A spring mechanism control method capable of realizing quick opening and closing

Abstract

The application provides a spring mechanism control method capable of realizing quick opening and closing functions, comprising: collecting stress gradient concentration along the short axis direction of the spring wire section, measuring the aspect ratio of the spring wire section, scanning the residual tensile stress coverage width of the spring wire section edge area, and identifying the initial stress distribution form after shot blasting treatment of the spring wire surface; for the abnormal recession interval marked by the abnormal energy storage recession identifier, extracting the stress gradient concentration evolution along the short axis direction of the section, classifying the boundary points of the initial relaxation delay and the middle and later relaxation acceleration, and substituting the stress concentration threshold value of the boundary point into the closing release force judgment condition; under the updated closing release force judgment condition, the remaining elastic potential energy feedback of the spring mechanism is obtained, and whether the remaining elastic potential energy after long-term standby conforms to the factory calibration range is evaluated.

Description

Technical Field

[0001] This invention relates to the field of information technology, and in particular to a spring mechanism control method that enables rapid opening and closing of circuit breakers. Background Technology

[0002] In the field of power equipment, circuit breakers, as key components for rapid disconnection and restoration of power grid faults, directly determine the system's response speed to short circuits or overloads through their rapid opening and closing functions. The realization of this function highly depends on the energy storage and release performance of the spring mechanism. The spring must maintain a stable preload in long-term standby mode to ensure that the operating speed at the moment of opening or closing precisely matches the design requirements. Otherwise, any energy attenuation may lead to delayed contact closure, amplifying the impact of the fault and even triggering a chain reaction that threatens the stability of the entire power grid. Current research focuses primarily on upgrading spring materials or adjusting basic structures, neglecting the complex interaction between the aspect ratio of the spring wire cross-section and surface strengthening processes such as shot peening. This interaction causes unpredictable changes in stress distribution during long-term energy storage, becoming a bottleneck restricting performance optimization. Specifically, the aspect ratio of the spring wire cross-section, i.e., the ratio of the major axis to the minor axis, directly affects its bending and compression recovery capabilities. A rectangular or elliptical cross-section design with a higher aspect ratio can enhance the bending stiffness in the minor axis direction, allowing the spring to exhibit stronger elastic recovery force during initial compression, thereby theoretically improving energy storage capacity and initial fatigue resistance. However, the situation changes drastically when shot peening is used to strengthen the surface. This process introduces shallow residual compressive stress to improve fatigue life by impacting the surface with high-speed steel shot, but at the same time, it creates localized tensile stress zones at the edges and corners. The depth of these stress layers and the width of the tensile stress distribution are highly dependent on the cross-sectional geometry: as the aspect ratio increases, the compressive stress layer tends to thin, while the tensile stress zone at the edges expands accordingly, causing the intended surface strengthening to backfire. In the standby state, the spring is under constant preload, and the creep and relaxation effects accumulated over time cause the compressive stress zone to gradually spread and erode into the surrounding tensile stress zone, accelerating the overall stress decay. This inherent contradiction between the initial increase in stiffness and the later exacerbation of stress decay makes the long-term stability of high aspect ratio springs inferior to that of low aspect ratio designs. For example, in high-voltage circuit breaker applications, a device using a high aspect ratio rectangular wire spring achieved a perfect closing speed of within 50ms during factory testing. However, after being placed in a substation standby environment for several months, due to the expansion of the edge tensile stress zone and the shrinkage of the effective compressive stress zone, the released energy was only 85% of the factory value. This caused the initial closing speed to drop to 70ms, missing the fault response window, resulting in a prolonged short-circuit current duration and a surge in the risk of equipment overheating. Similar problems frequently occur in vacuum circuit breakers: shot-peened circular cross-section springs with low aspect ratios, although having a smaller initial tensile stress zone, have insufficient bending stiffness and a low energy storage limit; switching to elliptical cross-section springs with high aspect ratios, however, results in accelerated stress transformation during the standby period, causing energy output fluctuations of over 15%, which cannot meet the precision requirements of grid dispatch for repetitive operations. Furthermore, environmental factors such as high temperature and humidity further amplify this contradiction. In the Southern Power Grid scenario, springs that have been in standby for more than a year often show a steepened stress decay curve, with release speed deviations exceeding the allowable threshold of 5%, directly weakening the circuit breaker's ability to isolate transient faults.More seriously, the unpredictability of this stress evolution stems from the insufficient understanding of the coupling effect between aspect ratio and surface treatment. Traditional tests are mostly conducted under short-term cycles, neglecting microscopic changes under long-term static energy storage, such as how grain boundary slip or dislocation climb is affected by cross-sectional shape. This leads to significant differences in the rate at which tensile stress zones "eat" compressive stress zones across different designs. As a result, it is difficult to predict the performance degradation of circuit breakers during the standby period before actual commissioning, requiring frequent calibration or replacement during operational maintenance, increasing costs and reducing the overall reliability of the power grid. Especially in ultra-high voltage direct current transmission systems, spring performance deviations can be amplified into cross-regional faults, necessitating a thorough analysis of this technical contradiction to ensure that equipment maintains its factory operating parameters under various conditions. Summary of the Invention

[0003] This invention provides a spring mechanism control method for achieving rapid opening and closing of the circuit breaker. The method includes: acquiring stress gradient concentration along the minor axis of the spring wire cross-section, measuring the aspect ratio of the spring wire cross-section, scanning the residual tensile stress coverage width of the edge region of the spring wire cross-section, and identifying the initial stress distribution pattern after shot peening of the spring wire surface; extracting the boundary position between compressive and tensile stress along the minor axis of the cross-section based on the initial stress distribution pattern, evaluating the relaxation change path after the cross-section aspect ratio and shot peening residual stress are superimposed, analyzing the residual elastic potential energy decay process based on the relaxation change path, comparing the real-time decay inflection point position with the factory-calibrated inflection point position, and determining the degree of forward shift of the decay curve inflection point; analyzing whether the degree of forward shift of the decay curve inflection point exceeds a preset threshold, and if it does, merging... The decay process of residual elastic potential energy and the coverage width of residual tensile stress in the edge region are used to obtain an abnormal energy storage degradation indicator. For the abnormal degradation interval marked by the abnormal energy storage degradation indicator, the boundary points of the initial relaxation delay and the mid-to-late-stage relaxation acceleration are classified, and the stress concentration thresholds corresponding to the boundary points are substituted into the closing release force judgment conditions. Under the updated closing release force judgment conditions, the residual elastic potential energy feedback is obtained to assess whether it meets the factory calibration range after long-term standby. If it does not meet the criteria, the release force output adjustment range is defined according to the forward shift of the inflection point, and the closing operation speed adjustment scheme is determined. If it meets the criteria, the release force output remains unchanged. The release force output is adjusted according to the adjustment scheme to drive the circuit breaker to perform the closing operation. The stress distribution pattern of the spring wire is scanned after the operation to confirm that the abnormal energy storage degradation has been eliminated.

[0004] Furthermore, the process of acquiring stress gradient concentration along the minor axis of the spring wire cross-section, measuring the aspect ratio of the spring wire cross-section, scanning the residual tensile stress coverage width of the edge region of the spring wire cross-section, and identifying the initial stress distribution pattern after shot peening of the spring wire surface includes: laying out a detection path along the outer surface of the spring wire with the minor axis of the cross-section as the reference; acquiring the residual stress value along the depth direction by X-ray diffraction to obtain the stress gradient concentration; obtaining the aspect ratio of the spring wire cross-section from the ratio of the geometric coordinates of the major axis endpoint to the minor axis endpoint; continuously scanning along the contour tangent direction for the edge region, obtaining the residual tensile stress coverage width of the edge region from the arc length between the residual stress transition point and the termination point; splicing the stress gradient concentration, the aspect ratio of the spring wire cross-section, and the residual tensile stress coverage width of the edge region according to the cross-sectional position sequence to form a stress distribution sequence unfolding along the circumference of the spring wire, identifying the proportion and connection order of the middle straight section, the transition section, and the edge section in the circumferential direction, and obtaining the initial stress distribution pattern.

[0005] Furthermore, the step of extracting the boundary position between compressive and tensile stress along the minor axis of the cross section based on the initial stress distribution pattern, evaluating the relaxation change path after the cross section aspect ratio and shot peening residual stress are superimposed, analyzing the residual elastic potential energy decay process based on the relaxation change path, comparing the real-time decay inflection point position with the factory-calibrated inflection point position, and determining the degree of forward shift of the decay curve inflection point includes: retrieving the stress sign zero-crossing position from the surface to the core along the minor axis of the cross section as the boundary position; weighting and superimposing the cross section aspect ratio and shot peening residual stress amplitude in the neighborhood of the boundary position to obtain a coupled stress curve; collecting the trajectory of the boundary position migrating to the surface as the standby time is used as the relaxation change path; performing volume integration on the compressive stress action area along the relaxation change path to obtain the decay process curve; calculating the peak time of the second-order rate of change of the decay process curve as the decay inflection point position, and subtracting it from the factory-calibrated inflection point position coordinates to obtain the degree of forward shift of the decay curve inflection point.

[0006] Furthermore, the analysis determines whether the forward shift of the inflection point of the decay curve exceeds a preset threshold. If it does, the remaining elastic potential energy decay process is integrated with the width of the residual tensile stress coverage in the edge region to obtain an abnormal energy storage decay indicator. This includes: normalizing the width of the residual tensile stress coverage in the edge region according to the factory-calibrated width to obtain a tensile stress erosion weight; multiplying and weighting the residual elastic potential energy extension segment after the inflection point at each time step to obtain a corrected decay sequence; using least squares fitting along the mid-to-late stage of relaxation acceleration anomaly to obtain a decay trend line; and combining the decay rate component of the absolute value of the slope of the decay trend line with the residual potential energy component at the end of the stage to form the abnormal energy storage decay indicator.

[0007] Furthermore, for the abnormal decline interval marked by the abnormal energy storage decline indicator, the boundary points for the initial relaxation delay and the mid-to-late relaxation acceleration are classified, and the stress concentration threshold corresponding to the boundary point is substituted into the closing release force judgment condition. This includes: retrieving the stress gradient concentration value moment by moment along the standby time axis of the abnormal decline interval and arranging it in time sequence to obtain the stress gradient concentration evolution trajectory along the short axis of the cross section; calculating the difference between the values ​​at adjacent time moments to obtain a point-by-point drop rate sequence; retrieving the position where the drop rate sequence turns and crosses the preset rate threshold as the boundary point; and extracting the value corresponding to the boundary point as the stress concentration threshold.

[0008] Furthermore, the step of obtaining the remaining elastic potential energy feedback under the updated closing release force determination condition and assessing whether it meets the factory calibration range after long-term standby includes: obtaining the remaining elastic potential energy feedback by jointly converting the displacement sensing data and tension sensing data built into the spring mechanism according to the elastic strain energy accumulation formula under the correspondence between spring compression and tension; comparing the remaining elastic potential energy feedback with the lower limit value and upper limit value registered in the factory inspection file in sequence, and determining compliance if it falls within the factory calibration range, otherwise determining non-compliance.

[0009] Furthermore, when the condition does not meet the requirements, the release force output adjustment range is defined according to the magnitude of the forward shift of the inflection point, and the closing operation speed adjustment scheme is determined. When the condition meets the requirements, the release force output remains unchanged. This includes: when the condition does not meet the requirements, the abnormal energy storage degradation identifier is fused with the updated criterion content formed after being incorporated into the closing release force judgment condition to form a comprehensive degradation file containing the load degradation rate component, the residual level component, and the stress concentration threshold component. The comprehensive degradation file registers all stress distribution samples in the inflection point forward shift stage using the standby time as an index. The attenuation curve is divided into low-level, medium-level, and high-level groups according to the magnitude of the forward shift of the inflection point. For each level group, an upward adjustment ratio range given by the corresponding level group degradation rate component, based on the factory rated release force, is matched as the release force output adjustment range. The closing operation speed adjustment scheme is formed by the upward adjustment ratio range. When the condition meets the requirements, the current release force output remains unchanged, the spring mechanism is marked as normal standby state and written into the standby state registration bit of the control unit.

[0010] Furthermore, the step of adjusting the release force output according to the adjustment scheme, driving the circuit breaker to perform a closing operation, scanning the stress distribution of the spring wire after execution, and confirming the elimination of abnormal energy storage decay includes: issuing an upward adjustment command to the release force execution circuit based on the correction coefficient obtained by interpolation within the upper adjustment ratio range and increasing the release force by a preset step size; when the value reported by the tension feedback channel falls within the release force output adjustment range, it is recorded as reaching the target value of the adjustment range; issuing a closing drive signal to drive the circuit breaker to perform a closing operation, and scanning the stress distribution of the spring wire after execution by setting up a detection path along the outer surface of the spring wire again; comparing the boundary of the compressive stress layer in the stress distribution of the spring wire after execution with the initial boundary at the factory, and statistically analyzing the dispersion of the closing contact time series of multiple closing operations; when the boundary of the compressive stress layer returns to the factory state and the dispersion falls within the allowable fluctuation range of the closing speed, it is determined that the abnormal energy storage decay has been eliminated.

[0011] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention discloses a control method for a spring mechanism that enables rapid opening and closing. Addressing the issue of abnormal closing speed caused by the decay of residual elastic potential energy in the spring mechanism after long-term standby, this invention constructs a complete stress gradient and elastic potential energy decay trend analysis mechanism by integrating residual stress detection, stress distribution pattern analysis, and assessment of the forward shift of the decay curve inflection point. First, this invention detects the stress distribution across the spring wire cross-section and the width of residual tensile stress coverage in the edge region to extract the initial stress pattern and relaxation change path. Then, it analyzes the abnormal stages in the elastic potential energy decay process, identifies the degree of inflection point forward shift, and uses threshold values ​​to determine abnormal energy storage decay indicators. Finally, it optimizes the release force output based on the adjustment range to ensure that the closing speed stably reproduces the factory calibration range. This invention effectively solves the energy storage decay problem caused by stress relaxation in the spring mechanism, significantly improving the reliability and stability of the circuit breaker closing operation and achieving rapid opening and closing functionality. Attached Figure Description

[0012] Figure 1 This is a flowchart of a spring mechanism control method for realizing rapid opening and closing of the circuit breaker according to the present invention.

[0013] Figure 2 This is a schematic diagram of a spring mechanism control method for realizing rapid opening and closing of the circuit breaker according to the present invention.

[0014] Figure 3 This is another schematic diagram of a spring mechanism control method for realizing rapid opening and closing of the circuit breaker according to the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0016] like Figures 1-3 This embodiment of a spring mechanism control method for achieving rapid opening and closing of the circuit breaker may specifically include: S101. Collect stress gradient concentration along the short axis of the spring wire cross section, measure the aspect ratio of the spring wire cross section, scan the width of residual tensile stress coverage in the edge region of the spring wire cross section, and identify the initial stress distribution pattern after shot peening treatment of the spring wire surface.

[0017] A detection path is laid out along the outer surface of the spring wire, extending with the minor axis of the cross-section as the reference. X-ray diffraction is used to collect the residual stress values ​​from the surface to the subsurface of the spring wire. The stress gradient concentration is obtained based on the decreasing slope of the numerical change along the minor axis depth direction. This stress gradient concentration reflects the compactness of the compressive stress layer transitioning from the surface to the core under shot peening. The stress gradient concentration is mapped one-to-one with the geometric contour data of the spring wire according to the cross-sectional position to determine the reference coordinate position for subsequent cross-sectional parameter measurements. A cross-sectional contour image of the spring wire is acquired at the reference coordinate position, and the geometric coordinates of the endpoints of the major and minor axes are extracted. The aspect ratio of the spring wire cross-section is obtained based on the ratio of the major axis length to the minor axis length. This aspect ratio is used to divide the cross-section into a straight central region and two edge regions. For the edge regions, continuous scanning is conducted along the tangent direction of the contour to record the transition point of residual stress from compression to tension and the termination point where tensile stress decays to zero. The residual tensile stress coverage width of the edge region is obtained based on the arc length between the transition point and the termination point. The stress gradient concentration, the aspect ratio of the spring wire cross section, and the width of the residual tensile stress coverage in the edge region are spliced ​​together according to the cross-sectional position sequence to form a stress distribution sequence that unfolds along the circumference of the spring wire. The stress distribution sequence is used to identify the straight middle section dominated by compressive stress, the transition section at the junction of tension and compression, and the edge section dominated by tensile stress. The initial stress distribution pattern after shot peening of the spring wire surface is obtained according to the proportion and connection order of the three sections in the circumferential direction.

[0018] In the long-term standby state of the circuit breaker spring mechanism, the residual stress distribution formed on the surface of the spring wire after shot peening has a decisive influence on the energy storage stability. The residual stress detection module is deployed at the inspection station before the spring mechanism is assembled. It moves and positions the spring wire segment by segment along its axis and performs cross-sectional stress scanning for each positioning segment.

[0019] Specifically, the residual stress detection module includes an X-ray diffraction probe, a rotatable clamping stage, and a contour image acquisition unit. The spring wire is clamped on the rotatable clamping stage, and the X-ray diffraction probe has a detection path laid out along the outer surface of the spring wire, extending with the minor axis of the cross-section as a reference. In one embodiment, the circuit breaker opening and closing springs often use rectangular or elliptical cross-section wires. The minor axis corresponds to the direction with the smaller cross-sectional thickness and is also the dominant direction of bending stress during compression energy storage. Placing detection points along the minor axis can capture the stress attenuation trajectory of the shot peening impact layer in the most sensitive direction.

[0020] It is understandable that the X-ray diffraction method is based on the principle that the interplanar spacing of crystal planes shifts slightly under residual stress, and the stress value is inferred by measuring the angular displacement of the diffraction peaks.

[0021] For example, for spring steel materials such as 4Cr13 or 60Si2Mn, residual stress values ​​at several discrete points within a depth range of 0 to 0.3 mm on the surface are collected. The residual stress values ​​show compressive stress extremes on the surface and gradually decrease towards the core and approach zero. The stress value change from the surface to the subsurface forms a decreasing curve along the depth direction.

[0022] It should be noted that the stress gradient concentration reflects the compactness of the transition of the compressive stress layer from the surface to the core under shot peening strengthening.

[0023] Specifically, the slope of the decreasing curve is calculated along the depth direction, and the position with the largest absolute value of the slope is defined as the transition core point. The slope value at the transition core point is used as the value of the stress gradient concentration. The steeper the slope, the more compact the transition of compressive stress to the core, and vice versa. In the detection of the tripping spring of a high-voltage circuit breaker, the stress gradient concentration is directly related to the particle size, coverage, and spraying angle of the shot peening medium. After the stress gradient concentration is obtained, the geometric contour data of the spring wire, which is acquired synchronously with the contour image acquisition unit, is matched one-to-one with the cross-sectional position to determine the reference coordinate position for subsequent cross-sectional parameter measurements. The reference coordinate position is recorded as the axial coordinate of the spring wire plus the circumferential angle of the cross-section. At the reference coordinate position, the contour image acquisition unit acquires the cross-sectional contour image of the spring wire and extracts the geometric coordinates of the major axis endpoint and the minor axis endpoint on the closed contour of the cross-section.

[0024] Preferably, the length of the major axis is the distance between the two points on the contour furthest from the centroid, and the length of the minor axis is the distance between the two intersection points of the contour in the direction perpendicular to the major axis. The ratio of the two is the aspect ratio of the spring wire cross section.

[0025] For example, the aspect ratio of a conventional circular cross-section is close to 1, while the aspect ratio of a rectangular cross-section can be between 1.5 and 2.5. The aspect ratio of the spring wire cross-section is used to divide the cross-section into a straight central region and two edge regions.

[0026] Specifically, traversing the circumferential contour of the cross-section, arc segments with a radius of curvature below a threshold are identified as edge regions, while arc segments with a larger radius of curvature and a gentler change are identified as the central straight region. For the edge regions, continuous point scanning is performed along the contour tangent, and the surface residual stress value is collected at each point. The transition point where the residual stress changes from compressive to tensile and the termination point where the tensile stress decays to zero are recorded. Near the edge of the spring wire after shot peening, due to the rebound and tangential impact of the shot peening medium on the protruding geometric area, the surface stress transitions from a compressive stress state in the central straight region to a tensile stress state. The transition point is the arc length where the compressive stress value crosses the zero line to become tensile stress, and the termination point is the arc length where the tensile stress decays back to the zero line. The arc length between the transition point and the termination point is recorded as the residual tensile stress coverage width of the edge region. Furthermore, for the elliptical cross-section of the vacuum circuit breaker closing spring, the residual tensile stress coverage width of the edge region typically expands with increasing aspect ratio.

[0027] In one embodiment, the tensile stress coverage width of an elliptical cross-section with an aspect ratio of 2.0 can be increased by approximately 40% compared to a cross-section with an aspect ratio of 1.2. This coverage width constitutes the geometric scale for evaluating the range of shot peening side effects. The stress gradient concentration, the aspect ratio of the spring wire cross-section, and the residual tensile stress coverage width of the edge region are spliced ​​together according to the cross-sectional position sequence to form a stress distribution sequence unfolding circumferentially along the spring wire. The stress distribution sequence is plotted with the circumferential angle as the horizontal axis and the values ​​of each physical quantity as the vertical axis, recording three sets of values ​​for each angle. For the stress distribution sequence, the straight section in the middle dominated by compressive stress, the transition section at the junction of tension and compression, and the edge section dominated by tensile stress are identified.

[0028] Specifically, the three types of arc segments are arranged in order of proportion according to their circumferential position. Together with the stress jump amplitude at the joint of each segment, the initial stress distribution pattern after shot peening of the spring wire surface is obtained. The initial stress distribution pattern serves as the factory benchmark record for stress relaxation assessment under subsequent long-term standby conditions.

[0029] S102. Based on the initial stress distribution pattern, extract the boundary position of compressive stress and tensile stress in the short axis direction of the cross section, evaluate the relaxation change path after the cross section aspect ratio and shot peening residual stress are superimposed, analyze the decay process of the remaining elastic potential energy based on the relaxation change path, compare the inflection point position in the real-time decay process with the factory-calibrated inflection point position, and determine the degree of forward shift of the inflection point of the decay curve.

[0030] Based on the initial stress distribution pattern, a continuous trajectory of stress value variation with depth is extracted along the minor axis of the cross section. The zero-crossing position where the stress sign changes from negative to positive is retrieved from the surface to the core along this continuous trajectory. This zero-crossing position is marked as the boundary between compressive and tensile stress along the minor axis of the cross section. This boundary position corresponds to the effective boundary of the compressive stress layer of the spring wire. The aspect ratio of the spring wire cross section and the residual stress amplitude from shot peening are then weighted and superimposed within the neighborhood of this boundary position to obtain a coupled stress curve reflecting the coupling effect of cross-sectional geometry and surface strengthening. Starting from this coupled stress curve, the trajectory of the boundary position migrating towards the surface with the length of the standby time is collected under continuous preload of the spring mechanism. This migration trajectory reflects the evolution process of the tensile stress zone encroaching on the compressive stress zone. This migration trajectory is defined as a relaxation change path. Volume integration is performed along this relaxation change path on the effective compressive stress zone based on the relationship between stress and strain energy density to obtain the residual elastic potential energy of the spring wire at each standby time. This residual elastic potential energy forms a monotonically decreasing decay curve with the length of the standby time. The second-order rate of change is calculated for the decay process curve. The time corresponding to the peak value of the absolute value of the second-order rate of change is marked as the real-time decay inflection point position. The factory calibration inflection point position of the same spring wire under the calibration condition is retrieved from the factory test file. The coordinates of the real-time decay inflection point position on the time axis are subtracted from the coordinates of the factory calibration inflection point position to obtain the degree of forward shift of the decay curve inflection point.

[0031] The initial stress distribution pattern after shot peening of the spring wire surface is indexed by the circumferential position of the cross section, and the stress value sequence along the minor axis at each position is recorded.

[0032] It should be noted that the short axis direction is the direction dominated by the bending deformation of the spring wire during compression energy storage, and the relative thickness of the compressive stress layer and the tensile stress layer in this direction is directly related to the storage capacity of elastic potential energy.

[0033] Specifically, for the initial stress distribution pattern, a continuous trajectory of stress value variation with depth is extracted along the minor axis of the cross-section. This continuous trajectory is formed by cubic spline interpolation of discrete stress measurement points from the surface layer, subsurface layer to the core. The zero-crossing position where the stress sign changes from negative to positive is retrieved along this continuous trajectory from the surface layer to the core. Negative values ​​represent compressive stress, and positive values ​​represent tensile stress. This zero-crossing position is the effective boundary of the compressive stress layer. The depth coordinate of the boundary between compressive and tensile stress along the minor axis of the cross-section is denoted as h0. In one embodiment, for the rectangular cross-section wire of the high-voltage circuit breaker tripping spring, the boundary position is generally located between 0.15 mm and 0.35 mm below the surface layer. The larger the aspect ratio of the cross-section, the closer the boundary position is to the surface layer.

[0034] It is understood that after the boundary position is calibrated, the aspect ratio of the spring wire section and the residual stress amplitude of the shot peening are weighted and superimposed in the neighborhood of the boundary position to form a coupled stress curve.

[0035] Specifically, the weighted superposition rule involves taking a certain depth range from the boundary position towards both the surface and the core, using the aspect ratio as the stress amplification weight in the edge direction and the residual stress amplitude from shot peening as the baseline amplitude, and multiplying and summing the coordinates along the minor axis for each depth to obtain a coupled stress curve reflecting the coupling effect of cross-sectional geometry and surface strengthening. This coupled stress curve exhibits a significant stress jump characteristic in the neighborhood of the boundary position. This coupled stress curve serves as the initial baseline for evaluating the long-term standby performance of the spring wire. Further, after the spring mechanism is assembled into the circuit breaker housing and a preload is applied, the spring wire is in a continuously compressed energy storage state. Under continuous preload conditions, the depth coordinates of the boundary position in the minor axis direction are periodically collected at fixed points along the axial direction. These depth coordinates show a tendency to migrate towards the surface as the standby time increases; this migration trajectory is defined as the relaxation change path. This relaxation change path reflects the evolution process of the tensile stress zone encroaching on the compressive stress zone, that is, the physical process by which the shallow compressive stress layer introduced by shot peening is gradually eroded by the edge tensile stress zone under creep and stress relaxation.

[0036] It should be noted that the grazing rate is positively correlated with the aspect ratio of the cross section.

[0037] In one embodiment, the relaxation path of the elliptical cross-section wire with an aspect ratio of 2.0 exhibits a significantly increased slope after a standby period of 6 months, much earlier than the moment when the circular cross-section wire with an aspect ratio of 1.2 exhibits the same slope.

[0038] Specifically, along the relaxation path, the volume integral of the effective compressive stress zone is performed based on the relationship between stress and strain energy density to obtain the residual elastic potential energy of the spring wire at each standby time. The relationship between strain energy density adopts the mechanical relationship that the strain energy per unit volume is proportional to the square of the stress within the linear elastic range. The arc segment of the coupled stress curve from the boundary to the outer surface is expanded into volume units along the circumference and axial direction of the spring wire. The strain energy density of each volume unit is summed to obtain the residual elastic potential energy value U. The residual elastic potential energy U forms a monotonically decreasing decay process curve with the standby time. The decay process curve initially shows a slow, delayed decline, and later a steep, accelerated decline, with a sudden change in the rate of decline at the junction of the two segments. A second-order rate of change is calculated for the decay process curve.

[0039] Specifically, using the standby time as the independent variable and the remaining elastic potential energy U as the dependent variable, the first difference is first calculated to obtain the descent rate sequence, and then the first difference is calculated on the descent rate sequence to obtain the second-order rate of change sequence. The time corresponding to the peak value of the absolute value of the second-order rate of change is marked as the real-time decay inflection point position, which is the critical moment for the transition from the delay phase to the acceleration phase. The factory calibration inflection point position of the same specification of spring wire under calibration conditions is retrieved from the factory inspection file. The factory inspection file is pre-collected by the manufacturing process on an accelerated aging test bench before the spring mechanism leaves the factory, recording the calibration decay process curve of the spring wire of that specification and its inflection point time coordinates. The coordinates of the real-time decay inflection point position on the time axis are subtracted from the coordinates of the factory calibration inflection point position to obtain the degree of forward shift of the decay curve inflection point Δt. The degree of forward shift of the inflection point Δt is used to characterize the advance of the stress relaxation process under long-term standby conditions relative to the factory calibration. In the application scenario of vacuum circuit breaker closing spring, the degree of forward shift of the inflection point Δt is positive and the larger the value, the more it indicates that the erosion rate of the tensile stress zone of the spring wire edge to the compressive stress zone exceeds the calibration expectation, and the attenuation acceleration phase enters earlier.

[0040] S103. Analyze whether the forward shift of the inflection point of the decay curve exceeds the preset threshold. If it exceeds the preset threshold, integrate the decay process of the remaining elastic potential energy with the coverage width of the residual tensile stress in the edge region to assess the decay trend of the remaining elastic potential energy in the abnormal stage of relaxation acceleration in the middle and late stages, and obtain the abnormal energy storage decay indicator.

[0041] The degree of forward shift of the inflection point of the decay curve is compared with a preset threshold. If the degree of forward shift of the inflection point exceeds the preset threshold, the spring wire is determined to have entered the mid-to-late stage of relaxation acceleration anomaly. The extension segment of the residual elastic potential energy decay process curve after the inflection point and the current value of the residual tensile stress coverage width of the edge region are retrieved as the input sequence for subsequent fusion processing. For the input sequence, the residual tensile stress coverage width of the edge region is normalized according to the factory calibration width to obtain the tensile stress erosion weight. The residual elastic potential energy of the extension segment is multiplied and weighted at each moment using the tensile stress erosion weight to obtain a corrected decay sequence reflecting the edge tensile stress erosion effect. The corrected decay sequence is fitted with least squares along the mid-to-late stage of relaxation acceleration anomaly to obtain a decay trend line. The absolute value of the slope of the decay trend line represents the decay rate of the residual elastic potential energy in the stage. An abnormal energy storage decay indicator is formed by combining the absolute value of the slope of the decay trend line and the residual potential energy of the decay trend line at the end of the stage. The abnormal energy storage decay indicator consists of a decay rate component and a residual level component, and is used to mark the abnormal decay section of the spring wire that deviates from the factory-calibrated decay law.

[0042] One possible combination method is to set the absolute slope as S and the residual amount as R. First, normalize S and R, where S is divided by the factory-calibrated maximum slope of 5.0 to obtain Sn, and R is divided by the factory-calibrated initial potential energy of 100.0 to obtain Rn. Then, calculate the combination value ID = 0.6*Sn + 0.4*Rn with weights of 0.6 and 0.4, which serves as the weighted sum of the decay rate component and the residual level component.

[0043] For example, if S=3.0 and R=40.0, then Sn=0.6, Rn=0.4, and ID=0.52 are used to mark the abnormal decay section of the spring wire that deviates from the factory-calibrated decay pattern. The degree to which the inflection point of the decay curve shifts forward reflects the advance of the stress relaxation process of the spring wire under long-term standby conditions relative to the factory calibration.

[0044] It should be noted that the degree of forward shift of the inflection point only indicates an abnormal relaxation process when it exceeds a certain limit; deviations within the limit are considered normal process fluctuations.

[0045] Specifically, the numerical value indicating the degree of forward shift of the inflection point of the attenuation curve is compared with a preset threshold. The preset threshold is determined based on the dispersion of the inflection point offset distribution of samples of the same specification under accelerated aging conditions in the spring wire's factory inspection file, and is conventionally set as the upper bound of the 95% confidence interval of the file distribution. In one embodiment, for rectangular cross-section wires used for high-voltage circuit breaker tripping springs, the preset threshold is set to 8% of the calibrated reserve period; for elliptical cross-section wires used for vacuum circuit breaker closing springs, the preset threshold is set to 6% of the calibrated reserve period. If the degree of forward shift of the inflection point of the attenuation curve exceeds the preset threshold, the spring wire is determined to have entered the mid-to-late stage of accelerated relaxation abnormality.

[0046] Specifically, the extended segment of the residual elastic potential energy decay process curve after the inflection point is retrieved. This extended segment starts at the real-time decay inflection point and ends at the current time of the standby duration, recording the trajectory of the residual elastic potential energy value decreasing over time within this interval. Simultaneously, the current value of the residual tensile stress coverage width of the edge region is retrieved, taken from the most recent residual stress detection scan result. These two sets of data together constitute the input sequence for subsequent fusion processing. For this input sequence, the residual tensile stress coverage width of the edge region is normalized according to the factory-calibrated width to obtain the tensile stress erosion weight.

[0047] Specifically, normalization employs a ratio method, dividing the current coverage width by the factory-calibrated width to obtain a dimensionless tensile stress erosion weight W. A W value greater than 1 indicates that the edge tensile stress zone has expanded compared to the factory state; the greater the expansion, the larger the W value. Further, the tensile stress erosion weight W is used to multiply and weight the remaining elastic potential energy of the extended section at each time step.

[0048] In one embodiment, the discrete potential energy value U(t) on the extension segment is multiplied by the weight W at each time step to obtain the corrected potential energy value U'(t) = W·U(t). The U'(t) is arranged along the time axis to form a corrected decay sequence. The corrected decay sequence shows an overall upward movement relative to the original extension segment under the condition that the edge tensile stress zone expands significantly, reflecting the actual effect of edge tensile stress erosion on the evolution of residual elastic potential energy.

[0049] It is understood that the corrected decay sequence is the corrected decay sequence for the mid-to-late stage of relaxation acceleration anomaly. A decay trend line is obtained by least-squares fitting of the corrected decay sequence along the mid-to-late stage of relaxation acceleration anomaly. The least-squares fitting uses the reserve time as the independent variable and the corrected potential energy value as the dependent variable. The slope and intercept of the fitted line are solved by minimizing the sum of squared deviations of each discrete point from the vertical direction of the fitted line. The absolute value of the slope of the decay trend line characterizes the decay rate of the remaining elastic potential energy in the mid-to-late stage of relaxation acceleration anomaly; the larger the absolute value of the slope, the steeper the potential energy decrease in this stage.

[0050] In one embodiment, for an elliptical cross-section closing spring that has been in reserve for more than one year in a power grid substation, the absolute value of the slope of the degradation trend line is significantly greater than the absolute value of the calibrated slope under the same specifications at the factory condition, reflecting the effect of intensified edge tensile stress erosion under long-term high humidity environment. Further, an abnormal energy storage degradation indicator is formed by combining the absolute value of the slope of the degradation trend line and the residual potential energy at the end of the stage. The end of the stage is the corresponding position on the standby time axis at the current assessment time, and the residual potential energy is the vertical coordinate value of the degradation trend line at that position. The abnormal energy storage degradation indicator consists of a degradation rate component and a residual level component; the former characterizes the rate of decline, and the latter characterizes the current potential energy level. The abnormal energy storage degradation indicator is used to mark abnormal degradation sections where the spring wire deviates from the factory-calibrated degradation law. The starting point of the section corresponds to the real-time degradation inflection point, and the ending point of the section corresponds to the current assessment time. The degradation rate component and the residual level component within the section together constitute a quantitative record of abnormal energy storage degradation under long-term standby conditions.

[0051] S104. For the abnormal decline interval marked by the abnormal energy storage decline indicator, extract the stress gradient concentration evolution along the short axis of the cross section, classify the boundary points of the initial relaxation delay and the mid-to-late relaxation acceleration, and substitute the stress concentration threshold of the boundary point into the closing release force judgment condition.

[0052] Retrieve the numerical values of the stress gradient concentration of the spring wire along the short axis of the cross-section moment by moment along the standby duration axis of the abnormal energy storage decay interval marked by the abnormal energy storage decay identifier, arrange the numerical values of the stress gradient concentration in chronological order to obtain the evolution trajectory of the stress gradient concentration along the short axis of the cross-section. The evolution trajectory reflects the change process of the compactness of the shot-peened compressive stress layer retreating from the surface to the core in the abnormal decay interval. Take the difference of the numerical values at adjacent moments on the stress gradient concentration evolution trajectory to obtain a sequence of point-by-point drop rates, retrieve the position where the drop rate sequence has a kink and crosses a preset rate threshold, divide the trajectory segment before this position into the initial relaxation delay stage, divide the trajectory segment after this position into the middle and late relaxation acceleration stage, this position is the boundary point between the initial relaxation delay and the middle and late relaxation acceleration, extract the numerical value of the stress gradient concentration corresponding to the boundary point, and denote it as the stress concentration threshold. Retrieve the original criterion for the breaker closing release force determination condition. The original criterion is the built-in criterion written into the control unit during the factory commissioning stage of the breaker, with the corresponding relationship between the remaining elastic potential energy E and the rated release force F as the core constraint, that is, F = k * E, where k is a preset proportional coefficient of 0.8. Incorporate the stress concentration threshold T as a new trigger component into the original criterion. The specific incorporation method is to append a conditional branch: input the current stress gradient concentration G, if G < T, then start the release force correction branch, calculate the corrected release force F' = F * (1 - 0.1 * (T - G) / T), and output F' as the final determination value; otherwise, directly output the original F. Obtain the updated closing release force determination condition. The updated closing release force determination condition is used to start the release force correction branch when the stress gradient concentration of the spring wire is lower than the stress concentration threshold, and apply this branch to calculate the correction value rather than just comparing the potential energy after subsequent activation.

[0053] The abnormal decay interval marked by the abnormal energy storage decay identifier has a clear start point and an end point on the standby duration axis. The start point corresponds to the position of the real-time decay inflection point, and the end point corresponds to the current evaluation moment. For the abnormal decay interval, retrieve the numerical values of the stress gradient concentration of the spring wire along the short axis of the cross-section moment by moment along the standby duration axis of the abnormal decay interval.

[0054] It should be noted that the stress gradient concentration values ​​were recorded in the database according to the periodic scanning plan during the aforementioned residual stress detection process. Each scan yields the decreasing slope of the stress value change from the surface layer to the subsurface layer along the short axis depth direction, and this decreasing slope is the stress gradient concentration value at that moment. Arranging the stress gradient concentration values ​​in chronological order yields the stress gradient concentration evolution trajectory along the short axis of the cross-section. This evolution trajectory reflects the compactness change process of the shot-peened compressive stress layer from the surface layer to the core within the abnormal decay range. The trajectory is gentle in the initial stage and drops sharply in the middle and later stages. In one embodiment, for the rectangular cross-section wire of the high-voltage circuit breaker tripping spring, the evolution trajectory shows a slow downward movement of values ​​in the first 30% of the abnormal decay range, a significant inflection point in values ​​between 30% and 60% of the range, and a rapid downward movement of values ​​after 60%.

[0055] Specifically, the difference between adjacent time values ​​on the stress gradient concentration evolution trajectory is used to obtain a point-by-point drop rate sequence. The difference is performed using a backward difference method, subtracting the previous time value from the current time value and then dividing by the time interval to obtain the drop rate component V at the current time. The drop rate components V are arranged sequentially along the time axis to form the drop rate sequence. Further, the position where the drop rate sequence shows a turning point and crosses a preset rate threshold is retrieved. The turning point is defined as the position where the slope sign of the drop rate sequence reverses or the absolute value shows a step increase. The preset rate threshold is determined based on the mean plus two standard deviations of the drop rate distribution of spring wires of the same specification under the calibrated decay process in the factory inspection file. Crossing the preset rate threshold indicates that the drop rate has entered an acceleration phase from a delay phase. The trajectory segment before the position is classified as the initial relaxation delay phase, and the trajectory segment after the position is classified as the mid-to-late relaxation acceleration phase. The two phases are connected end-to-end on the evolution trajectory, with no overlapping segments in between.

[0056] It is understood that the aforementioned location is the boundary point between the initial relaxation delay and the mid-to-late-stage relaxation acceleration. The stress gradient concentration value corresponding to this boundary point is extracted and denoted as the stress concentration threshold T0. The stress concentration threshold T0 is a key basis for updating the subsequent closing release force determination conditions. Further, the original criteria for the circuit breaker closing release force determination conditions are retrieved. These original criteria are built into the control unit during the circuit breaker's factory commissioning phase, with the correspondence between remaining elastic potential energy and rated release force as the core constraint.

[0057] Specifically, the original criterion stipulates that when the residual elastic potential energy of the spring mechanism falls within the allowable range corresponding to the rated release force, the spring mechanism is deemed to have the ability to perform closing. The allowable range is enclosed by the upper and lower limits of the residual elastic potential energy specified at the factory, and the upper and lower limits are registered in the factory inspection file. The stress concentration threshold T0 is added as a new triggering component and incorporated into the original criterion.

[0058] Specifically, a parallel condition branch is added to the original criterion. This parallel condition branch uses the comparison between the real-time value of the stress gradient concentration and the stress concentration threshold T0 as the criterion. When the real-time value of the stress gradient concentration is lower than the stress concentration threshold T0, it is determined that the compactness of the spring wire compression stress layer has degraded to the level of the mid-to-late stage relaxation acceleration phase, and the release force correction branch is activated. When the real-time value of the stress gradient concentration is higher than the stress concentration threshold T0, the correspondence between the residual elastic potential energy and the rated release force of the original criterion is used. After this incorporation process, an updated closing release force determination condition is obtained. The updated closing release force determination condition combines the constraints of residual elastic potential energy and stress gradient concentration. In the application example of the vacuum circuit breaker closing spring, the updated closing release force determination condition can activate the release force correction branch when the stress gradient concentration of the spring mechanism is lower than the stress concentration threshold T0, avoiding the determination lag caused by relying solely on the residual elastic potential energy threshold, and enabling the closing release force assessment under long-term standby conditions to have the ability to identify the mid-to-late stage relaxation acceleration phase.

[0059] S105. Under the updated closing release force judgment conditions, obtain the feedback of the remaining elastic potential energy of the spring mechanism and evaluate whether the remaining elastic potential energy after long-term standby meets the factory calibration range.

[0060] Under the condition that the updated closing release force judgment condition is activated, the residual elastic potential energy feedback value of the spring mechanism in the long-term standby final state is obtained. The long-term standby final state refers to the final state after the equipment has been idle for 6 months. The residual elastic potential energy feedback value is obtained by jointly converting the displacement sensing data and tension sensing data built into the spring mechanism according to the elastic strain energy accumulation formula based on the correspondence between spring compression and tension. The upper and lower limits of the residual elastic potential energy registered in the factory inspection file are retrieved. These upper and lower limits constitute the factory calibration range. The residual elastic potential energy feedback value is first compared with the lower limit of the factory calibration range, and then compared with the upper limit of the factory calibration range. If the residual elastic potential energy feedback value falls within the factory calibration range, it is determined to be compliant; otherwise, it is determined to be non-compliant, thus obtaining the compliance result of the residual elastic potential energy after long-term standby.

[0061] The updated closing release force determination condition activates the release force correction branch when the stress gradient concentration of the spring wire is lower than the stress concentration threshold. Under the condition that the updated closing release force determination condition is activated, the remaining elastic potential energy feedback value of the spring mechanism in the long-term standby final state is obtained through the potential energy feedback acquisition port on the spring mechanism control unit.

[0062] Specifically, the potential energy feedback acquisition port is simultaneously connected to two signal channels built into the spring mechanism: displacement sensing and tension sensing. The displacement sensing data reflects the current compression displacement of the spring mechanism, and the tension sensing data reflects the current bearing tension of the spring mechanism. In one embodiment, for the high-voltage circuit breaker tripping spring, the elastic strain energy accumulation formula is given as the integral of the tension along the compression displacement interval. The displacement sensing data is used as the upper limit of the integral, and the tension sensing data is used as the integrand. The remaining elastic potential energy feedback value Ufb is obtained by accumulating the data point by point. Further, the upper and lower limits of the remaining elastic potential energy registered in the factory inspection file of the spring mechanism are retrieved. These upper and lower limits are recorded through multiple closing tests under calibrated operating conditions during the factory commissioning phase. The lower limit Ulow corresponds to the minimum energy storage level to ensure the rated closing speed, and the upper limit Uhigh corresponds to the maximum energy storage level to avoid closing overshoot. The two together form the factory calibration range.

[0063] In one embodiment, the remaining elastic potential energy feedback value Ufb is first compared with the lower limit of the factory calibration range, Ulow. If Ufb is lower than Ulow, an under-storage deviation is recorded. Then, it is compared with the upper limit of the factory calibration range, Uhigh. If Ufb is higher than Uhigh, an over-storage deviation is recorded. If Ufb falls within the Ulow to Uhigh range, it is considered compliant; otherwise, it is considered non-compliant, thus obtaining the compliance result of the remaining elastic potential energy after long-term standby. The compliance result is used to characterize the direction and degree of deviation of the energy retention level of the spring mechanism in the final state of long-term standby from the factory calibration.

[0064] S106. If not met, integrate the abnormal energy storage degradation identifier and correction results, group the stress distribution samples of the inflection point forward stage of the decay curve, define the adjustment range of the release force output according to the magnitude of the forward shift of the inflection point, and determine the adjustment scheme of the closing operation speed. If met, keep the current release force output unchanged and mark the spring mechanism as being in normal standby state.

[0065] The remaining elastic potential energy compliance result after long-term standby is obtained. If the compliance result is non-compliant, the abnormal energy storage degradation identifier and the stress concentration threshold are merged into the criterion update content formed by incorporating them into the closing release force judgment condition. This results in a comprehensive degradation file containing the bearing degradation rate component, residual level component, and stress concentration threshold component. The comprehensive degradation file registers all stress distribution samples in the inflection point forward shift stage using the standby duration as an index. For the stress distribution samples in the inflection point forward shift stage in the comprehensive degradation file, they are divided into low-level, medium-level, and high-level groups according to the magnitude of the degree of forward shift of the inflection point of the attenuation curve. For each level group, a release force output adjustment range calibrated during the factory commissioning stage is matched. The release force output adjustment range is based on the factory rated release force and provides an upward adjustment ratio range according to the degradation rate component of the corresponding level group. The upward adjustment ratio range is used to form an adjustment scheme for the closing operation speed. If the compliance result is satisfactory, the current release force output remains unchanged, the spring mechanism is marked as normal standby state, and the normal standby state is written into the standby state registration bit of the spring mechanism control unit as a baseline state reference for subsequent periodic scanning plans.

[0066] The remaining elastic potential energy compliance result after long-term standby is divided into two values: compliant and non-compliant, which correspond to the energy storage level of the spring mechanism falling into or deviating from the factory calibration range, respectively.

[0067] Specifically, if the compliance result is non-compliant, the abnormal energy storage degradation identifier and stress concentration threshold are merged into the criterion update content formed after the closing release force judgment condition, and the fields are fused. In one embodiment, the field fusion is carried out in the storage area of ​​the spring mechanism control unit to open a comprehensive degradation archive data structure. The data structure contains three component fields. The first field is written with the degradation rate component in the abnormal energy storage degradation identifier, reflecting the rate of decrease of the remaining elastic potential energy in the mid-to-late stage of relaxation acceleration abnormality. The second field is written with the residual level component in the abnormal energy storage degradation identifier, reflecting the difference between the current remaining elastic potential energy value and the factory calibration lower limit. The third field is written with the stress concentration threshold component, reflecting the compactness level of the spring wire compressive stress layer at the boundary point. The comprehensive degradation archive registers all stress distribution samples in the inflection point forward stage with the standby time as the index. Each index item records the stress value sequence along the short axis direction of the spring wire cross section and the residual tensile stress coverage width of the edge region at that standby time. Furthermore, for the stress distribution samples in the stage of forward inflection point in the comprehensive decay archive, they are divided into low-level group, medium-level group and high-level group according to the magnitude of the forward shift of the inflection point of the decay curve.

[0068] Specifically, the stress relaxation level is divided into intervals, using the percentage of the factory-calibrated spare period as the dividing line. Samples with an inflection point shift below 5% are classified into the low-level group, those between 5% and 10% into the medium-level group, and those exceeding 10% into the high-level group. These low-level, medium-level, and high-level groups correspond to different degrees of stress relaxation deviation; the higher the group, the greater the deviation of the relaxation process from the factory calibration.

[0069] Understandably, each magnitude group is matched with a release force output adjustment range calibrated during the factory commissioning phase. The release force output adjustment range is pre-collected by the manufacturing process on a calibration test bench before the circuit breaker leaves the factory, and three sets of upward adjustment ratio ranges are recorded for the low-magnitude group, medium-magnitude group, and high-magnitude group respectively.

[0070] Specifically, the release force output adjustment range is based on the factory rated release force and gives an upward adjustment ratio range according to the decay rate component of the corresponding magnitude group.

[0071] In one embodiment, the adjustment ratio range is 0% to 3% for the low-level group, 3% to 7% for the medium-level group, and 7% to 12% for the high-level group. The specific value within the adjustment ratio range is obtained by linear interpolation of the relative position of the decay rate component within the group; the larger the decay rate component, the closer the adjustment ratio is to the upper limit of the range. The adjustment ratio range is used to form the adjustment scheme for the closing operation speed.

[0072] Specifically, the adjustment scheme is characterized by a correction coefficient for the release force output command. This correction coefficient is equal to 1 plus a specific value within the upward adjustment range, and is written into the release force command register of the spring mechanism control unit. This ensures that the spring mechanism performs energy release according to the corrected release force during closing, thereby returning the closing operation speed to the factory calibration range. In an application example of a vacuum circuit breaker closing spring, after long-term standby and reassignment to the medium-duty group, the closing contact closing speed returns from the deviation value to the factory calibration speed range after matching and upward adjustment. Further, if the compliance result is satisfactory, the current release force output remains unchanged, and the spring mechanism is marked as being in normal standby status. The normal standby status is written into the standby status registration bit of the spring mechanism control unit in the form of a status code. The standby status registration bit is a single-byte register reserved inside the control unit, and the status code value is fixed, distinguishing between normal and abnormal values. If the condition is met, a normal code is written; if not, the aforementioned adjustment scheme handles the situation. The normal standby state serves as the baseline state reference for subsequent periodic scanning plans. In the next scanning cycle, the residual stress detection module will still collect the residual stress distribution pattern of the spring mechanism according to the factory-calibrated scanning interval, without needing to switch to the abnormal decay tracking mode.

[0073] S107. Adjust the release force output in the spring mechanism control according to the adjustment range defined in the adjustment scheme. After the release force output reaches the target value of the adjustment range, drive the circuit breaker to perform the closing operation. Scan the stress distribution pattern of the spring wire after execution, evaluate whether the closing speed stably reproduces the factory calibration range, and confirm that the abnormal energy storage decay has been eliminated.

[0074] According to the adjustment range of the release force output defined in the adjustment scheme of the closing operation speed, the spring mechanism control unit sends a release force upward adjustment command to the release force execution circuit. The release force upward adjustment command is based on the correction coefficient obtained by interpolation within the upward adjustment ratio range, and raises the release force output value of the spring mechanism by a preset step size. The value is synchronously compared on the tension feedback channel. When the value reported by the tension feedback channel falls within the release force output adjustment range, it is recorded that the release force output has reached the target value of the adjustment range. In the state that the release force output has reached the target value of the adjustment range, the spring mechanism control unit sends a closing drive signal to drive the circuit breaker to perform a closing operation. After the closing operation is completed, a detection path is set up again along the outer surface of the spring wire to scan the stress value change of the spring wire along the short axis of the cross section and the residual stress distribution in the edge area after the closing operation, so as to obtain the stress distribution shape of the spring wire after the operation. By comparing the effective boundary of the compressive stress layer in the stress distribution pattern of the spring wire after execution with the effective boundary of the compressive stress layer in the initial stress distribution pattern at the factory, the contact closing time series during multiple repeated closing processes are collected simultaneously. The dispersion of the contact closing time series is statistically analyzed and compared with the allowable fluctuation range of the closing speed calibrated at the factory. If the effective boundary of the compressive stress layer returns to the factory state and the dispersion falls within the allowable fluctuation range of the closing speed, it is determined that the closing speed stably reproduces the factory calibration range and the abnormal energy storage degradation has been eliminated.

[0075] The release force output adjustment range defined in the closing operation speed adjustment scheme has been written into the release force instruction register of the spring mechanism control unit, and will be called in the subsequent instruction execution stage.

[0076] Specifically, the spring mechanism control unit issues a release force adjustment command to the release force execution circuit. The release force adjustment command is based on a correction coefficient obtained by interpolation within the adjustment ratio range. This correction coefficient is equal to 1 plus the specific adjustment ratio value for the corresponding magnitude group. In one embodiment, for the medium-magnitude group spring mechanism, the correction coefficient falls within the range of 1.03 to 1.07, and the control unit calculates the target release force value after the increase accordingly. Further, the release force output value of the spring mechanism is increased by a preset step size.

[0077] Specifically, the preset step size is obtained by dividing the difference between the target value of the release force and the current value of the release force by the preset number of increments. After each lifting level is completed, a short time interval is paused to allow the mechanism to stabilize before proceeding to the next lifting level.

[0078] In one embodiment, for the tripping spring of a high-voltage circuit breaker, the preset step size is between 1 / 5 and 1 / 10 of the difference in release force, and the increment level is between 5 and 10 levels, so as to gradually raise the spring in a steady state and avoid the impact on the mechanism caused by sudden changes in release force.

[0079] It should be noted that the tension feedback channel is arranged on the spring guide rod of the spring mechanism, and the tension sensor collects the current tension of the spring mechanism in real time. The tension value increases synchronously with the spring deformation after each lifting stage. During the dwell period after each lifting stage, the spring mechanism control unit compares the measured value of the tension feedback channel with the boundary value of the release force output adjustment range. If the measured value is still lower than the lower boundary of the adjustment range, the next lifting stage continues; if the measured value falls within the release force output adjustment range, the lifting is stopped, and it is recorded as the release force output reaching the target value of the adjustment range. When the release force output reaches the target value of the adjustment range, the spring mechanism control unit sends a closing drive signal to drive the circuit breaker to perform a closing operation.

[0080] Specifically, the closing drive signal unlocks the opening and closing pins through the release force execution circuit. The spring mechanism releases the stored elastic potential energy, driving the linkage mechanism to move the moving contact towards the stationary contact until it closes. After the closing operation is completed, the residual stress detection module again lays out a detection path along the outer surface of the spring wire. The detection path still extends with the short axis of the cross-section as the reference, and the scanning position covers the straight area in the middle and the edge areas at both ends of the spring wire.

[0081] Specifically, the stress value change of the spring wire along the short axis of the cross section is scanned after the closing operation, and the decreasing slope of the stress value change from the surface layer to the subsurface layer along the short axis depth direction is recorded; the residual stress distribution in the edge region is scanned simultaneously, and the transition point of residual stress from compression to tension and the termination point where tensile stress decays to zero are recorded. The decreasing slope and the arc length of the transition point and termination point together constitute the stress distribution pattern of the spring wire after the operation.

[0082] It is understandable that the stress distribution pattern of the spring wire after execution is reorganized relative to the final state of the abnormal decay range. The reorganization direction depends on the stress release caused by the increase in release force and the stress redistribution under the new round of compression energy storage. Furthermore, the effective boundary of the compressive stress layer in the stress distribution pattern of the spring wire after execution is compared with the effective boundary of the compressive stress layer in the initial stress distribution pattern at the factory.

[0083] Specifically, the effective action boundary of the compressive stress layer, that is, the coordinate of the zero-crossing position where the stress sign changes from negative to positive in the short-axis depth direction. Denote the coordinate after execution as hpost and the initial coordinate at the factory as horigin, and compare the absolute value of the difference between the two with the preset regression tolerance.

[0084] In one embodiment, the preset regression tolerance is 5% of the initial coordinate at the factory. Synchronously collect the contact closing time series during multiple repeated closing processes.

[0085] Specifically, the time interval from when the spring mechanism control unit issues a closing drive signal to when the breaker auxiliary contact detects the mechanical closing of the contact is denoted as the single contact closing time ti. Continuously perform multiple closing operations to obtain the time series {t1, t2,..., tn}. Statistically analyze the dispersion of the contact closing time series. The dispersion is characterized by the standard deviation, and the calculation method is to take the arithmetic square root of the sum of the squares of the differences between each value of the time series and the mean of the series divided by the length of the series, obtaining the dispersion value σt. Further, compare the dispersion value σt with the allowable fluctuation range of the closing speed calibrated at the factory. The allowable fluctuation range of the closing speed is recorded through multiple closing tests during the factory commissioning stage of the breaker and is given as the allowable deviation range of the mean contact closing time. In the determination step, if the effective action boundary of the compressive stress layer returns to the factory state, that is, the absolute value of the difference between hpost and horigin falls within the preset regression tolerance, and the dispersion value σt falls within the allowable fluctuation range of the closing speed, it is determined that the closing speed is stably reproduced within the factory-calibrated range and the abnormal energy storage decay has been eliminated. In an application example of a breaker supporting a UHVDC transmission system, after the above adjustment and scanning remeasurement of the closing spring that has been in long-term standby for more than one year, the contact closing time returns from the deviation value to the factory-calibrated interval, and the status code of the spring mechanism changes from abnormal to normal.

[0086] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spring mechanism control method for realizing rapid opening and closing of the circuit breaker, characterized in that, The method includes: acquiring stress gradient concentration along the minor axis of the spring wire cross-section, measuring the aspect ratio of the spring wire cross-section, scanning the residual tensile stress coverage width in the edge region of the spring wire cross-section, and identifying the initial stress distribution pattern after shot peening of the spring wire surface; extracting the boundary position between compressive and tensile stress along the minor axis of the cross-section based on the initial stress distribution pattern, evaluating the relaxation change path after the cross-section aspect ratio and shot peening residual stress are superimposed, analyzing the residual elastic potential energy decay process based on the relaxation change path, comparing the real-time decay inflection point position with the factory-calibrated inflection point position, and determining the degree of forward shift of the decay curve inflection point; analyzing whether the degree of forward shift of the decay curve inflection point exceeds a preset threshold, and if it does, integrating the residual elastic potential energy decay process with the edge region... The residual tensile stress coverage width is used to obtain an abnormal energy storage degradation indicator. For the abnormal degradation interval marked by the abnormal energy storage degradation indicator, the boundary points of the initial relaxation delay and the mid-to-late-stage relaxation acceleration are classified, and the stress concentration threshold corresponding to the boundary points is substituted into the closing release force judgment condition. Under the updated closing release force judgment condition, the remaining elastic potential energy feedback is obtained to assess whether it meets the factory calibration range after long-term standby. If it does not meet the criteria, the release force output adjustment range is defined according to the forward shift of the inflection point, and the closing operation speed adjustment scheme is determined. If it meets the criteria, the release force output remains unchanged. The release force output is adjusted according to the adjustment scheme to drive the circuit breaker to perform the closing operation. The stress distribution pattern of the spring wire is scanned after the operation to confirm that the abnormal energy storage degradation has been eliminated.

2. The spring mechanism control method for realizing rapid opening and closing functions according to claim 1, characterized in that, The process of acquiring stress gradient concentration along the minor axis of the spring wire cross-section, measuring the aspect ratio of the spring wire cross-section, scanning the residual tensile stress coverage width of the edge region of the spring wire cross-section, and identifying the initial stress distribution pattern after shot peening of the spring wire surface includes: laying out a detection path along the outer surface of the spring wire with the minor axis of the cross-section as the reference; obtaining the stress gradient concentration by acquiring the decreasing slope of the residual stress value along the depth direction using X-ray diffraction; obtaining the aspect ratio of the spring wire cross-section from the ratio of the geometric coordinates of the major axis endpoint to the minor axis endpoint; continuously scanning along the contour tangent direction for the edge region, obtaining the residual tensile stress coverage width of the edge region from the arc length between the residual stress transition point and the termination point; splicing the stress gradient concentration, the aspect ratio of the spring wire cross-section, and the residual tensile stress coverage width of the edge region according to the cross-sectional position sequence to form a stress distribution sequence unfolding along the circumference of the spring wire, identifying the proportion and connection order of the middle straight section, the transition section, and the edge section in the circumferential direction, and obtaining the initial stress distribution pattern.

3. The spring mechanism control method for realizing rapid opening and closing functions according to claim 1, characterized in that, The process involves extracting the boundary between compressive and tensile stress along the minor axis of the cross section based on the initial stress distribution pattern, evaluating the relaxation change path after the cross section aspect ratio and shot peening residual stress are superimposed, analyzing the decay process of residual elastic potential energy based on the relaxation change path, comparing the real-time decay inflection point position with the factory-calibrated inflection point position, and determining the degree of forward shift of the decay curve inflection point. This includes: retrieving the stress sign zero-crossing position from the surface to the core along the minor axis of the cross section as the boundary position; weighting and superimposing the cross section aspect ratio and shot peening residual stress amplitude in the neighborhood of the boundary position to obtain a coupled stress curve; collecting the trajectory of the boundary position migrating towards the surface as the standby time as the relaxation change path; performing volume integration on the compressive stress action area along the relaxation change path to obtain the decay process curve; calculating the peak time of the second-order rate of change of the decay process curve as the decay inflection point position, and subtracting the coordinates of the factory-calibrated inflection point position to obtain the degree of forward shift of the decay curve inflection point.

4. The spring mechanism control method for realizing rapid opening and closing functions according to claim 1, characterized in that, The analysis determines whether the forward shift of the inflection point of the decay curve exceeds a preset threshold. If it does, the remaining elastic potential energy decay process is integrated with the width of the residual tensile stress coverage in the edge region to obtain an abnormal energy storage decay indicator. This includes: normalizing the width of the residual tensile stress coverage in the edge region according to the factory-calibrated width to obtain a tensile stress erosion weight; multiplying and weighting the residual elastic potential energy extension segment after the inflection point at each time step to obtain a corrected decay sequence; using least squares fitting along the mid-to-late stage of relaxation acceleration anomaly to obtain a decay trend line; and combining the decay rate component of the absolute value of the slope of the decay trend line with the residual potential energy component at the end of the stage to form the abnormal energy storage decay indicator.

5. The spring mechanism control method for realizing rapid opening and closing functions according to claim 1, characterized in that, The process for classifying the abnormal decay interval marked by the abnormal energy storage decay indicator into boundary points for the initial relaxation delay and the mid-to-late relaxation acceleration, and substituting the stress concentration threshold corresponding to the boundary point into the closing release force determination condition, includes: retrieving stress gradient concentration values ​​hourly along the standby time axis of the abnormal decay interval and arranging them in chronological order to obtain the stress gradient concentration evolution trajectory along the short axis of the cross section; calculating the difference between adjacent time values ​​to obtain a point-by-point drop rate sequence; retrieving the position where the drop rate sequence shows a turning point and crosses a preset rate threshold as the boundary point; and extracting the value corresponding to the boundary point as the stress concentration threshold.

6. The spring mechanism control method for realizing rapid opening and closing functions according to claim 1, characterized in that, The process of obtaining the remaining elastic potential energy feedback under the updated closing release force determination conditions and assessing whether it meets the factory calibration range after long-term standby includes: obtaining the remaining elastic potential energy feedback by jointly converting the displacement sensing data and tension sensing data built into the spring mechanism according to the elastic strain energy accumulation formula under the correspondence between spring compression and tension; comparing the remaining elastic potential energy feedback with the lower limit value and upper limit value registered in the factory inspection file in sequence, and determining compliance if it falls within the factory calibration range, otherwise determining non-compliance.

7. The spring mechanism control method for realizing rapid opening and closing functions according to claim 1, characterized in that, When the conditions are not met, the release force output adjustment range is defined according to the magnitude of the forward shift of the inflection point, and the closing operation speed adjustment scheme is determined. When the conditions are met, the release force output remains unchanged. This includes: when the conditions are not met, the abnormal energy storage decay identifier is merged with the updated criterion content formed after being incorporated into the closing release force judgment condition to form a comprehensive decay file containing the bearing decay rate component, residual level component, and stress concentration threshold component. The comprehensive decay file registers all stress distribution samples in the inflection point forward shift stage using the standby time as an index. The decay curve inflection point forward shift is divided into low-level, medium-level, and high-level groups. For each level group, an upward adjustment ratio range given by the decay rate component of the corresponding level group is matched based on the factory rated release force as the benchmark, and the closing operation speed adjustment scheme is formed by the upward adjustment ratio range. When the conditions are met, the current release force output remains unchanged, the spring mechanism is marked as normal standby state and written into the standby state registration bit of the control unit.

8. The spring mechanism control method for realizing rapid opening and closing functions according to claim 1, characterized in that, The process of adjusting the release force output according to the adjustment scheme, driving the circuit breaker to perform a closing operation, scanning the stress distribution of the spring wire after execution, and confirming the elimination of abnormal energy storage decay includes: sending an upward adjustment command to the release force execution circuit based on the correction coefficient obtained by interpolation within the upper adjustment ratio range and increasing the release force by a preset step size; when the value reported by the tension feedback channel falls within the release force output adjustment range, it is recorded as reaching the target value of the adjustment range; sending a closing drive signal to drive the circuit breaker to perform a closing operation, and scanning the stress distribution of the spring wire after execution by setting up a detection path along the outer surface of the spring wire again; comparing the boundary of the compressive stress layer in the stress distribution of the spring wire after execution with the initial boundary at the factory, and statistically analyzing the dispersion of the closing contact time series of multiple closing operations; when the boundary of the compressive stress layer returns to the factory state and the dispersion falls within the allowable fluctuation range of the closing speed, it is determined that the abnormal energy storage decay has been eliminated.

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