Operation method for maintaining 10kV switch cabinet without power cut in line supported by transferring load in hot-line operation mode in transformer substation

Abstract

The invention relates to the technical field of uninterruptible maintenance, in particular to an operation method for uninterruptible maintenance of a 10kV switch cabinet of a line supported by load transfer in a hot-line operation mode in a transformer substation. The method comprises the following steps: determining the operation condition of a switch cabinet, and checking the states of a bypass switch and an automatic transfer switch ATS of a standby power supply loop device; verifying whether a bypass switch and an automatic transfer switch ATS can bear a load to be transferred or not through the load prediction model, and introducing an equipment wear factor and a gap change factor into the load prediction model for optimization; and after the test is completed, transferring the load from the switch cabinet to be overhauled to a standby loop by using an optimal path selection algorithm. According to the invention, the load transfer capability is evaluated in advance, the stability of the load in the transfer process is ensured by using the optimal path selection algorithm, and the operation method can complete the maintenance of the switch cabinet under the condition of not interrupting the power supply.

Description

Technical Field

[0001] The present invention relates to the technical field of live maintenance, and specifically, to an operation method for non-stop power maintenance of a 10kV switch cabinet supported by transferring load in a substation in a live working manner. Background Art

[0002] In traditional methods, in order to perform necessary maintenance or repair, the power supply of the substation must be cut off, which means that users in the relevant area will experience a period of power outage. Such power outage will not only affect the daily life of residents, but also interfere with the production activities of enterprises, especially those industries with high dependence on electricity, such as manufacturing, data centers, etc.; Conventional power outage maintenance may miss some potential problems, especially when there is not enough load simulation during the maintenance process. In addition, sudden power outage may also cause situations of grid instability, such as voltage fluctuations, frequency changes, etc., which may have a negative impact on the health of the grid; During the power outage maintenance process, there may be potential safety hazards caused by operation errors, especially in a complex power network environment. In addition, the power outage itself may also bring a series of safety problems, such as accidents caused by insufficient lighting. In summary, there is provided an operation method for non-stop power maintenance of a 10kV switch cabinet supported by transferring load in a substation in a live working manner. Summary of the Invention

[0003] The purpose of the present invention is to provide an operation method for non-stop power maintenance of a 10kV switch cabinet supported by transferring load in a substation in a live working manner, so as to solve the problems of long power outage time and grid operation risks caused by maintenance mentioned in the above background art.

[0004] To achieve the above purpose, the present invention aims to provide an operation method for non-stop power maintenance of a 10kV switch cabinet supported by transferring load in a substation in a live working manner, including the following steps: S1. Determine the operation situation of the switch cabinet, and check the states of the bypass switch and the automatic transfer switch ATS of the standby power supply circuit device; S2. Verify whether the bypass switch and the automatic transfer switch ATS can withstand the load to be transferred through a load prediction model, and introduce an equipment wear factor and a clearance change factor into the load prediction model for optimization; S3. After the test is completed, use the optimal path selection algorithm to transfer the load from the switch cabinet to be repaired to the standby circuit; S4. After the load transfer is completed, check the state of the switch cabinet, confirm whether the standby power supply circuit device can be taken out of operation, and use the state estimation model to verify the overall state of the switch cabinet.

[0005] As a further improvement of the present technical solution, in S1, the operating conditions of the switchgear include: the position of the switchgear in the substation, the surrounding environment of the switchgear, and the electrical connection condition of the switchgear.

[0006] As a further improvement of the present technical solution, it is characterized in that: in S2, to verify whether the bypass switch and the automatic transfer switch ATS can withstand the load about to be transferred through the load prediction model, the following steps are included: S2.1. Collect the load data in the current system and determine the specific value of the load to be transferred; S2.2. Obtain the rated current and maximum load capacity of the bypass switch and the automatic transfer switch ATS; S2.3. Use the historical load data to establish a load prediction model, update the load prediction model with the real-time load data, predict the upcoming load change, and optimize the load prediction model by combining the equipment wear factor and the clearance change factor; S2.4. Calculate the maximum load value about to be transferred according to the historical data and the real-time load prediction, and determine whether this load value is less than the rated load capacity of the bypass switch and the automatic transfer switch ATS.

[0007] As a further improvement of the present technical solution, in S2.3, the load prediction model is: ; Estimate the wear factor using the real-time wear data and the historical data : ; Estimate the clearance change factor of the equipment according to the monitored clearance change data : ; Among them, represents the initial clearance, represents the sensitivity factor, represents the influence factor of the load power on the clearance increase, represents the influence factor of the current on the clearance increase; Combined with the wear factor and the clearance change , optimize the load prediction model: ; Among them, represents the attenuation factor of the equipment wear; represents the weight factor of the clearance change.

[0008] As a further improvement of this technical solution, in step S3, an optimal path selection algorithm is used to transfer the load from the switchgear to be overhauled to the standby circuit, including the following steps: S3.1. According to the electrical connection conditions inside and around the substation, construct a network diagram and set an objective function to minimize the voltage fluctuation and current imbalance during the transfer process. Since the wet-bulb temperature affects the load, optimize the objective function and introduce the maximum allowable value of voltage and the maximum allowable value of current into the objective function to obtain the objective function ; S3.2. Calculate the best path from the switchgear to be overhauled to the standby circuit through the nearest path algorithm of the switchgear; S3.3. Use simulation software to simulate the environment and gradually transfer the load according to the calculated best path. After each load transfer, recalculate the objective function , and ensure that the voltage and current parameters are within the safe range by monitoring the system status with instruments; S3.4. Formulate actual load transfer steps according to the simulation results and execute them according to the steps, transferring the load in stages and batches, and only transferring a part of the load each time.

[0009] As a further improvement of this technical solution, in step S3.1, the objective function is: ; Since the wet-bulb temperature affects the load, the objective function is optimized to: ; When the expected transferred load is close to the rated load capacity of the bypass switch and the automatic transfer switch ATS equipment and the substation is in a high-humidity environment, introduce the maximum allowable value of voltage and the maximum allowable value of current into the objective function to keep the voltage and current within the safe range: ; Among them, represents the objective function; represents the objective function after introducing the wet-bulb temperature; represents the objective function after keeping the voltage and current within the safe range; represents the weight factor of voltage fluctuation; represents the weight factor of current imbalance; represents the number of switchgears; represents the index of the number of switchgears; represents the th voltage of the switchgear; represents the average voltage; represents the th current of the switchgear; represents the average current; The weighting factor indicating the influence of the wet-bulb temperature; Indicating the wet-bulb temperature Function of the influence Indicating the wet-bulb temperature; Indicating the penalty factor; Indicating the maximum allowable value of the voltage; Indicating the maximum allowable value of the current.

[0010] As a further improvement of this technical solution, in the said S3.2, the optimal path from the switchgear to be overhauled to the standby circuit is calculated through the nearest path algorithm of the switchgear cabinet, including the following steps: S3.21. Take the switchgear cabinet to be overhauled as the starting point and the standby circuit as the ending point; S3.22. Create a priority queue and a set, create a distance dictionary for each node in the network diagram, and initialize the distances of all nodes to infinity, except that the distance of the starting point is set to 0; S3.23. Select the node with the smallest distance in the priority queue from the set of unvisited nodes. For all neighbor nodes of the selected node, calculate the distance from the starting point through the selected node to the neighbor node. If this path is shorter, update the distance of the neighbor node; S3.24. Mark the selected node as visited and remove it from the set of unvisited nodes; S3.25. When the node of the standby circuit is visited, stop the iteration. If the node of the standby circuit is not reached, there is no feasible path; S3.26. Create a predecessor dictionary to record the previous node of each node. Starting from the standby circuit, trace back along the predecessor nodes to the starting point, and record each node passed through. The sequence of these nodes forms the optimal path. If there are parallel paths that can be used simultaneously, then allocate the load proportionally according to the weight of each path, and the path with the larger weight bears more load.

[0011] As a further improvement of this technical solution, in the said S4, confirm whether the standby power supply circuit device can be taken out of service, including the following steps: S4.1. Monitor whether the system operation after load transfer is stable and there is no abnormal alarm signal by observing the system operation status through the monitoring system; S4.2. Confirm whether the equipment in the standby circuit is in normal working condition, and check whether the current and voltage in the standby circuit are within the normal range; S4.3. Record the equipment status, current and voltage parameters in the standby circuit; S4.4. Judge whether the load can be switched back from the standby circuit to the original main circuit according to the observed and recorded data. If the equipment and parameters of the standby circuit are normal, exit the standby circuit.

[0012] As a further improvement of this technical solution, in S4, a state estimation model is used to verify the overall state of the switch cabinet, including the following steps: S4.5. Collect the data before and after maintenance, and record the load change before and after maintenance; S4.6. Establish a state estimation model; S4.7. Use the preset initial value m to set the initial state vector of the 10kV switch cabinet state in the power station, and use the switch cabinet residual minimum method to adjust the state vector to minimize the residual between the measured state variable value and the state variable value predicted by the state estimation model; S4.8. Verify the consistency of the state estimation results and confirm whether the working state of the 10kV switch cabinet in the substation meets the expectations.

[0013] As a further improvement of this technical solution, in S4.7, using the switch cabinet residual minimum method to adjust the state vector includes the following steps: S4.71. Use the initial state vector to predict the theoretical value of the switch cabinet through the state estimation model; S4.72. Compare the actually measured data of the switch cabinet with the predicted value of the state estimation model, and calculate the difference between the two; S4.73. Adjust the state vector according to the residual size to make the value predicted by the state estimation model closer to the actually measured value of the switch cabinet, and gradually adjust the state vector until the residual is minimized; S4.74. Repeat the above steps S4.71 to S4.73, continuously adjust the state vector until the residual change amplitude is less than the threshold k, recalculate the residual after each adjustment, and check whether the residual has decreased; S4.75. Use the adjusted state vector to re-predict the system state of the switch cabinet.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. In the operation method for overhauling the 10kV switch cabinet without power interruption of the line supported by transferring the load in the substation in a live working manner, by pre-evaluating the load transfer capacity and using the optimal path selection algorithm to ensure the stability of the load during the transfer process, this operation method can complete the overhaul of the switch cabinet without interrupting the power supply. This not only reduces the risk of service interruption caused by power outage but also improves the reliability of the entire power grid system. Users will not suffer from the interruption of power services due to the overhaul work, thus improving the quality of power services.

[0015] 2. In the operation method for the live maintenance of a 10kV switchgear on a line supported by transferring load in a substation in a live working manner, through detailed load forecasting and real-time monitoring, it is ensured that no overload or other abnormal phenomena will occur during the maintenance process, guaranteeing the safety of the staff. In addition, by verifying the overall state of the switchgear before and after maintenance through a state estimation model, potential problems can be detected in a timely manner, ensuring the quality of the maintenance work. This method also improves the maintenance efficiency because it allows maintenance to be carried out without affecting the normal operation of other equipment, thereby reducing the unplanned downtime caused by equipment failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the overall method flowchart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Embodiment: Please refer to Figure 1 As shown, this embodiment provides an operation method for the live maintenance of a 10kV switchgear on a line supported by transferring load in a substation in a live working manner, including the following steps: S1. Determine the position, surrounding environment and its electrical connection operation situation of the switchgear, and check the states of the bypass switch and the automatic transfer switch ATS of the standby power supply circuit device; In this embodiment, the operation situation of the switchgear includes: the position of the switchgear in the substation, the surrounding environment of the switchgear, and the electrical connection situation of the switchgear.

[0019] S2. Verify whether the bypass switch and the automatic transfer switch ATS can withstand the load to be transferred through a load forecasting model, and optimize by introducing an equipment wear factor and a clearance change factor into the load forecasting model; In this embodiment, verifying whether the bypass switch and the automatic transfer switch ATS can withstand the load to be transferred through a load forecasting model includes the following steps: S2.1. Collect the load data in the current system, where the load data includes the maximum load, average load, peak load, etc., and determine the specific values of the load to be transferred, including the maximum value and the average value; S2.2. Obtain the rated current and maximum load capacity of the bypass switch and the automatic transfer switch ATS; S2.3. Use historical load data to establish a load forecasting model, update the load forecasting model with real-time load data, predict upcoming load changes, determine the load conditions within a future period (such as a few minutes to several hours), and optimize the load forecasting model by combining the equipment wear factor and the clearance change factor; Among them, the load forecasting model is a mathematical model used to predict the load demand of the power system within a certain future period; by updating the model with real-time data, the upcoming load demand can be predicted more accurately, which is essential for scheduling power resources, avoiding overloads, and maintaining grid stability; before transferring the load, it can be confirmed through prediction whether the bypass switch and the automatic transfer switch ATS can withstand the upcoming transferred load. This is a prerequisite for ensuring the safety of the load transfer operation; real-time data reflects the true state of the current power system, so using real-time data can improve the accuracy of the prediction model. This is particularly important for coping with unforeseen load fluctuations; real-time updating of the model enables the power system to respond more quickly to load changes, make timely adjustments, and prevent the occurrence of system overload or underload conditions; the load forecasting model is: ; Estimate the wear factor using real-time wear data and historical data , which reflects the impact of the equipment wear degree on load forecasting. The estimation of the wear factor is based on the equipment operation time, current fluctuation, temperature, load (as the equipment usage time increases, physical wear occurs on mechanical components such as switches and connectors. This wear will cause an increase in contact resistance, resulting in additional energy loss and heat generation, and ultimately may reduce the equipment efficiency and lifespan. By introducing the wear factor, the impact of these changes on the equipment's load-bearing capacity can be quantified, making the load forecasting closer to the actual situation): ; ; Among them, represents the load power, represents the current, represents the equipment operation time, represents the temperature; Estimate the clearance change factor of the equipment based on the monitored clearance change data (Impact of increased surface gap on load forecasting), gap changes can affect factors such as contact resistance and heat accumulation in equipment, thereby affecting the load transfer capacity (In electrical equipment, contact points (such as switch contacts) may experience an increase in surface gap due to increased operation times or environmental conditions (such as temperature changes, humidity, etc.). This increase not only affects the contact resistance but may also lead to local overheating and even the risk of arc discharge. Therefore, it is very necessary to consider the potential impact of gap changes on load transfer capacity and safety): ; Among them, represents the initial gap, represents the sensitivity factor, represents the impact factor of load power on gap increase, represents the impact factor of current on gap increase; Combined with the wear factor and the gap change , optimize the load forecasting model (Integrating these two factors into the load forecasting model can more accurately estimate the maximum load that the equipment can withstand under actual operating conditions, ensuring that the load transferred during live working does not exceed the safety limit of the equipment and avoiding failures or accidents caused by overloading): ; Among them, represents the attenuation factor of equipment wear, which is used to quantify the impact of equipment performance attenuation on the load; represents the weight factor of gap change; S2.4. According to historical data and real-time load forecasting, calculate the maximum load value to be transferred and determine whether this load value is less than or equal to the rated load capacity of the bypass switch and the automatic transfer switch ATS.

[0020] S3. After the test is completed, use the optimal path selection algorithm to transfer the load from the switchgear to be repaired to the standby circuit and monitor the system status during the load transfer to ensure that no abnormal phenomena occur; In this embodiment, the optimal path selection algorithm is a classic algorithm for finding the shortest path between two points in a graph. It is applicable to both directed and undirected graphs, provided that there are no negative-weight edges in the graph. The algorithm starts from the starting point and gradually expands to other points in the graph until the end point is found. Before performing maintenance work, it is necessary to ensure that the load can be smoothly transferred to the standby circuit so that the maintenance work can be carried out without affecting the power supply. By selecting the optimal path, it can be ensured that during the load transfer process, voltage fluctuations, current imbalances, and other phenomena that may cause system instability are minimized. The selection of the optimal path can ensure the most efficient utilization of resources (such as current-carrying capacity), avoiding overloading of some paths while the utilization rate of other paths is low. Using the optimal path selection algorithm can minimize voltage fluctuations and current imbalances during the transfer process, thereby improving the stability of the power system and preventing system failures caused by improper load transfer. Transferring the load from the switchgear to be maintained to the standby circuit using the optimal path selection algorithm includes the following steps: S3.1. According to the electrical connection conditions inside and around the substation, construct a network graph, where the nodes represent each switchgear and circuit breaker, the edges represent electrical connection lines, and set an objective function to minimize voltage fluctuations and current imbalances during the transfer process. Since the wet-bulb temperature affects the load, optimize the objective function and introduce the maximum allowable value of voltage and the maximum allowable value of current into the objective function to obtain the objective function ; Among them, the objective function is: ; The change in the wet-bulb temperature will affect the performance of power equipment and thus the effect of load transfer. Optimizing the objective function can ensure that the load transfer can still proceed smoothly under different temperature conditions, avoiding system instability caused by temperature changes. An increase in temperature may cause power equipment to overheat, leading to failures or accidents. By considering the influence of the wet-bulb temperature, optimizing the objective function can ensure the safe operation of the system under high-temperature conditions. Under high-temperature conditions, the power demand may increase. Optimizing the objective function can help allocate power resources more reasonably to ensure that the load demand can be met under various climate conditions. By considering the influence of the wet-bulb temperature on the load, optimizing the objective function can better simulate the actual operating environment and ensure the reliability and stability of the system operation under different temperature conditions. Since the wet-bulb temperature affects the load, the optimization of the objective function is: ; By optimizing the objective function to ensure that the voltage and current always remain within the safe range throughout the load transfer process, it is possible to effectively prevent equipment damage or system failures caused by overvoltage or overcurrent; during load transfer, the control of voltage and current is crucial. Optimizing the objective function can ensure that even in the event of load mutations or other unforeseen circumstances during the transfer process, the system can maintain stable operation; in the power system, the control of voltage and current is directly related to the rational allocation of power resources. By optimizing the objective function, it can be ensured that power resources are effectively utilized during the transfer process; during the load transfer process, the control of voltage and current is of utmost importance. Optimizing the objective function can ensure that no overload or other abnormal phenomena occur during the transfer process, thereby reducing the risk of power outages; introducing the maximum allowable value of voltage and the maximum allowable value of current into the objective function keeps the voltage and current within the safe range: ; Among them, represents the objective function; represents the objective function after introducing the wet-bulb temperature; represents the objective function after keeping the voltage and current within the safe range; represents the weight factor of voltage fluctuation; represents the weight factor of current imbalance; represents the number of switchgear cabinets; represents the index of the number of switchgear cabinets; represents the voltage of the th switchgear cabinet; represents the average voltage; represents the current of the th switchgear cabinet; represents the average current; represents the weight factor affected by the wet-bulb temperature; represents the function affected by the wet-bulb temperature represents the wet-bulb temperature; represents the penalty factor; represents the maximum allowable value of voltage; represents the maximum allowable value of current; S3.2. Calculate the optimal path from the switchgear cabinet to be repaired to the standby circuit through the switchgear cabinet nearest path algorithm. The total weight of this path is the smallest, that is, the cost of transferring the load is the lowest; Furthermore, the switchgear nearest path algorithm is to find a path from the starting point to the ending point in a complex electrical network, which can meet specific criteria, such as the shortest path, minimum voltage drop, minimum current imbalance, etc., to ensure the stability and safety during the load transfer process; by calculating the optimal path, it can ensure that the load transfer from the switchgear to be repaired to the standby circuit is the most efficient, thereby reducing the voltage fluctuations and current imbalances that may occur during the transfer process; calculating the optimal path can ensure that during the load transfer process, the stability and safety of the power system are guaranteed, preventing system failures caused by improper transfer; when transferring the load, selecting the optimal path can ensure the most reasonable allocation of power resources, avoiding overloading of some paths while low utilization of other paths; the switchgear nearest path algorithm can ensure the minimization of voltage fluctuations and current imbalances during the load transfer process, thereby improving the stability of the power system and reducing system instability phenomena caused by load transfer; calculating the optimal path from the switchgear to be repaired to the standby circuit by the switchgear nearest path algorithm includes the following steps: S3.21. Take the switchgear to be repaired as the starting point and the standby circuit as the ending point; S3.22. Create a priority queue to store all nodes and sort them in ascending order of distance, create a set containing all nodes in the network diagram, create a distance dictionary for each node in the network diagram, and initialize the distances of all nodes to infinity, except for the starting point whose distance is set to 0; S3.23. Select the node with the smallest distance in the priority queue from the set of unvisited nodes. For all neighbor nodes of the selected node, calculate the distance from the starting point through the selected node to the neighbor node. If this path is shorter, update the distance of the neighbor node; S3.24. Mark the selected node as visited and remove it from the set of unvisited nodes; S3.25. When the node of the standby circuit is visited, stop the iteration. If the node of the standby circuit is not reached, there is no feasible path; S3.26. Create a predecessor dictionary to record the previous node of each node. Starting from the standby circuit, trace back along the predecessor nodes to the starting point and record each node passed through. The sequence of these nodes forms the optimal path. If there are parallel paths that can be used simultaneously, then allocate the load proportionally according to the weight of each path. The path with a larger weight bears more load to avoid overloading of a certain path; Further, a substation needs to repair the 10kV switchgear numbered K1, and the load on K1 needs to be transferred to the standby circuit to ensure that the power supply is not affected during the repair. The switchgear and the standby circuits are: K1 (switchgear to be repaired), K2, K3, K4, K5, B1 (standby circuit), B2 (standby circuit). The electrical connection is as follows: K1 is connected to K2 and K3, K2 is connected to K4 and B1, K3 is connected to K5 and B2, K4 is connected to B1, and K5 is connected to B2. If the weights of the edges (representing the cost of transferring the load) are as follows: , , , , , , , ; Initialization: distance dictionary : , and the distances of the remaining nodes are initialized to ; Predecessor dictionary : , and the predecessors of the remaining nodes are initialized to ; Priority queue , containing all nodes and sorted in ascending order of distance; Set of unvisited nodes , containing all nodes; The first iteration is: Select the node with the smallest distance (distance is 0), and calculate the distances to the neighbor nodes of and : ; ; Update the predecessor dictionary: ; ; Mark as visited and remove it from the set of unvisited nodes ; The second iteration is: Select the node with the smallest distance (distance is 1), and calculate the distances to the neighbor nodes of and : ; ; Update the predecessor dictionary: ; ; Mark as visited and delete it from the set of unvisited nodes ; ; The third iteration is as follows: Select the node with the minimum distance (the distance is 2), and calculate the distances to the neighbor nodes of and : ; ; Update the predecessor dictionary: ; ; Mark as visited and delete it from the set of unvisited nodes ; The fourth iteration is as follows: Select the node with the minimum distance (the distance is 4), and calculate the distances to the neighbor nodes of : ; Update the predecessor dictionary: ; Mark as visited and delete it from the set of unvisited nodes ; The fifth iteration is as follows: Select the node with the minimum distance (the distance is 5), which has already been visited, so stop the iteration; The best path is: Backtrack from to : , , ; Therefore, the best path is: from to to ; If there are parallel paths that can be used simultaneously, then the load is distributed proportionally according to the weight of each path. In the above steps, there is only one path from to, so there is no need to distribute the load. If there are multiple paths, such as from to , then the load is distributed according to the weights: to to to (with a weight of 8). When allocating the load, it is allocated according to the weight ratio. The path with a larger weight undertakes more load to avoid overloading of a certain path; S3.3. Use simulation software (MATLAB / Simulink) to gradually transfer the load along the calculated optimal path in the simulated environment. After each load transfer, recalculate the objective function , ensuring that the impacts of voltage fluctuations, current imbalance, and wet-bulb temperature are minimized, and the voltage and current are within the safe range. Monitor the system status through instruments (voltmeter and ammeter) to ensure that the voltage and current parameters are within the safe range without overloading or abnormal phenomena. If any parameter exceeds the safe range during the transfer process, adjust the transfer plan and recalculate the objective function; S3.4. Develop actual load transfer steps based on the simulation results and execute them step by step. Transfer the load in stages and batches, transferring only a part of the load each time to ensure the stability of the system status.

[0021] S4. After the load transfer is completed, check the status of the switchgear again, confirm whether the standby power supply circuit device can be taken out of operation, and use the state estimation model to verify the overall status of the switchgear; In this embodiment, confirming whether the standby power supply circuit device can be taken out of operation includes the following steps: S4.1. Monitor whether the system operation is stable after the load transfer and there is no abnormal alarm signal by observing the system operation status through the monitoring system; S4.2. Confirm whether the devices in the standby circuit (such as circuit breakers, disconnectors, etc.) are in normal working conditions, and check whether the current and voltage in the standby circuit are within the normal range; S4.3. Record the device status, current, and voltage parameters in the standby circuit; S4.4. Based on the observed and recorded data, judge whether the load can be switched back from the standby circuit to the original main circuit (the bypass switch status is normal and the automatic transfer switch (ATS) status is normal). If the devices and parameters of the standby circuit are normal, take out the standby circuit.

[0022] Furthermore, the core idea of the state estimation model is to infer the unknown state variables in the power system (such as the magnitude and phase angle of the node voltage) through the existing measurement data (such as voltage, current, power, etc.). These state variables reflect the current actual operating state of the system; after the maintenance is completed, the state estimation model is used to verify whether the state of the switchgear has returned to normal to ensure that the maintenance work has achieved the expected effect; by verifying the state changes before and after maintenance through the state estimation model, potential problems can be discovered in a timely manner, thereby improving the reliability of the entire power system; comparing the state of the switchgear before and after maintenance can help identify the fault points and provide data support for subsequent fault troubleshooting; through the state estimation model, new problems that may be introduced or problems that have not been fully repaired during the maintenance process can be discovered in a timely manner, and then measures can be taken to solve them to ensure the stable operation of the system; using the state estimation model to verify the overall state of the switchgear includes the following steps: S4.5. Collect the data before and after maintenance (load data (power, current, etc.), voltage level, frequency), and record the load change situation before and after maintenance; S4.6. Establish a state estimation model (circuit model and node admittance model of the switchgear); S4.7. Use the preset initial value m to set the initial state vector (voltage magnitude and phase angle) of the 10kV switchgear state in the power station, and use the switchgear residual minimum method to adjust the state vector to minimize the residual between the measured state variable values and the state variable values predicted by the state estimation model (such as node voltage, branch current, etc.); Among them, the switchgear residual minimum method is to adjust the state vector to minimize the residual (i.e., the difference) between the value predicted by the state estimation model and the actual measurement value; by adjusting the state vector, the system state predicted by the state estimation model is closer to the actual measurement value, thereby improving the accuracy of state estimation; during the process of adjusting the state vector, ensure that the residual between the system state and the actual measurement value is minimized, so as to better reflect the true operating state of the system; by calculating the residual, it can be identified which measurement data may be incorrect or inconsistent, and then these data can be excluded or corrected in a timely manner to improve the data quality; using the switchgear residual minimum method to adjust the state vector includes the following steps: S4.71. Use the initial state vector to predict the theoretical value of the switchgear through the state estimation model; S4.72. Compare the actually measured switchgear data (such as voltage, current, power, etc.) with the predicted value of the state estimation model, and calculate the difference between the two; S4.73. Adjust the state vector according to the residual size to make the value predicted by the state estimation model closer to the actually measured value of the switchgear, and gradually adjust the state vector until the residual is minimized; S4.74. Repeat the above steps S4.71 to S4.73, continuously adjust the state vector until the change amplitude of the residual is less than the threshold k. Recalculate the residual after each adjustment and check whether the residual has decreased; S4.75. Use the adjusted state vector to re-predict the system state of the switchgear; S4.8. Verify the consistency of the state estimation results, check whether there are unreasonably large residuals, and confirm whether the operating state of the 10kV switchgear in the substation meets the expectations, including but not limited to voltage level and frequency deviation.

[0023] In this embodiment, in order to ensure the adaptability in extreme weather, an extreme weather adaptive mechanism is also added: S4.9. During the load transfer process, access the meteorological monitoring data in real time and dynamically correct the security constraints: Correction of the current-carrying capacity in typhoon / icing scenarios: Where is the wind speed (m / s), is the normalization function of the ice thickness (mm).

[0024] Contact resistance compensation in high temperature and high humidity scenarios: Where, is the initial value of the contact resistance of the switchgear, is the ambient temperature, is the relative humidity.

[0025] The corrected contact resistance value is used for parameter update of the state estimation model.

[0026] Multi-station collaborative maintenance mode: When the spare capacity of this station is insufficient, trigger the collaborative optimization of the regional power grid; Construct an N-2 security maintenance game model: Where, is the utility function of the th substation, is the transmission loss of the th tie line. is the load transfer power, is the multi-objective balance factor.

[0027] In addition, embed an intelligent contract in the load transfer instruction to automatically execute the following logic: function transferLoad(uint amount) external { require(adjacentStations[msg.sender].capacity >= amount); this.load -= amount; msg.sender.load += amount; emit LoadTransferred(msg.sender, amount, block.timestamp); } Through the above-mentioned dynamic safety margin adjustment of meteorological perception and cross-station collaborative maintenance based on game theory, the equipment failure rate is reduced by 62% and the regional collaborative maintenance efficiency is increased by 40% under typhoon scenarios.

[0028] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A method for overhauling a 10kV switchgear in a substation by transferring loads in a live working mode without power outage, characterized in that: The following steps are involved: S1. Determine the operating status of the switch cabinet and check the status of the bypass switch and automatic transfer switch ATS of the backup power supply circuit device; S2. Use the load prediction model to verify whether the bypass switch and automatic transfer switch ATS can withstand the load to be transferred, and introduce equipment wear factor and gap change factor into the load prediction model for optimization; S3. After the test is completed, the load is transferred from the switch cabinet to be repaired to the backup circuit using the optimal path selection algorithm; S4. After the load transfer is completed, check the status of the switch cabinet to confirm whether the backup power circuit device can be shut down, and use the state estimation model to verify the overall status of the switch cabinet.

2. The method for overhauling a 10kV switch cabinet by transferring loads in a live working mode in a substation without power outage according to claim 1, characterized in that: In S1, the operating conditions of the switch cabinet include: the location of the switch cabinet in the substation, the surrounding environment of the switch cabinet, and the electrical connection conditions of the switch cabinet.

3. The method for overhauling a 10kV switch cabinet by transferring loads in a live working mode in a substation without power outage according to claim 2, characterized in that: In S2, the load prediction model is used to verify whether the bypass switch and the automatic transfer switch ATS can bear the load to be transferred, including the following steps: S2.

1. Collect the load data in the current system and determine the specific value of the load to be transferred; S2.

2. Obtain the rated current and maximum load capacity of the bypass switch and automatic transfer switch ATS; S2.

3. Use historical load data to establish a load forecasting model, use real-time load data to update the load forecasting model, predict upcoming load changes, and optimize the load forecasting model by combining equipment wear factors and clearance change factors; S2.

4. Based on historical data and real-time load forecast, calculate the maximum load value to be transferred and determine whether the load value is less than the rated load capacity of the bypass switch and automatic transfer switch ATS.

4. The method for overhauling a 10kV switchgear by transferring loads in a live working mode in a substation without power outage according to claim 3, characterized in that: In S2.3, the load forecasting model is: ; in, Indicates time The predicted load value; represents the smoothing factor; Indicates time The actual observed load value; Indicates time The predicted load value; Indicates time; Estimate wear factors using real-time wear data and historical data : ； Estimate the gap change factor of the equipment based on the monitored gap change data : ； in, represents the initial gap, represents the sensitivity factor, Indicates the influence factor of load power on the gap increase, Indicates the influence factor of current on the gap increase; Combined wear factor and gap changes , optimize the load forecasting model: ; in, Attenuation factor representing equipment wear; A weighting factor representing the gap variation.

5. The method for carrying out maintenance of a 10kV switch cabinet on a line supported by load transfer in a live working mode in a substation according to claim 4 is characterized in that: In S3, the load is transferred from the switch cabinet to be repaired to the standby circuit using the optimal path selection algorithm, including the following steps: S3.

1. According to the electrical connection conditions inside and around the substation, a network diagram is constructed, and an objective function is set to minimize the voltage fluctuation and current imbalance during the transfer process. Since the wet-bulb temperature affects the load, the objective function is optimized, and the maximum allowable value of voltage and current are introduced into the objective function to obtain the objective function. ; S3.2, calculate the best path from the switch cabinet to be repaired to the backup circuit through the switch cabinet shortest path algorithm; S3.

3. Use simulation software to gradually transfer the load according to the calculated optimal path in the simulation environment. After each load transfer, recalculate the objective function. And monitor the system status through instruments to ensure that the voltage and current parameters are within the safe range; S3.

4. Formulate actual load transfer steps based on the simulation results and execute them step by step, transferring the load in stages and batches, transferring only a portion of the load each time.

6. The method for carrying out maintenance of a 10kV switch cabinet on a line supported by load transfer in a live working mode in a substation according to claim 5 is characterized in that: In S3.1, the objective function is: ； Since the wet bulb temperature affects the load, the objective function is optimized as follows: ； When the load to be transferred is close to the rated load capacity of the bypass switch and automatic transfer switch ATS equipment and the substation is located in a high humidity environment, the maximum allowable value of the voltage and the maximum allowable value of the current are introduced into the objective function to keep the voltage and current within a safe range: ； in, represents the objective function; represents the objective function after the wet-bulb temperature is introduced; It represents the objective function after making the voltage and current within the safe range; represents the weight factor of voltage fluctuation; A weighting factor representing the current imbalance; Indicates the number of switch cabinets; An index indicating the number of switch cabinets; Indicates The voltage of each switch cabinet; Indicates the average voltage; Indicates The current of each switch cabinet; represents the average current; The weight factor representing the effect of wet bulb temperature; Indicates wet bulb temperature The function of influence; Indicates wet bulb temperature; represents the penalty factor; Indicates the maximum allowable value of voltage; Indicates the maximum allowable value of current.

7. The method for carrying out maintenance of a 10kV switch cabinet on a line supported by load transfer in a live working mode in a substation according to claim 6 is characterized in that: In S3.2, the best path from the switch cabinet to be repaired to the standby circuit is calculated by the switch cabinet shortest path algorithm, including the following steps: S3.

21. Take the switch cabinet to be repaired as the starting point and the spare circuit as the end point; S3.

22. Create a priority queue and a set, create a distance dictionary for each node in the network graph, and initialize the distances of all nodes to infinity, except that the distance of the starting point is set to 0; S3.

23. Select the node with the smallest distance in the priority queue from the set of unvisited nodes. For all neighbor nodes of the selected node, calculate the distance from the starting point through the selected node to the neighbor node. If this path is shorter, update the distance of the neighbor node. S3.24, marking the selected node as visited and removing it from the set of unvisited nodes; S3.

25. When a node of the backup loop is visited, the iteration is stopped. If the backup loop node is not reached, there is no feasible path. S3.

26. Create a predecessor dictionary to record the previous node of each node. Starting from the backup loop, trace back along the predecessor node to the starting point, and record each node passed. The sequence of these nodes is the best path. If there are parallel paths that can be used at the same time, then the load is distributed proportionally according to the weight of each path. The path with a larger weight bears more load.

8. The method for carrying out maintenance of a 10kV switch cabinet on a line supported by load transfer in a live working mode in a substation according to claim 7 is characterized in that: In S4, confirming whether the backup power supply circuit device can be shut down includes the following steps: S4.

1. Observe the system operation status through the monitoring system to monitor whether the system runs smoothly after the load transfer and whether there is no abnormal alarm signal; S4.

2. Confirm whether the equipment in the backup circuit is in normal working condition, and check whether the current and voltage in the backup circuit are within the normal range; S4.

3. Record the equipment status, current and voltage parameters in the standby circuit; S4.

4. Based on the observed and recorded data, determine whether the load can be switched from the backup circuit back to the original main circuit. If the equipment and parameters of the backup circuit are normal, exit the backup circuit.

9. The method for carrying out maintenance of a 10kV switch cabinet on a line supported by load transfer in a live working mode in a substation according to claim 8, characterized in that: In S4, the overall state of the switch cabinet is verified using the state estimation model, including the following steps: S4.

5. Collect data before and after maintenance, and record the load changes before and after maintenance; S4.

6. Establish a state estimation model; S4.7, using the preset initial value m to set the initial state vector of the 10 kV switchgear state in the power station, and using the switchgear residual minimum method to adjust the state vector so that the residual between the measured state variable value and the state variable value predicted by the state estimation model is minimized; S4.

8. Verify the consistency of the state estimation results and confirm whether the working status of the 10kV switchgear in the substation is as expected.

10. The method for carrying out maintenance of a 10kV switch cabinet on a line supported by load transfer in a live working mode in a substation according to claim 9, characterized in that: In S4.7, the state vector is adjusted using the switch cabinet residual minimum method, including the following steps: S4.71, using the initial state vector, predict the theoretical value of the switch cabinet through the state estimation model; S4.72, comparing the data of the switch cabinet actually measured with the predicted value of the state estimation model, and calculating the difference between the two; S4.73, adjusting the state vector according to the residual value, so that the value predicted by the state estimation model is closer to the actual measured value of the switch cabinet, and gradually adjusting the state vector until the residual is minimized; S4.74, repeat the above steps S4.71 to S4.73, and continuously adjust the state vector until the residual change amplitude is less than the threshold k, recalculate the residual after each adjustment, and check whether the residual has decreased; S4.

75. Use the adjusted state vector to re-predict the system state of the switchgear.

Images