, after charging the energy storage sub-unit at full power (the maximum charging power determined by the charging power and available charging capacity) during off-peak hours, the energy storage sub-unit is charged during normal-price periods to fill the charging gap in the charging plan. Alternatively, after charging at full power during both off-peak and normal-price periods, the energy storage sub-unit is charged during peak-price periods, ultimately achieving the lowest-cost charging.

[0024] Based on the real-time monitored line voltage of the transformer substation, the discharge parameters of the energy storage subunit are dynamically matched as follows:

[0025] Based on the timeline and the voltage change trend at each moment of the predicted risk period, the time-series curve of the compensation power at each moment of the associated risk period is obtained.

[0026] Based on the compensation power at each moment in the time-series curve, the reference discharge parameters of the energy storage sub-unit at each moment are formulated and implemented.

[0027] Under the current reference discharge parameters, when the deviation of the real-time monitoring result of the transformer area line voltage from the predicted voltage at the current moment reaches a set threshold, the discharge parameters of the energy storage sub-unit are dynamically matched, wherein:

[0028] The set threshold includes multiple set thresholds with different values, and each set threshold is configured with a different compensation power adjustment amount;

[0029] Based on the degree of deviation, the compensation power adjustment amount is set at a threshold, and the discharge parameters are adjusted on the basis of the reference discharge parameters.

[0030] The above provides a specific implementation method for dynamic matching of discharge parameters. In this scheme, the compensation power at each moment during the risk period is obtained by predicting the voltage change trend. Based on the compensation power, reference discharge parameters for each moment of the energy storage sub-unit are formulated. During the discharge process of low voltage mitigation, the transformer area is treated according to the reference discharge parameters at the current moment. During the treatment process, the line voltage of the transformer area is monitored in real time, and the compensation power is adjusted differently based on the deviation between the detected value and the predicted voltage, according to the reference discharge parameters. In this scheme, the reference discharge parameters are obtained before the actual low voltage mitigation is carried out by using a prediction method. Subsequently, during the actual low voltage mitigation process, the differentiated compensation power adjustment is matched based on the reference discharge parameters and the measured results of the line voltage of the transformer area. This is a predictive discharge plan formulation and execution method. For example, based on the predicted voltage drop, low voltage mitigation is achieved through the current reference discharge parameters. This avoids the problem of response lag in the pure feedback system commonly used in existing technologies, which affects the smoothness, continuity and orderliness of the low voltage mitigation process. Furthermore, the current reference discharge parameters serve as feedforward for the low-voltage management control composite structure, while the real-time monitoring results of the transformer area line voltage serve as feedback. Predictive low-voltage management is achieved through feedforward, and accurate low-voltage management is achieved through feedback, thus achieving an optimized balance between low-voltage management response speed and control quality. Furthermore, the differentiated compensation power adjustment configured for each set threshold uses the threshold as a trigger condition to avoid the impact on system lifespan caused by frequent actions of the energy storage unit during low-voltage management. Simultaneously, the differentiated compensation power adjustment aims to form a stepped response hierarchy, making the quantitative action mechanism simpler and reliably implementable in embedded systems, which is beneficial to system operational stability.

[0031] When the discharge parameters are adjusted, the energy storage sub-unit discharges with increased power relative to the compensation power in the time-series curve. If the increase in discharge power exceeds the set value or the duration of increased power discharge exceeds the set value, the number of energy storage sub-units used for low voltage management during risk periods will be increased and / or a risk alarm for low voltage management resource shortage will be output.

[0032] The above provides a more specific implementation method for achieving dynamic matching of discharge parameters. In this scheme, based on the above focus on current voltage recovery and governance, it further introduces the concept of an increased power discharge relative to the predicted compensation power (the discharge power of the energy storage sub-unit is greater than the compensation power in the time series curve). By further monitoring the increase in discharge power or the duration of the increased power discharge, it determines whether to automatically increase the number of energy storage sub-units actually participating in this low voltage governance and / or output a risk alarm of low voltage governance resource shortage. This aims to solve the sustainability problem of low voltage governance. Specifically, the above increase and the duration of the increased power discharge are used to determine the degree of deviation between the predicted reference discharge parameters and the actual situation, and serve as the basis for identifying whether governance resources are tight. Subsequently, by increasing the number of energy storage sub-units participating in this low voltage governance, the governance resources can be expanded online to solve the problem of insufficient system-allocated governance resources, thereby improving the system's adaptability and robustness. The risk alarm is used to guide maintenance personnel to promptly investigate and handle abnormal situations, and to enable overall system expansion.

[0033] After the low voltage mitigation during the risk period is completed, the energy storage unit's sustainable mitigation capability for the next low voltage risk is assessed based on the final state of charge of the energy storage sub-unit used for the low voltage mitigation during the risk period, as well as the available charging time and charging power before the next expected risk period.

[0034] When the assessment result is lower than the preset capability threshold, maintenance suggestion information is generated to prompt adjustment of the state of charge operating range or expansion of the energy storage capacity of the energy storage unit.

[0035] The above provides a method for implementing full lifecycle management of the system. In this solution, based on the final state of charge, available charging time, and charging power, the system's ability to participate in the next low-voltage governance is assessed. Based on the assessment results, maintenance suggestion information is generated to assist in the long-term availability of the system's governance capabilities. Specifically, the final state of charge indicates the remaining power of the current energy storage unit, the available charging time indicates the charging window duration, and the charging power indicates the charging speed. Based on these conditions, the ability of the energy storage unit to restore governance resources before the arrival of the next risk period can be obtained. Based on the sustainable governance capability assessment results, the energy replenishment of the energy storage unit during the next risk period can be adjusted by adjusting the operating range of the state of charge. For example, by increasing the upper limit of the operating range of the state of charge and decreasing the lower limit of the operating range of the state of charge, the single discharge capacity of the energy storage unit can meet the low-voltage governance requirements. Alternatively, the system can prompt maintenance personnel to increase the overall capacity of the energy storage unit, thereby solving the problem of a gap between governance resources and actual needs from a hardware perspective, and ultimately achieving the goal of proactively preventing insufficient governance capabilities in the next low-voltage period.

[0036] After the low voltage management during the risk period ends, the final state of charge of each energy storage sub-unit participating in the low voltage management during the risk period is obtained, as well as the rated capacity, charging power and the next energy replenishment period of each energy storage sub-unit participating in the low voltage management during the risk period. The number of energy storage sub-units that can charge the power to above the preset lower limit of the state of charge range before the next risk period is calculated.

[0037] When the number of energy storage sub-units is lower than the minimum energy storage sub-unit number threshold required to maintain low voltage management, maintenance suggestion information is generated to prompt adjustment of the state of charge operating range or expansion of the energy storage capacity of the energy storage unit.

[0038] The above provides a more specific implementation method for achieving full lifecycle management of the system. In this solution, based on the number of energy storage sub-units that can charge the power to above the preset lower limit of the state of charge range before the next risk period, the number of energy storage sub-units that can participate in the next low-voltage risk management is obtained. As those skilled in the art know, the number of energy storage sub-units determines the total compensation power that the energy storage units can provide during the next low-voltage management process, avoiding the problem of mismatch between management resources and actual management needs from a power perspective. For example, when it is lower than the minimum energy storage sub-unit number threshold, it means that the next low-voltage management capability is insufficient or the system redundancy is insufficient. Through maintenance suggestion information, by sacrificing battery health or expanding the overall capacity of the system, the next low-voltage management can be successfully implemented.

[0039] Based on the real-time monitored line voltage of the transformer substation, the discharge parameters of the energy storage subunit are dynamically matched as follows:

[0040] Real-time acquisition of the current state of charge of each energy storage sub-unit;

[0041] Calculate the remaining dischargeable energy required to maintain the state of charge of each energy storage sub-unit at the end of the discharge range equal to the lower limit of the state of charge range;

[0042] The discharge power of each energy storage sub-unit is dynamically adjusted, and at the end of the discharge, the state of charge of the battery in each energy storage sub-unit is within the range of the stated state of charge.

[0043] The above provides a method for achieving dynamic matching of discharge parameters. It aims to prevent over-discharge of energy storage sub-units by real-time monitoring of state of charge and calculation of dischargeable energy in a predictive manner. Specifically, the current state of charge is used to characterize the dischargeable energy of each energy storage sub-unit. Based on the current state of charge, the discharge power is adjusted by predictive calculation to protect each energy storage sub-unit from over-discharge during the discharge process, thus avoiding the rapid decline in battery life after deep discharge, which would affect the long-term economic efficiency and feasibility of the system.

[0044] The state of charge range is a dynamic range value based on the periodic variation law of the transformer area load and the health status parameters of each battery.

[0045] Among them, the lower limit of the state of charge range of each battery is positively correlated with the predicted load of the next risk period of the distribution area, and the lower limit of the state of charge range of each battery is negatively correlated with the health status parameter of that battery.

[0046] The above provides an implementation using a dynamic state of charge (SOC) range. Specifically, this solution correlates the SOC operating range with the periodic variation pattern of the transformer area load and the health status parameters of each battery. The periodic variation pattern of the transformer area load represents the low voltage management needs of the transformer area, and the health status parameters of each battery represent the health status of the energy storage unit. Through adaptive / dynamically adjustable SOC range, the aim is to achieve the following: For example, when it is determined based on the periodic variation pattern of the transformer area load that the management resources required for the next risk period are high, the energy supply capacity of the energy storage system can be improved by expanding the width of the SOC range; when it is determined based on the health status parameters of each battery that the health of one or more batteries is low, the width of the SOC range, the lower limit value, and the upper limit value can be reduced to achieve shallow charging and shallow discharging of these batteries, thereby delaying the performance degradation of these batteries, extending their lifespan, and reducing the probability of risks such as thermal runaway.

[0047] This solution also relates to a low-voltage management system based on power distribution energy storage, which is used to implement the low-voltage management method described in any of the above embodiments. The system includes:

[0048] The data acquisition module is used to collect historical load data of the transformer area, real-time line voltage, and real-time status information of each energy storage sub-unit.

[0049] The predictive analysis module is used to predict load or voltage change trends and obtain the compensation power and total compensation power required during risk periods.

[0050] The decision-making module is used to determine the energy storage sub-units to be used for low voltage mitigation during this risk period, and to formulate and execute charging plans.

[0051] The dynamic matching module is used to perform discharge control of the energy storage sub-unit during risky periods and dynamically adjust the discharge power of the energy storage sub-unit according to the real-time line voltage.

[0052] As those skilled in the art will recognize, this low-voltage mitigation system is a system for implementing any of the low-voltage mitigation methods described above.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] This solution is a method for managing low voltage in distribution areas based on energy storage devices. It aims to transform the management mode from traditional passive response to active defense through load or voltage prediction, providing a solution that enables proactive management.

[0055] This solution uses forward-looking forecasting to identify energy storage sub-units and pre-charge them before risk periods, thereby ensuring that available governance resources are available during risk periods and guaranteeing the sustainability of governance during risk periods.

[0056] This solution optimizes the charging and discharging strategy by setting the state of charge range, thereby avoiding damage to battery health during low voltage management, extending the entire life cycle of the energy storage unit, and ensuring the long-term reliable operation of the low voltage management system.

[0057] This solution ensures voltage quality in the distribution area and guarantees user satisfaction by dynamically matching discharge parameters during the discharge process of the energy storage unit. Attached Figure Description

[0058] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0059] Figure 1 This is a flowchart of a specific embodiment of a low-voltage management method based on power distribution energy storage according to the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0061] Example 1:

[0062] like Figure 1 As shown, this embodiment of the invention provides a low-voltage management method based on distribution energy storage. This method achieves low-voltage management of the distribution area by discharging energy storage units to the distribution area. In this method, based on the historical load data of the distribution area, the load or voltage change trend of the distribution area in the future set time period is predicted. The risk period of line low voltage is obtained from the future set time period, as well as the compensation power and total compensation power required for low voltage management in the risk period.

[0063] Collect the current energy storage status of the energy storage unit and the charging and discharging power of the energy storage unit;

[0064] Based on the compensation power, total compensation capacity, discharge power and capacity of the energy storage unit, and the state of charge range set for the batteries in the energy storage unit, the energy storage sub-units used for low voltage management during this risk period are identified from the energy storage unit.

[0065] The time between the current moment and the risk period is set as the energy replenishment period of the energy storage sub-unit. Based on the total compensation power and the state of charge range, a charging plan for the energy storage sub-unit is formulated during the energy replenishment period. The energy storage sub-unit is charged during the energy replenishment period. After charging is completed and low voltage management is completed, the state of charge of the battery in the energy storage sub-unit is within the state of charge range.

[0066] During the low voltage mitigation process, the discharge parameters of the energy storage sub-units are dynamically matched based on the real-time monitored voltage of the transformer substations.

[0067] This solution is a method for managing low voltage in distribution areas based on energy storage devices. It transforms the traditional passive response approach into a proactive defense strategy through load or voltage prediction, providing a forward-looking management solution. Furthermore, through forward-looking prediction, this solution identifies energy storage sub-units and pre-charges them before high-risk periods, ensuring available management resources during these periods and providing a sustainable management solution. Additionally, by setting a state of charge range and optimizing charging and discharging strategies, this solution avoids damage to battery health during low voltage management, extending the entire lifecycle of the energy storage unit and providing a technical solution for ensuring the long-term reliable operation of the low voltage management system. Finally, during the discharge process of the energy storage unit, this solution provides a technical solution to ensure voltage quality in the distribution area and guarantee user satisfaction with electricity usage by dynamically matching discharge parameters.

[0068] Specifically: The energy storage unit is charged before the risk period, and the stored electrical energy serves as a usable resource for managing the risk period. In the specific process, the future set time period can be defined as a day, such as the next 24 hours. Load or voltage change trends are preferably predicted based on historical load data of the transformer area, weather type, work or holiday type, and season. Specifically, the trend can be based on the time-series curve of the associated load or voltage predicted by a neural network model. Preferably, manual adjustments are made based on experience after the time-series curve is predicted to better incorporate variables that are difficult to quantify, such as perceived temperature and local traditional festivals. The risk period is the time period within the set time period during which a line low-voltage event occurs. The compensation power is used to achieve wind... The line compensation power required for low voltage mitigation during high-risk periods, the total compensation power is the total compensation power provided by the energy storage unit to the line during high-risk periods, the compensation power, total compensation power, discharge power and capacity, and state of charge range are used to delineate energy storage sub-units that meet the low voltage mitigation requirements from the energy storage sub-units, so as to avoid all batteries in the energy storage unit participating in charging and discharging every time. The state range is used to limit the depth of charge and discharge and optimize the impact of battery cycle on the life of energy storage unit. The current energy storage state, as well as the charging power of the energy storage unit, the duration of the energy replenishment period, the total compensation power, and the current energy storage state, determine the charging plan and ensure that there are available mitigation resources during high-risk periods. The dynamic matching of the discharge parameters of the energy storage sub-unit is used to ensure the voltage quality of the transformer area and ensure user electricity satisfaction.

[0069] More specifically, in one embodiment, the off-peak electricity price period generally extends from nighttime to the early morning of the next day, such as from 11 PM to 7 AM. Low voltage risk periods in residential areas are mostly concentrated between 6 PM and 9 PM in summer. Since it is necessary to delineate energy storage sub-units and formulate and implement charging plans for the delineated sub-units after identifying the risk periods, and to extend the duration of the replenishment period, optimize battery charging power and costs, and reduce the impact of charging on line load, the trend prediction is set to begin at 11 PM. Charging starts immediately after the charging plan is formulated. For distribution energy storage systems serving a single line, a battery cluster with multiple battery packs is configured so that different battery packs, as energy storage modules for different energy storage sub-units, can be used alternately during each low voltage mitigation process. For example, based on the state of charge (SBC), battery packs with high SBCs are assigned to energy storage sub-units to reduce the number of charge-discharge cycles during low voltage mitigation. Alternatively, based on the cumulative number of charge-discharge cycles of each battery pack, battery packs with fewer charge-discharge cycles are included in the energy storage sub-units to extend the overall lifespan of the battery cluster and increase its utilization rate. The state of charge (SCC) range of each battery pack is dynamically adjusted based on the total compensation capacity and battery pack health parameters. For example, to meet low-voltage mitigation requirements and slow down the performance degradation rate of energy storage units, the upper limit of the SCC range increases with the increase of the total compensation capacity during risk periods, while the lower limit decreases with the increase of the predicted load in the distribution area. The upper limit decreases as the battery health deteriorates, and the lower limit increases as the battery health deteriorates. In determining the upper and lower limits of the SCC range, battery packs with different battery health states have differentiated upper and lower limits. For example, the upper limit for batteries in good health is set at 95%, and the lower limit at 15%; the upper limit for batteries in average health is set at 90%, and the lower limit at 20%; and the upper limit for batteries in poor health is set at 80%, and the lower limit at 30%. During low-voltage mitigation, if the line voltage drops below the set threshold under the current energy storage sub-unit discharge parameters due to sudden high-power consumption by multiple users, discharge parameter adjustment is performed to ensure power quality for users.

[0070] Example 2:

[0071] This embodiment is a further refinement of embodiment 1:

[0072] The number of energy storage sub-units used for low voltage mitigation during this risk period is multiple, and the energy storage sub-units used for low voltage mitigation during this risk period form an energy storage sub-unit set.

[0073] In the process of delineating energy storage sub-units, the energy storage sub-units in the energy storage unit are sorted according to their state of charge (SOC). The energy storage sub-units with the highest SOC in the SOC are designated as the set of energy storage sub-units used for low voltage management during this risk period.

[0074] Alternatively, based on the historical cumulative charge-discharge cycle count of each energy storage sub-unit in the energy storage unit, the energy storage sub-units with the fewest historical cumulative charge-discharge cycle counts in the ranking can be designated as the set of energy storage sub-units for low voltage management during this risk period.

[0075] This solution aims to provide a specific implementation form of energy storage unit and energy storage sub-unit. Specifically, the energy storage unit includes multiple energy storage sub-units that can independently discharge for the transformer area. When performing low voltage management during risk periods, a portion of the energy storage sub-units are selected as the set of energy storage sub-units for low voltage management during this risk period. By using the energy storage sub-units to work in turn and the low voltage management resource system to integrate, the robustness and lifespan of the system in response to different low voltage management needs are improved. Furthermore, energy storage sub-units are categorized based on their state of charge (SOC). Sub-units selected for inclusion in the energy storage sub-unit cluster have a higher initial SOC. This approach not only ensures that sub-units have sufficient charge before charging during low-voltage management, guaranteeing the reliability of low-voltage management, but also narrows the SOC range during charging, minimizing the impact of charging plans on battery lifespan. Alternatively, energy storage sub-units can be categorized based on their historical cumulative charge-discharge cycle count. Specifically, batteries with fewer cycles are prioritized to balance losses across the entire energy storage sub-unit cluster and maximize the system's lifespan value.

[0076] Example 3:

[0077] This embodiment is a further refinement of embodiment 1:

[0078] During the charging process of the energy storage sub-units during the replenishment period, based on the grid time-of-use electricity price information, the charging power of the energy storage sub-units, and the historical load of the replenishment period, a charging volume plan for the energy storage sub-units is set for the off-peak electricity price period, the normal electricity price period, and the peak electricity price period. The charging volume plan includes:

[0079] Plan 1: When the charging power of the energy storage sub-unit and the available charging capacity of the line during off-peak electricity price periods meet the charging power demand of the energy storage sub-unit, the charging of the energy storage sub-unit will be completed during off-peak electricity price periods.

[0080] Plan 2: When the energy storage sub-unit is fully charged during the off-peak electricity price period based on the charging power of the energy storage sub-unit and the available charging capacity of the line during the normal electricity price period, and the charging power of the energy storage sub-unit and the available charging capacity of the line during the normal electricity price period meet the charging power gap of the energy storage sub-unit, the charging of the energy storage sub-unit is completed during the normal electricity price period.

[0081] Plan 3: Based on the charging power of the energy storage sub-unit and the available charging capacity of the line during off-peak and normal electricity price periods, the energy storage sub-unit will be fully charged during off-peak and normal electricity price periods, and then the charging of the energy storage sub-unit will be completed during peak electricity price periods.

[0082] The above scheme provides a specific method for implementing a charging plan, aiming to provide a technical solution for economical charging as much as possible when charging conditions permit. Specifically: This scheme is based on the grid time-of-use pricing rules. When the charging capacity of the energy storage sub-unit and the charging capacity of the line meet the charging requirements during off-peak hours, the energy storage sub-unit is charged during off-peak hours. Otherwise, after charging the energy storage sub-unit at full power (the maximum charging power determined by the charging power and available charging capacity) during off-peak hours, the energy storage sub-unit is charged during normal-price periods to fill the charging gap in the charging plan. Alternatively, after charging at full power during both off-peak and normal-price periods, the energy storage sub-unit is charged during peak-price periods, ultimately achieving the lowest-cost charging.

[0083] Example 4:

[0084] This embodiment is a further refinement of embodiment 1:

[0085] Based on the real-time monitored line voltage of the transformer substation, the discharge parameters of the energy storage subunit are dynamically matched as follows:

[0086] Based on the timeline and the voltage change trend at each moment of the predicted risk period, the time-series curve of the compensation power at each moment of the associated risk period is obtained.

[0087] Based on the compensation power at each moment in the time-series curve, the reference discharge parameters of the energy storage sub-unit at each moment are formulated and implemented.

[0088] Under the current reference discharge parameters, when the deviation of the real-time monitoring result of the transformer area line voltage from the predicted voltage at the current moment reaches a set threshold, the discharge parameters of the energy storage sub-unit are dynamically matched, wherein:

[0089] The set threshold includes multiple set thresholds with different values, and each set threshold is configured with a different compensation power adjustment amount;

[0090] Based on the degree of deviation, the compensation power adjustment amount is set at a threshold, and the discharge parameters are adjusted on the basis of the reference discharge parameters.

[0091] The above provides a specific implementation method for dynamic matching of discharge parameters. In this scheme, the compensation power at each moment during the risk period is obtained by predicting the voltage change trend. Based on the compensation power, reference discharge parameters for each moment of the energy storage sub-unit are formulated. During the discharge process of low voltage mitigation, the transformer area is treated according to the reference discharge parameters at the current moment. During the treatment process, the line voltage of the transformer area is monitored in real time, and the compensation power is adjusted differently based on the deviation between the detected value and the predicted voltage, according to the reference discharge parameters. In this scheme, the reference discharge parameters are obtained before the actual low voltage mitigation is carried out by using a prediction method. Subsequently, during the actual low voltage mitigation process, the differentiated compensation power adjustment is matched based on the reference discharge parameters and the measured results of the line voltage of the transformer area. This is a predictive discharge plan formulation and execution method. For example, based on the predicted voltage drop, low voltage mitigation is achieved through the current reference discharge parameters. This avoids the problem of response lag in the pure feedback system commonly used in existing technologies, which affects the smoothness, continuity and orderliness of the low voltage mitigation process. Furthermore, the current reference discharge parameters serve as feedforward for the low-voltage management control composite structure, while the real-time monitoring results of the transformer area line voltage serve as feedback. Predictive low-voltage management is achieved through feedforward, and accurate low-voltage management is achieved through feedback, thus achieving an optimized balance between low-voltage management response speed and control quality. Furthermore, the differentiated compensation power adjustment configured for each set threshold uses the threshold as a trigger condition to avoid the impact on system lifespan caused by frequent actions of the energy storage unit during low-voltage management. Simultaneously, the differentiated compensation power adjustment aims to form a stepped response hierarchy, making the quantitative action mechanism simpler and reliably implementable in embedded systems, which is beneficial to system operational stability.

[0092] Example 5:

[0093] This embodiment is a further refinement of embodiment 4:

[0094] When the discharge parameters are adjusted, the energy storage sub-unit discharges with increased power relative to the compensation power in the time-series curve. If the increase in discharge power exceeds the set value or the duration of increased power discharge exceeds the set value, the number of energy storage sub-units used for low voltage management during risk periods will be increased and / or a risk alarm for low voltage management resource shortage will be output.

[0095] The above provides a more specific implementation method for achieving dynamic matching of discharge parameters. In this scheme, based on the above focus on current voltage recovery and governance, it further introduces the concept of an increased power discharge relative to the predicted compensation power (the discharge power of the energy storage sub-unit is greater than the compensation power in the time series curve). By further monitoring the increase in discharge power or the duration of the increased power discharge, it determines whether to automatically increase the number of energy storage sub-units actually participating in this low voltage governance and / or output a risk alarm of low voltage governance resource shortage. This aims to solve the sustainability problem of low voltage governance. Specifically, the above increase and the duration of the increased power discharge are used to determine the degree of deviation between the predicted reference discharge parameters and the actual situation, and serve as the basis for identifying whether governance resources are tight. Subsequently, by increasing the number of energy storage sub-units participating in this low voltage governance, the governance resources can be expanded online to solve the problem of insufficient system-allocated governance resources, thereby improving the system's adaptability and robustness. The risk alarm is used to guide maintenance personnel to promptly investigate and handle abnormal situations, and to enable overall system expansion.

[0096] Example 6:

[0097] This embodiment is a further refinement of embodiment 1:

[0098] After the low voltage mitigation during the risk period is completed, the energy storage unit's sustainable mitigation capability for the next low voltage risk is assessed based on the final state of charge of the energy storage sub-unit used for the low voltage mitigation during the risk period, as well as the available charging time and charging power before the next expected risk period.

[0099] When the assessment result is lower than the preset capability threshold, maintenance suggestion information is generated to prompt adjustment of the state of charge operating range or expansion of the energy storage capacity of the energy storage unit.

[0100] The above provides a method for implementing full lifecycle management of the system. In this solution, based on the final state of charge, available charging time, and charging power, the system's ability to participate in the next low-voltage governance is assessed. Based on the assessment results, maintenance suggestion information is generated to assist in the long-term availability of the system's governance capabilities. Specifically, the final state of charge indicates the remaining power of the current energy storage unit, the available charging time indicates the charging window duration, and the charging power indicates the charging speed. Based on these conditions, the ability of the energy storage unit to restore governance resources before the arrival of the next risk period can be obtained. Based on the sustainable governance capability assessment results, the energy replenishment of the energy storage unit during the next risk period can be adjusted by adjusting the operating range of the state of charge. For example, by increasing the upper limit of the operating range of the state of charge and decreasing the lower limit of the operating range of the state of charge, the single discharge capacity of the energy storage unit can meet the low-voltage governance requirements. Alternatively, the system can prompt maintenance personnel to increase the overall capacity of the energy storage unit, thereby solving the problem of a gap between governance resources and actual needs from a hardware perspective, and ultimately achieving the goal of proactively preventing insufficient governance capabilities in the next low-voltage period.

[0101] Example 7:

[0102] This embodiment is a further refinement of embodiment 6:

[0103] After the low voltage management during the risk period ends, the final state of charge of each energy storage sub-unit participating in the low voltage management during the risk period is obtained, as well as the rated capacity, charging power and the next energy replenishment period of each energy storage sub-unit participating in the low voltage management during the risk period. The number of energy storage sub-units that can charge the power to above the preset lower limit of the state of charge range before the next risk period is calculated.

[0104] When the number of energy storage sub-units is lower than the minimum energy storage sub-unit number threshold required to maintain low voltage management, maintenance suggestion information is generated to prompt adjustment of the state of charge operating range or expansion of the energy storage capacity of the energy storage unit.

[0105] The above provides a more specific implementation method for achieving full lifecycle management of the system. In this solution, based on the number of energy storage sub-units that can charge the power to above the preset lower limit of the state of charge range before the next risk period, the number of energy storage sub-units that can participate in the next low-voltage risk management is obtained. As those skilled in the art know, the number of energy storage sub-units determines the total compensation power that the energy storage units can provide during the next low-voltage management process, avoiding the problem of mismatch between management resources and actual management needs from a power perspective. For example, when it is lower than the minimum energy storage sub-unit number threshold, it means that the next low-voltage management capability is insufficient or the system redundancy is insufficient. Through maintenance suggestion information, by sacrificing battery health or expanding the overall capacity of the system, the next low-voltage management can be successfully implemented.

[0106] Example 8:

[0107] This embodiment is a further refinement of embodiment 1:

[0108] Based on the real-time monitored line voltage of the transformer substation, the discharge parameters of the energy storage subunit are dynamically matched as follows:

[0109] Real-time acquisition of the current state of charge of each energy storage sub-unit;

[0110] Calculate the remaining dischargeable energy required to maintain the state of charge of each energy storage sub-unit at the end of the discharge range equal to the lower limit of the state of charge range;

[0111] The discharge power of each energy storage sub-unit is dynamically adjusted, and at the end of the discharge, the state of charge of the battery in each energy storage sub-unit is within the range of the stated state of charge.

[0112] The above provides a method for achieving dynamic matching of discharge parameters. It aims to prevent over-discharge of energy storage sub-units by real-time monitoring of state of charge and calculation of dischargeable energy in a predictive manner. Specifically, the current state of charge is used to characterize the dischargeable energy of each energy storage sub-unit. Based on the current state of charge, the discharge power is adjusted by predictive calculation to protect each energy storage sub-unit from over-discharge during the discharge process, thus avoiding the rapid decline in battery life after deep discharge, which would affect the long-term economic efficiency and feasibility of the system.

[0113] Example 9:

[0114] This embodiment is a further refinement of embodiment 1:

[0115] The state of charge range is a dynamic range value based on the periodic variation law of the transformer area load and the health status parameters of each battery.

[0116] Among them, the lower limit of the state of charge range of each battery is positively correlated with the predicted load of the next risk period of the distribution area, and the lower limit of the state of charge range of each battery is negatively correlated with the health status parameter of that battery.

[0117] The above provides an implementation using a dynamic state of charge (SOC) range. Specifically, this solution correlates the SOC operating range with the periodic variation pattern of the transformer area load and the health status parameters of each battery. The periodic variation pattern of the transformer area load represents the low voltage management needs of the transformer area, and the health status parameters of each battery represent the health status of the energy storage unit. Through adaptive / dynamically adjustable SOC range, the aim is to achieve the following: For example, when it is determined based on the periodic variation pattern of the transformer area load that the management resources required for the next risk period are high, the energy supply capacity of the energy storage system can be improved by expanding the width of the SOC range; when it is determined based on the health status parameters of each battery that the health of one or more batteries is low, the width of the SOC range, the lower limit value, and the upper limit value can be reduced to achieve shallow charging and shallow discharging of these batteries, thereby delaying the performance degradation of these batteries, extending their lifespan, and reducing the probability of risks such as thermal runaway.

[0118] Example 10:

[0119] This embodiment, based on Embodiment 1, provides a low-voltage management system based on power distribution energy storage. This low-voltage management system is used to implement the low-voltage management method described in Embodiment 1. The system includes:

[0120] The data acquisition module is used to collect historical load data of the transformer area, real-time line voltage, and real-time status information of each energy storage sub-unit.

[0121] The predictive analysis module is used to predict load or voltage change trends and obtain the compensation power and total compensation power required during risk periods.

[0122] The decision-making module is used to determine the energy storage sub-units to be used for low voltage mitigation during this risk period, and to formulate and execute charging plans.

[0123] The dynamic matching module is used to perform discharge control of the energy storage sub-unit during risky periods and dynamically adjust the discharge power of the energy storage sub-unit according to the real-time line voltage.

[0124] As those skilled in the art will recognize, this low-voltage mitigation system is a system for implementing the aforementioned low-voltage mitigation method.

[0125] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-voltage management method based on distribution energy storage, wherein the method achieves low-voltage management of the distribution area by discharging energy storage units to the distribution area, characterized in that, In this method, based on the historical load data of the transformer area, the load or voltage change trend of the transformer area in the future set time period is predicted, and the risk period of low voltage on the line is obtained from the future set time period, as well as the compensation power and total compensation power required for low voltage mitigation during the risk period. Collect the current energy storage status of the energy storage unit and the charging and discharging power of the energy storage unit; Based on the compensation power, total compensation capacity, discharge power and capacity of the energy storage unit, and the state of charge range set for the batteries in the energy storage unit, the energy storage sub-units used for low voltage management during this risk period are identified from the energy storage unit. The time between the current moment and the risk period is set as the energy replenishment period of the energy storage sub-unit. Based on the total compensation power and the state of charge range, a charging plan for the energy storage sub-unit is formulated during the energy replenishment period. The energy storage sub-unit is charged during the energy replenishment period. After charging is completed and low voltage management is completed, the state of charge of the battery in the energy storage sub-unit is within the state of charge range. During the low voltage mitigation process, the discharge parameters of the energy storage sub-units are dynamically matched based on the real-time monitored voltage of the transformer substations.

2. The low-voltage management method based on power distribution energy storage according to claim 1, characterized in that, The number of energy storage sub-units used for low voltage mitigation during this risk period is multiple, and the energy storage sub-units used for low voltage mitigation during this risk period form an energy storage sub-unit set. In the process of delineating energy storage sub-units, the energy storage sub-units in the energy storage unit are sorted according to their state of charge (SOC). The energy storage sub-units with the highest SOC in the SOC are designated as the set of energy storage sub-units used for low voltage management during this risk period. Alternatively, based on the historical cumulative charge-discharge cycle count of each energy storage sub-unit in the energy storage unit, the energy storage sub-units with the fewest historical cumulative charge-discharge cycle counts in the ranking can be designated as the set of energy storage sub-units for low voltage management during this risk period.

3. The low-voltage management method based on power distribution energy storage according to claim 1, characterized in that, During the charging process of the energy storage sub-units during the replenishment period, based on the grid time-of-use electricity price information, the charging power of the energy storage sub-units, and the historical load of the replenishment period, a charging volume plan for the energy storage sub-units is set for the off-peak electricity price period, the normal electricity price period, and the peak electricity price period. The charging volume plan includes: Plan 1: When the charging power of the energy storage sub-unit and the available charging capacity of the line during off-peak electricity price periods meet the charging power demand of the energy storage sub-unit, the charging of the energy storage sub-unit will be completed during off-peak electricity price periods. Plan 2: When the energy storage sub-unit is fully charged during the off-peak electricity price period based on the charging power of the energy storage sub-unit and the available charging capacity of the line during the normal electricity price period, and the charging power of the energy storage sub-unit and the available charging capacity of the line during the normal electricity price period meet the charging power gap of the energy storage sub-unit, the charging of the energy storage sub-unit is completed during the normal electricity price period. Plan 3: Based on the charging power of the energy storage sub-unit and the available charging capacity of the line during off-peak and normal electricity price periods, the energy storage sub-unit will be fully charged during off-peak and normal electricity price periods, and then the charging of the energy storage sub-unit will be completed during peak electricity price periods.

4. The low-voltage management method based on power distribution energy storage according to claim 1, characterized in that, Based on the real-time monitored line voltage of the transformer substation, the discharge parameters of the energy storage subunit are dynamically matched as follows: Based on the timeline and the voltage change trend at each moment of the predicted risk period, the time-series curve of the compensation power at each moment of the associated risk period is obtained. Based on the compensation power at each moment in the time-series curve, the reference discharge parameters of the energy storage sub-unit at each moment are formulated and implemented. Under the current reference discharge parameters, when the deviation of the real-time monitoring result of the transformer area line voltage from the predicted voltage at the current moment reaches a set threshold, the discharge parameters of the energy storage sub-unit are dynamically matched, wherein: The set threshold includes multiple set thresholds with different values, and each set threshold is configured with a different compensation power adjustment amount; Based on the degree of deviation, the compensation power adjustment amount is set at a threshold, and the discharge parameters are adjusted on the basis of the reference discharge parameters.

5. A low-voltage management method based on power distribution energy storage according to claim 4, characterized in that, When the discharge parameters are adjusted, the energy storage sub-unit discharges with increased power relative to the compensation power in the time-series curve. If the increase in discharge power exceeds the set value or the duration of increased power discharge exceeds the set value, the number of energy storage sub-units used for low voltage management during risk periods will be increased and / or a risk alarm for low voltage management resource shortage will be output.

6. The low-voltage management method based on power distribution energy storage according to claim 1, characterized in that, After the low voltage mitigation during the risk period is completed, the energy storage unit's sustainable mitigation capability for the next low voltage risk is assessed based on the final state of charge of the energy storage sub-unit used for the low voltage mitigation during the risk period, as well as the available charging time and charging power before the next expected risk period. When the assessment result is lower than the preset capability threshold, maintenance suggestion information is generated to prompt adjustment of the state of charge operating range or expansion of the energy storage capacity of the energy storage unit.

7. A low-voltage management method based on power distribution energy storage according to claim 6, characterized in that, After the low voltage management during the risk period ends, the final state of charge of each energy storage sub-unit participating in the low voltage management during the risk period is obtained, as well as the rated capacity, charging power and the next energy replenishment period of each energy storage sub-unit participating in the low voltage management during the risk period. The number of energy storage sub-units that can charge the power to above the preset lower limit of the state of charge range before the next risk period is calculated. When the number of energy storage sub-units is lower than the minimum energy storage sub-unit number threshold required to maintain low voltage management, maintenance suggestion information is generated to prompt adjustment of the state of charge operating range or expansion of the energy storage capacity of the energy storage unit.

8. The low-voltage management method based on power distribution energy storage according to claim 1, characterized in that, Based on the real-time monitored line voltage of the transformer substation, the discharge parameters of the energy storage subunit are dynamically matched as follows: Real-time acquisition of the current state of charge of each energy storage sub-unit; Calculate the remaining dischargeable energy required to maintain the state of charge of each energy storage sub-unit at the end of the discharge range equal to the lower limit of the state of charge range; The discharge power of each energy storage sub-unit is dynamically adjusted, and at the end of the discharge, the state of charge of the battery in each energy storage sub-unit is within the range of the stated state of charge.

9. A low-voltage management method based on distribution energy storage according to any one of claims 1 to 8, characterized in that, The state of charge range is a dynamic range value based on the periodic variation law of the transformer area load and the health status parameters of each battery. Among them, the lower limit of the state of charge range of each battery is positively correlated with the predicted load of the next risk period of the distribution area, and the lower limit of the state of charge range of each battery is negatively correlated with the health status parameter of that battery.

10. A low-voltage management system based on power distribution energy storage, characterized in that, The low-voltage mitigation system is used to implement the low-voltage mitigation method according to any one of claims 1 to 9, the system comprising: The data acquisition module is used to collect historical load data of the transformer area, real-time line voltage, and real-time status information of each energy storage sub-unit. The predictive analysis module is used to predict load or voltage change trends and obtain the compensation power and total compensation power required during risk periods. The decision-making module is used to determine the energy storage sub-units to be used for low voltage mitigation during this risk period, and to formulate and execute charging plans. The dynamic matching module is used to perform discharge control of the energy storage sub-unit during risky periods and dynamically adjust the discharge power of the energy storage sub-unit according to the real-time line voltage.

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