Active power distribution network construction type distributed energy storage capacity configuration optimization method and system

Abstract

The invention discloses an active power distribution network construction type distributed energy storage capacity configuration optimization method and system, and the method comprises the steps: building an island division index system of an active power distribution network in a fault power failure duration, and determining the capacity configuration range and load distribution of construction type energy storage in each island in the active power distribution network based on the island division index system; the maximum recovery load capacity, the maximum recovery load weighted sum, the minimum system network loss and the minimum switching operation frequency are taken as objective functions, and a connectivity constraint, a current and voltage constraint, a branch power constraint, a network construction type energy storage constraint and an island division index system form a combined constraint condition; based on a 0 / 1 knapsack theory, establishing an optimization model by using an objective function and a combined constraint condition; and iteratively solving the optimization model by taking the determined capacity configuration range and load distribution of the grid-type energy storage in the island as input parameters to obtain an active power distribution network grid-type distributed energy storage capacity configuration optimization scheme, thereby solving the problems of the optimal access position and capacity distribution of the power distribution network grid-type distributed power supply.

Description

Technical Field

[0001] The present invention belongs to the technical field of grid-type distributed energy storage capacity configuration, and specifically, relates to a method and system for optimizing the configuration of active distribution network grid-type distributed energy storage capacity. Background Art

[0002] At present, with the rapid development of new energy technologies, the access of new energy to the distribution network has become the trend of future smart grid development. When the distribution network system fails, the distribution network will lose power and form a dead island. When a grid-type distributed power source is introduced into the system, the distribution network system can enter an isolated island operation state, which can not only restore the power supply to important loads to the maximum extent, but also respond to other serious emergencies. By reasonably arranging the access location of the grid-type distributed power source, the power backup capacity can be maximized, so that it can better play the emergency power supply capacity of the distribution network when it is in isolated operation, thereby comprehensively improving the disaster prevention and mitigation capabilities of my country's distribution network system under the influence of extreme weather disasters.

[0003] In the prior art, the distributed power optimization configuration method based on the improved genetic algorithm starts from the system component failure factors, comprehensively considers the influence of component aging failure rate, line outage probability and weather factors on component failure probability, and considers the operating risk cost and potential risk cost factors, establishes a probability model, and uses the genetic algorithm to obtain the optimal configuration of the distributed power supply, but only considers the economic efficiency of the site selection and capacity setting scheme, and does not consider the multiple factors of economy and risk separately, lacking accuracy and flexibility. The distribution network operation risk assessment method containing distributed power sources calculates the failure probability of distribution lines under different weather types and the failure probability of distributed power sources under different weather types and operating life. According to the failure probability of distribution lines and distributed power sources, the operating state of the distribution network is simulated through the pre-constructed distributed power output model, and the operating risk of the distribution network is evaluated according to the simulation results, but the operating cost risk and potential cost risk factors on the distribution network of distributed power sources are not considered, so the accuracy of the distribution network operation risk assessment cannot be fully guaranteed.

[0004] In summary, the existing technology only starts from the operating characteristics of distributed power sources, ignores the safety of the grid-type distributed power sources themselves, and cannot meet the safety requirements of the grid-type power sources. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a method and system for optimizing the capacity configuration of distributed energy storage in an active distribution network. By establishing a capacity configuration optimization model for distributed power sources in a distribution network system, weighting different load nodes is processed based on the input-output method, and then an island partitioning MILP model is constructed under the condition of considering the island operation constraints, thereby solving the problem of optimal access location and capacity allocation of distributed power sources in the distribution network.

[0006] The present invention adopts the following technical solution.

[0007] The present invention proposes a method for optimizing the configuration of distributed energy storage capacity in an active distribution network, comprising: When a system fails, obtain the duration of the power outage, the output power of each distributed power source, and the power demand of the power-off load in the system to determine the power and remaining power of the grid-connected energy storage; Using the power and remaining power of the grid-forming energy storage, an index system for island division of the active distribution network within the duration of the fault outage is established, including: the discharge power duration index, discharge remaining capacity duration index, charging power duration index, charging remaining capacity duration index, power balance duration index, and power balance duration index of the grid-forming energy storage; based on the island division index system, the capacity configuration range and load distribution of the grid-forming energy storage in each island in the active distribution network are determined; Taking the maximum restored load, the maximum weighted sum of restored loads, the minimum system network loss and the minimum number of switch operations as the objective function, the connectivity constraint, current and voltage constraint, branch power constraint, grid-type energy storage constraint and island division index system constitute the joint constraint conditions; based on the 0 / 1 knapsack theory, the optimization model is established using the objective function and the joint constraint conditions; taking the determined capacity configuration range of the grid-type energy storage in the island and the load distribution as input parameters, the optimization model is iteratively solved to obtain the capacity configuration optimization scheme of the grid-type distributed energy storage in the active distribution network.

[0008] Preferably, the power outage duration satisfy , is the fault start time, is the fault recovery time; The power of grid-type energy storage satisfies the following relationship:

[0009] In the formula, For the moment The power of grid-type energy storage, For the moment The output power of distributed power generation, For the moment The power demand of the power-off load in the system, Power outage duration Moments within; when When When , the grid-type energy storage discharges.

[0010] The remaining power of the grid-type energy storage satisfies the following relationship:

[0011] In the formula, For the moment The remaining power of the grid-type energy storage, The fault start time The amount of electricity used for grid-type energy storage.

[0012] Preferably, the discharge power duration index of the grid-type energy storage satisfies the following relationship:

[0013] In the formula, It is the discharge power duration index of the grid-type energy storage within the fault outage duration. is the charging and discharging power sampling time interval, is the discharge power indicator, The total number of sampling moments of the charge and discharge power during the fault power outage duration; Satisfies the following relationship:

[0014] Satisfies the following relationship:

[0015] In the formula, is the discharge power sampling value, is the maximum discharge power.

[0016] Preferably, the discharge remaining capacity index of the grid-type energy storage satisfies the following relationship:

[0017] In the formula, It is the discharge remaining capacity indicator of the grid-type energy storage within the fault power outage duration. is the remaining power sampling time interval, It is the mark of the remaining discharge capacity. The total number of sampling times of the remaining charge and discharge power during the fault power outage duration; Satisfies the following relationship:

[0018] Satisfies the following relationship:

[0019] In the formula, is the remaining power sampling value, The minimum remaining power.

[0020] Preferably, the charging power duration index of the grid-type energy storage satisfies the following relationship:

[0021] In the formula, It is the charging power duration indicator of the grid-type energy storage within the fault power outage duration. It is the charging power indicator; Satisfies the following relationship:

[0022] In the formula, is the charging power sampling value, The maximum charging power.

[0023] Preferably, the remaining charge capacity index of the grid-type energy storage satisfies the following relationship:

[0024] In the formula, It is the charging remaining capacity indicator of the grid-type energy storage within the duration of the fault power outage. It is the mark of the remaining power of charging; Satisfies the following relationship:

[0025] In the formula, is the remaining power sampling value, The maximum value of remaining power.

[0026] Preferably, the power balance duration indicator satisfies the following relationship:

[0027] In the formula, It is an indicator of the power balance duration of grid-type energy storage within the duration of a fault power outage.

[0028] Preferably, the power balance duration indicator satisfies the following relationship:

[0029] In the formula, It is an indicator of the electricity balance duration of grid-type energy storage within the duration of a fault power outage.

[0030] Preferably, when the discharge power duration index or the discharge remaining capacity duration index of the grid-type energy storage reaches zero, the load with the largest weight is connected to the grid-type energy storage; after the connection, when the charging power duration index or the charging remaining capacity duration index reaches the minimum value, the output of the distributed power source and the capacity configuration range of the grid-type energy storage are adjusted; with the goal of maximizing both the power balance duration index and the power balance duration index, the load distribution connected to the grid-type energy storage is determined according to the adjusted distributed power source output and the capacity configuration range of the grid-type energy storage.

[0031] Preferably, the weight of the load corresponding to the production and supply industry of electricity, heat and water is 1, and the input-output method is used to determine the weight of the load according to the industry to which the load belongs.

[0032] Preferably, the weighted sum of the restoration loads satisfies the following maximum relationship:

[0033] In the formula, To restore the maximum value of the weighted sum of loads, For the The load collection of an isolated island, For load The state variables, Indicates load On the isolated island, It means load Not on an isolated island, For load The weight of For load Power; The minimum system network loss satisfies the following relationship:

[0034] In the formula, To minimize the system network loss, For connected A collection of branches, and Branch The active power and reactive power of For branch The resistance, For branch Voltage; The minimum number of switch operations satisfies the following relationship:

[0035] In the formula, To minimize the number of switching operations, In the failover region A set of switches, Switch before failure recovery The state of the switch is 1, which means the switch is closed, and 0, which means the switch is open. Switch after failure recovery The state of the switch is 1, which means the switch is closed, and 0, which means the switch is open.

[0036] Preferably, the island division index system is transformed into the following constraints:

[0037] In the formula, For the The load collection of an isolated island, For the The total charging and discharging power of the grid-type distributed energy storage in each isolated island, For the Load in an island The power, For the The total power of all loads in an island;

[0038] In the formula, It is the power balance duration indicator of grid-type energy storage within the fault outage duration. For the The distributed storage system in the isolated island can The total charge and discharge power, For the The total capacity of the grid-type distributed energy storage in each island, It is the available state of charge of grid-type energy storage;

[0039] In the formula, and They are the maximum and minimum values ​​of the available state of charge of the grid-type energy storage respectively;

[0040] In the formula, For the The maximum total capacity of the distributed energy storage network in each island is: It is the electricity balance duration indicator of grid-type energy storage within the duration of fault power outage. For the Distributed power generation moment in an island Total output of

[0041] In the formula, Provide margin for island safety operation.

[0042] Preferably, the 0 / 1 backpack theory is improved, including: taking integers for input parameters and restoring power supply according to load weights.

[0043] The present invention also proposes an active distribution network type distributed energy storage capacity configuration optimization system, comprising: The data acquisition and processing module is used to obtain the duration of power outage, the output power of each distributed power source, and the power demand of the power-off load in the system when the system fails, so as to determine the power and remaining power of the grid-type energy storage; The island division module is used to establish an island division index system for the active distribution network within the duration of the fault power outage, including: the discharge power duration index, the discharge remaining capacity duration index, the charging power duration index, the charging remaining capacity duration index, the power balance duration index, and the power balance duration index of the grid-forming energy storage; based on the island division index system, the capacity configuration range and load distribution of the grid-forming energy storage in each island in the active distribution network are determined; The capacity configuration optimization module is used to take the maximum restored load, the maximum weighted sum of restored loads, the minimum system network loss and the minimum number of switch operations as the objective function, and to form joint constraints with connectivity constraints, current and voltage constraints, branch power constraints, grid-type energy storage constraints and island division index system; based on the 0 / 1 knapsack theory, an optimization model is established using the objective function and joint constraints; with the determined capacity configuration range of the grid-type energy storage in the island and the load distribution as input parameters, the optimization model is iteratively solved to obtain the capacity configuration optimization plan for the active distribution network grid-type distributed energy storage.

[0044] The present invention is also a terminal, comprising a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0045] The present invention is also a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0046] The beneficial effects of the present invention are that, compared with the prior art, at least the present invention proposes a method for optimizing the capacity configuration of distributed power sources in a distribution network, and by constructing an island partition MILP model that meets the island partition index and constraints, the access position of the distributed power source in the network is reasonably arranged, so that the backup capacity of the power source is maximized. By reasonably configuring the access position and capacity of the power source and other measures, the power capacity is fully utilized, the island emergency supply capability of the distributed power source in the network is better utilized, and the disaster resistance and mitigation capability of the distribution network under extreme disasters and the resilience of the power system itself are comprehensively improved, which has the characteristics of fast calculation time and strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a logic block diagram of a distributed energy storage capacity configuration optimization method for an active distribution network proposed by the present invention; Figure 2 is a schematic diagram of distribution network line planning in an embodiment of the present invention; Figure 3 This is the division scheme of DG25 & DG18 in the embodiment of the present invention; Figure 4 This is the division scheme of DG25 & DG15 in the embodiment of the present invention; Figure 5 This is the division scheme of DG25 & DG26 in the embodiment of the present invention; Figure 6 This is the division scheme of DG25 & DG28 in the embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0049] The present invention proposes a method for optimizing the configuration of distributed energy storage capacity in an active distribution network. Figure 1 As shown, including: Step 1: When a system fails, obtain the duration of the power outage, the output power of each distributed power source, and the power demand of the power-off load in the system to determine the discharge power and remaining power of the grid-connected energy storage.

[0050] Specifically, the duration of the power outage satisfy , is the fault start time, is the fault recovery time; Whether the active distribution network can operate in an isolated state under system failure, the charging and discharging power and remaining power of the grid-connected energy storage are key indicators, which can effectively reflect the actual operating conditions of the active distribution network in an isolated state and provide an important basis for evaluating the operating performance of the active distribution network during off-grid period.

[0051] The power of grid-type energy storage satisfies the following relationship:

[0052] In the formula, For the moment The power of grid-type energy storage, For the moment The output power of distributed power generation, For the moment The power demand of the power-off load in the system, Power outage duration Moments within; when When When , the grid-type energy storage discharges.

[0053] The remaining power of the grid-type energy storage satisfies the following relationship:

[0054] In the formula, For the moment The remaining power of the grid-type energy storage, The fault start time The amount of electricity used for grid-type energy storage.

[0055] Step 2: Establish an island division index system for the active distribution network within the fault outage duration, including: the discharge power duration index, discharge remaining capacity duration index, charging power duration index, charging remaining capacity duration index, power balance duration index, and power balance duration index of the grid-connected energy storage; divide the active distribution network into islands based on the island division index system.

[0056] After the active distribution network is divided into islands based on the island division index system, the grid-connected energy storage connected to the islands is used as the planning scheme for the grid-connected distributed energy storage.

[0057] Specifically, the island division index system of the active distribution network within the fault outage duration includes: the discharge power duration index, the discharge remaining capacity duration index, the charging power duration index, the charging remaining capacity duration index, the power balance duration index, and the power balance duration index of the grid-type energy storage; Specifically, step 2 includes: Step 2.1, during the fault power outage duration, a discharge power identifier is set according to the relationship between the discharge power of the grid-type energy storage and the maximum discharge power, and the sum of all discharge power identifiers is used as the discharge power duration indicator; a discharge residual capacity identifier is set according to the relationship between the residual capacity of the grid-type energy storage and the minimum residual capacity, and the sum of all discharge residual capacity identifiers is used as the discharge residual capacity duration indicator; In the embodiment, the power outage duration is (Unit: hour), if the grid-type energy storage is discharged, the discharge power of the grid-type energy storage in the island must be detected every 1 minute, so Discharge power sampling value ,when Discharge power indicator Set to 1, when Discharge power indicator Set to 0, Discharge power indicator The sum of is the discharge power duration index of the grid-type energy storage within the fault outage duration, which satisfies the following relationship:

[0058] In the formula, It is the discharge power duration index of the grid-type energy storage within the fault outage duration. is the charging and discharging power sampling time interval, which is 1 minute in the embodiment, is the discharge power indicator, The total number of sampling moments of the charge and discharge power during the fault power outage duration; Satisfies the following relationship:

[0059] In the formula, the power outage duration is satisfy , is the fault start time, The fault recovery time. The unit of the fault power outage duration is hours. The 60 in the numerator represents 60 minutes, and the 1 in the denominator represents 1 minute. Satisfies the following relationship:

[0060] In the formula, is the discharge power sampling value, is the maximum discharge power; The discharge power duration index proposed in the present invention characterizes the statistical result of the duration that the discharge power exceeds the maximum value. When the discharge power duration index is zero, it means that the discharge power of the grid-type energy storage exceeds the maximum value during the fault power outage duration. The discharge power sampling time interval of 1 minute is a non-restrictive and preferred choice.

[0061] In the embodiment, the power outage duration is (Unit: hour), if the grid-type energy storage is discharged, the remaining power of the grid-type energy storage in the island must be detected every 15 minutes, so Remaining power sampling value ,when Remaining power indicator Set to 1, when Remaining power indicator Set to 0, Remaining power indicator The sum of is the discharge remaining capacity index of the grid-type energy storage within the fault outage duration, which satisfies the following relationship:

[0062] In the formula, It is the discharge remaining capacity indicator of the grid-type energy storage within the fault power outage duration. is the remaining power sampling time interval, which is 15 minutes in the embodiment, It is the mark of the remaining discharge capacity. The total number of sampling times of the remaining discharge power during the fault power outage duration; Satisfies the following relationship:

[0063] In the formula, the power outage duration is satisfy , is the fault start time, The fault recovery time. The unit of the fault power outage duration is hours. The 60 in the numerator means 60 minutes, and the 15 in the denominator means 15 minutes. Satisfies the following relationship:

[0064] In the formula, is the remaining power sampling value, is the minimum value of remaining power; The discharge remaining power index proposed in the present invention characterizes the statistical result of the duration during which the remaining power is not less than the minimum value during discharge. When the discharge remaining power index is zero, it means that the remaining power of the grid-type energy storage is not less than the minimum value within the duration of the fault power outage. The remaining power sampling time interval of 15 minutes is a non-restrictive and preferred choice.

[0065] When the discharge power duration index and the discharge residual capacity duration index proposed in the present invention are both zero, they constitute the zero-value criterion for the island operation of the active distribution network. In the island operation state, if the discharge power of the grid-type energy storage in the island is lower than a certain limit, and the remaining power drops below the critical threshold, the system will lose the dynamic power balancing ability. At this time, it is necessary to execute the load reduction strategy according to the load priority sorting, and give priority to cutting off the loads with lower weight levels to maintain the safe and stable operation of the system. If control measures are not taken in time, the key parameters of the system (such as voltage amplitude) will deviate from the safety threshold range, which will not only expand the scope of the original power outage area, but also may cause chain power outage accidents, and even lead to complex faults such as deterioration of the system operation state and malfunction of multi-level protection devices. Therefore, the zero-value criterion is a safety indicator for island division.

[0066] Step 2.2, during the fault power outage duration, the grid-type energy storage is charged, and the charging power identifier is set according to the relationship between the grid-type energy storage charging power and the maximum charging power, and the sum of all charging power identifiers is used as the charging power duration indicator. The charging remaining capacity identifier is set according to the relationship between the remaining capacity of the grid-type energy storage and the maximum remaining capacity, and the sum of all charging remaining capacity identifiers is used as the charging remaining capacity duration indicator; In the embodiment, the power outage duration is (Unit: hour), if the grid-type energy storage is discharged, the charging power of the grid-type energy storage in the island must be detected every 1 minute, so Charging power sampling value ,when Charging power indicator Set to 1, when Charging power indicator Set to 0, Charging power indicator The sum of is the charging power duration index of the grid-type energy storage within the fault outage duration, which satisfies the following relationship:

[0067] In the formula, It is the charging power duration indicator of the grid-type energy storage within the fault power outage duration. is the charging and discharging power sampling time interval, which is 1 minute in the embodiment, It is the charging power indicator. The total number of sampling moments of the charge and discharge power during the fault power outage duration; Satisfies the following relationship:

[0068] In the formula, is the charging power sampling value, is the maximum charging power; The charging power duration index proposed in the present invention characterizes the statistical result of the duration during which the charging power does not exceed the maximum value. The smaller the charging power duration index is, the shorter the duration during which the charging power of the grid-type energy storage does not exceed the maximum value during the fault power outage. A charging power sampling time interval of 1 minute is a non-restrictive and preferred choice.

[0069] In the embodiment, the power outage duration is (Unit: hour), if the grid-type energy storage is charged, the remaining power of the grid-type energy storage in the island must be detected every 15 minutes, so Remaining power sampling value ,when Remaining power indicator Set to 1, when Remaining power indicator Set to 0, Remaining charge indicator The sum of is the charging remaining capacity index of the grid-type energy storage within the fault power outage duration, which satisfies the following relationship:

[0070] In the formula, It is the charging remaining capacity indicator of the grid-type energy storage within the duration of the fault power outage. is the remaining power sampling time interval, which is 15 minutes in the embodiment, It is the indicator of the remaining power of charging. The total number of sampling times of the remaining charging capacity during the power outage duration; Satisfies the following relationship:

[0071] In the formula, is the remaining power sampling value, The maximum value of remaining power; The charging remaining capacity index proposed in the present invention characterizes the statistical result of the duration during which the charging remaining capacity does not exceed the maximum value. The smaller the charging remaining capacity index is, the shorter the duration during which the charging remaining capacity of the grid-type energy storage does not exceed the maximum value during the fault power outage. The charging remaining capacity sampling time interval of 15 minutes is a non-restrictive and preferred choice.

[0072] Distributed power sources are connected to the island, so when the island is operating, the grid-type energy storage must be in a charging state. The charging power duration index and the charging remaining capacity duration index proposed in the present invention are the minimum criteria for the island operation of the active distribution network when they reach the minimum value. If the charging power of the grid-type energy storage in the island exceeds the maximum charging power and the remaining power of the grid-type energy storage exceeds the limit, effective measures must be taken to control the power generation power of the DG. In order to effectively utilize energy, load power supply must be ensured as much as possible, wind and solar power abandonment should be reduced, and the minimum criterion should be followed. Therefore, the minimum criterion is an economic indicator for island division.

[0073] Step 2.3, the difference between the fault power outage duration and the discharge power duration index and the charging power duration index is used as the power balance duration index, and the difference between the fault power outage duration and the discharge remaining power duration index and the charging remaining power duration index is used as the power balance duration index; Specifically, the power balance duration indicator satisfies the following relationship:

[0074] In the formula, It is the power balance duration indicator of the grid-type energy storage within the fault power outage duration; The power balance duration indicator satisfies the following relationship:

[0075] In the formula, It is an indicator of the duration of power balance of grid-type energy storage within the duration of power outage; When the zero value criterion and the minimum value criterion are met, the power balance duration index and the power balance duration index proposed by the present invention both reach the maximum value, constituting the maximum value criterion for the island operation of the active distribution network. When the island is in an effective operating state, the charging and discharging power and the remaining power of the grid-forming energy storage need to meet certain requirements. During the operation of the island, it should be ensured as much as possible that the grid-forming energy storage is within the effective adjustment range, and the power and the remaining power are well balanced. Therefore, the maximum value criterion is a stability indicator for the island division.

[0076] The island division index system of the active distribution network within the fault outage duration also includes: load restoration power supply priority index, distributed power supply parameter index, and active distribution network topology index; In the prior art, qualitative indicators or local, single quantitative indicators are used for islanding of active distribution networks. However, the present invention not only proposes quantitative indicators that cover multiple aspects of safety, economy and stability and are organically connected, but also proposes the following indicators: 1) Load restoration power supply priority index The load restoration power supply priority index is the same as the load importance level; Restoration of important loads should be the most important part of restoring power supply in the distribution network system. In the distribution network system, loads can be divided into primary loads, secondary loads and tertiary loads according to their importance. Therefore, when restoring power supply in the distribution network system after a fault, important loads must be restored first.

[0077] 2) Distributed power supply parameter indicators Distributed power supply parameter indicators include but are not limited to: power supply voltage, power supply frequency; Use highly reliable distributed power sources. In an isolated island operation environment, the distributed power sources must have stable power supply voltage and frequency, and reduce intermittency and volatility. In the embodiment, energy storage and wind and photovoltaic power sources with a grid-building inverter interface are used.

[0078] 3) Active distribution network topology indicators In the distribution system, the radial topology usually adopts the "closed-loop design, open-loop operation" approach, which requires ensuring the radial structure of the distribution network system after an accident occurs.

[0079] The above indicators are actually a series of fixed prerequisite indicators, and will not change significantly due to the fault state of the active distribution network. The discharge power duration indicator, the discharge remaining capacity duration indicator, the charging power duration indicator, the charging remaining capacity duration indicator, the power balance duration indicator, and the power balance duration indicator are a set of dynamic a posteriori indicators. Changes in the fault state of the active distribution network will be clearly reflected in these indicators. Therefore, these indicators can not only serve as the basis for islanding the active distribution network, but also become indicators of the fault state of the active distribution network.

[0080] Step 2.4, determining the capacity configuration range and load distribution of the grid-type energy storage in each island in the active distribution network based on the island division index system; The island division index system proposed in the present invention does not directly divide the active distribution network into islands, nor does it configure the access position and capacity of the grid-forming energy storage. Instead, it adopts the island division index system of the active distribution network to realize the multi-stage dynamic allocation of the grid-forming energy storage and the load in the island. In fact, the specific situation of the grid-forming energy storage connected to the divided island is the preliminary planning scheme of the grid-forming distributed energy storage. This method avoids the existing energy storage planning scheme that only considers the economic and safety requirements of the active distribution network but ignores the impact of the layout scheme of the grid-forming distributed energy storage on the safety, economy and stability of the active distribution network when it is declassified as an island under a fault state. Moreover, based on the island division index system proposed in the present invention, when facing different fault states of the active distribution network, the island division results are different, and the planning scheme of the grid-forming distributed energy storage can be adaptively adjusted.

[0081] In the embodiment, during the duration of the fault power outage, the charging and discharging power, remaining power, distributed power output and load demand data of the grid-type energy storage are collected in real time, and a time series data set is generated according to the preset sampling interval (power every 1 minute, power every 15 minutes). Calculate each indicator, and determine whether to trigger the zero value criterion (discharging power duration indicator, charging remaining capacity duration indicator is zero) or the minimum value criterion (charging power duration indicator or charging remaining capacity duration indicator reaches the critical value); the existing technology mostly uses static thresholds (such as charging and discharging power ≤ maximum value, energy storage capacity ≥ minimum value) as constraints, while the present invention constructs dynamic indicators through high-frequency sampling statistics to quantify the operating time characteristics of the grid-type energy storage, such as the duration of the indicator exceeding the limit, and more accurately reflects the changes in the energy storage state during the fault.

[0082] Specifically, when the discharge power duration index or the discharge remaining capacity duration index of the grid-type energy storage reaches zero, the load with the largest weight is connected to the grid-type energy storage; after the connection, when the charging power duration index or the charging remaining capacity duration index reaches the minimum value, the output of the distributed power source and the capacity configuration range of the grid-type energy storage are adjusted; with the goal of maximizing both the power balance duration index and the power balance duration index, the load distribution connected to the grid-type energy storage is determined according to the adjusted distributed power output and the capacity configuration range of the grid-type energy storage; In the embodiment, if the zero value criterion is triggered (discharge power or remaining capacity exceeds the limit), high-weight loads (such as primary loads) are preferentially connected directly to the grid-type energy storage to form an independent island to ensure power supply to critical loads; if the minimum value criterion is triggered (charging power or remaining capacity exceeds the limit), the output of distributed power sources is adjusted (such as reducing the wind and solar power abandonment rate), and the energy storage charging period is reallocated to optimize energy utilization; according to the principle of maximizing the power balance duration indicator and the power balance duration indicator, the island boundary is dynamically adjusted to ensure the timing matching of energy storage charging and discharging with load demand.

[0083] In the embodiment, topology connectivity verification is also performed to verify the connectivity between the nodes in the island and the grid-forming energy storage, to ensure that the island topology is a radial structure, and to avoid circulating current or voltage exceeding the limit problem.

[0084] The determined capacity configuration range and load distribution of the grid-type energy storage in each island are used as the input parameters and initial conditions of the MILP optimization model to solve the optimal capacity configuration plan; and the relevant indicators are converted into dynamic constraints of the optimization model to ensure that the configuration plan matches the actual operation requirements.

[0085] Among them, the input-output method is used to determine the weight of each load, including: The power loss load value model is an electricity value model that uses the input-output method. For the civil power industry, the produced electricity must first be transmitted through substations, and then distributed to various production departments through transmission equipment. Through the input-output method, the relationship between the input and output of different production departments can be linked to determine the value of electricity, and the value of electricity can be linked to the load weight to determine the weight.

[0086] The value of electricity consumption includes the direct value of electricity generation and the indirect value of electricity generation, which satisfies the following relationship:

[0087] In the formula, For the The total value of electricity production in each sector, For the The direct value of electricity generated by each sector, For the the indirect value of electricity generated by each sector;

[0088] In the formula, For the The output value added of each sector, For the The amount of electricity consumed by each department;

[0089]

[0090] In the formula, is the total output of the electricity sector, For The corresponding total electricity output value is is the direct consumption coefficient, which indicates the consumption of the first The intermediate inputs of the sector, For the The value added rate of a sector, which means that the value added rate is the ratio of value added to gross output.

[0091] The power value and load weight of each industry are calculated, as shown in Table 1. The load weight is based on the production and supply of electricity, heat and water, and the load weight is set to 1. The load weights of other industries are reduced by this multiple to obtain the load weights of each industry.

[0092] Table 1 Production load power value and load weight

[0093] Step 3, taking the maximum restored load, the maximum weighted sum of restored loads, the minimum system network loss and the minimum number of switch operations as the objective function, the connectivity constraint, the current and voltage constraint, the branch power constraint, the grid-type energy storage constraint and the island division index system constitute the joint constraint condition; based on the 0 / 1 knapsack theory, the objective function and the joint constraint condition are used to form an optimization model; taking the determined capacity configuration range of the grid-type energy storage in the island and the load distribution as input parameters, the optimization model is iteratively solved to obtain the active distribution network grid-type distributed energy storage capacity configuration optimization plan.

[0094] From the perspective of economy and importance, important loads should be restored as much as possible after an accident caused by a disaster. In the distribution network, due to the access of grid-type energy storage, an island operation condition is formed. The power outage area should be minimized to ensure the continuous power supply of key loads and minimize the impact of disasters in order to achieve the purpose of optimizing the island division. The goals of distribution network fault reconstruction include maximizing load recovery, minimizing system network losses, and minimizing the number of switches; therefore, the present invention proposes a MILP optimization model for island division based on the improved 0 / 1 knapsack theory.

[0095] Specifically, the restored load is the load whose power supply is restored after the island division, and the weighted sum of the restored loads satisfies the following relationship:

[0096] In the formula, To restore the maximum value of the weighted sum of loads, For the The load collection of an isolated island, For load The state variables, Indicates load On the isolated island, It means load Not on an isolated island, For load The weight of For load Power; In the embodiment, the weight of the load corresponding to the production and supply of electricity, heat and water is 1, and the input-output method is used to calculate the load. The industry to which the load belongs determines the load The weight of Specifically, the minimum system network loss satisfies the following relationship:

[0097] In the formula, To minimize the system network loss, For connected A collection of branches, and Branch The active power and reactive power of For branch The resistance, For branch Voltage; Specifically, the number of switch operations at least satisfies the following relationship:

[0098] In the formula, To minimize the number of switching operations, In the failover region A set of switches, Switch before failure recovery The state of the switch is 1, which means the switch is closed, and 0, which means the switch is open. Switch after failure recovery The state of the switch is 1, which means the switch is closed, and 0, which means the switch is open.

[0099] The joint constraints are composed of connectivity constraints, current and voltage constraints, branch power constraints, grid-type energy storage constraints and island division index system, including: 1) Connectivity constraint: According to the radial network structure of the distribution network system, from the perspective of energy and power balance, there is at least one path connecting the node formed by each island to the distributed power node. The connectivity is constrained by the power flow on the lines at both ends of the node. When the grid-type distributed power source is connected to the island, its access point is the root node. In order to ensure the success of power supply, all the nodes it includes must be connected to the root node to satisfy the following relationship:

[0100] 2) Current and voltage constraints: The divided islands must make the actual current of the transformer and transmission line less than their corresponding rated current, satisfying the following relationship:

[0101] In the formula, is the maximum current on the line and transformer, is the rated current on the line and transformer; The voltage fluctuation range is generally required to be ±5%. Voltage that is too high or too low will have a negative impact and satisfy the following relationship:

[0102] In the formula, For the Real-time voltage of bus segment; is the rated voltage of the busbar.

[0103] 3) Branch power constraints:

[0104] In the formula, For branch At the moment Active power of For branch The maximum active power.

[0105] 4) Convert the island division index system into the following constraints:

[0106] In the formula, For the The load collection of an isolated island, For the The total charging and discharging power of the grid-type distributed energy storage in each isolated island, For the Load in an island The power, For the The total power of all loads in an island;

[0107] In the formula, It is the power balance duration indicator of grid-type energy storage within the fault outage duration. For the The distributed storage system in the isolated island can The total charge and discharge power, For the The total capacity of the grid-type distributed energy storage in each island, It is the available state of charge of grid-type energy storage;

[0108] In the formula, and They are the maximum and minimum values ​​of the available state of charge of the grid-type energy storage respectively;

[0109] In the formula, For the The maximum total capacity of the distributed energy storage network in each island is: It is the electricity balance duration indicator of grid-type energy storage within the duration of fault power outage. For the Distributed power generation moment in an island Total output of

[0110] In the formula, Provide margin for island safety operation.

[0111] In the present invention, the constraint conditions established based on the island division index system take the charging and discharging capacity of the distributed grid-type energy storage as a new constraint, and add the charging and discharging power limit and the energy storage capacity limit in the optimization model to achieve the purpose of optimizing the utilization rate of the grid-type energy storage, reducing load losses and improving the stability of energy storage. In the prior art, the charging and discharging power limit and the energy storage capacity limit are usually static constraints (setting the maximum charging and discharging power or capacity threshold), and only focus on the instantaneous value or total amount limit. The indicators proposed by the grid-type energy storage constraint are dynamic time series statistical indicators. These indicators dynamically capture the energy storage operation status through high-frequency sampling (detecting power every minute and detecting the remaining power every 15 minutes), and quantify it into constraints in the time dimension. This dynamic constraint can more accurately reflect the actual operating characteristics of the energy storage system during a fault, rather than simply relying on instantaneous values ​​or total amount limits. This constitutive grid-type energy storage constraint further combines the above indicators with the power balance duration indicator and the power balance duration indicator to form a multi-dimensional constraint system. Safety: through the discharge power duration indicator and the discharge remaining capacity duration indicator, ensure that the power and power do not exceed the safety threshold during energy storage discharge; Economy: through the charging power duration indicator and the charging remaining capacity duration indicator, avoid energy waste during charging; Stability: through the power and power balance duration indicators, ensure the dynamic balance of energy storage charging and discharging during island operation. Stability constraint: through the power and power balance duration indicators, ensure the dynamic balance of energy storage charging and discharging during island operation. This multi-indicator collaborative constraint mechanism solves the one-sidedness of the optimization target caused by a single constraint in the existing technology (such as only considering power or capacity), and achieves comprehensive optimization of safety, economy, and stability.

[0112] The 0 / 1 knapsack problem is to give a knapsack with limited capacity and a series of items, each with weight and value. The goal is to select items to maximize the total value without exceeding the capacity of the knapsack. In the island partitioning application, the capacity of the knapsack corresponds to the remaining power or power of the grid-type energy storage. The items correspond to different loads, and their "weight" refers to the power demand of the load, while the "value" refers to the priority or importance of the load. In the planning scheme of grid-type distributed energy storage based on the results of island division, the capacity of grid-type energy storage and load power do not always appear in integer form, but often have decimal parts. The 0 / 1 knapsack problem belongs to the category of integer programming in dynamic programming, and can obtain integer solutions for the capacity configuration of grid-type distributed energy storage; in the planning scheme of grid-type distributed energy storage based on the results of island division, for any load, if it is divided into a certain island, then all loads and branches on the path from the load to the grid-type energy storage are included in this island, that is, the connectivity constraint problem of the network within the island. When the load is divided into the island, the current needs to form a path between all nodes within the entire island, but the 0 / 1 knapsack theory fails to solve the connectivity constraint problem of the network within the island. The 0 / 1 knapsack model mainly focuses on isolated "points", while the mathematical model of island division not only considers each independent "point", but also needs to take into account the connection relationship between "points" and "points" on this basis. Therefore, the traditional 0 / 1 knapsack problem cannot be used to solve the island division problem. It is necessary to make new adjustments and improvements to the distribution network parameters and network structure containing distributed power sources and grid-type energy storage based on the 0 / 1 knapsack theoretical model. The improvement strategies are as follows: (1) Take integers for input parameters: In the process of island partitioning, since there may be decimal parts in the grid-type energy storage capacity and load power, the capacity dimension needs to be discretized when using dynamic programming. Take integers for values ​​such as load, load weight, distributed power source, and grid-type energy storage capacity. Because these power values ​​are relatively large and have low sensitivity to decimals, integer processing will not affect the final model solution partitioning results; you can set a suitable accuracy , multiply the capacity value by Convert to an integer, perform the calculation, and then convert the result back to an actual value.

[0113] (2) Restoring power supply according to load weight: Add automation devices between the nodes corresponding to the load to cooperate with the improved 0 / 1 backpack theoretical model. In the island, there is a tree-like line with nodes A, B, and C distributed on it in sequence. When performing the restoration operation, the improved 0 / 1 backpack theoretical method is used for analysis. The analysis results show that the loads connected to nodes A and C can meet the restoration conditions, but node B in the middle position fails to meet the restoration standard due to its low importance level coefficient. At this time, nodes A, B, and C are in the same line. When the current flows through node B, according to the established island division scheme, the distribution network automation device will receive the corresponding signal and block the switch between node B and the load connected to it. In this way, point B only serves as a path point for the current to pass, ensuring that nodes A, C and other similar loads with high importance level coefficients can restore power supply first. Through this series of operations, the total weighted value of the load in the island is finally maximized according to a specific function.

[0114] By improving the 0 / 1 knapsack theory, it is convenient to adopt the mixed integer linear programming (MILP) method and establish an optimization model using the objective function and joint constraints; taking the determined capacity configuration range of the grid-type energy storage in the isolated island and the load distribution as input parameters, the optimization model is iteratively solved to obtain the capacity configuration optimization scheme of the active distribution network grid-type distributed energy storage.

[0115] The present invention also proposes an active distribution network type distributed energy storage capacity configuration optimization system, comprising: The data acquisition and processing module is used to obtain the duration of power outage, the output power of each distributed power source, and the power demand of the power-off load in the system when the system fails, so as to determine the power and remaining power of the grid-type energy storage; The island division module is used to establish an island division index system for the active distribution network within the duration of the fault power outage, including: the discharge power duration index, the discharge remaining capacity duration index, the charging power duration index, the charging remaining capacity duration index, the power balance duration index, and the power balance duration index of the grid-forming energy storage; based on the island division index system, the capacity configuration range and load distribution of the grid-forming energy storage in each island in the active distribution network are determined; The capacity configuration optimization module is used to take the maximum restored load, the maximum weighted sum of restored loads, the minimum system network loss and the minimum number of switch operations as the objective function, and to form joint constraints with connectivity constraints, current and voltage constraints, branch power constraints, grid-type energy storage constraints and island division index system; based on the 0 / 1 knapsack theory, an optimization model is established using the objective function and joint constraints; with the determined capacity configuration range of the grid-type energy storage in the island and the load distribution as input parameters, the optimization model is iteratively solved to obtain the capacity configuration optimization plan for the active distribution network grid-type distributed energy storage.

[0116] The feasibility and effectiveness of the present invention are verified by MATLAB. Using IEEE 33-node power distribution system data, MATLAB software is used for modeling and analysis. The IEEE 33-node power distribution system parameters used for modeling are shown in Table 2. The distribution network line planning is shown in Table 2. Figure 2 shown.

[0117] Table 2 IEEE33 node distribution system parameters

[0118] The load node size and weight obtained by the input-output method are shown in Table 3. According to Table 3, the total load capacity of the distribution network can be calculated to be 6.6MVA, and the total capacity of the two grid-type distributed generation sources added together should be 1.65MVA according to the constraints.

[0119] Table 3 Distribution network load node types and their load weights

[0120] The MILP model for optimizing the capacity configuration of distributed generation in the distribution network is used for calculation. The four DG recovery node division schemes are shown in Table 4. The simulation results of MATLAB are as follows: Table 4 Results of four DG recovery node division schemes

[0121] Figure 3 This is the division scheme of DG25 & DG18 in the embodiment of the present invention. Figure 4 This is the division scheme of DG25 & DG15 in the embodiment of the present invention. Figure 5 This is the division scheme of DG25 & DG26 in the embodiment of the present invention. Figure 6 This is the division scheme of DG25 & DG28 in the embodiment of the present invention.

[0122] Four grid-type distributed power capacity optimization allocation schemes are shown in Table 5: Table 5 Results of four DG capacity allocation schemes

[0123] Through the analysis of Table 5, it can be concluded that when Scheme 1 and Scheme 2 are selected, the total capacity of the two grid-type distributed power sources is 1.65MVA; when Scheme 3 and Scheme 4 are selected, the total capacity of the two grid-type distributed power sources is 1.64MVA. In terms of the total weight of the load that the grid-type power source can restore, the total weight of the load node of Scheme 3 is 30.077. Compared with the other three schemes, this scheme has the largest value, and the total capacity of the power source is lower than that of Scheme 1 and Scheme 2. Finally, the analysis shows that Scheme 3 is the optimal MILP optimization configuration scheme for the grid-type distributed power source of the distribution network.

[0124] It can be seen that the method proposed in the present invention solves the problem of optimal access position and capacity allocation of distributed power sources in the distribution network. By reasonably configuring the access position and capacity of the power source, the power capacity is fully utilized, and the island emergency supply capability of the distributed power source in the distribution network is better utilized. The disaster resistance and mitigation capabilities of the distribution network under extreme disasters and the resilience of the power system itself are comprehensively improved. It has the characteristics of fast calculation time and strong applicability, as follows: (1) Fast calculation time: The model of the present invention uses mixed integer linear programming, which is a mathematical model applied to optimization problems. The decision variables involved include both integer variables and continuous variables. It has more advantages in solving problems containing binary variables and some decision variables. It can quickly solve the model and obtain the island planning and grid-type distributed power planning solutions of the distribution network.

[0125] (2) Strong applicability: The model of the present invention can adapt to different scenario requirements through the input-output method. This method comprehensively considers the economic benefits and load levels of different load points, restores more important loads as much as possible, reduces the scope of power outages in the distribution network, and reduces the losses caused by power outages. It has wide applicability.

[0126] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0127] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above. More specific examples (a non-exhaustive list) of computer-readable storage media include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the above. The computer-readable storage medium used herein is not to be interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0128] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0129] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect through the Internet). In some embodiments, by using the state information of the computer-readable program instructions to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit may execute the computer-readable program instructions, thereby implementing various aspects of the present disclosure.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing the configuration of distributed energy storage capacity in an active distribution network, characterized in that: include: When a system fails, the duration of the power outage, the output power of each distributed power source, and the power demand of the power-off load in the system are obtained to determine the power and remaining power of the grid-forming energy storage; using the power and remaining power of the grid-forming energy storage, an island-based division index system for the active distribution network during the power outage duration is established to determine the capacity configuration range and load distribution of the grid-forming energy storage in each island in the active distribution network; Taking the maximum restored load, the maximum weighted sum of restored loads, the minimum system network loss and the minimum number of switch operations as the objective function, the connectivity constraint, current and voltage constraint, branch power constraint, grid-type energy storage constraint and island division index system constitute the joint constraint conditions; based on the 0 / 1 knapsack theory, the optimization model is established using the objective function and the joint constraint conditions; taking the determined capacity configuration range of the grid-type energy storage in the island and the load distribution as input parameters, the optimization model is iteratively solved to obtain the capacity configuration optimization scheme of the grid-type distributed energy storage in the active distribution network.

2. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 1, characterized in that: Fault power outage duration satisfy , is the fault start time, is the fault recovery time; The power of grid-type energy storage satisfies the following relationship: In the formula, For the moment The power of grid-type energy storage, For the moment The output power of distributed power generation, For the moment The power demand of the power-off load in the system, Power outage duration Moments within; when When When , the grid-type energy storage discharges; The remaining power of the grid-type energy storage satisfies the following relationship: In the formula, For the moment The remaining power of the grid-type energy storage, The fault start time The amount of electricity used for grid-type energy storage.

3. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 2, characterized in that: The island division index system includes: the discharge power duration index, the discharge remaining capacity duration index, the charging power duration index, the charging remaining capacity duration index, the power balance duration index, and the power balance duration index of the grid-type energy storage.

4. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 3 is characterized in that: The discharge power duration index of grid-type energy storage satisfies the following relationship: In the formula, It is the discharge power duration index of the grid-type energy storage within the fault outage duration. is the charging and discharging power sampling time interval, is the discharge power indicator, The total number of sampling moments of the charge and discharge power during the fault power outage duration; Satisfies the following relationship: Satisfies the following relationship: In the formula, is the discharge power sampling value, is the maximum discharge power.

5. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 4, characterized in that: The discharge residual power index of grid-type energy storage satisfies the following relationship: In the formula, It is the discharge remaining capacity indicator of the grid-type energy storage within the fault power outage duration. is the remaining power sampling time interval, It is the mark of the remaining discharge capacity. The total number of sampling times of the remaining charge and discharge power during the fault power outage duration; Satisfies the following relationship: Satisfies the following relationship: In the formula, is the remaining power sampling value, The minimum remaining power.

6. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 5, characterized in that: The charging power duration index of grid-type energy storage satisfies the following relationship: In the formula, It is the charging power duration indicator of the grid-type energy storage within the fault power outage duration. It is the charging power indicator; Satisfies the following relationship: In the formula, is the charging power sampling value, The maximum charging power.

7. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 6, characterized in that: The remaining charge capacity index of the grid-type energy storage satisfies the following relationship: In the formula, It is the charging remaining capacity indicator of the grid-type energy storage within the duration of the fault power outage. It is the mark of the remaining power of charging; Satisfies the following relationship: In the formula, is the remaining power sampling value, The maximum value of remaining power.

8. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 7, characterized in that: The power balance duration indicator satisfies the following relationship: In the formula, It is an indicator of the power balance duration of grid-type energy storage within the duration of a fault power outage.

9. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 8, characterized in that: The power balance duration indicator satisfies the following relationship: In the formula, It is an indicator of the electricity balance duration of grid-type energy storage within the duration of a fault power outage.

10. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 1, characterized in that: When the discharge power duration index or the discharge remaining capacity duration index of the grid-type energy storage reaches zero, the load with the largest weight is connected to the grid-type energy storage; after the connection, when the charging power duration index or the charging remaining capacity duration index reaches the minimum value, the output of the distributed power source and the capacity configuration range of the grid-type energy storage are adjusted; with the goal of maximizing both the power balance duration index and the power balance duration index, the load distribution connected to the grid-type energy storage is determined according to the adjusted distributed power output and the capacity configuration range of the grid-type energy storage.

11. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 10, characterized in that: The weight of the load corresponding to the production and supply of electricity, heat and water is 1, and the input-output method is used to determine the weight of the load according to the industry to which the load belongs.

12. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 1, characterized in that: The maximum weighted sum of the recovery loads satisfies the following relationship: In the formula, To restore the maximum value of the weighted sum of loads, For the The load collection of an isolated island, For load The state variables, Indicates load On the isolated island, It means load Not on an isolated island, For load The weight of For load Power; The minimum system network loss satisfies the following relationship: In the formula, To minimize the system network loss, For connected A collection of branches, and Branch The active power and reactive power of For branch The resistance, For branch Voltage; The minimum number of switch operations satisfies the following relationship: In the formula, To minimize the number of switching operations, In the failover region A set of switches, Switch before failure recovery The state of the switch is 1, which means the switch is closed, and 0, which means the switch is open. Switch after failure recovery The state of the switch is 1, which means the switch is closed, and 0, which means the switch is open.

13. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 1, characterized in that: The island division index system is transformed into the following constraints: In the formula, For the The load collection of an isolated island, For the The total charging and discharging power of the grid-type distributed energy storage in each isolated island, For the Load in an island The power, For the The total power of all loads in an island; In the formula, It is the power balance duration indicator of grid-type energy storage within the fault outage duration. For the The distributed storage in the isolated island can The total charge and discharge power, For the The total capacity of the grid-type distributed energy storage in each island, It is the available state of charge of grid-type energy storage; In the formula, and They are the maximum and minimum values ​​of the available state of charge of the grid-type energy storage respectively; In the formula, For the The maximum total capacity of the distributed energy storage network in each island is: It is the electricity balance duration indicator of grid-type energy storage within the duration of fault power outage. For the Distributed power generation moment in an island Total output of In the formula, Provide margin for island safety operation.

14. The method for optimizing the configuration of distributed energy storage capacity in an active distribution network according to claim 1, characterized in that: Improvements are made to the 0 / 1 backpack theory, including taking integers for input parameters and restoring power supply according to load weights.

15. An active distribution network type distributed energy storage capacity configuration optimization system, characterized in that: include: The data acquisition and processing module is used to obtain the duration of power outage, the output power of each distributed power source, and the power demand of the power-off load in the system when the system fails, so as to determine the power and remaining power of the grid-type energy storage; The island division module is used to establish an island division index system for the active distribution network within the duration of the fault power outage, including: the discharge power duration index, the discharge remaining capacity duration index, the charging power duration index, the charging remaining capacity duration index, the power balance duration index, and the power balance duration index of the grid-forming energy storage; based on the island division index system, the capacity configuration range and load distribution of the grid-forming energy storage in each island in the active distribution network are determined; The capacity configuration optimization module is used to take the maximum restored load, the maximum weighted sum of restored loads, the minimum system network loss and the minimum number of switch operations as the objective function, and to form joint constraints with connectivity constraints, current and voltage constraints, branch power constraints, grid-type energy storage constraints and island division index system; based on the 0 / 1 knapsack theory, an optimization model is established using the objective function and joint constraints; with the determined capacity configuration range of the grid-type energy storage in the island and the load distribution as input parameters, the optimization model is iteratively solved to obtain the capacity configuration optimization plan for the active distribution network grid-type distributed energy storage.

16. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 14.

17. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 14 are implemented.

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