A high-voltage circuit breaker operating state intelligent evaluation method

Abstract

The application provides a high-voltage circuit breaker operation state intelligent evaluation method, comprising the following steps: collecting the actual length of a high-voltage circuit breaker pull rod and the initial speed of contact separation through a displacement sensor and a speed monitoring device, filtering out high-frequency noise interference, and obtaining the pull rod deformation growth, the contact stroke change and the initial speed sequence of contact separation; evaluating the corresponding change relationship between the pull rod deformation growth and the contact stroke change, determining the time delay and amplitude amplification ratio of the pull rod deformation growth transmission to the contact stroke change; if the deterioration progress speed presents an accelerated upward trend and the mutation amplitude of the initial speed of separation exceeds the preset allowable limit, the critical condition of high-voltage circuit breaker shutdown maintenance is determined; generating a pull rod replacement warning, a contact adjustment warning and a whole machine maintenance warning according to the critical condition judgment result, and outputting a high-voltage circuit breaker operation state evaluation report.

Description

Technical Field

[0001] This invention relates to the field of information technology, and in particular to an intelligent assessment method for the operating status of high-voltage circuit breakers. Background Technology

[0002] High-voltage circuit breakers, as core equipment in power systems, are responsible for the rapid switching of circuits under high-voltage conditions, ensuring the safe and stable operation of the power grid. Their performance directly affects the reliability of power supply. With the expansion of power system scale and the increasing complexity of operating environments, assessing the operational status of circuit breakers has become a crucial link in ensuring equipment safety. Traditional assessment methods rely heavily on periodic maintenance and manual inspections, but these methods struggle to capture real-time dynamic changes within the equipment, making it difficult to detect potential faults in a timely manner and increasing the risks to power grid operation. Existing methods for monitoring the operational status of circuit breakers primarily rely on static parameter testing or offline diagnostics to determine the equipment's health condition.

[0003] However, these methods are ill-suited to the dynamic degradation process of high-voltage circuit breakers during long-term operation, especially under frequent operation, where the performance degradation of internal mechanical components often exhibits non-linear changes. For example, the insulating tie rod, as a crucial component connecting the transmission system and the contacts, undergoes material property changes after repeated stress. However, existing monitoring methods struggle to accurately capture the correlation between these changes and contact movement deviations, thus failing to accurately predict equipment failures. In circuit breaker operation, material creep of the insulating tie rod is a core technical factor leading to mechanical performance degradation. Creep refers to the slow deformation of the insulating material under long-term mechanical stress and high-temperature conditions, causing the tie rod length to gradually increase. This length change directly affects the accuracy of the contact closing position, leading to abnormal initial velocity during contact separation and ultimately compromising the accuracy of contact movement. For instance, in a certain high-voltage circuit breaker, the increased tie rod length due to creep caused a shift in the contact closing position, resulting in a sudden change in velocity at the moment of separation, degrading arc extinguishing performance, and increasing the risk of equipment burnout. The transmission process of deformation and contact movement deviation caused by material creep is difficult to quantify in real time using traditional monitoring methods, making it a core technical challenge in operational status assessment.

[0004] Therefore, how to capture the length change of the insulating tie rod due to creep and its impact on the contact movement accuracy in real time during the operation of the circuit breaker, establish the dynamic correlation between the two, and accurately identify the resulting mechanical performance degradation and abnormal contact movement has become a key issue in the intelligent assessment of the operating status of high-voltage circuit breakers. Summary of the Invention

[0005] This invention provides an intelligent assessment method for the operating status of high-voltage circuit breakers, the method comprising:

[0006] The actual length of the circuit breaker tie rod and the initial velocity of contact separation are collected by displacement sensor and velocity monitoring device. High-frequency noise is filtered out to obtain the sequence of tie rod deformation growth, contact stroke change and initial velocity of contact separation.

[0007] Evaluate the corresponding relationship between the increase in the deformation of the tie rod and the change in the stroke of the contact, and determine the time delay and amplitude amplification factor of the transmission of the increase in the deformation of the tie rod to the change in the stroke of the contact.

[0008] The time delay and amplitude amplification factor are compared with the allowable range of the contact mechanism. The abrupt change in the initial separation velocity between adjacent actions is determined by the initial separation velocity sequence of the contact. Based on the comparison results and the abrupt change amplitude, the mechanical strength degradation level caused by the creep of the insulating tie rod is determined.

[0009] Collect contact closing delay, contact overtravel, and contact bounce count. Classify the contact action abnormality type based on the contact closing delay, contact overtravel, and contact bounce count. Combine the mechanical strength degradation level to determine the severity level of contact motion accuracy damage.

[0010] Obtain the health baseline value of the same type of circuit breaker in history, and determine the deterioration rate of the operating mechanism based on the difference and rate of change of the current severity level relative to the health baseline value.

[0011] If the rate of degradation accelerates and the magnitude of the initial separation velocity change exceeds the preset allowable limit, then the critical condition for shutdown and maintenance is determined to have been met.

[0012] Based on the critical condition determination results, early warnings for tie rod replacement, contact adjustment, and overall machine maintenance are generated, and an operational status assessment report is output.

[0013] Furthermore, the actual length of the circuit breaker tie rod and the initial velocity of contact separation are collected by the displacement sensor and velocity monitoring device, high-frequency noise is filtered out, and the sequence of tie rod deformation growth, contact stroke change, and initial velocity of contact separation is obtained, including:

[0014] The actual length data of the opening and closing process is collected by a displacement sensor installed at the end of the tie rod according to a preset sampling period. A Butterworth low-pass filter is used to filter out power frequency interference. The difference between the filtered length signal and the pre-calibrated tie rod reference length is used to obtain the deformation growth of the tie rod.

[0015] Furthermore, the evaluation of the corresponding relationship between the increase in the deformation of the tie rod and the change in the contact stroke, and the determination of the time delay and amplitude amplification factor in the transmission of the increase in the deformation of the tie rod to the change in the contact stroke, includes:

[0016] Using the rising edge of the opening and closing operation signal as the action trigger time, for each opening and closing action, the deformation growth of the pull rod and the change in the contact stroke within the same time window are extracted and the waveforms are aligned to obtain the deformation waveform and the stroke waveform.

[0017] The correlation coefficient is calculated using a cross-correlation function between the deformed waveform and the travel waveform. The time offset corresponding to the maximum value is taken as the time delay. The deformed waveform is compensated for by translation based on the time delay. The ratio of the maximum amplitude point after compensation to the maximum amplitude point of the travel waveform is taken as the amplitude amplification factor.

[0018] Furthermore, the comparison of the time delay and amplitude amplification with the allowable range of the contact mechanism, the determination of the abrupt change in the initial separation velocity between adjacent actions based on the initial separation velocity sequence of the contact, and the determination of the mechanical strength degradation level caused by the creep of the insulating tie rod based on the comparison results and the abrupt change amplitude, includes:

[0019] The pre-established contact mechanism allowable range file is invoked. The contact mechanism allowable range file records the time delay boundary value and amplitude amplification factor boundary value calibrated during the factory commissioning stage of the same model of circuit breaker. The time delay and amplitude amplification factor are respectively subtracted from the corresponding boundary values ​​to obtain the degree of delay exceeding the limit and the degree of amplification factor exceeding the limit.

[0020] Furthermore, the comparison of the time delay and amplitude amplification factor with the allowable range of the contact mechanism, the determination of the abrupt change in the initial separation velocity between adjacent actions based on the initial separation velocity sequence of the contact, and the determination of the mechanical strength degradation level caused by the creep of the insulating tie rod based on the comparison results and the abrupt change amplitude, further includes:

[0021] The degree of delay exceeding the limit, the degree of multiplier exceeding the limit, and the magnitude of the initial velocity change during separation form a multidimensional feature vector, which is input to a pre-trained support vector machine classifier to output the mechanical strength degradation level.

[0022] Furthermore, the method involves collecting contact closing delay, contact overtravel, and contact bounce counts. Based on these parameters, the contact movement abnormality types are classified, and the severity level of contact movement accuracy impairment is determined by combining the mechanical strength degradation level. This includes:

[0023] The contact closing delay is taken from the time interval from the issuance of the closing command to the first contact between the moving and stationary contacts; the contact overtravel is taken from the displacement distance traveled by the automatic contact after passing the contact position of the stationary contact; and the contact bounce count is taken from the number of times the contact bounces after the first contact and then immediately separates and re-contacts.

[0024] The three parameters are compared with the normal operating characteristic range to obtain three deviation indicators. The abnormal contact action type is classified by the combination of deviation indicators. The severity level is obtained by querying the two-dimensional mapping table in combination with the mechanical strength degradation level.

[0025] Furthermore, the step of obtaining historical health baseline values ​​for circuit breakers of the same model, and determining the rate of deterioration progression of the operating mechanism based on the difference and rate of change of the current severity level relative to the health baseline values, includes:

[0026] Sample data on contact closing delay, contact overtravel, and contact bounce count were collected during the initial healthy operation phase of the same type of circuit breaker in the early stage of commissioning. The arithmetic mean of each parameter was calculated to obtain the health benchmark value.

[0027] Furthermore, the step of obtaining historical health baseline values ​​for circuit breakers of the same model, and determining the rate of deterioration progression of the operating mechanism based on the difference and rate of change of the current severity level relative to the health baseline values, also includes:

[0028] The difference amplitude vector is obtained by subtracting the corresponding health benchmark value from the current contact closing delay, contact overtravel amount and contact bounce number, and taking the absolute value. The change rate is obtained by performing a time-series difference operation on the difference amplitude vector. The change rate and the difference amplitude vector are input into a preset deterioration progress rate evaluation rule table to obtain the deterioration progress rate.

[0029] Furthermore, if the rate of degradation accelerates and the abrupt change in the initial separation velocity exceeds a preset allowable limit, then the critical condition for shutdown and maintenance is determined to have been met, including:

[0030] The degradation progression rate is arranged in chronological order of action occurrence to obtain a time series. The gear rise slope is obtained by differential operation of adjacent gears. The gear rise slope is compared with the acceleration judgment threshold to obtain an acceleration trend indicator. The acceleration trend indicator and the comparison result of the separation initial velocity change amplitude with the allowable limit are used to jointly determine the critical condition.

[0031] Furthermore, based on the critical condition determination results, the system generates early warnings for tie rod replacement, contact adjustment, and overall machine maintenance, and outputs an operational status assessment report, including:

[0032] The critical condition determination results are mapped according to the early warning distribution rules. If the mechanical strength degradation level is in the severe degradation level, the tie rod replacement early warning is triggered. If the severity level exceeds the preset warning level, the contact adjustment early warning is triggered. If the critical condition is met, the whole machine overhaul early warning is triggered. The results are then summarized and filled into the operating status assessment report template.

[0033] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0034] This invention discloses an intelligent assessment method for the operating status of high-voltage circuit breakers. Addressing the challenges of undetectable creep in insulating tie rods, difficulty in quantifying the degradation process of contact mechanisms, and difficulty in accurately determining the timing of shutdowns for maintenance, this method uses displacement sensors and speed monitoring devices to simultaneously collect the actual length of the tie rod and the initial velocity of contact separation. After high-frequency noise filtering, it obtains the increase in tie rod deformation, the change in contact stroke, and the sequence of initial separation velocities. It then assesses the corresponding relationship between deformation and stroke, extracts the time delay and amplitude amplification factor of deformation-to-stroke transmission, compares it with allowable ranges, and combines the abrupt change in the initial separation velocity of adjacent actions to jointly determine the level of mechanical strength degradation caused by insulation tie rod creep. Based on this, it collects closing delay, overtravel amount, and bounce number to classify abnormal contact action types, integrates the mechanical strength degradation level to assess the severity of motion accuracy damage, and calculates the rate of deterioration of the operating mechanism based on the difference and rate of change of historical health benchmark values ​​for the same model. When the deterioration accelerates and the abrupt change exceeds the limit, it determines the critical condition for shutdown maintenance, and outputs graded warnings for tie rod replacement, contact adjustment, and overall machine maintenance. This invention enables end-to-end tracing and intelligent early warning from microscopic creep to macroscopic abnormal operation, significantly improving the accuracy of circuit breaker operating status assessment and the timeliness of maintenance decisions. Attached Figure Description

[0035] Fig. 1 This is a flowchart of an intelligent evaluation method for the operating status of a high-voltage circuit breaker according to the present invention.

[0036] Fig. 2 This is a schematic diagram of an intelligent evaluation method for the operating status of a high-voltage circuit breaker according to the present invention.

[0037] Fig. 3 This is another schematic diagram of an intelligent evaluation method for the operating status of a high-voltage circuit breaker according to the present invention. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0039] like Figs. 1-3 This embodiment of a method for intelligent assessment of the operating status of a high-voltage circuit breaker may specifically include:

[0040] Step S101: The actual length of the high-voltage circuit breaker tie rod and the initial velocity of contact separation are collected by the displacement sensor and the velocity monitoring device. High-frequency noise interference is filtered out to obtain the sequence of tie rod deformation growth, contact stroke change and initial velocity of contact separation.

[0041] A displacement sensor installed at the end of the high-voltage circuit breaker rod collects the actual length data of the rod during the opening and closing operation according to a preset sampling period. Simultaneously, a moving contact displacement sensor collects the moving contact displacement signal, obtaining the original length signal and the original velocity signal. A Butterworth low-pass filter is used to filter out power frequency interference and high-frequency noise components introduced by mechanical vibration from the original length signal and the original velocity signal. The difference between the filtered length signal and the pre-calibrated rod reference length is used to obtain the rod deformation growth. Simultaneously, a linear displacement sensor installed on the moving contact operating link independently collects the moving contact displacement signal during the opening and closing process, and the same filtering process is used to obtain the contact stroke change. This makes the rod deformation growth and contact stroke change two signals measured independently at the rod end and contact end, respectively. The initial velocity data are arranged according to the opening and closing operation sequence to obtain the contact separation initial velocity sequence.

[0042] In one embodiment, an eddy current non-contact displacement sensor is selected as the displacement sensor and is installed on a fixed bracket near the connection end of the transmission mechanism on the insulating tie rod of the high-voltage circuit breaker. The probe faces the metal reflector on the end face of the tie rod and continuously samples the axial position of the tie rod at a sampling period of 1 millisecond. The output voltage signal is linearly related to the actual length of the tie rod, forming the original displacement sequence. The speed monitoring device uses a photoelectric encoder on the moving contact side in conjunction with a speed measuring gear. During the circuit breaker's opening action, the angular displacement change is continuously recorded at a period of 1 millisecond. The angular velocity sequence is obtained by dividing the difference in angular displacement between adjacent sampling points by the sampling time interval, and then multiplied by the gear radius r to convert it into a linear velocity sequence, where r is 0.05 meters, forming the original velocity sequence. The original displacement sequence and the original velocity sequence are respectively processed by a fourth-order Butterworth low-pass filter for passband flattening. The cutoff frequency is set to 300 Hz, which is higher than the main mechanical operation frequency of the circuit breaker but lower than the mechanical resonance frequency band of several hundred Hz. This filters out mechanical resonance noise while preserving the dynamic characteristics of the opening and closing operation process. For the 50 Hz power frequency and its harmonic interference, a 50 Hz power frequency notch filter is used to suppress it separately. After filtering, the signal enters the subsequent processing stage.

[0043] Specifically, the original length signal and the original speed signal are mixed with power frequency electromagnetic interference and high-frequency disturbance components introduced by the mechanical vibration of the circuit breaker body during transmission. The frequencies are mainly distributed in the 50 Hz power frequency harmonic and the mechanical resonance frequency band above several hundred Hz.

[0044] In one possible implementation, the main mechanical operating frequency of the circuit breaker is first determined, which is typically between 50 and 200 Hz. The original length and speed signals are then filtered using a fourth-order Butterworth low-pass filter with a cutoff frequency fc of 300 Hz. This satisfies the condition that fc is higher than the main mechanical operating frequency but lower than the mechanical resonance frequency band. The even-order Butterworth filter has no ripple in its amplitude-frequency response within the passband, thus preserving the dynamic characteristics of the opening and closing operation to support subsequent cross-correlation calculations with millisecond-level time delays, while filtering out mechanical resonance components above several hundred Hz. This yields a rod length signal and contact initial velocity signal that retain the dynamics of the operation.

[0045] It should be noted that the slow creep component generated by the tie rod under temperature changes and long-term stress, with a frequency of approximately 0.01 to 0.5 Hz, is a low-frequency trend reflecting the accumulation of long-term deformation. This component is extracted separately by a low-pass filter with a cutoff frequency not exceeding 1 Hz and stored according to the action cycle; it is not involved in the processing of the dynamic waveform in this step. For the smoothed tie rod length signal, the difference is calculated with the pre-calibrated tie rod reference length. The tie rod reference length L0 is taken from the initial assembly length value measured at a standard temperature of 25 degrees Celsius during the circuit breaker's factory commissioning phase. The difference result ΔL = L - L0 is the amount of tie rod deformation growth, where L is the smoothed tie rod length signal.

[0046] In one embodiment, the change in contact stroke is taken from the displacement waveform independently measured and filtered by a linear displacement sensor installed on the moving contact operating link during the opening and closing process. The theoretical geometric relationship between this waveform and the increase in rod deformation is determined by the mechanical structural dimensions of the crank-connecting rod system. In actual transmission, due to mechanical hysteresis and non-ideal deformation of the connecting rod, there is a time delay and an amplified deviation from the theoretical value, constituting two independent inputs for the subsequent S102 transmission characteristic analysis. The time first derivative is calculated on the independently measured waveform of the change in contact stroke, and the velocity value within a short time window after the inflection point of the stroke curve from the stationary segment to the rapid change segment in each opening and closing action is extracted as the initial velocity of contact separation for this action. These values ​​are arranged in chronological order of action occurrence to form a sequence of initial velocities for contact separation. The increase in rod deformation, the change in contact stroke, and the sequence of initial velocities for contact separation together constitute the basic data for the mechanical condition assessment of the high-voltage circuit breaker.

[0047] Step S102: Evaluate the corresponding relationship between the increase in rod deformation and the change in contact stroke, and determine the time delay and amplitude amplification factor of the transmission of the increase in rod deformation to the change in contact stroke.

[0048] The sequence of the increase in rod deformation and the sequence of changes in contact stroke are obtained. Using the rising edge of the circuit breaker opening / closing operation signal as the trigger time, two sets of sample data within the same time window are extracted for each opening / closing operation. The two sets of sample data are then waveform aligned according to the trigger time to obtain deformation and stroke waveforms with consistent time axes. For the deformation and stroke waveforms, a cross-correlation function is used to calculate their correlation coefficient point-by-point along the time axis. The time offset corresponding to the maximum value of the cross-correlation function is the time delay in the transmission of rod deformation increase to contact stroke change. This time delay reflects the mechanical response interval experienced by the force deformation of the insulating rod to the moving contact actuator. The deformation waveform is compensated for along the time axis based on the time delay. The maximum amplitude point of the compensated deformation waveform and the maximum amplitude point of the stroke waveform are extracted, and their ratio is calculated to obtain the amplitude amplification factor of the transmission of rod deformation increase to contact stroke change. This amplitude amplification factor and the time delay together constitute the corresponding relationship between the increase in rod deformation and the change in contact stroke.

[0049] In one embodiment, the sequence of changes in tie rod deformation is acquired by a displacement sensor installed on the circuit breaker tie rod, and the sequence of changes in contact stroke is acquired by a displacement sensor installed at the contact and then converted by the transmission ratio of the transmission mechanism. The sequence of changes in tie rod deformation is acquired by a displacement sensor at the tie rod end, and the sequence of changes in contact stroke is acquired independently by a displacement sensor at the moving contact end. Both are acquired synchronously along the time axis at a sampling frequency of 100 Hz to 1000 Hz to ensure accurate time correspondence of the data. The ratio of the peak value of contact end stroke to the peak value of tie rod end deformation is the amplitude amplification factor K, and its design amplification ratio is determined by the linkage geometry. Under normal operating conditions, K is stable near this design amplification ratio.

[0050] It should be noted that as a component bearing the transmission force, the change in the displacement of the end of the insulating tie rod is not reflected instantaneously to the moving contact actuator. There is a certain mechanical response interval in the transmission process through the crank-connecting rod mechanism. At the same time, due to the existence of the lever ratio, the small deformation of the tie rod end will be amplified or reduced and reflected in the contact stroke.

[0051] Specifically, a time window of equal length is extracted for each opening and closing operation, with the starting point of the window aligned with the rising edge of the circuit breaker's opening and closing operation signal. The operation signal is taken from the current signal of the opening and closing coil in the circuit breaker control circuit. The moment the current jumps from zero and first exceeds a preset threshold is determined as the trigger moment. Considering that the coil's no-load noise current is typically below 20mA, while the rated value of the normal excitation current is in the range of 1A to 5A, the preset threshold is taken as 10% to 20% of the rated excitation current. In engineering implementation, it is generally set to 0.2A to 0.5A, which avoids static noise and surge interference while ensuring reliable triggering within milliseconds of the start of the operation. The time window length is determined based on the total mechanical action time of this type of circuit breaker, covering the entire process from coil energization, core engagement, lever transmission to contact reaching its final position and stabilizing, with an approximately 20% margin reserved for waveform steady-state comparison. Typical opening time is 60ms to 100ms, and typical closing time is 80ms to 150ms. The window length remains fixed during the analysis of the same equipment. Based on the above action trigger times, sample data from the corresponding window are extracted from the lever deformation growth sequence and the contact stroke change sequence at the same sampling rate to obtain time-axis aligned deformation and stroke waveforms.

[0052] In one possible implementation, although the deformed waveform and the travel waveform have the same starting point on the time axis, there is still a relative lag between the waveforms along the time axis. The cross-correlation function adopts the classic academic definition of signal processing, in which one waveform is successively shifted along the time axis by different offsets τ, and the values ​​of the other waveform at corresponding times are multiplied point by point and summed to obtain the correlation coefficient R(τ) under different offsets.

[0053] Specifically, the correlation coefficient R(τ) is expressed as R(τ) = Σx(t) × y(t + τ), where x(t) represents the value of the increase in rod deformation at time t, and y(t + τ) represents the value of the change in contact stroke at time t + τ. The summation covers the entire time window. The correlation coefficient R(τ) changes with the offset τ. When the offset τ is exactly equal to the actual lag time experienced by the deformation waveform to the stroke waveform, the two waveforms achieve optimal overlap, and the correlation coefficient R(τ) shows a peak value. The offset τ corresponding to this peak value is determined as the time delay of the increase in rod deformation to the change in contact stroke.

[0054] In one embodiment, continuous tripping operation monitoring is performed on a certain type of 252 kV high-voltage circuit breaker. The time delay value falls within the range of several milliseconds to more than ten milliseconds, reflecting the mechanical response interval experienced by the force deformation of the insulating tie rod through the transmission mechanism to the moving contact actuator. The time delay only describes the timing characteristics during the transmission process and does not describe the amplitude transmission characteristics. Based on the time delay, the deformed waveform is translated along the time axis for compensation. The translation direction is a shift along the positive time axis equal to the time delay value, resulting in a translated deformed waveform. The translated deformed waveform and the stroke waveform are completely overlapped in timing and can be directly compared at the amplitude level. The maximum amplitude point of the translated deformed waveform during the tripping operation is extracted and recorded as the tie rod end deformation peak value D1; the maximum amplitude point of the stroke waveform during the same tripping operation is extracted and recorded as the contact end stroke peak value S1. Since both the peak deformation D1 at the tie rod end and the peak stroke S1 at the contact end represent displacement, and both have the same dimension, dividing S1 by D1 yields the amplitude amplification factor K = S1 / D1. The amplitude amplification factor K numerically reflects the actual amplification characteristics of the circuit breaker's transmission mechanism from the tie rod end deformation to the contact end stroke. During normal operation, K stabilizes near the design amplification ratio determined by the connecting rod geometry, typically ranging from 1.2 to 2.5. Creep degradation of the insulating tie rod will cause K to deviate from this design amplification ratio.

[0055] It should be noted that the time delay and the amplitude amplification factor together constitute the corresponding relationship between the increase in rod deformation and the change in contact stroke. This corresponding relationship establishes a quantitative correlation between the deformation characteristics of the insulating rod and the motion characteristics of the contact actuator, characterizing the transmission characteristics of motion deviation from the material level to the mechanical level due to the cumulative deformation.

[0056] Step S103: Compare the time delay and amplitude amplification factor with the allowable range of the high-voltage circuit breaker contact mechanism, and determine the abrupt change amplitude of the initial separation velocity between adjacent actions based on the initial separation velocity sequence of the contacts. The mechanical strength degradation level caused by the creep of the insulating tie rod is determined by the comparison result and the abrupt change amplitude.

[0057] The time delay and amplitude amplification factor of the transmission of the increase in the deformation of the tie rod to the change in the contact stroke are obtained. A pre-established allowable range file for the high-voltage circuit breaker contact mechanism is retrieved. This file records the time delay boundary values ​​and amplitude amplification factor boundary values ​​calibrated during the factory commissioning phase of the same model of circuit breaker. The time delay and amplitude amplification factor are subtracted from their corresponding boundary values ​​to obtain the degree of delay exceeding the limit and the degree of amplitude exceeding the limit. For the contact separation initial velocity sequence, pairs are formed according to the order of occurrence of two adjacent opening and closing actions. The difference between the separation initial velocity of the later action and the separation initial velocity of the previous action in the adjacent pair is taken as the absolute value to obtain the separation initial velocity mutation amplitude sequence between adjacent actions. This separation initial velocity mutation amplitude sequence reflects the jump in speed characteristics of the contact actuator during continuous operation. The delay limit exceedance, the multiplier limit exceedance, and the initial velocity mutation amplitude sequence are combined to form a multidimensional feature vector, which is then input into a pre-trained support vector machine classifier. The training samples of the support vector machine classifier are derived from the operation data marked with creep degradation levels in the historical dismantling and maintenance files of the same type of circuit breaker. The classifier outputs the mechanical strength degradation level caused by the current insulation rod creep.

[0058] In one implementation, the permissible range profile of the high-voltage circuit breaker contact mechanism is organized on a per-model basis. The profile parameters are derived from data obtained through repeated mechanical calibration during the factory commissioning phase. The profile records two types of boundary values: a time delay boundary value, representing the maximum permissible mechanical response interval during the transmission of deformation from the insulating tie rod to the moving contact, ranging from 8 to 15 milliseconds; and an amplitude amplification factor boundary value, representing the upper limit of the permissible geometric amplification of the transmission linkage mechanism, ranging from 1.2 to 2.5 times. Taking a certain model of vacuum circuit breaker as an example, its calibrated time delay boundary value is 12 milliseconds, and its amplitude amplification factor boundary value is 1.8 times. These parameters constitute the benchmark reference for the health assessment of the contact mechanism of this model of circuit breaker.

[0059] Specifically, the difference between the previously obtained time delay and the time delay boundary value is the degree of delay exceeding the limit; the difference between the previously obtained amplitude amplification factor and the amplitude amplification factor boundary value is the degree of amplification factor exceeding the limit. These two limit-exceeding values ​​characterize the degree to which the high-voltage circuit breaker contact mechanism deviates from the normal operating boundary in terms of transmission characteristics.

[0060] It should be noted that relying solely on time delay and amplitude amplification factor is insufficient to reflect the evolution of the contact actuator's speed characteristics during multiple operations. Further processing is performed on the initial contact separation velocity sequence. This sequence originates from the stroke waveform in S102 after cross-correlation alignment and amplification factor correction. For each opening and closing operation, the inflection point where the stroke curve transitions from a stationary phase to a rapidly changing phase is taken as the contact separation moment. Stroke data within a 2-millisecond window following this moment is extracted, and its first time derivative is calculated, with the window mean taken. The result is the initial contact separation velocity value for this operation. These values ​​are arranged sequentially according to the order of the opening and closing operations, forming the initial contact separation velocity sequence, denoted as v1, v2, v3…vn, where vk represents the initial contact separation velocity of the k-th opening and closing operation, and n is the cumulative number of opening and closing operations within the statistical period, typically ranging from 20 to 50 times. This sequence, after generation, is sent to S103 along with the waveform characteristics from S102, serving as the core input for mechanical condition assessment and subsequent discrimination.

[0061] Specifically, the circuit is paired up according to the order of two adjacent opening and closing actions. The difference between the initial separation velocity of the later action and the initial separation velocity of the earlier action in each pair is taken as the absolute value, i.e., Δvk = |vk+1 - vk|, where Δvk represents the magnitude of the change in initial separation velocity between the k-th and (k+1)-th actions. All Δvk values ​​obtained from pairing adjacent actions are arranged in the order of action to form a sequence of changes in initial separation velocity magnitudes between adjacent actions. This sequence of changes in initial separation velocity magnitudes reflects the jumps in the speed characteristics of the contact actuator during continuous operation.

[0062] It is understandable that under long-term creep, the increased length of the insulating rod will alter the contact closing position, thus causing a deviation in the initial contact separation position at the moment of opening, ultimately manifesting as a sudden jump in the initial separation velocity between different actions. The larger the numerical value of the initial separation velocity abrupt change sequence, the worse the motion consistency at the contact actuator end. Furthermore, the maximum value s is extracted from the initial separation velocity abrupt change sequence. max Mean s mean with standard deviation s std The three statistical measures, as fixed-dimensional velocity jump characteristics, together with the delay exceedance degree d1 and the multiplier exceedance degree d2, form a fixed-dimensional feature vector, denoted as x = [d1, d2, s]. max s mean s std This ensures that the feature vector dimension does not change with the number of actions n within the statistical period, satisfying the requirement of a constant input dimension for the support vector machine classifier. The multidimensional feature vector constitutes a specific sample point in the numerical space.

[0063] In one embodiment, a support vector machine (SVM) classifier is used to determine the degradation level of the multidimensional feature vectors. The SVM classifier is a classic classifier based on the principle of minimizing structural risk. Its core idea is to separate sample points of different categories by finding a hyperplane with the largest classification margin in the feature space. For the nonlinearly separable scenario of determining the mechanical strength degradation level of high-voltage circuit breakers, the SVM classifier uses a radial basis function kernel to map the original feature space to a high-dimensional space, constructing a classification hyperplane in the high-dimensional space. The training samples for the SVM classifier come from historical dismantling and maintenance archives of circuit breakers of the same model. These archives record the delay exceeding limits, rate exceeding limits, and initial separation velocity mutation amplitude sequences collected during the last operating cycle before shutdown for each circuit breaker that has been decommissioned and dismantled. They also record manually labeled creep degradation level tags after dismantling inspection, which are divided into three levels: slight degradation, moderate degradation, and severe degradation. During the training phase, historical samples are input into the support vector machine classifier, and the hyperplane parameters and support vector set are iteratively solved to obtain the trained classifier model.

[0064] Specifically, during the online operation phase, the multi-dimensional feature vector obtained from the current opening and closing action is fed into the trained support vector machine classifier. The classifier outputs the mechanical strength degradation level caused by the current insulation rod creep. The mechanical strength degradation level corresponds to one of three levels: slight degradation, moderate degradation, and severe degradation.

[0065] For example, for a certain high-voltage circuit breaker, if the degree of delay exceeding the limit is in a slightly deviated range, that is, the difference between the time delay and the time delay boundary value does not exceed 5% of the boundary value and s max If the speed is less than 0.3 m / s, the support vector machine classifier outputs a slight degradation level; if the rate exceeds the limit by more than 15% and s max If the speed is greater than 0.8 m / s, the support vector machine classifier outputs a severe degradation level.

[0066] It should be noted that the mechanical strength degradation level is characterized by discrete labels to represent the cumulative impact of insulation rod creep on the mechanical transmission characteristics of the circuit breaker. The cumulative deformation at the rod material level and the motion deviation at the contact actuator end are quantitatively compared and classified into a unified degradation characterization index.

[0067] Step S104: Collect contact closing delay, contact overtravel amount, and contact bounce number. Classify the contact action abnormality type based on the contact closing delay, contact overtravel amount, and contact bounce number. Combine the mechanical strength degradation level to determine the severity level of contact motion accuracy damage.

[0068] The contact closing delay, contact overtravel, and contact bounce count are obtained by synchronously acquiring the auxiliary contact signal and moving contact displacement signal of the high-voltage circuit breaker. The contact closing delay is taken as the time interval from the moment the closing operation command is issued to the moment the moving and stationary contacts first make contact. The contact overtravel is taken as the displacement distance that the automatic contact continues to travel after passing the contact position of the stationary contact. The contact bounce count is taken as the number of instantaneous separation and re-contact occurrences after the automatic stationary contact makes its first contact. The contact closing delay, contact overtravel, and contact bounce count are compared with the pre-established normal operation characteristic interval to obtain delay deviation, overtravel deviation, and bounce deviation indicators. The contact action abnormality type is classified according to the combination of the three deviation indicators. The contact action abnormality type includes closing timing inaccuracy type, travel overlimit type, and contact chatter type. Obtain the mechanical strength degradation level obtained in the previous step, and match the mechanical strength degradation level with the contact movement abnormality type according to a pre-established two-dimensional level mapping table. The two-dimensional level mapping table uses the mechanical strength degradation level as the row index and the contact movement abnormality type as the column index. Each cell in the table records the severity level of contact movement accuracy damage under the corresponding combination. The severity level of the current contact movement accuracy damage is obtained from the matching query result.

[0069] In one embodiment, the auxiliary contact signal of the high-voltage circuit breaker is taken from the output signal of the normally open node of the auxiliary switch, which is synchronously linked with the main circuit contacts, and the displacement signal of the moving contact is taken from the output of a linear displacement sensor installed on the moving contact operating linkage. The two signals are synchronously acquired by a synchronous sampling module at a unified sampling clock, forming the original data source for determining the mechanical action characteristics of the contacts.

[0070] Specifically, the contact closing delay is defined as the time interval from the moment the high-voltage circuit breaker receives the closing operation command to the moment the moving contact displacement signal indicates that the moving contact and the stationary contact first make metal contact.

[0071] For example, for a certain type of 126 kV high-voltage circuit breaker, the contact closing delay value usually falls in the tens of milliseconds range.

[0072] It should be noted that the contact overtravel amount refers to the amount by which the moving contact continues to compress the stationary contact assembly a certain distance after the initial contact between the moving and stationary contacts. The moving contact does not immediately stop advancing at the moment of contact, but instead continues to do so due to the preload of the closing spring. This distance is the contact overtravel amount. The contact overtravel amount directly reflects the preload of the contact pressure between the contact assemblies and is obtained from the displacement increment of the moving contact after the initial contact.

[0073] In one possible implementation, the number of contact bounces is obtained by accumulating the number of transient disconnections and reconnections of the auxiliary contact signal after its initial connection. Further, the bounce duration is obtained by statistically analyzing the time interval from the initial connection of the auxiliary contact signal until the pulse completely disappears and the steady-state level is maintained, and this duration is collected together with the number of bounces from the same auxiliary contact signal. At the moment of initial contact between the moving and stationary contacts, a rebound phenomenon occurs due to mechanical collision, resulting in a very short period of separation and re-contact between the contacts. The auxiliary contact signal will then superimpose several pulses onto the steady-state level after the closing is completed. Counting the number of these pulses yields the number of contact bounces.

[0074] Specifically, the normal operation characteristic range is established for each mechanical action parameter, and the upper and lower limits of the normal operation characteristic range are taken from the allowable fluctuation range calibrated by repeated mechanical actions during the factory commissioning stage of the same model of circuit breaker. The contact closing delay is compared with the closing delay range in the normal operation characteristic range. If the contact closing delay falls outside the range, the delay deviation flag is set to 1; otherwise, it is set to 0. The overtravel deviation flag and bounce deviation flag are obtained in the same way. Further, the three deviation flags form a three-bit binary combination, and the contact action abnormality type is classified according to the combination form of the deviation flags.

[0075] In one embodiment, if the delay deviation indicator is set to 1 while the other two deviation indicators are both 0, it is determined to be a closing timing inaccuracy type, reflecting that the overall action time of the closing operation mechanism deviates from the normal range; if the overtravel deviation indicator is set to 1 while the other two deviation indicators are both 0, it is determined to be a travel overlimit type, reflecting that the distance by which the moving contact compresses the stationary contact assembly exceeds the allowable range; if the bounce deviation indicator is set to 1 while the other two deviation indicators are both 0, it is determined to be a contact chatter type, reflecting that the contact has bounced multiple times at the moment of closing. When two or more of the three deviation indicators are set simultaneously, they are classified into the dominant abnormality type according to a pre-established combination priority rule. The combination priority rule is: the delay deviation indicator has a higher priority than the overtravel deviation indicator, the overtravel deviation indicator has a higher priority than the bounce deviation indicator, and the abnormality is classified according to the abnormality type corresponding to the single deviation indicator with the highest priority. The delay deviation indicator is set when the closing delay T exceeds the normal range T0±ΔT1, where T0 is the rated closing delay and ΔT1 is the delay tolerance, preferably ranging from 3 milliseconds to 5 milliseconds; the overtravel deviation indicator is set when the overtravel amount Sc exceeds the allowable range S0±ΔS1, where S0 is the rated overtravel amount and ΔS1 is the overtravel tolerance, preferably ranging from 0.5 mm to 1 mm; the bounce deviation indicator is set when the number of bounces N exceeds the threshold N0, preferably N0 is 3 times. The delay deviation indicator is set when the closing delay T exceeds the normal range T0±ΔT1, where T0 is the rated closing delay and ΔT1 is the delay tolerance, preferably ranging from 3 to 5 milliseconds; the overtravel deviation indicator is set when the overtravel amount Sc exceeds the allowable range S0±ΔS1, where S0 is the rated overtravel amount and ΔS1 is the overtravel tolerance, preferably ranging from 0.5 mm to 1 mm; the bounce deviation indicator is set when the number of bounces N exceeds the threshold N0 or the bounce duration t. b If the threshold D0 is exceeded, N0 is preferably set to 3 times, and D0 is preferably set to 2 milliseconds.

[0076] Understandably, relying solely on the contact actuation anomaly type only characterizes the phenomenon at the end of the operation and does not yet take into account the mechanical strength degradation of the internal transmission chain of the high-voltage circuit breaker. It is necessary to couple the previously obtained mechanical strength degradation level with the contact actuation anomaly type for determination.

[0077] Specifically, the two-dimensional grade mapping table is pre-established before commissioning. The table uses three levels of mechanical strength degradation—slight degradation, moderate degradation, and severe degradation—as row indexes, and three types of contact movement abnormalities—closing timing inaccuracy, travel over-limit, and contact chattering—as column indexes. The two-dimensional grade mapping table comprises 3×3=9 cells. Each cell records the severity level of the contact movement accuracy damage, which is divided into four levels: Level 1, Level 2, Level 3, and Level 4. The values ​​of each cell in the mapping table are pre-defined based on the correlation between mechanical strength degradation and contact movement abnormalities in historical dismantling and maintenance files of circuit breakers of the same model. For example, slight degradation and closing timing inaccuracy correspond to Level 1, and severe degradation and contact chattering correspond to Level 4.

[0078] In one embodiment, the currently obtained mechanical strength degradation level and the contact movement abnormality type are respectively used as row index values ​​and column index values ​​and sent to the two-dimensional level mapping table for matching query. The two-dimensional level mapping table returns the level value recorded in the corresponding cell, which is the current severity level of contact movement accuracy damage.

[0079] It should be noted that the severity level of contact motion accuracy damage is determined by coupling the mechanical strength degradation caused by rod creep with the abnormal movement exhibited at the end of the moving contact, thus integrating the deterioration causes on the internal transmission chain of the circuit breaker with the phenomena at the external moving end into a unified accuracy damage characterization index.

[0080] Step S105: Obtain the contact closing delay, contact overtravel, and contact bounce count of historical circuit breakers of the same model as health baseline values. Based on the difference and rate of change between the current severity level and the health baseline values, determine the deterioration rate of the high-voltage circuit breaker operating mechanism.

[0081] Sample data on contact closing delay, contact overtravel, and contact bounce counts collected during the initial healthy operation phase of historical circuit breakers of the same model are retrieved. The arithmetic mean of each parameter is calculated from these sample data to obtain baseline values ​​for contact closing delay, contact overtravel, and contact bounce counts. These three baseline values ​​together constitute the health baseline values ​​for the high-voltage circuit breaker's operating mechanism. The severity level of the current contact movement accuracy impairment is obtained, along with the corresponding contact closing delay, contact overtravel, and contact bounce counts collected for that action. The corresponding health baseline values ​​are subtracted from each of the three current parameters, and the absolute values ​​are taken to obtain a difference amplitude vector. This difference amplitude vector is then labeled according to the severity level. The difference amplitude vector is subjected to time-series difference operation according to the time sequence of action occurrence to obtain the successive rate of change of the difference amplitude between two adjacent actions. The rate of change and the difference amplitude vector are input together into a pre-established degradation progress rate assessment rule table. The degradation progress rate assessment rule table gives the corresponding degradation progress rate level according to the combination relationship between the difference amplitude level and the rate of change level. The degradation progress rate of the high-voltage circuit breaker operating mechanism is obtained from the table lookup result.

[0082] In one implementation, the sample data collected from the historical circuit breakers of the same model during their initial healthy operation phase are taken from multiple opening and closing operation records within a certain time interval after the circuit breakers of the same model were put into operation. During this initial time interval, the circuit breakers have not yet experienced significant creep accumulation in the insulation rods, and all components of the contact mechanism transmission chain are in good assembly condition. The collected values ​​for contact closing delay, contact overtravel, and contact bounce count can represent the healthy operating level of the circuit breaker model under the factory manufacturing process.

[0083] Specifically, each parameter in the sample data is processed independently. The contact closing delay values ​​in the sample data are summed and divided by the number of samples to obtain the contact closing delay baseline value. Similarly, the contact overtravel and contact bounce counts are calculated by taking their arithmetic averages to obtain the contact overtravel baseline value and contact bounce count baseline value. These three baseline values ​​together constitute the health baseline value of the high-voltage circuit breaker operating mechanism. Deviation values ​​at a single moment only reflect the transient state of that action and are insufficient to characterize the deterioration progress of the operating mechanism over time. Therefore, the current delay difference component, overtravel difference component, and bounce difference component are timestamped into the equipment operation file and concatenated with the corresponding records of the most recent 10 actions to form a trend sequence. This sequence allows for subsequent extraction of the rate of change over time, thereby identifying gradual deterioration trends before a single overtravel reaches the alarm threshold.

[0084] In one possible implementation, the severity level of the current contact motion accuracy failure is obtained, along with the contact closing delay, contact overtravel, and contact bounce count collected for that action.

[0085] Specifically, the delay difference component is obtained by subtracting the contact closing delay reference value from the current contact closing delay and taking the absolute value; the overtravel difference component is obtained by subtracting the contact overtravel reference value from the current contact overtravel amount and taking the absolute value; and the bounce difference component is obtained by subtracting the contact bounce number reference value from the current contact bounce number. These three difference components are arranged in sequence to form a difference amplitude vector. Furthermore, the severity level of the contact motion accuracy damage is stored along with the difference amplitude vector for anomaly tracing and record labeling. During subsequent table lookups, the row index of the deterioration progression rate assessment rule table is uniformly taken as the low, medium, or high level categorized by the relative deviation L2 norm, and the column index is taken as the slow, moderate, or fast level categorized by the rate of change. The severity level is not involved in determining the row index of this table.

[0086] It is understandable that the difference magnitude vector only describes the degree of deviation at a certain moment of action. To describe the rate of deterioration, it is necessary to introduce the trend of change in the time dimension.

[0087] In one embodiment, the difference amplitude vectors of the most recent opening and closing actions are arranged in chronological order of their occurrence. A time-series difference operation is performed along the time axis, that is, the rate of change of the difference amplitude between two adjacent actions is obtained by taking the difference between the difference amplitude vectors corresponding to two adjacent actions. The larger the rate of change, the faster the operating mechanism deviates from the healthy baseline value in a short period of time. The degradation progress rate assessment rule table is pre-established before commissioning. To eliminate the influence of inconsistent dimensions among the various difference components, the delay difference component, overtravel difference component, and bounce difference component are first divided by their respective health benchmark values ​​to obtain dimensionless relative deviation components. Then, the L2 norm of this relative deviation vector is calculated as the basis for single-dimensional classification, dividing it into three levels: low, medium, and high. A L2 norm less than 0.15 is classified as low, greater than or equal to 0.15 and less than 0.35 as medium, and greater than or equal to 0.35 as high. The above thresholds are determined by taking the quantiles of the distribution of the L2 norm of relative deviation in the historical operation records of circuit breakers of the same model. For example, the 60th and 85th percentiles are taken as the boundaries between low / medium and medium / high. The rate of change is obtained by dividing the difference in the L2 norm of the relative deviation between two adjacent actions by the time interval between the two actions, and then converting it into the absolute value of the L2 norm increment for each natural month for classification: a monthly increment of less than 0.02 is classified as slow, greater than or equal to 0.02 and less than 0.05 as moderate, and greater than or equal to 0.05 as fast. The two categories are arranged into 3×3=9 cells according to their combination relationship. Each cell records the degradation progress rate level under that combination. For example, when the difference magnitude is high and the rate of change is fast, the corresponding cell records the severe degradation progress rate level; when the difference magnitude is low and the rate of change is slow, the corresponding cell records the slight degradation progress rate level, and so on for the remaining cells. The degradation rate is uniformly divided into four levels: slow, moderate, fast, and accelerating. Cells with a high difference magnitude and a fast rate of change are recorded as accelerating; cells with a low difference magnitude and a slow rate of change are recorded as slow; and the remaining cells correspond to either moderate or fast levels based on the combination of difference magnitude and rate of change. Further, the current rate of change and the difference magnitude vector are entered into the degradation rate assessment rule table according to their corresponding levels for query matching. The degradation rate assessment rule table returns the level value recorded in the corresponding cell, which is the degradation rate of the high-voltage circuit breaker operating mechanism.

[0088] It should be noted that the degradation progress rate is obtained by comparing historical health benchmarks with the current severity level, difference magnitude vector and time-series change rate, and connecting the deviation state of the operating mechanism at different times into a progress trend curve, thus quantitatively characterizing the cumulative degradation process of the internal mechanical transmission chain of the circuit breaker as a readable level indicator.

[0089] Step S106: If the rate of deterioration accelerates and the magnitude of the initial velocity change exceeds the preset allowable limit, then the critical condition for shutting down and maintaining the high-voltage circuit breaker is determined.

[0090] The historical value sequence of the degradation progress rate of the high-voltage circuit breaker operating mechanism is obtained, and arranged in chronological order of action occurrence to obtain a degradation progress rate time series. The degradation progress rate time series is then processed using adjacent rate difference operations to obtain the successive rate of increase for each rate. This rate of increase is compared with a pre-established acceleration threshold to obtain an acceleration trend indicator for the degradation progress rate. The mutation amplitude value corresponding to the current action in the initial velocity mutation amplitude sequence is obtained, and this mutation amplitude value is compared with a pre-set allowable limit. The allowable limit is taken from the upper bound of the initial velocity jump corresponding to the arc extinguishing performance of the high-voltage circuit breaker arc-extinguishing chamber under calibrated operating conditions. The comparison result serves as a mutation exceeding the limit indicator. A joint judgment is made based on the acceleration trend indicator and the mutation exceeding the limit indicator. If the acceleration trend indicator shows that the degradation progress rate is accelerating, and the mutation exceeding the limit indicator shows that the initial velocity mutation amplitude exceeds the allowable limit, then the critical condition for shutting down and maintaining the high-voltage circuit breaker is determined.

[0091] In one embodiment, the degradation progression rate setting of the high-voltage circuit breaker operating mechanism is a discrete level value obtained during the preceding processing. The degradation progression rate setting is updated once after each opening and closing operation. The degradation progression rate settings are arranged in chronological order of operation occurrence to form a degradation progression rate time sequence.

[0092] Specifically, the degradation progress rate time series is processed using adjacent gear differential calculation. This involves subtracting the degradation progress rate gear value corresponding to the previous action from the degradation progress rate gear value corresponding to the subsequent action to obtain the gear increment between adjacent actions. This gear increment is then divided by the actual time interval between the two actions, and the quotient is the gear rise slope for that action, measured in gears per second, thus aligning with the gear per second dimension of the acceleration judgment threshold. The gear rise slope reflects the speed at which the deteriorated gear of the operating mechanism jumps upward between adjacent actions. A positive gear rise slope indicates a jump towards a higher degradation direction, while zero or negative values ​​indicate that the gear remains stable or falls back. The single gear rise slope only depicts the instantaneous jump of one action. When identifying whether the degradation progress rate shows an accelerating upward trend, the gear rise slope is compared with a pre-established acceleration judgment threshold. The acceleration judgment threshold is determined by the following method: collect no less than 500 sets of historical operating data of the same type of circuit breaker, extract the gear rise slope of each operation, remove outliers, perform statistical analysis on the valid data, and calculate the 95th percentile as the upper limit of normal operating gear transition. This upper limit is usually between 0.8 and 1.2 gears per second. In actual testing, the threshold of a certain 10 kV circuit breaker is 1.05 gears per second. When the real-time monitored gear rise slope exceeds this upper limit, it is identified as an abnormal accelerated transition.

[0093] In one possible implementation, the number of times the gear rise slope corresponding to the most recent opening and closing actions continuously exceeds the acceleration judgment threshold is accumulated. If the accumulated number exceeds a preset cumulative threshold, the acceleration trend indicator of the deterioration progress rate is set to 1; otherwise, it is set to 0. The acceleration trend indicator numerically indicates whether the current deterioration progress rate of the operating mechanism has entered an accelerated upward phase.

[0094] It is understandable that relying solely on the acceleration trend indicator is insufficient to determine whether the high-voltage circuit breaker has reached the critical state requiring shutdown and maintenance; further judgment is needed based on the initial separation velocity fluctuation. In this embodiment, the fluctuation amplitude value corresponding to the current action is extracted from the previously obtained initial separation velocity fluctuation amplitude sequence, and the fluctuation amplitude value is compared with a pre-set allowable limit. Since the deterioration of contact motion performance directly affects the arc extinguishing capability of the arc-extinguishing chamber, the physical source of the allowable limit lies in the quantitative correspondence between the arc extinguishing performance of the high-voltage circuit breaker's arc-extinguishing chamber and the initial contact separation velocity. When the initial separation velocity is too low, the arc cannot be effectively elongated and extinguished before the zero rest point, and the contact surface is prone to burning. Considering that the arc extinguishing performance depends on the absolute level of the initial contact separation velocity, the allowable limit is set based on the minimum absolute value of the initial separation velocity required to ensure reliable arc extinguishing: when the absolute value of the initial separation velocity of a certain action is lower than this minimum value, or when the fluctuation amplitude of the initial separation velocity between adjacent actions is too large, causing the absolute value of the initial velocity of this action to fall below this minimum value, it is determined to be out of limit. For 110 kV circuit breakers, the absolute value of the minimum initial separation velocity is typically 3 to 5 m / s, and the upper limit of the allowable abrupt change is typically 0.3 to 0.5 m / s, depending on the arc-extinguishing chamber structure and contact material properties.

[0095] In one embodiment, for a 252 kV single-break circuit breaker, the allowable limit is obtained by converting the initial separation velocity tolerance under the rated breaking current condition given in the arc-extinguishing chamber design document. The specific conversion method is as follows: read the nominal initial separation velocity v0 and the tolerance δv from the design document, take 80% of the tolerance as the safety margin coefficient, and calculate the allowable limit value v0. lim =v0×Δv×0.8. For example, when the nominal value is 5 meters per second and the tolerance is ±10%, the allowable limit is calculated as 5×0.1×0.8 equals 0.4 meters per second. If the magnitude of the sudden change exceeds the allowable limit, the sudden change exceeding the limit flag is set to 1; otherwise, it is set to 0. Further, a joint determination is performed on the acceleration trend flag and the sudden change exceeding the limit flag, using a logical AND operation to merge the two flags. If the merged result is 1, that is, both conditions are met simultaneously, it is determined that the high-voltage circuit breaker has reached the critical condition for shutdown and maintenance; otherwise, it is determined that the critical condition has not yet been reached.

[0096] It should be noted that the critical condition for shutdown and maintenance is determined by combining two independent judgment dimensions: the accelerating trend of the deterioration progress rate and the exceeding of the limit of the initial separation velocity change. This couples the cumulative deterioration process of the entire operating mechanism with the instantaneous abnormal performance of the contact actuator, forming a clear judgment result on whether the high-voltage circuit breaker needs to be shut down for maintenance.

[0097] Step S107: Based on the critical condition determination results, generate early warnings for tie rod replacement, contact adjustment, and overall machine maintenance, and output a high-voltage circuit breaker operation status assessment report.

[0098] The critical condition determination result is obtained, and the previously obtained mechanical strength degradation level, contact movement accuracy damage severity level, and deterioration progress rate level are extracted. The critical condition determination result is mapped according to a pre-established early warning distribution rule. If the mechanical strength degradation level is at the severe degradation level, a lever replacement early warning is triggered. If the contact movement accuracy damage severity level exceeds a preset warning level, a contact adjustment early warning is triggered. If the critical condition is met, a whole-machine overhaul early warning is triggered. The lever replacement early warning, contact adjustment early warning, and whole-machine overhaul early warning are summarized according to early warning level and trigger time, and along with the mechanical strength degradation level, contact movement accuracy damage severity level, and deterioration progress rate level, are entered into a pre-established high-voltage circuit breaker operating status assessment report template. The high-voltage circuit breaker operating status assessment report is then output.

[0099] In one implementation, the early warning distribution rule is established in advance before commissioning. The early warning distribution rule maps the mechanical strength degradation level, the severity level of contact movement accuracy damage, and the critical condition judgment result to three types of early warning flags, respectively.

[0100] Specifically, regarding the mechanical strength degradation level, if its value falls within the severe degradation range, the tie rod replacement warning sign position will be adjusted, indicating that the internal insulation tie rod of the high-voltage circuit breaker has reached the point where it needs to be replaced due to creep accumulation; regarding the severity level of contact movement accuracy damage, if its value exceeds the preset warning level, the contact adjustment warning sign position will be adjusted, indicating that the closing position and overtravel parameters of the contact actuator have deviated from the allowable range; regarding the critical condition judgment result, if it is determined to be valid, the whole machine maintenance warning sign position will be adjusted, indicating that the entire circuit breaker has reached a state where it must be shut down for maintenance.

[0101] It should be noted that the three types of warning flags are independent of each other in terms of judgment logic and correspond to different handling levels. The lever replacement warning is for the transmission component level of the high-voltage circuit breaker, the contact adjustment warning is for the contact actuator level, and the overall maintenance warning is for the circuit breaker as a whole. The three types of warnings output corresponding warning content according to the setting status of their respective flags, along with the trigger time information. The high-voltage circuit breaker operation status assessment report template is divided into three sections: basic information, status indicators, and warning information. The basic information section is filled with the circuit breaker equipment number, model and specifications, rated voltage, commissioning date, substation, assessment time, and sampling data period, used to identify the assessed object and data source. The status indicator column should be filled with the mechanical strength degradation level, the severity level of contact motion accuracy damage, and the deterioration rate level. The mechanical strength degradation level is described in three levels: slight, moderate, and severe. The severity level of contact motion accuracy damage is described in four levels: level one, level two, level three, and level four. The deterioration rate level is described in four levels: slow, moderate, fast, and accelerating. The naming of each indicator should be consistent with the definitions in the previous steps. In the warning information column, the warning levels for lever replacement warnings, contact adjustment warnings, and overall machine maintenance warnings are divided according to the extent and scope of the triggered indicator exceeding the limit: a single indicator exceeding the limit and the deterioration rate level being slight is classified as level 3 (notice); two indicators exceeding the limit or the deterioration rate level being moderate is classified as level 2 (attention); and three indicators exceeding the limit simultaneously or the deterioration rate level being severe is classified as level 1 (emergency). The warnings should be entered in order of recent to oldest time stamp. After all three columns are filled in, a complete high-voltage circuit breaker operation status assessment report is output, so that the basic information, status indicators and early warning information form a self-consistent closed loop, which serves as the basis for operation and maintenance personnel to carry out on-site handling.

[0102] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for intelligently evaluating the operating status of a high-voltage circuit breaker, characterized in that, The method includes: The actual length of the circuit breaker tie rod and the initial velocity of contact separation are collected by displacement sensor and velocity monitoring device. High-frequency noise is filtered out to obtain the sequence of tie rod deformation growth, contact stroke change and initial velocity of contact separation. Evaluate the corresponding relationship between the increase in the deformation of the tie rod and the change in the stroke of the contact, and determine the time delay and amplitude amplification factor of the transmission of the increase in the deformation of the tie rod to the change in the stroke of the contact. The time delay and amplitude amplification factor are compared with the allowable range of the contact mechanism. The abrupt change in the initial separation velocity between adjacent actions is determined by the initial separation velocity sequence of the contact. Based on the comparison results and the abrupt change amplitude, the mechanical strength degradation level caused by the creep of the insulating tie rod is determined. Collect contact closing delay, contact overtravel, and contact bounce count. Classify the contact action abnormality type based on the contact closing delay, contact overtravel, and contact bounce count. Combine the mechanical strength degradation level to determine the severity level of contact motion accuracy damage. Obtain the health baseline value of the same type of circuit breaker in history, and determine the deterioration rate of the operating mechanism based on the difference and rate of change of the current severity level relative to the health baseline value. If the rate of degradation accelerates and the magnitude of the initial separation velocity change exceeds the preset allowable limit, then the critical condition for shutdown and maintenance is determined to have been met. Based on the critical condition determination results, early warnings for tie rod replacement, contact adjustment, and overall machine maintenance are generated, and an operational status assessment report is output.

2. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 1, characterized in that, The actual length of the circuit breaker tie rod and the initial velocity of contact separation are collected by a displacement sensor and a velocity monitoring device. High-frequency noise is filtered out to obtain a sequence of tie rod deformation growth, contact stroke change, and initial contact separation velocity, including: The actual length data of the opening and closing process is collected by a displacement sensor installed at the end of the tie rod according to a preset sampling period. A Butterworth low-pass filter is used to filter out power frequency interference. The difference between the filtered length signal and the pre-calibrated tie rod reference length is used to obtain the deformation growth of the tie rod.

3. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 1, characterized in that, The evaluation of the corresponding relationship between the increase in the deformation of the tie rod and the change in the contact stroke, and the determination of the time delay and amplitude amplification factor in the transmission of the increase in the deformation of the tie rod to the change in the contact stroke, includes: Using the rising edge of the opening and closing operation signal as the action trigger time, for each opening and closing action, the deformation growth of the pull rod and the change in the contact stroke within the same time window are extracted and the waveforms are aligned to obtain the deformation waveform and the stroke waveform. The correlation coefficient is calculated using a cross-correlation function between the deformed waveform and the travel waveform. The time offset corresponding to the maximum value is taken as the time delay. The deformed waveform is compensated for by translation based on the time delay. The ratio of the maximum amplitude point after compensation to the maximum amplitude point of the travel waveform is taken as the amplitude amplification factor.

4. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 1, characterized in that, The comparison of the time delay and amplitude amplification with the allowable range of the contact mechanism, the determination of the abrupt change in the initial separation velocity between adjacent actions based on the initial separation velocity sequence of the contact, and the determination of the mechanical strength degradation level caused by the creep of the insulating tie rod based on the comparison results and the abrupt change amplitude include: The pre-established contact mechanism allowable range file is invoked. The contact mechanism allowable range file records the time delay boundary value and amplitude amplification factor boundary value calibrated during the factory commissioning stage of the same model of circuit breaker. The time delay and amplitude amplification factor are respectively subtracted from the corresponding boundary values ​​to obtain the degree of delay exceeding the limit and the degree of amplification factor exceeding the limit.

5. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 4, characterized in that, The comparison of the time delay and amplitude amplification with the allowable range of the contact mechanism, the determination of the abrupt change in the initial separation velocity between adjacent actions based on the initial separation velocity sequence of the contact, and the determination of the mechanical strength degradation level caused by the creep of the insulating tie rod based on the comparison results and the abrupt change amplitude, further includes: The degree of delay exceeding the limit, the degree of multiplier exceeding the limit, and the magnitude of the initial velocity change during separation form a multidimensional feature vector, which is input to a pre-trained support vector machine classifier to output the mechanical strength degradation level.

6. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 1, characterized in that, The system collects contact closing delay, contact overtravel, and contact bounce counts. Based on these data, it categorizes contact movement anomalies and determines the severity of contact motion accuracy degradation by combining these metrics with the mechanical strength degradation level. This includes: The contact closing delay is taken from the time interval from the issuance of the closing command to the first contact between the moving and stationary contacts; the contact overtravel is taken from the displacement distance traveled by the automatic contact after passing the contact position of the stationary contact; and the contact bounce count is taken from the number of times the contact bounces after the first contact and then immediately separates and re-contacts. The three parameters are compared with the normal operating characteristic range to obtain three deviation indicators. The abnormal contact action type is classified by the combination of deviation indicators. The severity level is obtained by querying the two-dimensional mapping table in combination with the mechanical strength degradation level.

7. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 1, characterized in that, The process of obtaining historical health baseline values ​​for circuit breakers of the same model, and determining the rate of deterioration progression of the operating mechanism based on the difference and rate of change of the current severity level relative to the health baseline values, includes: Sample data on contact closing delay, contact overtravel, and contact bounce count were collected during the initial healthy operation phase of the same type of circuit breaker in the early stage of commissioning. The arithmetic mean of each parameter was calculated to obtain the health benchmark value.

8. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 7, characterized in that, The step of obtaining historical health baseline values ​​for circuit breakers of the same model, and determining the rate of deterioration progression of the operating mechanism based on the difference and rate of change of the current severity level relative to the health baseline values, further includes: The difference amplitude vector is obtained by subtracting the corresponding health benchmark value from the current contact closing delay, contact overtravel amount and contact bounce number, and taking the absolute value. The change rate is obtained by performing a time-series difference operation on the difference amplitude vector. The change rate and the difference amplitude vector are input into a preset deterioration progress rate evaluation rule table to obtain the deterioration progress rate.

9. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 1, characterized in that, If the rate of degradation accelerates and the abrupt change in the initial separation rate exceeds a preset allowable limit, then the critical condition for shutdown and maintenance is determined to have been met, including: The degradation progression rate is arranged in chronological order of action occurrence to obtain a time series. The gear rise slope is obtained by differential operation of adjacent gears. The gear rise slope is compared with the acceleration judgment threshold to obtain an acceleration trend indicator. The acceleration trend indicator and the comparison result of the separation initial velocity change amplitude with the allowable limit are used to jointly determine the critical condition.

10. The intelligent evaluation method for the operating status of a high-voltage circuit breaker according to claim 1, characterized in that, Based on the critical condition determination results, the system generates early warnings for tie rod replacement, contact adjustment, and overall machine maintenance, and outputs an operational status assessment report, including: The critical condition determination results are mapped according to the early warning distribution rules. If the mechanical strength degradation level is in the severe degradation level, the tie rod replacement early warning is triggered. If the severity level exceeds the preset warning level, the contact adjustment early warning is triggered. If the critical condition is met, the whole machine overhaul early warning is triggered. The results are then summarized and filled into the operating status assessment report template.

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