Load transfer method suitable for 10kV-110kV power grid

Abstract

The invention provides a load transfer method suitable for a 10kV-110kV power grid, and the method comprises the steps: obtaining power grid model information, operation mode information and equipment parameter information in real time, and building an initial section for fault recovery analysis; aiming at the fault conditions of different levels of equipment, generating a load transfer scheme by adopting a layered and partitioned recovery load transfer method, and carrying out fault recovery power supply; establishing a constraint matrix based on a fault recovery algorithm of a critical path algorithm, and performing feasibility verification on the generated load transfer scheme so as to select the load transfer scheme; and for the selected load transfer scheme, in combination with a multi-target fault recovery algorithm, constructing a fault recovery model, optimizing the fault recovery model, and determining an optimal load transfer scheme. According to the invention, research and optimization of the load transfer method suitable for the 10kV-110kV power grid are provided, and the stability and reliability of power supply are guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of power system automation, and in particular relates to a load transfer method suitable for 10kV to 110kV power grids. Background Art

[0002] With the continuous growth of electricity demand and the increasing complexity of the power grid structure, the power system needs to quickly and accurately formulate and implement load transfer plans when facing equipment failures, planned power outages or load fluctuations to ensure the continuity and stability of power supply. Traditional load transfer plans often rely on manual experience judgment and lack intelligent and automated support, resulting in low efficiency of load transfer and long recovery time when the power grid fails, and it is difficult to ensure the stability and economy of the power grid after the transfer. In addition, with the opening of the power market and the diversification of power users' needs, load characteristics have become more complex and changeable, and traditional load transfer plans can no longer meet the needs of modern power grids. Therefore, an efficient and intelligent load transfer plan and optimization method are particularly important. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a load transfer method suitable for 10kV to 110kV power grids, aiming to solve the problem that when a power grid fails, the load transfer efficiency is low, the recovery time is long, and it is difficult to ensure the stability of the power grid after the transfer due to the lack of intelligent and automated support in response to manual experience judgment.

[0004] In a first aspect, an embodiment of the present invention provides a load transfer method applicable to a 10 kV to 110 kV power grid, comprising the following steps:

[0005] S1. Obtain the grid model information, operation mode information and equipment parameter information in real time, and establish the initial section for fault recovery analysis;

[0006] S2. According to the fault conditions of equipment at different levels, a load transfer method of hierarchical and partitioned recovery is adopted to generate a load transfer plan and perform fault recovery power supply;

[0007] S3. Based on the fault recovery algorithm of the critical path algorithm, a constraint matrix is ​​established, and the feasibility of the generated load transfer scheme is verified, so as to select the load transfer scheme;

[0008] S4. For the selected load transfer scheme, a fault recovery model is constructed and optimized in combination with a multi-objective fault recovery algorithm to determine the optimal load transfer scheme.

[0009] Preferably, the acquired information includes primary equipment model, standby automatic transfer model, remote signaling, remote measurement, equipment parameters, and connection relationship.

[0010] Preferably, S2 further includes:

[0011] Monitor fault diagnosis results in real time, exchange information using message messages, and automatically start fault recovery analysis after receiving fault alarms;

[0012] Read the real-time power grid section and find the power outage scope affected by the faulty equipment, including the power plant, power outage equipment and lost load;

[0013] According to the obtained power outage range results, automatically search for available power points outside the area;

[0014] Combined with the power supply point and the loss load, find the power supply path, mark the operable switch sequence, adjust the operation mode, and provide the operation steps of the load transfer plan;

[0015] According to different operation steps, analyze the transfer plant and transfer branch of the power source point, use the topological flow to analyze the load rate index of the transfer path, consider the feasibility of the load transfer plan, and determine the operation steps and evaluation information of the load transfer plan.

[0016] Preferably, the key path algorithm in S3 is specifically:

[0017] After the fault isolation operation is completed, a sound area that needs to be transferred is formed;

[0018] Check whether the current single power supply path can meet the power supply needs of the healthy area.

[0019] If yes, a critical path is generated. If no, a full-path fault recovery and reconstruction solution is generated for the healthy area according to the constraints of the power supply path.

[0020] Perform power supply capacity verification on all generated reconstruction schemes, generate a load shedding operation step sequence and scheme attributes based on the verification results, and further generate a critical path, where the scheme attributes include the total load shedding capacity, load balancing value, and the number of operation steps;

[0021] According to the generated critical path, the final fault recovery reconstruction operation steps are generated, the final operation steps are written into the database, and the fault recovery reconstruction is completed.

[0022] Preferably, the step S3 establishes a constraint matrix and performs a feasibility check on the generated load transfer scheme, and further includes:

[0023] A path constraint matrix is ​​established based on the power supply rules in the network topology, and the key paths of each node are dynamically constrained, and the power supply capacity is verified and the load shedding operation is optimized.

[0024] Preferably, the method for verifying power supply capacity is that different trunk connection nodes may be powered by different transfer power supply nodes; for each transfer power supply path node, its available capacity is compared with the sum of the node load values ​​of all the trunk connection nodes it carries; when the sum of the node load values ​​exceeds the available capacity of the transfer power supply path node, the scheme is determined to be a scheme with insufficient power supply capacity.

[0025] Preferably, the method for optimizing the generation of load shedding operation is:

[0026] Accumulate the attached load node queues of all the trunk line connection nodes on the transfer power path node with insufficient power supply capacity in the load distribution plan to form a transfer power load node queue;

[0027] According to the sorting principle, the loads are arranged one by one according to their importance level, and the load queues with the same importance level are arranged one by one according to the load size;

[0028] According to the ordered load queue, add load nodes of the load shedding queue one by one starting from 0 until the power supply capacity of the transferred power supply load node meets the demand;

[0029] The same calculation is performed on other transfer power path nodes with insufficient power supply capacity in the load distribution scheme, and finally the overall load shedding node queue and the total load shedding amount of the load distribution scheme are generated;

[0030] According to the transfer capacity after load shedding, the load rate of the power supply equipment corresponding to each transfer power path node is generated, and the sample variance of the load rate is calculated as the load balancing value of the load distribution plan and the number of operation steps of each load distribution plan is calculated to complete the information generation of the power supply restoration plan;

[0031] Sort by preferred conditions and determine the best solution.

[0032] Preferably, the fault recovery model of S4 also includes an objective function and constraints.

[0033] The objective function is:

[0034]

[0035]

[0036] In the formula, λ 1 , 2 , 3 They represent the weight coefficients of load recovery, load priority and number of switch operations respectively; W i Indicates whether load i is on, if on, it is 1, otherwise, it is 0; P i Represents the active power of load i; C iIndicates the number of switch operations required for load i to be put into operation; N X Indicates the Xth load, W q(k) represents the importance coefficient of load K, is the weight factor, if W q(k) >W q(k+j) ,but If W q(k) <W q(k+j) ,but

[0037] Branch capacity constraints:

[0038] P i ≤P i.max

[0039] Where P i is the calculated value of branch capacity, P i.max is the branch capacity limit;

[0040] Node voltage constraints:

[0041] V i.min ≤V i ≤V i.max

[0042] Where V i.min , V i.max are the maximum and minimum values ​​of the grid node voltage allowable range, V i is the grid node voltage;

[0043] Network topology constraints: After fault recovery, the power grid maintains a radial operation mode.

[0044] The embodiments of the present invention bring the following beneficial effects:

[0045] The present invention realizes fast and efficient load transfer for equipment failures at different levels under multiple constraints by acquiring grid information in real time, intelligently analyzing the impact range of faults, optimizing load transfer plans, etc., thereby improving the efficiency and stability of power supply restoration of the grid and reducing the risk of power outages for users.

[0046] The present invention reduces the divergence of power supply schemes, reduces calculation time and improves processing efficiency through the critical path method algorithm and dynamic constraints. At the same time, through feasibility verification and scheme optimization, the optimality of the selected scheme in terms of power supply capacity, load balancing degree and number of switch operations is guaranteed, thereby improving the stability and recovery effect of the power grid.

[0047] Other features and advantages of the present invention will be described in the following description, and some features will become apparent from the description or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A flow chart of a load transfer method provided by an embodiment of the present invention;

[0050] Figure 2 A flowchart of a critical path generation algorithm provided by an embodiment of the present invention;

[0051] Figure 3 A regional power grid wiring diagram provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] To facilitate understanding of this embodiment, firstly, a load transfer method applicable to a 10kV to 110kV power grid disclosed in Embodiment 1 of the present invention is described in detail. Figure 1 As shown, including the following:

[0054] S1. Real-time acquisition of power grid model information, operation mode information and equipment parameter information, and establishment of the initial section of fault recovery analysis; wherein the acquired information includes primary equipment model, backup automatic switching model, remote signaling, remote measurement, equipment parameters, and connection relationship. Specifically,

[0055] After receiving the faulty equipment information, update the switch tripping information of the faulty equipment; start the standby automatic switching action analysis on the section after the tripped switch is actuated, and scan the busbars of the entire network; determine whether the busbar measurement information is undervoltage, and if undervoltage, determine the standby automatic switching action status in combination with the standby automatic switching model and action logic in the system, and obtain the switch action information connected to the undervoltage busbar; write the standby automatic switching switch action information, that is, the switch status, into the analysis section, and start the power outage range analysis based on this section; the power outage range analysis starts from the faulty equipment node and combines the power grid flow direction, uses a breadth-first search algorithm to find the power-off area, and marks the equipment on the search path; if a power-off area is determined during the search process, the power-off equipment is searched and the load transfer analysis is started; starting from the power-off load, use a breadth-first search algorithm to search for the hot standby switch on the path, and stop the search on the path after finding the hot standby switch, and obtain the standby power source point of the power-off area to which the load belongs, that is, the hot standby switch; through the comprehensive analysis of the flow calculation and the equipment parameters, evaluate the load rate of the connected equipment after the hot standby switch is put into operation. If it is found that this operation will cause the equipment load to exceed the limit, then exclude this backup power source point.

[0056] S2. According to the fault conditions of equipment at different levels, a load transfer method of hierarchical and partitioned recovery is adopted to generate a load transfer plan and perform fault recovery power supply; specifically,

[0057] Monitor fault diagnosis results in real time, exchange information using message messages, and automatically start fault recovery analysis after receiving fault alarms;

[0058] Read the real-time power grid section and find the power outage scope affected by the faulty equipment, including the power plant, power outage equipment and lost load;

[0059] According to the obtained power outage range results, automatically search for available power points outside the area;

[0060] Combined with the power supply point and the loss load, find the power supply path, mark the operable switch sequence, adjust the operation mode, and provide the operation steps of the load transfer plan;

[0061] According to different operation steps, analyze the transfer plant and transfer branch of the power source point, use the topological flow to analyze the load rate index of the transfer path, consider the feasibility of the load transfer plan, and determine the operation steps and evaluation information of the load transfer plan.

[0062] Furthermore, the load transfer method of hierarchical partition recovery includes an early information search stage, a recovery process stage, a strategy formulation stage, and a solution analysis stage, specifically,

[0063] Preliminary information search stage: Statistics are performed to find power plants affected by the fault; starting from the endpoint of the faulty equipment (load and other terminal equipment are the end points), the topology search is started using the breadth-first search algorithm, and disconnected switches and energized equipment are avoided during the search process. All equipment on the search path is the power-lost equipment; statistics are obtained on the power-lost plants and the loss load information of each power-lost plant; the power-lost plants are sorted by priority, and the sorting strategy includes the size of the loss load, the importance of the plant, etc., allowing manual modification of the recovery order.

[0064] Recovery process stage: determine whether there is a power plant station with lost power. If not, the recovery is completed. If yes, loop through the sorted power plants and stations, and count the power-lost buses of the plants and stations respectively; loop through the busbar equipment in the power grid model, obtain the busbar in the plant station, and determine whether the busbar is the power-lost equipment searched before; sort the power-lost buses in the plant station according to voltage level, and the busbar with a higher voltage level has a higher priority for recovery.

[0065] Strategy formulation stage: starting from the bus equipment endpoint, find the backup power point of the bus; use the breadth-first search algorithm to find the connection switch around the bus, and determine whether the node on the opposite side of the switch is energized. If it is energized, the switch is the backup power point; if the backup power point is put into operation, analyze whether the plant has a pressure-depleted bus. If not, the plant is successfully restored and the recovery strategy of the plant is obtained.

[0066] Scheme analysis phase: put the found hot standby switches into operation, and use the static safety analysis function on the updated power grid section to perform a static risk scan on the power grid after the power transfer to ensure the safe and stable operation of the power grid; decompose the power transfer plan into a switch action sequence to generate an operation plan to assist the dispatching and operating personnel in fault recovery; use power flow calculation and static safety analysis to evaluate the feasibility of the recovery plan.

[0067] S3. Based on the fault recovery algorithm of the critical path algorithm, a constraint matrix is ​​established, and the feasibility of the generated load transfer scheme is verified, so as to select the load transfer scheme; it is necessary to ensure that there is at least one feasible power supply scheme to ensure the validity of the calculation. Specifically,

[0068] A path constraint matrix is ​​established according to the power supply law in the network topology relationship, and the key path of each node is dynamically constrained to reduce the divergence of the power supply plan, reduce the order of magnitude of the generated plan, reduce the calculation time, and perform power supply capacity verification and optimize load shedding operation generation.

[0069] Among them, since the generated scheme only uses the constraints of the critical path and does not evaluate the power supply capacity, etc., it is necessary to perform a feasibility check on the generated load distribution scheme. The feasibility check includes two parts: power supply capacity check and optimized load shedding operation generation. Power supply capacity check is the process of evaluating whether the load distribution scheme meets the power supply capacity of the power grid. Optimized load shedding operation generation is a supplementary calculation for schemes with insufficient power supply capacity, aiming to make the power supply capacity of the transferred power source meet the demand through load shedding operation.

[0070] Furthermore, if Figure 2 As shown, the critical path algorithm is specifically:

[0071] After the fault isolation operation is completed, a sound area that needs to be transferred is formed;

[0072] Check whether the current single power supply path can meet the power supply needs of the healthy area.

[0073] If yes, a critical path is generated. If no, a full-path fault recovery and reconstruction solution is generated for the healthy area according to the constraints of the power supply path.

[0074] Perform power supply capacity verification on all generated reconstruction schemes, generate a load shedding operation step sequence and scheme attributes based on the verification results, and further generate a critical path, where the scheme attributes include the total load shedding capacity, load balancing value, and the number of operation steps;

[0075] According to the generated critical path, the final fault recovery reconstruction operation steps are generated, the final operation steps are written into the database, and the fault recovery reconstruction is completed.

[0076] Furthermore, the method for verifying the power supply capacity is that, in the load distribution scheme, different trunk connection nodes may adopt different transfer power supply nodes for power supply; for each transfer power supply path node, its available capacity is compared with the sum of the node load values ​​of all the trunk connection nodes it carries; when the sum of the node load values ​​exceeds the available capacity of the transfer power supply path node, the scheme is judged to be a scheme with insufficient power supply capacity.

[0077] Further, the method for optimizing the generation of load shedding operation is:

[0078] Accumulate the attached load node queues of all the trunk line connection nodes on the transfer power path node with insufficient power supply capacity in the load distribution plan to form a transfer power load node queue;

[0079] According to the sorting principle, the loads are arranged one by one according to their importance level, and the load queues with the same importance level are arranged one by one according to the load size;

[0080] According to the ordered load queue, add load nodes of the load shedding queue one by one starting from 0 until the power supply capacity of the transferred power supply load node meets the demand;

[0081] The same calculation is performed on other transfer power path nodes with insufficient power supply capacity in the load distribution scheme, and finally the overall load shedding node queue and the total load shedding amount of the load distribution scheme are generated;

[0082] According to the transfer capacity after load shedding, the load rate of the power supply equipment corresponding to each transfer power path node is generated, and the sample variance of the load rate is calculated as the load balancing value of the load distribution plan and the number of operation steps of each load distribution plan is calculated to complete the information generation of the power supply restoration plan;

[0083] Sort by preferred conditions and determine the best solution.

[0084] Among them, the preferred conditions are:

[0085] a. The size of the final load shedding in each power-off area: The smaller the load shedding, the smaller the impact of the scheme on the power-off area and the better the recovery effect.

[0086] b. Load balancing degree: The higher the load balancing degree, the more stable the grid operation will be after restoration, and the less likely new faults will occur.

[0087] c. Number of switch operations: The fewer the number of switch operations, the simpler the implementation of the solution and the smaller the disturbance to the power grid.

[0088] After sorting through the above-mentioned optimal conditions, an optimal large-scale power outage fault recovery solution is finally determined. This solution has achieved the optimal or relatively optimal level in terms of load shedding, load balancing degree and number of switch operations.

[0089] S4. For the selected load transfer scheme, a fault recovery model is constructed in combination with a multi-objective fault recovery algorithm, and the model is optimized to determine the optimal load transfer scheme;

[0090] Among them, by constructing a mathematical model, various factors can be systematically considered, including fault type, location, impact range, recovery objectives and constraints, so as to find the optimal or suboptimal recovery plan.

[0091] Furthermore, the fault recovery model also includes objective functions and constraints.

[0092] The objective function is:

[0093]

[0094] In the formula, λ 1 ,2 , 3 They represent the weight coefficients of load recovery, load priority and number of switch operations respectively; W i Indicates whether load i is on, if on, it is 1, otherwise, it is 0; P i Represents the active power of load i; C i Indicates the number of switch operations required for load i to be put into operation; N X Indicates the Xth load, W q(k) represents the importance coefficient of load K, is the weight factor, if W q(k) >W q(k+j) ,but If W q(k) <W q(k+j) ,but

[0095] Branch capacity constraints:

[0096] P i ≤P i.max

[0097] Where P i is the calculated value of branch capacity, P i.max is the branch capacity limit;

[0098] Node voltage constraints:

[0099] V i.min ≤V i ≤V i.max

[0100] Where V i.min , V i.max are the maximum and minimum values ​​of the grid node voltage allowable range, V i is the grid node voltage;

[0101] Network topology constraints: After fault recovery, the power grid maintains a radial operation mode.

[0102] There are multiple power-off areas in the fault, which are arranged according to the size of the power-off load and restored in order. Through the search, those switch pairs that cannot meet the radial topology constraints are eliminated. Consider those tie switches that are directly connected to the area to be restored at one end and connected to the normal power supply line at the other end. This strategy greatly reduces the search space and reduces the spatial dimension of the switch combination.

[0103] If a set of switches that meet the requirements is found, a power flow calculation is required to check whether this recovery plan can meet the node voltage and branch current constraints. If voltage and current exceed the limit at the same time, the current limit should be given priority. For situations where the constraints are not met, the constraints can be met by dividing the power-off area, adjusting the operation mode of the power-off area, and using multiple contact switches.

[0104] Example 2: Taking the voltage loss event of 10kV I section busbar of 110kV D station caused by the main transformer failure of 20kVA station as an example, Figure 3 Provide explanation.

[0105] Due to the heavy load at the D station, the 10kV busbar backup was automatically locked due to overload, resulting in a loss of voltage on the 10kV I busbar, which in turn caused a large-scale power outage in the downstream distribution network (dashed line part). After the main and distribution coordinated fault handling detected the loss of voltage on the 10kV I busbar:

[0106] Step 1: The system will first analyze and calculate the load that needs to be transferred on the depressurized bus.

[0107] Step 2: The distribution network side will calculate the line that needs to be transferred (such as line #1) and the corresponding switch action sequence (such as opening switch 110 and closing switch 121) based on the information of the voltage-depleted bus and the load to be transferred.

[0108] Step 3: The main grid side verifies the grid status after load transfer.

[0109] Check whether the 10kV busbar standby of station D will be locked due to overload after automatic switching action;

[0110] Will the #1 main transformer at station E exceed the operating limit?

[0111] Step 4: If all verification conditions are met, the system will generate a specific recovery plan, including the switch opening and closing operation sequence (open switch 110, close switch 121, open switch 101, close switch 100).

[0112] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0113] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A load transfer method applicable to 10kV to 110kV power grid, characterized in that: The following steps are involved: S1. Obtain the grid model information, operation mode information and equipment parameter information in real time, and establish the initial section for fault recovery analysis; S2. According to the fault conditions of equipment at different levels, a load transfer method of hierarchical and partitioned recovery is adopted to generate a load transfer plan and perform fault recovery power supply; S3. Based on the fault recovery algorithm of the critical path algorithm, a constraint matrix is ​​established, and the feasibility of the generated load transfer scheme is verified, so as to select the load transfer scheme; S4. For the selected load transfer scheme, a fault recovery model is constructed and optimized in combination with a multi-objective fault recovery algorithm to determine the optimal load transfer scheme.

2. The load transfer method according to claim 1, characterized in that: The acquired information includes primary equipment model, standby automatic switching model, remote signaling, remote measurement, equipment parameters, and connection relationship.

3. The load transfer method according to claim 1, characterized in that: Said S2 further comprises: Monitor fault diagnosis results in real time, exchange information using message messages, and automatically start fault recovery analysis after receiving fault alarms; Read the real-time power grid section and find the power outage scope affected by the faulty equipment, including the power plant, power outage equipment and lost load; According to the obtained power outage range results, automatically search for available power points outside the area; Combined with the power supply point and the loss load, find the power supply path, mark the operable switch sequence, adjust the operation mode, and provide the operation steps of the load transfer plan; According to different operation steps, analyze the transfer plant and transfer branch of the power source point, use the topological flow to analyze the load rate index of the transfer path, consider the feasibility of the load transfer plan, and determine the operation steps and evaluation information of the load transfer plan.

4. The load transfer method according to claim 1, characterized in that: The key path algorithm in S3 is specifically: After the fault isolation operation is completed, a sound area that needs to be transferred is formed; Check whether the current single power supply path can meet the power supply needs of the healthy area. If yes, a critical path is generated. If no, a full-path fault recovery and reconstruction solution is generated for the healthy area according to the constraints of the power supply path. Perform power supply capacity verification on all generated reconstruction schemes, generate a load shedding operation step sequence and scheme attributes based on the verification results, and further generate a critical path, where the scheme attributes include the total load shedding capacity, load balancing value, and the number of operation steps; According to the generated critical path, the final fault recovery reconstruction operation steps are generated, the final operation steps are written into the database, and the fault recovery reconstruction is completed.

5. The load transfer method according to claim 1, characterized in that: The constraint matrix is ​​established in S3, and the feasibility of the generated load transfer scheme is verified, and the following is also included: A path constraint matrix is ​​established based on the power supply rules in the network topology, and the key paths of each node are dynamically constrained, and the power supply capacity is verified and the load shedding operation is optimized.

6. The load transfer method according to claim 5, characterized in that: The method for power supply capability verification is: Different trunk connection nodes may use different transfer power supply nodes for power supply; for each transfer power supply path node, its available capacity is compared with the sum of the node load values ​​of all the trunk connection nodes it carries; when the sum of the node load values ​​exceeds the available capacity of the transfer power supply path node, the plan is judged to be a plan with insufficient power supply capacity.

7. The load transfer method according to claim 5, characterized in that: The method to optimize load shedding operation generation is, Accumulate the attached load node queues of all the trunk line connection nodes on the transfer power path node with insufficient power supply capacity in the load distribution plan to form a transfer power load node queue; According to the sorting principle, the loads are arranged one by one according to their importance level, and the load queues with the same importance level are arranged one by one according to the load size; According to the ordered load queue, add load nodes of the load shedding queue one by one starting from 0 until the power supply capacity of the transferred power supply load node meets the demand; The same calculation is performed on other transfer power path nodes with insufficient power supply capacity in the load distribution scheme, and finally the overall load shedding node queue and the total load shedding amount of the load distribution scheme are generated; According to the transfer capacity after load shedding, the load rate of the power supply equipment corresponding to each transfer power path node is generated, and the sample variance of the load rate is calculated as the load balancing value of the load distribution plan and the number of operation steps of each load distribution plan is calculated to complete the information generation of the power supply restoration plan; Sort by preferred conditions and determine the best solution.

8. The load transfer method according to claim 1, characterized in that: The fault recovery model of S4 also includes an objective function and constraints. The objective function is: Where λ1, λ2, and λ3 represent the weight coefficients of load recovery, load priority, and switch operation times, respectively; W i Indicates whether load i is on, if on, it is 1, otherwise, it is 0; P i Represents the active power of load i; C i Indicates the number of switch operations required for load i to be put into operation; N X Indicates the Xth load, W q(k) represents the importance coefficient of load K, is the weight factor, if W q(k) >W q(k+j) ,but If W q(k) <W q(k+j) ,but Branch capacity constraints: P i ≤P i.max Where P i is the calculated value of branch capacity, P i.max is the branch capacity limit; Node voltage constraints: In i.min ≤V i ≤V i.max Where V i.min , V i.max are the maximum and minimum values ​​of the grid node voltage allowable range, V i is the grid node voltage; Network topology constraints: After fault recovery, the power grid maintains a radial operation mode.

Images