A method for replacing a gas insulated combined electrical device current transformer

Abstract

The application discloses a replacement method of a gas insulated combined electric appliance current transformer. By establishing the loop resistance state baseline data before replacement, and according to the dynamic net distance calculation and space optimization of the circuit breaker body movement based on the three-dimensional model of the equipment, a safe integrated operation space is formed in a closed loop control mode. After the overall replacement of the three-phase current transformer is completed in the space, visual guidance information is generated based on real-time image and reference template matching to adjust and complete the circuit breaker reset alignment; finally, by comparing the loop resistance data before and after replacement, and based on the preset threshold, the three-phase extreme difference change rate and the change rate of each phase are quantitatively analyzed to complete acceptance. Thus, the operation safety is improved, the maintenance period is greatly shortened, the installation reset accuracy is ensured, and the equipment performance is restored to the original healthy state.

Description

Technical Field

[0001] This invention relates to the field of high-voltage electrical equipment maintenance technology, specifically to a method for replacing a gas-insulated switchgear current transformer. Background Technology

[0002] Gas-insulated metal-enclosed switchgear (GIS) is widely used in modern power systems due to its high reliability and small footprint. As its core metering and protection component, the performance of current transformers (CTs) is crucial. During long-term operation, replacement of current transformers may be necessary due to faults or upgrades. This work typically requires partial disassembly of the equipment, operating in extremely limited space, and involves disconnecting and reconnecting high-voltage conductive paths. The quality of this work directly affects the long-term operational safety and metering accuracy of the equipment after commissioning. Therefore, exploring a safe, efficient, and accurate replacement method is of clear engineering necessity.

[0003] Traditional replacement methods typically employ a phase-by-phase disassembly of the horizontal section of the cylinder. The process involves sequentially removing the inspection port covers of each phase's tee, then disconnecting the electrical connection between the vertical and horizontal sections. Next, the tee is disassembled, and protective measures are taken to avoid damaging the vertical section of the cylinder. Finally, the current transformer and connecting cylinder are replaced phase by phase. This method has significant limitations. The entire process is extremely cumbersome, requiring almost identical repetitive disassembly and installation of all three phases, multiplying the workload. The direct consequence is a significantly extended work period; a complete replacement usually takes several days, resulting in prolonged power outages and impacting grid operation. Repeated disassembly and installation repeatedly disturb the equipment's sealing surfaces, increasing the risk of gas leakage due to seal failure. Furthermore, repeated hoisting operations in confined spaces increase the probability of component damage from impacts. In terms of quality control, the uncertainties introduced by repeated disassembly and assembly often result in significant dispersion in loop resistance test data, making precise control of the three-phase resistance balance difficult and posing a potential threat to long-term stable equipment operation.

[0004] In summary, existing technical methods have revealed a series of interrelated technical problems during implementation. The lack of pre-simulation and path planning based on quantitative benchmarks throughout the operation process results in a high risk of collisions during the movement of large components such as the circuit breaker body. The sequential replacement of the three phases leads to a lengthy workflow and low overall replacement efficiency. In the critical circuit breaker reset and alignment stage, the operation relies entirely on the operator's visual experience and feel, making it difficult to achieve and verify sub-millimeter precision alignment requirements within the poorly oriented internal structure. This results in a lack of objective, quantitative data comparison with the pre-replacement state during the acceptance phase, making it difficult to scientifically determine whether the equipment performance has truly returned to its original healthy state. These problems collectively constrain the safety, economy, and reliability of current transformer replacement operations for GIS equipment. Summary of the Invention

[0005] In view of the above-mentioned actual situation, this application proposes a method for replacing the current transformer of a gas-insulated combined electrical appliance, in order to solve the technical problems existing in the prior art, such as high risk of operational collisions due to lack of quantitative benchmarks and planning, low efficiency of three-phase serial replacement, reliance on manual experience for accuracy of key reset links which is difficult to guarantee, and lack of objective data comparison for final acceptance.

[0006] A method for replacing a current transformer in a gas-insulated switchgear includes the following steps: S1, the equipment is powered off and safety isolation measures are implemented. The primary circuit resistance test is performed on the three-phase circuit containing the current transformer to be replaced, and the measured data is recorded as the status baseline data. The electrical secondary circuit wiring and related grounding connections of the three-phase circuit are disconnected. S2, Based on the three-dimensional model of the equipment, the dynamic clearance calculation and spatial optimization are performed on the translation path of the circuit breaker body along the direction away from the air chamber of the current transformer, the optimal translation target position is determined, and the circuit breaker body is controlled to move in a closed loop towards the optimal translation target position based on the dynamic clearance, forming an integrated working space. S3, within the integrated work space, simultaneously disconnect all mechanical and electrical connections of the old three-phase current transformer and move the old three-phase current transformer out as a whole; install the new current transformer group as a whole into the installation position and complete the initial connection between the new current transformer group and the adjacent fixed cylinder; S4. Acquire a real-time image of the flange end face of the moving contact of the circuit breaker body; perform feature matching between the real-time image and a pre-stored reference template image, and generate visual guidance information representing the alignment deviation based on the matching result; adjust the thrust applied to the circuit breaker body according to the visual guidance information, and iteratively execute this process until the alignment deviation meets the requirements, thereby completing the reset and alignment of the circuit breaker body. S5, restore all electrical connections and air chamber seals of the equipment, perform a second loop resistance test on the three-phase circuit containing the new current transformer group, and obtain acceptance data; compare and analyze the acceptance data with the status baseline data recorded in step S1, and if the comparison and analysis results meet the preset threshold, confirm that the replacement of the current transformer is complete.

[0007] Furthermore, step S2 includes: S201, based on the three-dimensional model of the equipment including the surrounding fixed components, simulate the horizontal movement of the circuit breaker body along the direction away from the current transformer air chamber, and calculate the dynamic clearance between each point on the movement path and the surrounding fixed components. S202, Based on the dynamic clearance, perform optimization calculations, select the position with the largest clearance margin in the movement path interval where the dynamic clearance is greater than or equal to the preset safety threshold throughout the entire process, and determine the position as the optimal translation target position of the circuit breaker body. S203, during the movement of the circuit breaker body, the dynamic clearance is used as the reference value to establish real-time feedback of displacement, direction and distance from surrounding components; the deviation of each feedback quantity from the corresponding reference value is calculated, and the translational and rotational degrees of freedom of the circuit breaker body are coordinated and adjusted according to the deviation to achieve closed-loop approach and locking to the optimal translational target position, thereby forming the integrated working space.

[0008] Furthermore, step S4 includes: S401, Obtain a reference image of the moving contact flange end face of the circuit breaker body in an ideal state after reset using an endoscope, and extract the contour edge features in the reference image to construct a reference template; S402, during the reset and adjustment process, a real-time image of the moving contact flange end face is obtained through the endoscope, the real-time image is matched with the reference template for edge features, and a virtual reference line corresponding to the contour in the reference template is generated by superimposing the real-time image on the reference image. S403, calculate the pixel offset between the corresponding contour in the real-time image and the virtual baseline, and generate a visual offset vector map reflecting the offset direction and magnitude; adjust the horizontal pushing force applied to the circuit breaker body according to the deviation direction and magnitude indicated by the visual offset vector map, and iteratively execute this step until the pixel offset approaches zero, thus completing the alignment.

[0009] Furthermore, step S5 includes: S501, restore the electrical connection and air chamber seal of the device, and sequentially perform vacuuming, filling with insulating gas and sealing test on the air chamber containing the new current transformer group; S502, perform a second loop resistance test on the three-phase circuit containing the new current transformer group to obtain acceptance data; calculate the first rate of change of the three-phase range of the acceptance data relative to the three-phase range of the state baseline data, and calculate the second rate of change of the acceptance data relative to the corresponding state baseline data for each phase. S503, when the first rate of change does not exceed the first preset threshold and the absolute value of the second rate of change in each phase does not exceed the second preset threshold, the current transformer replacement operation is confirmed to be completed.

[0010] Furthermore, based on the three-dimensional model of the equipment including surrounding fixed components, the simulation of the horizontal movement of the circuit breaker body along the direction away from the current transformer air chamber, and the calculation of the dynamic clearance between each point on the movement path and the surrounding fixed components, including dynamic clearance calculation processing and spatial geometric mapping processing.

[0011] Furthermore, the optimization calculation based on the dynamic clearance, selecting the position with the largest clearance margin within the movement path interval where the dynamic clearance is greater than or equal to the preset safety threshold throughout the entire process, and determining the position as the optimal translation target position of the circuit breaker body includes safety path interval identification processing and maximum clearance margin position optimization processing.

[0012] Furthermore, the real-time feedback of displacement, direction, and distance from surrounding components is achieved through inertial detection unit nodes deployed on the circuit breaker body and laser ranging sensor arrays installed on surrounding fixed components; the calculation of the deviation between each feedback quantity and the corresponding reference value, and the coordinated adjustment of the translational and rotational degrees of freedom of the circuit breaker body based on the deviation to achieve closed-loop approach and locking to the optimal translational target position, includes multi-source feedback deviation fusion processing and multi-degree-of-freedom coordinated control processing.

[0013] Furthermore, the process of obtaining a reference image of the moving contact flange end face of the circuit breaker body under ideal conditions after reset via endoscopy, and extracting the contour edge features in the reference image to construct a reference template, includes image feature extraction processing and reference template construction processing.

[0014] Furthermore, the step of matching the edge features of the real-time image with the reference template and overlaying them on the real-time image to generate a virtual reference line corresponding to the contour in the reference template includes real-time pose calculation processing and virtual reference line rendering processing.

[0015] Furthermore, the calculation of the pixel offset between the corresponding contour in the real-time image and the virtual baseline, and the generation of a visual offset vector map reflecting the offset direction and magnitude, includes offset quantization calculation processing and vector map synthesis and rendering processing. The replacement method for gas-insulated combined electrical current transformers proposed in this application achieves efficient replacement based on digital pre-simulation and real-time feedback of safe space creation, synchronous operation of three-phase components, precise reset alignment guided by machine vision, and quantitative quality verification based on closed-loop comparison of loop resistance data. This results in improved operational safety, significantly shortened maintenance period, guaranteed installation and reset accuracy, and ensured that equipment performance is restored to its original healthy state. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for replacing a current transformer in a gas-insulated combined electrical appliance according to this application. Figure 2 This is a schematic diagram illustrating the three-dimensional path planning and dynamic control system for forming an integrated work space process in the replacement method of a gas-insulated combined electrical current transformer proposed in this application. Figure 3 This is a schematic diagram illustrating the visual guidance alignment system during the reset and alignment of the circuit breaker body in the replacement method of the current transformer of the gas-insulated combined electrical appliance proposed in this application. Detailed Implementation

[0017] The simulation technology route in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] The features and performance of the present invention will be further described in detail below with reference to embodiments. Please refer to the appendix. Figure 1 As shown, a method for replacing a current transformer in a gas-insulated switchgear includes the following steps: S1, the equipment is powered off and safety isolation measures are implemented. The primary circuit resistance test is performed on the three-phase circuit containing the current transformer to be replaced, and the measured data is recorded as the status baseline data. The electrical secondary circuit wiring and related grounding connections of the circuit are disconnected. In some implementations, the safety isolation measures, based on electrical safety regulations, involve disconnecting all electrical connections between the equipment and the power supply, and applying visible physical isolation points, such as installing disconnect switches or removing fusible components, while simultaneously hanging warning signs to ensure the work area is de-energized. The fundamental purpose of these measures is to eliminate the risk of electric shock and potential misoperation during the work process, creating a safe environment for subsequent maintenance. It should be noted that the implementation of safety isolation must follow the principle of double isolation, i.e., at least two independent disconnection points, to prevent backfeeding of power due to a single device failure. Furthermore, after isolation is completed, a voltage tester must be used to test for voltage at each critical point of the equipment to confirm that the potential is zero. The voltage testing operation is well known to those skilled in the art and will not be elaborated upon here.

[0020] In this embodiment, an initial loop resistance test is performed on a three-phase circuit containing the current transformer to be replaced. The loop resistance test is based on Ohm's law and is implemented using the DC voltage drop method. Specifically, a constant DC current I is injected into the circuit under test, and the voltage drop U generated by this current in the circuit is measured. The loop resistance value R is calculated according to Ohm's law. The three-phase circuit refers to the independent conductive paths formed by phases A, B, and C in the equipment. During the test, a test current needs to be applied to each phase circuit sequentially. Preferably, the test current value needs to be large enough to overcome the influence of the contact oxide film. A DC current of not less than 100 amperes is selected to ensure that the measurement result reflects the true connection state of the circuit conductors. Furthermore, the testing instrument needs to be zeroed before the test to eliminate the systematic error introduced by the resistance of the test leads themselves. The specific circuit connection and instrument operation of the DC voltage drop method are well known to those skilled in the art and will not be described in detail here.

[0021] In some implementations, the measured data is recorded as baseline status data; the baseline status data refers to the set of original resistance values ​​characterizing the initial connection state of its three-phase circuits before any disassembly or replacement of the equipment, specifically including the resistance value of phase A. Phase B resistance value With the resistance value of phase C The recording process must ensure the integrity, accuracy, and traceability of the data. For example, the measured values, test time, ambient temperature, test instrument serial number, and operator information should be archived together. It should be noted that ambient temperature affects conductor resistance, according to the conductor resistance temperature coefficient formula. ,in The resistance at temperature t, The resistance at 20℃ The temperature coefficient of the conductor material; in this embodiment, to eliminate the interference of temperature fluctuations on the comparability of baseline data, the ambient temperature is measured and recorded simultaneously, or the measured values ​​at different temperatures are uniformly converted to the resistance value at the reference temperature according to the formula in subsequent comparative analysis; the temperature conversion process is a well-known implementation method for those skilled in the art, and will not be elaborated on here; the state baseline data constitutes a reliable reference for the acceptance data analysis in the subsequent step S5, forming the starting point for closed-loop control of work quality.

[0022] In this embodiment, the electrical secondary circuit wiring and related grounding connections of the circuit are disconnected. The electrical secondary circuit wiring refers to the connecting wires between the secondary winding of the current transformer and the measuring instruments, protection devices, or control equipment. The disconnection operation must follow the rule of proceeding from the load side to the power supply side, that is, disconnecting the connection of the remote equipment first, and then disconnecting the connection of the near-end terminal block, to avoid open-circuit induced high voltage. Specifically, the secondary winding of the current transformer is in a near-short-circuit state during operation. If it is opened while energized, high voltage will be generated at both ends of the winding, which will endanger the equipment and personal safety. Therefore, after power outage isolation, before disconnecting the secondary wiring, the winding terminals must still be reliably short-circuited using shorting pieces or wires. The related grounding connection refers to the grounding wire of the metal shell of the current transformer or the grounding wire of the winding neutral point, which is set to ensure safety. When disconnecting the grounding connection, insulated tools must be used and the operation must be carried out in the order of disconnecting the grounding wire connection point first, and then disconnecting the equipment end connection point, to prevent the risk of static electricity or residual charge release. Furthermore, all disconnected wiring and grounding wires must be marked and their original positions and connection relationships recorded to provide an accurate basis for the restoration operation in step S5.

[0023] S2, Based on the three-dimensional model of the equipment, the circuit breaker body is dynamically cleared and spatially optimized along the translation path away from the air chamber of the current transformer. The optimal translation target position is determined and the dynamic clearance is used as a reference. The circuit breaker body is controlled to move in a closed loop towards the optimal translation target position to form an integrated working space for simultaneous operation of the three-phase current transformers. Please see the appendix Figure 2 As shown in the attached diagram, this is a schematic representation of the three-dimensional path planning and dynamic control system that forms the integrated workspace process, used for intuitive understanding of the logic of this step. This step specifically includes the following sub-steps: S201, based on the three-dimensional model of the equipment including the surrounding fixed components, simulate the horizontal movement of the circuit breaker body along the direction away from the current transformer air chamber, and calculate the dynamic clearance between each point on the movement path and the surrounding fixed components. The simulation of the circuit breaker body's horizontal movement away from the current transformer's air chamber, based on a 3D model of the equipment including surrounding fixed components, and the calculation of the dynamic clearance between each point on the movement path and the surrounding fixed components, includes dynamic clearance calculation processing and spatial geometric mapping processing. The dynamic clearance calculation processing is a calculation process that calculates the minimum spatial distance between the outer surface of the moving component and the inner surface of all surrounding fixed components at each position on a preset trajectory, based on spatial geometric relationships. The spatial geometric mapping processing is a process that discretizes the continuous movement process of the circuit breaker body into a series of ordered position point sequences and transforms the spatial relationships of each component in the 3D model of the equipment into a data structure that can be mathematically calculated. These two processing logics are related. The spatial geometric mapping processing provides standardized geometric and position data input for the dynamic clearance calculation processing. The dynamic clearance calculation processing performs the core distance calculation operation based on this input, jointly generating a dynamic clearance dataset for subsequent path safety assessment.

[0024] In some implementations, under the physical state of power outage and safety isolation of the equipment, precise three-dimensional model data of the circuit breaker body, current transformer chamber, and all surrounding fixed components are acquired; the three-dimensional model data includes the surface geometry and spatial pose information of each component; preferably, the three-dimensional model is a computer-aided design model constructed based on equipment design drawings, or a point cloud model obtained by three-dimensional laser scanning of the actual equipment; in this embodiment, the three-dimensional model is preprocessed, a unified global coordinate system is defined, and the models of the circuit breaker body, current transformer chamber, and surrounding fixed components are placed in this coordinate system to determine their initial position and orientation.

[0025] In the spatial geometric mapping process, the horizontal movement of the circuit breaker body is simulated; this simulation is achieved by assigning a translational transformation to the three-dimensional model of the circuit breaker body; the movement direction vector is defined as... The vector is parallel to the horizontal plane and points away from the current transformer chamber; the total distance of the simulated movement is defined as... The movement step size is The process discretizes the continuous movement into... The simulation process involves several steps; for the i-th simulation step (i=0,1,2,...,N), the translation transformation matrix of the circuit breaker body is calculated. This is then applied to the coordinates of all vertices of the circuit breaker body model to obtain the temporary position model of the circuit breaker body in the global coordinate system under this step. The transformation matrix The derivation and application of this method belong to the rigid body kinematics and computer graphics transformation implementation methods that are well known to those skilled in the art, so we will not go into too much detail here; it should be noted that when i=0 is the identity matrix, it corresponds to the initial installation position of the circuit breaker body.

[0026] In this embodiment, after completing the spatial geometric mapping process, the dynamic net distance calculation process is initiated; for each temporary position model obtained in simulation step i... Calculate its relationship with all surrounding fixed component models (denoted as set). Minimum spatial distance between ) This distance is the dynamic net distance on the movement path corresponding to the position point of this step; the calculation is based on solving for point-to-surface distances in three-dimensional space; specifically, extracting... All vertices of the outer surface constitute a point set Extract the model of each fixed component. Outer surface triangular patch set For point sets any point in Calculate its distance to the fixed component Each triangular facet The minimum value among the perpendicular distances is taken as the point. Distance to the surface of the fixed component Then, the dynamic clearance between the circuit breaker body and the fixed component j when in position i is... Furthermore, considering all surrounding fixed components, the overall dynamic clearance at this location point... The subscript i indicates the i-th discrete position of the circuit breaker body on the simulated horizontal movement path; the subscript j indicates the j-th peripheral fixed component. This represents the k-th vertex in the surface geometry of the 3D model of the circuit breaker body when it is located at position i. This means iterating through the variable k within its domain (i.e., from 1 to the total number of vertices m) to find the minimum value. This calculation process iterates through all simulation steps i, generating a dynamic net distance sequence. Each element in the sequence corresponds one-to-one with a discrete location point on the movement path.

[0027] It should be noted that the point-to-surface distance... The calculation involves determining the distance from a point to a plane and whether the point lies within the projection region of the triangle; given a triangular facet... The three vertices The normal vector of the plane it lies in is ,point The distance to the plane is Furthermore, it is necessary to calculate the points. The projection point on the triangular plane And judge Is it located in a triangle? The projection point is inside the triangle; if the projection point is inside the triangle, then the point-to-plane distance is the distance from the point to the plane; if the projection point is outside the triangle, then the point-to-plane distance is the distance from the projection point to the plane. The shortest distance to the three side segments of the triangle; the calculation of the distance from the point to the line segment involves determining the position of the perpendicular foot through the vector dot product. This calculation method is well known to those skilled in the art and its implementation will not be elaborated on here.

[0028] In some implementations, the result of the dynamic clearance calculation, i.e., the dynamic clearance sequence, is the basic data for identifying positions that meet preset safety conditions in the subsequent step S202. The dynamic clearance directly represents the safety margin between the circuit breaker body and surrounding equipment at any point on the simulated path. The correspondence between the dynamic clearance sequence and the discrete position point sequence on the moving path constitutes a complete quantitative description of the spatial conflict risk during the translational movement, providing a preset expected value benchmark for trajectory planning and real-time monitoring during physical execution.

[0029] S202, Based on the dynamic clearance, perform optimization calculations, select the position with the largest clearance margin in the movement path interval where the dynamic clearance is greater than or equal to the preset safety threshold throughout the entire process, and determine the position as the optimal translation target position of the circuit breaker body. The optimization calculation based on the dynamic clearance, selecting the position with the largest clearance margin within the movement path interval where the dynamic clearance is greater than or equal to a preset safety threshold, and determining this position as the optimal translation target position of the circuit breaker body, includes a safe path interval identification process and a maximum clearance margin position optimization process. The safe path interval identification process is a process of traversing and conditionally judging the dynamic clearance sequence to filter out all consecutive movement position subsequences that meet the preset safety conditions. The maximum clearance margin position optimization process is a process of comparing and deciding within each consecutive safe position subsequence output by the safe path interval identification process to determine the single position point with the largest clearance margin value. These two processing logics are related. The safe path interval identification process defines the boundary and range of the decision search for the maximum clearance margin position optimization process, and the maximum clearance margin position optimization process performs a refined search and decision within each defined safety boundary range to jointly generate a unique target position to guide the physical movement.

[0030] In some implementations, the input dynamic clearance sequence for the safety path interval identification processing corresponds to a discrete simulated position point on the movement path for each element in the sequence; the preset safety threshold is a numerical constant pre-set based on the physical dimensions of the equipment, installation tolerances, tool space requirements, and safety regulations; specifically, the threshold represents the minimum permissible distance that the surface of the circuit breaker body must maintain with any surrounding fixed component surface during movement; preferably, the setting of the preset safety threshold needs to take into account sensor measurement errors and mechanism control errors to provide a safety margin for actual physical operation.

[0031] In this embodiment, the safe path interval identification process sequentially traverses each net distance value in the dynamic net distance sequence; the process compares the value with the preset safety threshold; when the dynamic net distance value corresponding to a certain location point is greater than or equal to the preset safety threshold, the location point is marked as a safe point; when the dynamic net distance value is less than the preset safety threshold, the location point is marked as a conflict risk point; furthermore, all consecutively arranged safe points are identified and aggregated into an independent safe path interval, and one or more such safe path interval sets are output. Each interval is defined by the starting location point index and the ending location point index, representing a continuous spatial clearance on the movement path that meets the safety requirements for movement.

[0032] In some implementations, the maximum clearance margin location optimization process is initiated after the safety path interval identification process is completed. The input to this process is one or more safety path interval data output by the previous process, as well as the original dynamic clearance values ​​corresponding to each location point within these intervals. The goal of the maximum clearance margin location optimization process is to find the specific location point where the dynamic clearance value reaches its maximum value within each independent safety path interval. Specifically, this process iterates and compares the dynamic clearance values ​​of all location points within each safety path interval, records and outputs the location index of the point with the maximum clearance value. It should be noted that the clearance margin refers to the specific value of the dynamic clearance. The larger the value, the greater the spatial clearance between the circuit breaker body and surrounding equipment at that location, providing more physical space for subsequent operations.

[0033] In some implementations, when the safety path interval identification process outputs multiple independent safety path intervals, the maximum clearance margin position optimization process will execute the above optimization operation in parallel or serially within each interval, thereby obtaining multiple candidate position points. Each candidate point has the maximum clearance margin within its respective safety interval. Further, it is necessary to determine a unique optimal translation target position from these candidate points. The determination process introduces a second-level decision rule, which includes, but is not limited to, selecting the position corresponding to the global maximum value of the clearance margin among all candidate points, or selecting the candidate point closest to the initial installation position and whose clearance margin meets the secondary threshold. The selection and implementation of the second-level decision rule depend on the specific operating scenario and efficiency requirements. This decision logic is within the scope of what those skilled in the art can implement based on the content of this disclosure, and will not be elaborated further here. Finally, the maximum clearance margin position optimization process outputs a definite position point index, and the three-dimensional spatial coordinates corresponding to this index are defined as the optimal translation target position of the circuit breaker body.

[0034] It should be noted that the determination of the optimal translation target position ensures that the working environment with the most spacious spatial conditions is created for subsequent operations while meeting the safety requirements of the entire movement process.

[0035] S203, during the movement of the circuit breaker body, the dynamic clearance is used as the reference value to establish real-time feedback of displacement, direction and distance from surrounding components; the deviation of each feedback quantity from the corresponding reference value is calculated, and the translational and rotational degrees of freedom of the circuit breaker body are coordinated and adjusted according to the deviation to achieve closed-loop approach and locking to the optimal translational target position, thereby forming the integrated working space.

[0036] In this embodiment, the real-time feedback of displacement, direction and distance from surrounding components is achieved through inertial detection unit nodes deployed on the circuit breaker body and laser ranging sensor arrays installed on surrounding fixed components. The calculation of the deviation between each feedback quantity and the corresponding reference value, and the coordinated adjustment of the translational and rotational degrees of freedom of the circuit breaker body based on the deviation to achieve closed-loop approach and locking to the optimal translational target position, includes multi-source feedback deviation fusion processing and multi-degree-of-freedom collaborative control processing. The multi-source feedback deviation fusion processing is the process of synchronizing the real-time data collected by the inertial detection unit node and the laser ranging sensor array in time and space and unifying the coordinate system, and calculating the deviation vector between it and the reference value generated in steps S201 and S202. The multi-degree-of-freedom collaborative control processing is based on the deviation vector, and the control algorithm calculates and outputs the collaborative control commands for the translational drive mechanism and the rotational adjustment mechanism of the circuit breaker body to drive the body posture to continuously reduce the deviation. These two processing logics are related. The multi-source feedback deviation fusion processing provides accurate, multi-dimensional quantified posture deviation input for the multi-degree-of-freedom collaborative control processing, and the multi-degree-of-freedom collaborative control processing generates specific actuator action strategies for this input. The two work together to achieve closed-loop approach and locking to the predetermined target position through a continuous "perception-decision-execution" cycle.

[0037] In some embodiments, the inertial detection unit node is fixedly installed at the centroid or geometric center of the circuit breaker body. This node measures the linear acceleration and angular velocity of the body in three-dimensional space in real time, and recursively calculates the real-time displacement vector and real-time attitude angle of the circuit breaker body relative to the starting point of movement through an inertial navigation calculation algorithm. It should be noted that the attitude angle defines the rotation state of the circuit breaker body coordinate system relative to the global coordinate system. Preferably, the inertial detection unit node performs initial alignment and zero-position calibration before the movement begins to eliminate initial errors. The attitude update and position integration algorithms involved in the inertial navigation calculation are well known to those skilled in the art and will not be described in detail here.

[0038] In this embodiment, the laser ranging sensor array installed at key locations on the peripheral fixed components emits laser beams that are directed and continuously illuminate specific reflective markers on the outer surface of the circuit breaker body; each sensor measures its distance from the corresponding reflective marker in real time. Where k represents the sensor index; given the installation position coordinates and beam direction vector of each sensor in the global coordinate system, and combining the geometric model of the circuit breaker body with the initial installation position of the reflection markers, a set of distance measurements are calculated through spatial geometry. The inverse solution process yields an independent position and attitude estimate of the circuit breaker body in the global coordinate system. This inverse solution involves least squares optimization; specifically, it involves finding a pose of the body (derived from the position vector). (and rotation matrix R), such that, in this pose, the theoretical distance values ​​from each reflective marker point to the corresponding sensor calculated according to the geometric model are equal to the actual measured values. The sum of squares of the errors is minimized; the establishment and solution of this optimization problem are well known to those skilled in the art, and will not be elaborated further here; the pose estimation value obtained by the laser ranging calculation and the inertial navigation calculation value together constitute multi-source real-time feedback data.

[0039] In the multi-source feedback deviation fusion processing, the inertial navigation data and the laser ranging solution data are time-stamp aligned and their coordinate systems are unified. The processing employs Kalman filtering or complementary filtering algorithms to fuse the two types of data, in order to suppress the cumulative drift error of inertial navigation and the instantaneous jump error that may exist in laser ranging, and output an optimally estimated real-time pose state. ,in The merged 3D position, The fused attitude angle; the specific implementation of the Kalman filter or complementary filter is well known to those skilled in the art, and will not be elaborated further here. Further, the processing calculates the deviation between the real-time pose state and the reference value; for the position deviation, the reference value is the optimal translation target position coordinate determined in step S202. Then the position deviation vector For attitude deviations, to simplify control, the reference value is usually set to the initial attitude at the start of the movement. (That is, the attitude should remain as constant as possible during the movement), then the attitude deviation vector Simultaneously, the processing also requires calculating the real-time safe distance deviation; specifically, based on the fused real-time pose... Using a fixed model of surrounding components, the minimum distance between the circuit breaker body and surrounding components in the current state is calculated in real time. The calculation method is the same as the dynamic clearance calculation process in step S201; its real-time safety distance deviation is... ,in This is the baseline net distance value corresponding to the current movement path point, obtained from the dynamic net distance sequence in step S201. The multi-source feedback deviation fusion processing ultimately outputs a value containing... , , The composite deviation vector.

[0040] In the multi-degree-of-freedom collaborative control process, the composite deviation vector serves as the input to the controller; the controller is designed as a multi-input multi-output structure, and its output is the control quantity applied to the circuit breaker body drive mechanism; specifically, the position deviation... and attitude deviation As the primary control objective, the safety distance deviation will be... As a constraint, the core of the process is to construct a control law that... and In satisfying Under the constraint that the actual distance is not less than the reference net distance, it asymptotically approaches zero. In this embodiment, a constrained proportional-integral-derivative control algorithm is used; for the translational degree of freedom, the control commands in the two vertical directions (assuming they are X and Y directions) in the horizontal plane are... , The generation method is as follows: the control command consists of a weighted sum of three feedback quantities; the first part is the component of the position deviation in the corresponding direction, multiplied by a proportional gain coefficient; the second part is the time integral value of the position deviation component, multiplied by an integral gain coefficient; the third part is the instantaneous rate of change of the position deviation component, multiplied by a differential gain coefficient; furthermore, to integrate the safety distance constraint, a fourth feedback quantity is introduced into the control command, which is determined by the real-time safety distance deviation function; the real-time safety distance deviation function outputs a positive value when the measured distance is less than the reference safety distance, otherwise it outputs zero; this output value is then multiplied by a specific constraint feedback gain coefficient and projected onto the corresponding control direction according to geometric relationships to form an additional correction command; the control command That is, the algebraic sum of the projections of the first, second, third, and fourth parts in the X direction; the control command The generation follows and The same logic applies, using the position deviation component in the Y direction and its integral and derivative, as well as the projection component of the safety distance constraint in the Y direction for calculation; for rotational degrees of freedom, the control command... The generation is based on the yaw angle deviation component in the attitude deviation, and also adopts the weighted sum of the proportional, integral and derivative feedback, but it is usually not directly coupled with the safety distance constraint; the parameter tuning method of each gain coefficient in the proportional-integral-derivative control law is a well-known implementation method for those skilled in the art, and will not be elaborated on here.

[0041] In some implementations, the control commands generated by the multi-degree-of-freedom cooperative control process , , The translation drive motor and rotation adjustment motor of the circuit breaker body are sent to the circuit breaker body; these motors execute the commands to adjust the pose of the circuit breaker body; this adjustment process changes the measurement values ​​of the inertial detection unit node and the laser ranging sensor array, and then generates a new deviation vector through the multi-source feedback deviation fusion processing, which is then input again into the multi-degree-of-freedom cooperative control processing to generate new control commands; the cycle continues until the position deviation... The module length is less than the preset position tolerance And attitude deviation All components are less than the preset attitude tolerance. At this point, it is determined that the circuit breaker body has been accurately moved and locked at the optimal translation target position, and the unobstructed area formed around this position constitutes the integrated working space for subsequent synchronous operation of the three-phase current transformer.

[0042] S3, within the integrated work space, simultaneously disconnect all mechanical and electrical connections of the old three-phase current transformers and move the old three-phase current transformers out as a whole; hoist the new current transformer group to the installation position as a whole and complete the initial connection between the new current transformer group and the adjacent fixed cylinder; In some implementations, step S3 is performed within the integrated work space formed via step S203. This step is a routine operation for replacing large modular components in the field of high-voltage electrical equipment maintenance. Specifically, the operator utilizes the unobstructed physical access provided by the integrated work space to simultaneously disconnect all bolted and other mechanical connections between the old three-phase current transformer and the adjacent gas chamber flange, as well as any existing internal primary electrical connections, using specialized tools. After the disconnection is completed, the transformer is removed from its installation position.

[0043] In this embodiment, the pre-assembled and debugged new current transformer assembly is then installed as a whole into the mounting position. During installation, it is necessary to ensure the spatial orientation of the new current transformer assembly and the parallelism and alignment with the docking flange. After installation, the operator immediately performs preliminary mechanical connection between the new current transformer assembly and the adjacent fixed cylinder, such as installing some positioning bolts or guide pins, to achieve temporary fixation and approximate alignment of the components, laying the foundation for the precise alignment and final connection in subsequent step S4. The detailed process specifications for the hoisting operation and preliminary connection are well known to those skilled in the art and will not be elaborated upon here.

[0044] S4. Acquire a real-time image of the flange end face of the moving contact of the circuit breaker body; perform feature matching between the real-time image and a pre-stored reference template image, and generate visual guidance information representing the alignment deviation based on the matching result; adjust the pushing force applied to the circuit breaker body according to the visual guidance information, and iteratively execute this process until the alignment deviation meets the requirements, thereby completing the reset and alignment of the circuit breaker body. Please see the appendix Figure 2 As shown in the attached diagram, this is a visually guided alignment system diagram for resetting and aligning the circuit breaker body, used to intuitively understand the logic of this step. This step specifically includes the following sub-steps: S401, Obtain a reference image of the moving contact flange end face of the circuit breaker body in an ideal state after reset using an endoscope, and extract the contour edge features in the reference image to construct a reference template; The process of acquiring a reference image of the moving contact flange end face of the circuit breaker body under ideal conditions after reset via endoscopy, and extracting contour edge features from the reference image to construct a reference template, includes image feature extraction processing and reference template construction processing. The image feature extraction processing is a process of performing pixel-level analysis on the reference image to identify and quantify the edge contour feature points that characterize the inherent geometric structure of the flange end face. The reference template construction processing is a process of generating a theoretical mathematical description of the key contours of the flange end face under absolutely ideal alignment conditions based on the extracted feature point set through geometric model fitting and optimization. These two processing logics are related. The image feature extraction processing provides discrete feature data input from the physical object for the reference template construction processing, while the reference template construction processing abstracts and idealizes the input data to output a precise digital reference for subsequent visual guidance comparison. Together, they realize the transformation from a physical entity image to a digital theoretical reference.

[0045] In some implementations, the ideal state after reset refers to the assembly state where the circuit breaker body and the current transformer chamber are precisely aligned and finally tightened; this state exists after the initial assembly of the equipment or after the last successful maintenance, but has been lost after this disassembly operation; the endoscope is inserted into the equipment at a designated observation point before this disassembly operation, or when the equipment is in a historically intact state, to obtain a digital image of the moving contact flange end face. As the reference image, it should be noted that the spatial position of the observation point must ensure that the optical axis of the endoscope is as perpendicular as possible to the flange end face plane in order to minimize perspective distortion, and the position of the observation point must be strictly reproduced in the subsequent alignment process.

[0046] In this embodiment, the image feature extraction process is applied to the reference image. The operation is performed; specifically, the process first converts the color image into a grayscale image. Next, an edge detection algorithm is applied. In this embodiment, the Canny operator is used to extract pixels with abrupt changes in grayscale in the image. These pixels correspond to physical edges on the flange end face, such as the inner and outer edges of bolt holes, the edges of sealing grooves, and the outer contour of the flange. The Canny edge detection involves calculating the image gradient magnitude. With direction Where (x, y) represents the two-dimensional integer coordinates of a pixel in the grayscale image. and These represent the grayscale gradient components of the pixel in the x-direction (horizontal direction) and y-direction (vertical direction), respectively. The gradient components are obtained by convolving the local neighborhood centered on the pixel (x,y) with gradient operators in the horizontal and vertical directions. This represents the image gradient magnitude calculated at pixel (x, y), a scalar value characterizing the degree of grayscale change at that location. Following non-maximum suppression and double-threshold hysteresis processing, a binarized edge image is finally obtained. The edge pixel value is 1, and the non-edge pixel value is 0. The specific implementation of the Canny operator is well-known to those skilled in the art and will not be elaborated upon here. Furthermore, the processing involves the edge image... The system identifies and separates different closed or nearly closed contours, especially circular contours; the identification employs a contour tracking algorithm to obtain a contour set composed of a series of ordered pixel coordinates. For each suspected circular contour, use the Hough circle transform or least squares circle fitting algorithm to calculate its center pixel coordinates. and radius; the Hough circle transform maps edge points in image space to parameter space. Where (a, b) is the center of the circle and r is the radius, the circle parameters are determined by finding the peak point in the parameter space using an accumulator. The basic mapping relationship is as follows: The least-squares circle fitting is performed by solving for parameters that minimize the sum of squared errors to fit a circle. The output of the image feature extraction processing is a set of the center pixel coordinates and radii of all key circular features (such as bolt hole circles) on the flange end face. , as well as the pixel set of other feature contours such as the flange outer contour.

[0047] In the reference template construction process, the feature set output by the image feature extraction process is used as input. The core task of this process is to establish a geometrically invariant theoretical template that does not depend on the pixel coordinates of a single captured image. Specifically, the process first selects at least three feature circles (e.g., three specific bolt holes) distributed on the flange end face and with relatively fixed positions from the extracted multiple circular features. Based on the pixel coordinates of these feature circles in the reference image... Combining the intrinsic parameter matrix K of the endoscope lens (obtained through pre-calibration) and the known three-dimensional coordinates of the feature circle in actual physical space (The Z-values ​​are the same on the same flange plane), the ideal pose of the flange plane corresponding to the endoscope camera coordinate system when the reference image is captured is calculated, including the rotation matrix. Translation vector The solution employs a perspective n-point algorithm, the implementation of which is well-known to those skilled in the art and will not be elaborated upon here. and Then, the spatial equation of the flange plane in the camera coordinate system under the "ideal centering state" was defined.

[0048] In this embodiment, the reference template construction process further generates a virtual reference line for subsequent matching; the process, based on the ideal pose and the computer-aided design model of the flange, projects key theoretical contours in the model (such as the ideal distribution circle of all bolt holes and the outer edge circle of the flange) onto the image plane; the projection formula is... Where (X,Y,Z) are the coordinates of the three-dimensional model points, (u,v) are the pixel coordinates after projection, and s is the scale factor; the calculation obtains a series of precise pixel positions of theoretical contours on the image, and these contour lines are defined as the reference template; the reference template Essentially, it is a predefined set of geometric curve parameters associated with the image pixel coordinate system, representing a perfect image of the flange end face profile that should be observed from the fixed observation point under absolutely ideal alignment. The reference template construction process stores the template as the absolute reference standard for feature matching and virtual baseline superposition in step S402.

[0049] S402, during the reset and adjustment process, a real-time image of the moving contact flange end face is obtained through the endoscope, the real-time image is matched with the reference template for edge features, and a virtual reference line corresponding to the contour in the reference template is generated by superimposing the real-time image on the reference image. The process of matching the edge features of the real-time image with the reference template and overlaying them on the real-time image to generate a virtual reference line corresponding to the contour in the reference template includes real-time pose calculation processing and virtual reference line rendering processing. The real-time pose calculation processing is the process of calculating the spatial pose deviation of the moving contact flange end face relative to the ideal alignment state at the current moment by solving the correspondence between the feature point set extracted from the real-time image and the three-dimensional geometric model in the reference template. The virtual reference line rendering processing is the process of projecting the theoretical contour in the reference template onto the real-time image coordinate system and performing graphic overlay based on the calculated real-time pose.

[0050] In some implementations, during the reset and adjustment process, an image of the moving contact flange end face is acquired in real time using an endoscope fixed at the observation point described in step S401. ;right Perform the same image feature extraction process as in S401 to obtain the set of pixel coordinates of key flange features (such as bolt holes) in the real-time image. .

[0051] In this embodiment, the real-time pose calculation process uses the aforementioned real-time feature point set and the reference template constructed in step S401. For input; the reference template contains the physical coordinates of the key features in three-dimensional space. And the endoscope intrinsic parameter matrix K; the core of the processing is to solve for the pose transformation at the current moment. This minimizes the reprojection error between the 3D feature points after this transformation and their corresponding pixels detected in the real-time image; this is a perspective n-point problem, mathematically expressed as minimizing the following objective function: The proj function represents the expression based on the formula. The 3D-to-2D projection calculation is performed (consistent with the S401 calculation method, e.g., s is the scale factor). The pose is... The solution employs an iterative optimization algorithm, the implementation of which is well-known to those skilled in the art and will not be elaborated upon here. The solution yields... It fully describes the current real-time spatial attitude and position of the flange end face.

[0052] In the virtual baseline rendering process, the output of the real-time pose calculation process is utilized. The process will use the reference template. The three-dimensional model points of all theoretical contours defined in the formula are used. Using the same projection principle, its application in the current real-time image is calculated. The expected projection coordinates on the pixel plane. Further, the processing connects these projection coordinate points into lines, and uses these lines to represent the real-time image. Semi-transparent lines, with a color different from the original image, are drawn over the image; these lines constitute the virtual baseline. The virtual baseline represents the position in the image where the flange end face should appear if it is perfectly aligned at this moment. By observing the visual deviation between the actual flange outline in the real-time image and the superimposed virtual baseline, the operator or automatic control system can intuitively perceive the direction and magnitude of the current alignment error. This visual information serves as the direct input for quantitative adjustment in step S403.

[0053] S403. Calculate the pixel offset between the corresponding contour in the real-time image and the virtual baseline, and generate a visual offset vector map reflecting the offset direction and magnitude; adjust the horizontal pushing force applied to the circuit breaker body according to the deviation direction and magnitude indicated by the visual offset vector map, and iteratively execute this step until the pixel offset approaches zero, thus completing the alignment.

[0054] The calculation of the pixel offset between the corresponding contour in the real-time image and the virtual baseline, and the generation of a visual offset vector map reflecting the offset direction and magnitude, includes offset quantization calculation processing and vector map synthesis rendering processing. The offset quantization calculation processing is a process of calculating and statistically analyzing the spatial distance between the actual contour feature points extracted from the real-time image and the corresponding theoretical projection points on the virtual baseline in the image pixel coordinate system, either point-by-point or region-by-region. The vector map synthesis rendering processing is a process of converting the calculated discrete offset data into visual vector symbols with direction and magnitude attributes, and superimposing and labeling them at the corresponding positions in the real-time image.

[0055] In some implementations, the offset quantization calculation process takes the real-time image output in step S402, the set of actual contour edge pixels detected in the real-time image, and the pixel coordinate data of the virtual baseline superimposed on the image as input. Specifically, the process selects multiple feature-corresponding regions in the image, such as local regions surrounding the virtual baseline rings of each bolt hole; for each actual edge pixel in this region, the Euclidean distance from it to the nearest point on the virtual baseline (such as the virtual ring) is calculated, and this distance value is the pixel offset of that point. Further, the process performs statistical analysis on all pixel offsets within the same feature region (such as a single bolt hole region), calculates its average offset as the overall offset representation of the feature, and determines the direction of the overall offset based on the positional distribution of the actual edge points relative to the virtual baseline, for example, the actual contour is located at the lower left of the virtual baseline circle. The process traverses all selected feature regions and outputs a dataset containing the average pixel offset of each region and the overall offset direction vector.

[0056] In this embodiment, the vector graph synthesis rendering process receives the dataset output by the offset quantization calculation process. The process transforms the data into a graphical overlay. Specifically, the process draws an arrow symbol at the center or centroid of each feature region; the direction of the arrow is determined by the overall offset direction vector calculated for that region; the length or thickness of the arrow is proportional to the average pixel offset of that region, for example, by setting a scaling factor to map the pixel offset to the physical pixel length on the screen display. Preferably, the process uses color coding to enhance the visualization effect, for example, using red to represent areas with large offsets, yellow to represent areas with medium offsets, and green to represent areas where the offset meets the tolerance requirements. The process renders all generated arrow symbols and possible color legends in a semi-transparent overlay on the video stream of the real-time image, forming the visualized offset vector graph. The visualized offset vector graph allows the misalignment of the flange end face in multiple local regions to be presented synchronously, quantitatively, and directionally.

[0057] In some implementations, the horizontal jacking force applied to the circuit breaker body is adjusted based on the deviation direction and magnitude indicated by the visualized offset vector map. This adjustment is performed by an operator observing the vector map on a screen and manually controlling the hydraulic jacking device, or by an automatic control system parsing the vector map data and driving the actuator. The goal of the adjustment is to continuously shorten the length of the arrows displayed in the newly generated visualized offset vector map in subsequently acquired real-time images, making their directions increasingly disordered, indicating that the pixel offset in each region approaches zero. The iterative process of image acquisition, offset calculation, vector map generation, and jacking force adjustment is executed until the pixel offset in all feature regions is less than a preset pixel tolerance threshold. At this point, it is determined that the moving contact flange end face of the circuit breaker body is precisely aligned with the target position. The closed-loop operation of mechanical adjustment based on visualized feedback until the tolerance requirements are met is a well-known implementation method for those skilled in the art and will not be elaborated upon here.

[0058] S5, restore all electrical connections and air chamber seals of the equipment, perform a second loop resistance test on the three-phase circuit containing the new current transformer group, and obtain acceptance data; compare and analyze the acceptance data with the status baseline data recorded in step S1, and if the comparison and analysis results meet the preset threshold, confirm that the replacement of the current transformer is complete.

[0059] Specifically, it includes the following sub-steps: S501, restore the electrical connection and air chamber seal of the device, and sequentially perform vacuuming, filling with insulating gas and sealing test on the air chamber containing the new current transformer group; In some implementations, step S501 is performed after the precise alignment of the circuit breaker body is completed in step S403. This step is part of the standard assembly and handling process after maintenance of gas-insulated metal-enclosed switchgear. Specifically, the operator restores all electrical secondary circuit wiring and related grounding connections of the equipment that were disconnected in step S1. Further, the gas chamber flange sealing surface containing the new current transformer assembly is cleaned, a sealing ring is placed, and all connecting bolts are tightened to restore the mechanical seal of the gas chamber.

[0060] In this embodiment, after the gas chamber seal is restored, the gas chamber is sequentially vacuumed, filled with insulating gas, and a sealing test is performed through a dedicated interface. The vacuuming operation reduces the gas pressure inside the gas chamber to a preset vacuum threshold and maintains this pressure for a specified time to remove air and moisture. After successful vacuuming, the gas chamber is filled with insulating gas at its rated pressure, such as sulfur hexafluoride. After filling, a leak detector with qualified sensitivity is used, or the gas pressure is monitored at specified time intervals, to perform a sealing test to verify the reliability of the gas chamber seal. The specific process parameters and operating procedures for vacuuming, filling with insulating gas, and sealing tests are well-known to those skilled in the art and will not be elaborated upon here. This step restores the gas chamber containing the new current transformer group to a sealed and insulated state suitable for electrical operation, providing the necessary physical conditions for the loop resistance acceptance test in step S502.

[0061] S502, perform a second loop resistance test on the three-phase circuit containing the new current transformer group to obtain acceptance data; calculate the first rate of change of the three-phase range of the acceptance data relative to the three-phase range of the state baseline data, and calculate the second rate of change of the acceptance data of each phase relative to the corresponding state baseline data for each phase. Specifically, step S502 involves performing a second loop resistance test on the three-phase circuit containing the new current transformer group and having completed the gas chamber treatment to obtain an acceptance data set. The acceptance data set includes the acceptance resistance value of phase A. Phase B acceptance resistance value Acceptance resistance value of phase C The principle, method, and conditions of the test are consistent with those of the initial circuit resistance test described in step S1 to ensure the comparability of the two test data. This test implementation method is well known to those skilled in the art, and will not be described in detail here.

[0062] In this embodiment, the first rate of change of the three-phase range of the acceptance data relative to the three-phase range of the state baseline data recorded in step S1 is calculated. Specifically, the three-phase range of the state baseline data is first calculated. Next, the three-phase range of the acceptance data is calculated. The first rate of change Defined as the percentage change in acceptance range relative to baseline range, its calculation expression is: It should be noted that the core function of the first rate of change is to monitor the balance and symmetry changes in the three-phase circuit connection status. This rate of change directly reflects whether the replacement operation has introduced inconsistencies in the three-phase circuit connection; if there is poor contact at a connection point in a phase, the resistance of that phase will increase abnormally, leading to an increase in the dispersion of the three-phase resistance values, thereby... Significantly greater than This leads to a positive increase in the first rate of change.

[0063] Furthermore, for each phase, a second rate of change of the acceptance data for that phase relative to the corresponding state baseline data recorded in step S1 is calculated. Specifically, the second rate of change of phase A is calculated respectively. The second rate of change of phase B and the second rate of change of the C phase. The second rate of change monitors the recovery of the absolute connection quality at each independent electrical connection point of each phase. This rate of change directly determines whether the circuit resistance of each phase has recovered or remained at the good level before replacement; it effectively compensates for the monitoring blind spots that may exist with the first rate of change. For example, when a systemic installation problem causes a slight deterioration in the three-phase connection quality to the same degree, the three-phase resistance will increase proportionally, and the three-phase range will... It may remain unchanged, making the first rate of change The effect is not significant, but at this time the second rate of change of each phase will simultaneously show an abnormally positive increase that exceeds the allowable range.

[0064] It should be noted that the calculation of the first rate of change and the second rate of change are complementary and indispensable. The first rate of change verifies the overall balance of the three phases from a horizontal perspective, while the second rate of change verifies the historical state of each phase from a vertical perspective. Together, they constitute a three-dimensional verification network for a comprehensive evaluation of the quality of the circuit connection after replacement. The reliability of the acceptance conclusion is based on a dual, cross-validation of balance and absolute quality, ensuring that the performance of the replaced equipment not only remains symmetrical across the three phases but also fully recovers to the original healthy state of electrical connection. The calculation results provide direct quantitative input for the threshold determination in step S503. S503, when the first rate of change does not exceed the first preset threshold and the absolute value of the second rate of change in each phase does not exceed the second preset threshold, the current transformer replacement operation is confirmed to be completed.

[0065] In this embodiment, step S503 performs the final work quality judgment based on the first rate of change calculated in step S502 and the second rate of change of each phase. The judgment is based on a preset quantization threshold, and this threshold judgment process constitutes the final decision node of the entire current transformer replacement work quality closed-loop control.

[0066] In this embodiment, the first preset threshold is set as The second preset threshold is The first preset threshold is an upper limit for constraining the relative variation of the resistance range of the three-phase circuits; the second preset threshold is an upper limit for constraining the absolute value of the relative variation of the resistance of each phase circuit. The threshold values ​​are... and The values ​​are predetermined based on equipment technical specifications, historical operation and maintenance data, and industry standards. The specific methods for selecting these values ​​fall within the scope of what a person skilled in the art can determine based on the specific application scenario, and will not be elaborated on further here.

[0067] The determination logic of step S503 consists of two parallel conditions that must be met simultaneously. Specifically, the first determination condition is that the first rate of change does not exceed the first preset threshold, and its expression is: It should be noted that this condition primarily verifies that the balance and symmetry of the three-phase circuit connection are maintained after the replacement operation. When this condition is met, it indicates that the maximum difference (range) between the three-phase resistance values ​​has not changed beyond the allowable range relative to the initial state before the operation, thus eliminating serious asymmetrical connection defects caused by improper installation that only affect one or two phases.

[0068] Furthermore, the second criterion is that the absolute value of the second rate of change in each phase does not exceed the second preset threshold, and its expression is: , , The conditions described herein provide a longitudinal assessment of the independent connection quality of each phase. When all conditions are met, it indicates that the resistance value of each phase circuit has recovered to or is close to its original healthy level before operation, and the variation range is controlled within an allowable small fluctuation range. These conditions effectively compensate for any blind spots that may exist in the first judgment condition, and can detect the synchronous abnormal rise in the resistance values ​​of each phase caused by a systematic deterioration in the three-phase connection quality of the same degree (e.g., slightly insufficient contact pressure).

[0069] In some implementations, the determination process is executed automatically based on the above logic; if and only if the logical expression When the calculation result is true, the system or operator confirms that the current transformer replacement operation is complete. The "complete" state is indeed the final sign of a successful closed loop between the "status baseline data" established in step S1 and the "acceptance data" obtained in step S5. It not only signifies the end of the physical replacement work but also proves from an electrical performance perspective that the equipment's loop connection status has passed rigorous quantitative verification and returned to a qualified operating baseline, marking the technical endpoint of the entire maintenance process. If any of the above conditions are not met, it indicates that the installation quality has not met the acceptance standards, and the relevant connections must be checked and retested until the conditions are met.

[0070] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for replacing a current transformer in a gas-insulated combined electrical appliance, characterized in that, Includes the following steps: S1, the equipment is powered off and safety isolation measures are implemented. The primary circuit resistance test is performed on the three-phase circuit containing the current transformer to be replaced, and the measured data is recorded as the status baseline data. The electrical secondary circuit wiring and related grounding connections of the three-phase circuit are disconnected. S2, based on the 3D model of the equipment, dynamic clearance calculation and spatial optimization are performed on the translation path of the circuit breaker body along the direction away from the air chamber of the current transformer to determine the optimal translation target position. Using the dynamic clearance as a reference, the circuit breaker body is controlled to move in a closed loop towards the optimal translation target position, forming an integrated working space. The dynamic clearance is the minimum spatial distance between the outer surface of the circuit breaker body and the inner surface of all surrounding fixed components at each position on the translation path. The dynamic clearance calculation process traverses the discrete position points on the translation path to generate a dynamic clearance sequence. Each element in the dynamic clearance sequence corresponds one-to-one with a discrete position point on the movement path. During the movement of the circuit breaker body, the reference clearance value corresponding to the current movement path point is obtained from the dynamic clearance sequence. The closed-loop movement refers to establishing real-time feedback of displacement, direction, and distance from surrounding components, calculating the deviation between each feedback quantity and the corresponding reference value, and coordinating the translational and rotational degrees of freedom of the circuit breaker body according to the deviation to achieve closed-loop approach and locking towards the optimal translation target position. S3, within the integrated work space, simultaneously disconnect all mechanical and electrical connections of the old three-phase current transformer and move the old three-phase current transformer out as a whole; install the new current transformer group as a whole into the installation position and complete the initial connection between the new current transformer group and the adjacent fixed cylinder; S4, acquire a real-time image of the flange end face of the moving contact of the circuit breaker body; perform feature matching between the real-time image and the pre-stored reference template image, and generate visual guidance information representing the centering deviation based on the matching result; The thrust applied to the circuit breaker body is adjusted according to the visual guidance information, and this process is iteratively executed until the alignment deviation meets the requirements, thus completing the reset and alignment of the circuit breaker body. S5, restore all electrical connections and air chamber seals of the equipment, perform a second loop resistance test on the three-phase circuit containing the new current transformer group, and obtain acceptance data; compare and analyze the acceptance data with the status baseline data recorded in step S1, and if the comparison and analysis results meet the preset threshold, confirm that the replacement of the current transformer is complete.

2. The method for replacing a gas-insulated switchgear current transformer according to claim 1, characterized in that, Step S2 includes: S201, based on the three-dimensional model of the equipment including the surrounding fixed components, simulate the horizontal movement of the circuit breaker body along the direction away from the current transformer air chamber, and calculate the dynamic clearance between each point on the movement path and the surrounding fixed components. S202, Based on the dynamic clearance, perform optimization calculations, select the position with the largest clearance margin in the movement path interval where the dynamic clearance is greater than or equal to the preset safety threshold throughout the entire process, and determine the position as the optimal translation target position of the circuit breaker body. S203, obtain the reference net distance value corresponding to the current moving path point from the dynamic net distance sequence, and establish real-time feedback of displacement, direction and distance from surrounding components; calculate the deviation of each feedback quantity from the corresponding reference value, and adjust the translational and rotational degrees of freedom of the circuit breaker body in a coordinated manner according to the deviation, so as to achieve closed-loop approach and locking to the optimal translational target position, thereby forming the integrated working space.

3. The method for replacing a current transformer in a gas-insulated combined electrical appliance according to claim 1, characterized in that, The S4 step includes: S401, Obtain a reference image of the moving contact flange end face of the circuit breaker body in an ideal state after reset using an endoscope, and extract the contour edge features in the reference image to construct a reference template; S402, during the reset and adjustment process, a real-time image of the moving contact flange end face is obtained through the endoscope, the real-time image is matched with the reference template for edge features, and a virtual reference line corresponding to the contour in the reference template is generated by superimposing the real-time image on the reference image. S403, calculate the pixel offset between the corresponding contour in the real-time image and the virtual baseline, and generate a visual offset vector map reflecting the offset direction and magnitude; adjust the horizontal pushing force applied to the circuit breaker body according to the deviation direction and magnitude indicated by the visual offset vector map, and iteratively execute this step until the pixel offset approaches zero, thus completing the alignment.

4. The method for replacing a gas-insulated switchgear current transformer according to claim 1, characterized in that, Step S5 includes: S501, restore the electrical connection and air chamber seal of the device, and sequentially perform vacuuming, filling with insulating gas and sealing test on the air chamber containing the new current transformer group; S502, perform a second loop resistance test on the three-phase circuit containing the new current transformer group to obtain acceptance data; calculate the first rate of change of the three-phase range of the acceptance data relative to the three-phase range of the state baseline data, and calculate the second rate of change of the acceptance data relative to the corresponding state baseline data for each phase. S503, when the first rate of change does not exceed the first preset threshold and the absolute value of the second rate of change in each phase does not exceed the second preset threshold, the current transformer replacement operation is confirmed to be completed.

5. The method for replacing a current transformer in a gas-insulated combined electrical appliance according to claim 2, characterized in that, The simulation of the circuit breaker body's horizontal movement away from the current transformer's air chamber, based on a 3D model of the equipment including surrounding fixed components, and the calculation of the dynamic clearance between each point on the movement path and the surrounding fixed components, includes dynamic clearance calculation processing and spatial geometric mapping processing. The dynamic clearance calculation processing is a calculation process that, based on spatial geometric relationships, calculates the minimum spatial distance between the outer surface of the circuit breaker body at each position on the movement path and the inner surfaces of all surrounding fixed components. The spatial geometric mapping processing is a process that discretizes the continuous movement process of the circuit breaker body into a series of ordered position point sequences and transforms the spatial relationships of each component in the 3D model of the equipment into a data structure that can be mathematically calculated. The spatial geometric mapping processing provides standardized geometric and positional data input for the dynamic clearance calculation processing.

6. The method for replacing a gas-insulated switchgear current transformer according to claim 2, characterized in that, The optimization calculation based on the dynamic clearance, selecting the position with the largest clearance margin within the movement path interval where the dynamic clearance is greater than or equal to a preset safety threshold, and determining the position as the optimal translation target position of the circuit breaker body, includes safe path interval identification processing and maximum clearance margin position optimization processing. Specifically, the safe path interval identification processing sequentially traverses each clearance value in the dynamic clearance sequence and compares the clearance value with the preset safety threshold. When the dynamic clearance value corresponding to a position point is greater than or equal to the preset safety threshold, the position point is marked as a safe point; when the dynamic clearance value is less than the preset safety threshold, the position point is marked as a conflict risk point, and all consecutively arranged safe points are identified and aggregated into a safe path interval. The maximum clearance margin position optimization processing traverses and compares the dynamic clearance values ​​of each position point within the safe path interval to determine the position point with the largest dynamic clearance value. The safe path interval identification processing defines the boundary and range of the decision search for the maximum clearance margin position optimization processing.

7. The method for replacing a current transformer in a gas-insulated combined electrical appliance according to claim 2, characterized in that, The real-time feedback of displacement, direction, and distance from surrounding components is achieved through inertial detection unit nodes deployed on the circuit breaker body and laser ranging sensor arrays installed on surrounding fixed components. The calculation of the deviation between each feedback quantity and its corresponding reference value, and the coordinated adjustment of the translational and rotational degrees of freedom of the circuit breaker body based on this deviation to achieve closed-loop approach and locking towards the optimal translational target position, includes multi-source feedback deviation fusion processing and multi-degree-of-freedom collaborative control processing. Specifically, the multi-source feedback deviation fusion processing timestamps and unifies the coordinate system of inertial navigation data and laser ranging calculation data, and uses Kalman filtering or complementary filtering algorithms to fuse the two types of data, outputting the real-time pose state. The multi-source feedback deviation fusion processing calculates the position and attitude deviations between the real-time pose state and the reference value, and calculates the real-time safety distance deviation, forming a composite deviation vector. The multi-degree-of-freedom collaborative control processing uses the composite deviation vector as the controller input, takes the position and attitude deviations as the main control targets, and uses the real-time safety distance deviation as a constraint condition.

8. The method for replacing a gas-insulated switchgear current transformer according to claim 3, characterized in that, The process of acquiring a reference image of the moving contact flange end face of the circuit breaker body in an ideal state after reset via endoscopy, and extracting contour edge features from the reference image to construct a reference template, includes image feature extraction processing and reference template construction processing. Specifically, the image feature extraction processing converts the reference image into a grayscale image and uses the Canny operator to extract edge pixels from the image. Contours are identified from the formed edge image, and for suspected circular contours, the Hough circle transform or least squares circle fitting algorithm is used to calculate the center pixel coordinates and radius. The reference template construction processing selects at least three feature circles distributed on the flange end face and with relatively fixed positions from the extracted circular features. Based on the pixel coordinates of the feature circles in the reference image, the intrinsic parameter matrix of the endoscope lens, and the known three-dimensional coordinates of the feature circles in actual physical space, the ideal pose is calculated using a perspective n-point algorithm. Based on the ideal pose and the computer-aided design model of the flange, the theoretical contour in the model is projected onto the image plane to form the reference template.

9. A method for replacing a current transformer in a gas-insulated combined electrical appliance according to claim 3, characterized in that, The process of matching edge features between the real-time image and the reference template, and then overlaying them on the real-time image to generate a virtual baseline corresponding to the contour in the reference template, includes real-time pose calculation processing and virtual baseline rendering processing. The real-time pose calculation processing takes the real-time feature point set extracted from the real-time image and the reference template as input. Based on the physical coordinates of the features in three-dimensional space and the endoscope intrinsic parameter matrix, it solves for the current pose transformation that minimizes the reprojection error between the three-dimensional feature points after pose transformation projection and the corresponding pixels in the real-time image. The virtual baseline rendering processing projects the three-dimensional model points of the theoretical contour defined in the reference template onto the pixel plane of the current real-time image, connects the resulting projected coordinate points into a line, and overlays it onto the real-time image to form the virtual baseline.

10. A method for replacing a gas-insulated switchgear current transformer according to claim 3, characterized in that, The calculation of pixel offsets between the corresponding contours in the real-time image and the virtual baseline, and the generation of a visual offset vector map reflecting the direction and magnitude of the offset, includes offset quantization calculation processing and vector map synthesis rendering processing. Specifically, the offset quantization calculation processing calculates the Euclidean distance from each actual edge pixel within the corresponding feature region to the nearest point on the virtual baseline as the pixel offset of that point. It then performs statistical analysis on all pixel offsets within the same feature region and calculates the average offset as the overall offset representation of the feature. The overall offset direction is determined based on the positional distribution of the actual edge points relative to the virtual baseline. The vector map synthesis rendering processing draws an arrow symbol at the center or centroid of each feature region. The direction of the arrow is determined by the overall offset direction of the region, and the length or thickness of the arrow is proportional to the magnitude of the average pixel offset of the region. The arrow symbol is then superimposed on the real-time image to form the visual offset vector map.

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