A pole-mounted circuit breaker opening and closing drive state analysis method

Abstract

The application provides a pole-mounted circuit breaker opening and closing driving state analysis method, comprising: acquiring an external vibration signal of a pole-mounted circuit breaker shell surface, performing frequency domain conversion on the external vibration signal to obtain a vibration spectrum, and extracting a target excitation frequency according to the vibration spectrum; acquiring a natural frequency of a moving iron core, evaluating whether the target excitation frequency falls into a resonance frequency band adjacent to the natural frequency, and identifying whether an iron core resonance phenomenon occurs; evaluating a target air gap size of the moving iron core under a resonance working condition according to the maximum transient displacement and a pre-acquired initial air gap; and acquiring a pre-established electromagnetic attraction variation law with air gap size, and evaluating a transient magnetic holding force of the moving iron core under the target air gap size according to the variation law.

Description

Technical Field

[0001] This invention relates to the field of information technology, and in particular to a method for analyzing the opening and closing drive status of a pole-mounted circuit breaker. Background Technology

[0002] As a core device for fault isolation and load control in power distribution networks, the reliability of pole-mounted circuit breakers in their closed-holding state directly affects the continuity of power supply and the safety of power grid operation. Current analytical methods for circuit breaker tripping primarily focus on static parameter verification at a single moment, determining the closing-holding capability by checking whether the magnetic holding force meets the design margin. This approach ignores the coupling effect between external vibration excitation and the internal dynamic response of the mechanism, and cannot identify the transient instability risk caused by resonance amplification effects in actual operating environments. A fundamental mechanical balance contradiction exists in the operating mechanism of pole-mounted circuit breakers in the closed-holding state. A larger preload of the opening spring results in more energy released during opening, leading to a higher movement speed of the moving contact, which is beneficial for quickly opening the arc and achieving reliable interruption. A larger preload of the contact pressure spring results in more stable contact pressure between the moving and stationary contacts after closing, lower contact resistance, and a lower risk of overheating during long-term current carrying. However, these two springs remain compressed during the closed-holding state. The restoring force they continuously exert on the moving iron core constitutes the static load that the magnetic holding force must overcome. The remaining force after deducting this static load is the safety margin against external vibration and shock. When a short-circuit fault in the line generates an electrodynamic shock wave, or strong winds cause the tower to sway and be transmitted to the circuit breaker housing through the mounting bracket, the vibration energy will excite the moving iron core to oscillate back and forth. If the external excitation frequency is close to the natural frequency of the system composed of the moving iron core and springs, even if the vibration amplitude is not large, the oscillation displacement of the moving iron core will be amplified sharply due to resonance. When the transient disengagement displacement causes the air gap to increase to a certain critical value, the rate at which the magnetic holding force decays with the increase of the air gap exceeds the rate at which the spring restoring force increases with the increase of the displacement. The force balance is broken, triggering the tripping mechanism to release and causing a sudden trip. Even if the magnetic holding force margin meets the design requirements under this resonance condition, when the transient disengagement displacement of the moving iron core in the resonance state is large enough, the magnitude of the magnetic holding force decay caused by the increase of the air gap may far exceed expectations. The originally sufficient force margin is quickly consumed during the dynamic process. The increased preload of the tripping spring and the preload of the contact pressure spring, intended to improve breaking performance and current carrying capacity, are considered performance enhancements during the static design phase. However, under resonant conditions, they become detrimental factors that exacerbate the risk of accidental tripping. This is because a larger static load means a smaller force margin left to resist vibration. This inherent conflict between performance optimization and vibration-resistant reliability requirements cannot be identified within the static analysis framework. Therefore, the key issue in achieving reliable closing and holding capacity assessment and accidental tripping warning for pole-mounted circuit breakers is how to monitor the transient motion state of the moving iron core in real time and dynamically assess whether the magnetic holding force margin is sufficient to resist the resonant amplification effect under current vibration conditions, while considering the matching relationship between the external vibration excitation frequency characteristics and the inherent frequency of the mechanism. Summary of the Invention

[0003] This invention provides a method for analyzing the opening and closing drive state of a pole-mounted circuit breaker, the method comprising: The external vibration signal on the surface of the pole-mounted circuit breaker housing is acquired, the external vibration signal is frequency domain converted to obtain the vibration spectrum, and the target excitation frequency is extracted based on the vibration spectrum. Obtain the natural frequency of the moving iron core, evaluate whether the target excitation frequency falls into the resonant frequency band adjacent to the natural frequency, and identify whether the iron core resonance phenomenon has occurred. After identifying the occurrence of core resonance, the shell vibration acceleration in the external vibration signal is obtained. Based on the shell vibration acceleration and the target excitation frequency, the reciprocating motion amplitude of the moving core under resonance conditions is evaluated, and the maximum transient disengagement displacement of the moving core is extracted. Based on the maximum transient disengagement displacement and the pre-acquired initial air gap, the target air gap size of the moving iron core under resonance conditions is evaluated. Obtain the pre-established law of electromagnetic attraction force variation with air gap size, and evaluate the transient magnetic holding force of the moving iron core under the target air gap size based on the law of variation; Obtain the spring tension of the opening spring and the contact pressure spring, evaluate the static load under the closing holding condition based on the spring tension, and evaluate the remaining vibration resistance margin of the moving iron core based on the transient magnetic holding force and the static load. The remaining vibration resistance margin is assessed to determine whether it is lower than the pre-established mechanical equilibrium critical point. Dynamic instability is identified, and a jump risk warning signal is generated and output to the terminal device after dynamic instability is identified.

[0004] Preferably, the step of acquiring the external vibration signal of the pole-mounted circuit breaker housing surface, performing frequency domain conversion on the external vibration signal to obtain a vibration spectrum, and extracting the target excitation frequency based on the vibration spectrum includes: The external vibration signals collected by the sensors on the shell surface are arranged into an original vibration sequence according to the sampling time. The original vibration sequence is then subjected to zero-point drift subtraction and abnormal peak removal to obtain the shell vibration time sequence. The vibration time sequence of the shell is divided into continuous window segments, and the corresponding vibration spectrum is obtained by performing a fast Fourier transform on the acceleration waveform within each window segment. Remove spectral peaks that are consistent with the power frequency and its harmonics, eliminate spectral peaks that appear only in a single window segment, retain the frequency positions that maintain the main peak state in continuous window segments, and determine the target excitation frequency of the external vibration signal.

[0005] Preferably, the steps of obtaining the natural frequency of the moving iron core, evaluating whether the target excitation frequency falls within the resonant frequency band adjacent to the natural frequency, and identifying whether iron core resonance has occurred include: The target natural frequency is obtained by reading the main oscillation frequency that is consistent with the current circuit breaker model and closing holding state from the pre-calibrated natural frequency record. The natural frequency record includes the circuit breaker model, closing holding state and the corresponding main oscillation frequency. The resonant frequency band is determined based on the target natural frequency and the bandwidth in the natural frequency record, and the upper and lower boundaries of the target excitation frequency and the resonant frequency band are compared. When the target excitation frequency falls within the resonant frequency band, it is determined that the core resonance phenomenon has occurred; when the target excitation frequency does not fall within the resonant frequency band, it is determined that the core resonance phenomenon has not occurred.

[0006] Preferably, after identifying the occurrence of the core resonance phenomenon, the step of acquiring the shell vibration acceleration in the external vibration signal, evaluating the reciprocating motion amplitude of the moving core under resonance conditions based on the shell vibration acceleration and the target excitation frequency, and extracting the maximum transient disengagement displacement of the moving core includes: After identifying the occurrence of the core resonance phenomenon, the shell vibration acceleration within the frequency band of the target excitation frequency is retained from the external vibration signal, and the target acceleration waveform is obtained by arranging them according to the sampling time. Based on the target acceleration waveform and the target excitation frequency, a pre-calibrated table corresponding to the shell acceleration and the iron core displacement is read. The iron core displacement table takes the target excitation frequency and acceleration amplitude as input parameters and outputs the corresponding moving iron core displacement amplitude to obtain the moving iron core displacement response curve.

[0007] Preferably, obtaining the displacement response curve of the moving iron core includes: The peak and valley times within a continuous reciprocating cycle are identified by the displacement response curve of the moving iron core. The peak and valley times correspond to the extreme positions of the moving iron core within the reciprocating cycle. The reciprocating motion amplitude of the moving iron core relative to the closing and holding position is determined, and the maximum transient disengagement displacement in the reciprocating motion amplitude is extracted.

[0008] Preferably, the step of evaluating the target air gap size of the moving iron core under resonant conditions based on the maximum transient disengagement displacement and the pre-acquired initial air gap includes: The initial air gap is the distance between the moving iron core and the magnetic yoke when the moving iron core is in the closed holding position, and the maximum transient disengagement displacement is the maximum displacement of the moving iron core away from the magnetic yoke. The target air gap size between the moving iron core and the magnetic yoke under resonance conditions is obtained by superimposing the initial air gap size and the maximum transient separation displacement in the direction away from the magnetic yoke of the moving iron core.

[0009] Preferably, the step of obtaining the pre-established law of electromagnetic attraction force variation with air gap size, and evaluating the transient magnetic holding force of the moving iron core under the target air gap size based on the law of variation, includes: The variation pattern includes multiple air gap nodes of the same circuit breaker model in the closed holding state, as well as the magnetic holding force record of the moving iron core corresponding to each air gap node. The air gap interval to which the air gap node belongs is determined according to the target air gap size; When the target air gap size is located between adjacent air gap nodes, the value is linearly taken according to the magnetic holding force record of the moving iron core corresponding to the adjacent air gap node. The transient magnetic holding force between the moving iron core and the magnetic yoke under the target air gap size is determined based on the linear value results.

[0010] Preferably, the step of obtaining the spring tension of the opening spring and the contact pressure spring, evaluating the static load under the closing holding condition based on the spring tension, and evaluating the remaining vibration resistance margin of the moving iron core based on the transient magnetic holding force and the static load includes: Obtain the opening preload of the opening spring and the contact preload of the contact pressure spring, and convert them into opening load components and contact load components respectively according to the direction of the moving iron core away from the magnetic yoke; The static load under the closing holding condition is obtained by adding the opening load component and the contact load component. The static load represents the restoring force on the moving iron core in the direction away from the yoke.

[0011] Preferably, obtaining the static load under the closing holding condition includes: By subtracting the static load from the transient magnetic holding force, the remaining vibration resistance margin of the moving iron core under resonance conditions is obtained.

[0012] Preferably, the step of assessing whether the remaining vibration resistance margin is lower than a pre-established mechanical equilibrium critical point, identifying whether dynamic instability has occurred, and generating a jump risk warning signal and outputting it to the terminal device after identifying dynamic instability includes: The mechanical equilibrium critical point is the minimum vibration resistance margin that allows the moving iron core of the pole-mounted circuit breaker to maintain engagement in the closed-hold state. The remaining vibration resistance margin is compared with the mechanical equilibrium critical point. When the remaining vibration resistance margin is lower than the mechanical equilibrium critical point, dynamic instability is determined to have occurred and an alarm trigger command is generated. The alarm trigger command generates a jump risk warning signal containing dynamic instability and outputs it to the terminal device.

[0013] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention discloses a method for analyzing the opening and closing drive state of a pole-mounted circuit breaker, addressing the problem of unintended tripping instability caused by resonance of the moving iron core under electromagnetic vibration conditions. By collecting vibration signals from the circuit breaker casing surface and performing frequency domain analysis, the target excitation frequency is extracted and compared with the natural frequency of the moving iron core to determine if it has entered the resonance frequency band. When core resonance is detected, this invention calculates the reciprocating motion amplitude of the moving iron core based on the casing vibration acceleration and excitation frequency, thereby obtaining the maximum transient disengagement displacement. The actual air gap size under resonance conditions is then assessed in conjunction with the initial air gap. Using a pre-established electromagnetic attraction force and air gap relationship model, the transient magnetic holding force after the air gap increases is calculated. This force is then used for mechanical balance analysis with the static loads of the opening spring and contact pressure spring to determine the remaining vibration resistance margin of the moving iron core. When the margin falls below a critical threshold, dynamic instability is determined, and a timely warning of unintended tripping risk is issued, effectively preventing the circuit breaker from tripping unexpectedly and ensuring the safe and stable operation of the power system. Attached Figure Description

[0014] Figure 1 This is a flowchart of a method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to the present invention.

[0015] Figure 2 This is a schematic diagram of a method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to the present invention.

[0016] Figure 3 This is another schematic diagram of the method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to the present invention. Detailed Implementation

[0017] 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.

[0018] like Figures 1-3 This embodiment of a method for analyzing the opening and closing drive state of a pole-mounted circuit breaker may specifically include: S101. Obtain the external vibration signal on the surface of the pole-mounted circuit breaker housing, perform frequency domain conversion on the external vibration signal to obtain the vibration spectrum, and extract the target excitation frequency based on the vibration spectrum.

[0019] External vibration signals collected by sensors on the surface of the pole-mounted circuit breaker housing are acquired and arranged into an original vibration sequence according to the sampling time. Zero-point drift subtraction and abnormal peak removal are performed on the original vibration sequence to obtain the housing vibration time sequence. The housing vibration time sequence is divided into continuous windows. A Fast Fourier Transform is performed on the acceleration waveform within each window to obtain the vibration spectrum corresponding to that window, and a record of the correspondence between frequency position and amplitude intensity is generated. Based on the vibration spectrum, spectral peaks consistent with the power frequency and its harmonics are removed, and spectral peaks appearing only in a single window are eliminated. Frequency positions that maintain the main peak state within continuous windows are retained to determine the target excitation frequency of the external vibration signal.

[0020] Specifically, external vibration signals are collected by an accelerometer arranged on the surface of the circuit breaker housing. The accelerometer is fixed on the side of the housing near the operating mechanism to obtain waveforms that reflect the vibration state transmitted to the housing.

[0021] Specifically, the acquired external vibration signals are arranged according to the sampling time to form the original vibration sequence. The original vibration sequence includes the acceleration amplitude corresponding to each sampling time, with the sampling times arranged sequentially in time. When processing the original vibration sequence, a static reference segment is first taken when the circuit breaker is in a stable closed-end state. The average acceleration amplitude of all sampling points within this segment is calculated as the zero-point offset. This zero-point offset characterizes the reference output value of the sensor in a vibration-free state. This zero-point offset is then subtracted from the original vibration sequence to form the drift-free vibration sequence. Further, abnormal spikes are removed from the drift-free vibration sequence. An abnormal spike refers to a single-point protrusion where the acceleration amplitude changes abruptly between adjacent sampling times and is not continuously maintained in adjacent sampling points. A dual threshold standard is used for judgment. The values ​​of 0.5g and 0.3g in the dual threshold standard are determined as follows: Statistical analysis is performed on the background noise of the same type of circuit breaker under no external excitation conditions. The mean of the absolute value of the noise acceleration amplitude plus three times the standard deviation is taken as 0.5g, and the mean of the noise difference between adjacent sampling points plus three times the standard deviation is taken as 0.3g. A sampling point is judged as an abnormal spike when it meets the following conditions: the absolute value of the acceleration amplitude at this point is greater than 0.5g, and the amplitude difference between this point and the previous sampling point or the next sampling point is greater than 0.3g. At the same time, the trend of change of less than two points within three sampling points before and after this point is consistent with that point. For a sampling point judged as an abnormal spike, the amplitude of the sampling point is replaced by the mean of the acceleration amplitude of one sampling point before and after it to obtain the shell vibration time sequence.

[0022] In one possible implementation, the shell vibration timing sequence is divided into multiple continuous window segments according to a preset time length. The preset time length is determined based on the fundamental frequency of the shell vibration and is taken as 3 to 5 times the fundamental frequency period to ensure that a single window segment can contain at least one complete vibration cycle. An overlapping region is set between adjacent window segments, with an overlap length of 20% to 50% of the window segment time length. The corresponding acceleration waveform is retained within each window segment. If there is a sampling gap within a certain window segment, two-point linear interpolation is performed to fill the gap based on the acceleration amplitudes of adjacent sampling times before and after the gap. Specifically, let the sampling time before the gap be t1 and the acceleration value be a1, and the sampling time after the gap be t2 and the acceleration value be a2. Then, the acceleration value a at any time t within the gap is a = a1 + (a2 - a1) × (t - t1) / (t2 - t1), resulting in a window segment waveform that can be used for frequency domain conversion.

[0023] For example, a Fast Fourier Transform is performed on the waveform of each window segment to convert the time-varying acceleration waveform into an amplitude distribution that varies with frequency, thus obtaining the vibration spectrum corresponding to that window segment. In the vibration spectrum, each frequency position corresponds to an amplitude intensity, where the frequency position represents the frequency of the vibration component, and the amplitude intensity represents the proportion of that frequency component in the waveform of the window segment. This forms a record of the correspondence between frequency positions and amplitude intensities.

[0024] Preferably, after obtaining the vibration spectrum corresponding to multiple window segments, spectral peaks consistent with the power frequency and its harmonics are removed. The power frequency and its harmonics refer to the periodic interference components corresponding to the power supply frequency of the distribution line and its integer multiples. If the frequency position of a certain spectral peak falls within the power frequency tolerance range, the spectral peak is deleted from the corresponding record. The power frequency tolerance range is ±0.5 Hz of the power supply frequency. Spectral peaks that appear only in a single window segment and do not appear in adjacent window segments are also removed from the corresponding record. Further, the retained frequency positions are compared in consecutive window segments, and the amplitude intensity of the same frequency position in multiple consecutive window segments is ranked. The average amplitude A of all retained spectral peaks in each window segment is calculated, and the spectral intensity threshold is set to 1.5A. If the amplitude intensity of a certain frequency position is higher than the spectral intensity threshold of the corresponding window segment in at least 3 consecutive window segments, the frequency position is determined as the target excitation frequency of the external vibration signal. The target excitation frequency serves as the dominant excitation frequency of the external vibration signal on the shell surface in the current acquisition cycle.

[0025] S102. Obtain the natural frequency of the moving iron core, evaluate whether the target excitation frequency falls into the resonant frequency band adjacent to the natural frequency, and identify whether the iron core resonance phenomenon has occurred.

[0026] Obtain a pre-calibrated record of the natural frequency of the moving iron core. This record includes the circuit breaker model, closing and holding state, and the corresponding main oscillation frequency. Read the main oscillation frequency that matches the current circuit breaker model and closing and holding state to determine the target natural frequency. Based on the target natural frequency and the bandwidth in the natural frequency record, determine the resonant frequency band adjacent to the target natural frequency. Compare the target excitation frequency with the upper and lower boundaries of the resonant frequency band to obtain a frequency matching result. If the frequency matching result indicates that the target excitation frequency falls within the resonant frequency band, then core resonance is confirmed; if the target excitation frequency does not fall within the resonant frequency band, then core resonance is confirmed not to have occurred.

[0027] The natural frequency record of the moving iron core is pre-calibrated using a pole-mounted circuit breaker of the same model in the closed-hold state. This natural frequency record includes at least the circuit breaker model, the closed-hold state indicator, the main oscillation frequency of the moving iron core, and the bandwidth. The closed-hold state indicator is used to distinguish the moving iron core in the holding position after it has been fully engaged, rather than in the transition position during the opening or closing process.

[0028] Specifically, the system obtains the circuit breaker model and closing holding status of the current pole-mounted circuit breaker. The circuit breaker model is determined by the device code stored in the controller. The contact position feedback signal is read; if the feedback signal indicates that all three phase contacts are in the closed position, the closing holding status is determined to be valid; otherwise, it is determined to be invalid. After confirming the current circuit breaker model and closing holding status, the corresponding main oscillation frequency is read from the natural frequency record and determined as the target natural frequency.

[0029] For example, the dominant frequency can be obtained through factory calibration or on-site calibration. During calibration, the moving iron core is held in the closed-hold position, and a small-amplitude sweep vibration or pulse excitation is applied to the housing. The iron core response component in the displacement response of the moving iron core or the response of the housing is collected, and the frequency with the largest response amplitude is determined as the dominant frequency. This calibration result is stored together with the circuit breaker model, spring configuration, and closed-hold position to form a readable natural frequency record. Further, the bandwidth is the frequency range that can deviate from the target natural frequency on both sides, and it comes from the same natural frequency record. The bandwidth is preferentially determined based on the amplitude attenuation boundary of the response on both sides of the dominant peak during calibration. The specific method is as follows: in the amplitude-frequency response curve obtained from calibration, find the dominant peak value, and find the frequency points corresponding to the amplitude attenuation to 40% of the dominant peak value on both the low-frequency and high-frequency sides. The frequency range between the two points is the bandwidth. The value of 40% is based on the critical attenuation ratio that can stably cover the main resonance energy region obtained through experiments and statistics of multiple similar devices. When calibration data is insufficient, collect the main resonant frequency samples of at least 50 circuit breakers of the same model, calculate the sample mean and standard deviation, and take the frequency range corresponding to the mean ± 2 times the standard deviation as the bandwidth value. After determining the target natural frequency and bandwidth, take the target natural frequency as the center frequency fc, and extend B / 2 to the low-frequency side and high-frequency side respectively to obtain the resonant frequency band, where B is the bandwidth, the lower boundary of the resonant frequency band is fc-B / 2, and the upper boundary is fc+B / 2.

[0030] In one possible implementation, the target excitation frequency is derived from the spectral extraction result of the external vibration signal on the shell surface. The target excitation frequency is compared with the lower and upper boundaries of the resonant frequency band. If the target excitation frequency is not lower than the lower boundary and not higher than the upper boundary, the frequency matching result indicates that it falls within the resonant frequency band; if the target excitation frequency is lower than the lower boundary or higher than the upper boundary, the frequency matching result indicates that it does not fall within the resonant frequency band.

[0031] Preferably, in embodiments with one or more target excitation frequencies, boundary comparisons can be performed on each target excitation frequency separately, and the number of frequencies falling into the resonant frequency band and their corresponding frequency positions can be recorded. If at least one target excitation frequency falls into the resonant frequency band, the frequency matching result indicates that a resonant match exists; if none of the target excitation frequencies fall into the resonant frequency band, the frequency matching result indicates that a resonant match does not exist. The processing of multiple frequency positions is still limited to the range near the natural frequency of the moving iron core.

[0032] Specifically, when the frequency matching result indicates that the target excitation frequency falls within the resonant frequency band, core resonance is determined to have occurred; when the frequency matching result indicates that the target excitation frequency does not fall within the resonant frequency band, core resonance is determined not to have occurred. The identification result of the core resonance phenomenon, together with the target natural frequency, the resonant frequency band, and the target excitation frequency, forms the frequency matching determination result under the current closed-and-held state.

[0033] S103. After identifying the occurrence of the core resonance phenomenon, obtain the shell vibration acceleration in the external vibration signal, evaluate the reciprocating motion amplitude of the moving core under the resonance condition based on the shell vibration acceleration and the target excitation frequency, and extract the maximum transient disengagement displacement of the moving core.

[0034] After identifying the core resonance phenomenon, the shell vibration acceleration within the frequency band of the target excitation frequency is retained from the external vibration signal and arranged according to the sampling time to obtain the target acceleration waveform. Based on the target acceleration waveform and the target excitation frequency, a pre-calibrated shell acceleration to core displacement correspondence table is read. The correspondence table uses the target excitation frequency and acceleration amplitude as input parameters and outputs the corresponding moving core displacement amplitude, realizing the mapping conversion from shell vibration to core displacement, and obtaining the moving core displacement response curve. The peak and valley times within the continuous reciprocating cycle are identified through the moving core displacement response curve to determine the reciprocating motion amplitude of the moving core relative to the closed holding position, and the maximum transient disengagement displacement in the reciprocating motion amplitude is extracted.

[0035] After identifying the core resonance phenomenon, the external vibration signal is no longer processed directly as a complete broadband signal, but is instead retained only in the frequency band containing the target excitation frequency. This external vibration signal originates from an accelerometer on the surface of the pole-mounted circuit breaker housing, and the target excitation frequency is the dominant excitation frequency determined in the aforementioned spectrum processing.

[0036] Specifically, a target retention frequency band is formed centered on the target excitation frequency and with a preset bandwidth. The external vibration signal is then bandwidth-retained, retaining only the shell vibration acceleration components falling within the target retention frequency band. Targeted bandwidth extraction filters out interference from irrelevant frequency components, improving the accuracy of core resonance state determination. The target retention frequency band is formed centered on the target excitation frequency and with a preset bandwidth. The preset bandwidth is determined based on the half-width at half-maximum (WHM) of the main peak in the vibration spectrum, specifically 3 to 5 times the frequency range corresponding to when the main peak amplitude decays to 50% of the peak value. The lower boundary of this target retention frequency band is lower than the target excitation frequency, and the upper boundary is higher than the target excitation frequency. The lower boundary is set as f0 - Δf, and the upper boundary is set as f0 + Δf, where f0 is the target excitation frequency and Δf is half of the preset bandwidth. When performing frequency band retention on the external vibration signal, only the shell vibration acceleration component falling within the target retention frequency band is retained, while power frequency interference, broadband impact residue, and high-frequency disturbance components unrelated to core resonance are removed to obtain the acceleration signal within the frequency band. Further, when superimposing and restoring the acceleration signal within the frequency band, the amplitude and phase information of each frequency component are retained. An inverse Fourier transform is performed on all frequency components within the target retention frequency band to convert the frequency domain signal into a time domain signal, which is then rearranged according to the sampling time to form the target acceleration waveform. The target acceleration waveform includes multiple consecutive sampling times and their corresponding shell vibration acceleration amplitudes, retaining the periodic variation characteristics near the target excitation frequency.

[0037] In one possible implementation, the correspondence table between housing acceleration and core displacement is pre-established during the calibration phase of the same type of pole-mounted circuit breaker. During calibration, the moving core is in the closed-hold position, and an acceleration sensor is arranged on the housing surface. The displacement of the moving core relative to the closed-hold position is acquired through displacement detection. The displacement detection method is determined based on the calibration accuracy requirements. When the calibration accuracy requirement is not less than 0.01 mm, a non-contact measurement method is adopted, which involves opening a detection observation window on the electromagnetic mechanism housing and installing a laser displacement sensor. Alternatively, a specially designed built-in detection rod is used to lead the core displacement to the outer shell and measure it in conjunction with a high-precision linear potentiometer to solve the problem of internal optical path obstruction. When the calibration accuracy requirement is less than 0.01 mm, the displacement detection component built into the equipment can be used directly. By applying external vibrations of different frequencies and positions and different acceleration amplitude ranges to the housing, the correspondence between each set of frequency positions, acceleration amplitude ranges, and moving core displacement amplitudes is recorded to form the aforementioned correspondence table. The frequency position in the corresponding table is used to match the target excitation frequency, the acceleration amplitude range is used to match the amplitude change in the target acceleration waveform, and the displacement amplitude of the moving iron core represents the distance of the moving iron core from the position held by the closing switch.

[0038] Specifically, when reading the corresponding table, the matching frequency position in the table is first determined based on the target excitation frequency. Then, the acceleration amplitude interval to which it belongs is found based on the acceleration amplitude at each sampling moment in the target acceleration waveform. If a certain acceleration amplitude falls between two adjacent intervals, the core displacement amplitude corresponding to that sampling moment is calculated using a linear interpolation method. Let the current acceleration amplitude be a, which is located between the boundary values ​​a1 and a2 of two adjacent acceleration intervals in the corresponding table. The corresponding moving core displacement amplitudes are d1 and d2, respectively. Then, the core displacement amplitude d calculated by linear interpolation is: d equals d1 plus the difference between a and a1 divided by the difference between a2 and a1, and then multiplied by the difference between d2 and d1.

[0039] For example, when a is 5.2g, if a1 is 5.0g and d1 is 0.8mm, and a2 is 5.5g and d2 is 0.9mm, then d is calculated to be 0.84mm.

[0040] For example, after obtaining the corresponding iron core displacement amplitude at each sampling moment in the target acceleration waveform through the corresponding table, the samples are arranged in the order of sampling moments to form the moving iron core displacement response curve. The moving iron core displacement response curve is arranged with time as the horizontal order and the displacement amplitude of the moving iron core relative to the closed and held position as the vertical change, reflecting the reciprocating motion state of the iron core under resonance conditions.

[0041] Preferably, when identifying peaks and valleys in the displacement response curve of the moving iron core, the peak moment when the displacement amplitude changes from rising to falling is first found in the continuous sampling time, and then the valley moment when the displacement amplitude changes from falling to rising is found. The absolute value of the displacement difference between adjacent peak moments and valley moments represents the motion amplitude within half a reciprocating cycle, and the interval between adjacent peak moments or adjacent valley moments represents one reciprocating cycle. Further, within the continuous reciprocating cycle, the reciprocating motion amplitude corresponding to each cycle is calculated, wherein the reciprocating motion amplitude of a single complete cycle is twice the absolute value of the difference between the peak displacement and the valley displacement within that cycle. The absolute value of the displacement difference between the peak displacement of the moving iron core away from the closing holding position and the closing holding position is taken as the candidate transient disengagement displacement. If there are multiple candidate transient disengagement displacements in the displacement response curve of the moving iron core, the magnitudes of each candidate transient disengagement displacement are compared, and the candidate transient disengagement displacement with the largest value is extracted to obtain the maximum transient disengagement displacement.

[0042] In one embodiment, when the pole-mounted circuit breaker is subjected to low-frequency vibration transmitted by the pole's sway, the target retained frequency band is concentrated near the low-frequency dominant excitation, and the result of the corresponding table reading forms a low-frequency displacement response curve. When the pole-mounted circuit breaker is subjected to the vibration aftershock of a line short-circuit electrodynamic impact, the target retained frequency band is concentrated near the dominant peak frequency that persists after the impact, and the result of the corresponding table reading forms a displacement response curve under the aftershock vibration. Both embodiments use the target acceleration waveform, the target excitation frequency, and the corresponding table as processing objects, and extract the maximum transient disengagement displacement of the moving iron core.

[0043] S104. Based on the maximum transient separation displacement and the pre-acquired initial air gap, evaluate the target air gap size of the moving iron core under resonance conditions.

[0044] The initial air gap and maximum transient disengagement displacement are obtained by pre-measuring. The initial air gap is the distance between the moving iron core and the magnetic yoke when the moving iron core is in the closed holding position. The maximum transient disengagement displacement is the maximum displacement of the moving iron core away from the magnetic yoke. Based on the initial air gap and the maximum transient disengagement displacement, the dimensions are superimposed in the direction away from the magnetic yoke by the moving iron core to obtain the target air gap size between the moving iron core and the magnetic yoke under resonance conditions.

[0045] The initial air gap refers to the distance between the contact end face of the moving iron core and the corresponding contact end face of the magnetic yoke when the pole-mounted circuit breaker is in the closed-hold state. This initial air gap can be measured during the factory calibration phase or read during the maintenance calibration phase using a displacement detection component. The displacement detection component includes a displacement sensor and a data acquisition module, used to monitor the position change of the moving iron core in real time, with a measurement accuracy of up to 0.01 mm. The read initial air gap value, along with the circuit breaker model and the closed-hold state indicator, is stored in the controller's non-volatile memory for subsequent status judgment and fault diagnosis.

[0046] Specifically, based on the displacement response curve of the moving iron core obtained through table lookup and inverse Fourier transform in the aforementioned steps, the maximum transient disengagement displacement is extracted. The maximum transient disengagement displacement extracted from this curve is the maximum displacement of the moving iron core relative to the closed-hold position along the direction away from the yoke. If there is a rebound displacement towards the yoke in the displacement response curve, this rebound displacement is not included in the air gap increase; only the displacement amplitude away from the yoke is selected as the maximum transient disengagement displacement. Further, after reading the initial air gap δ0 and the maximum transient disengagement displacement Δδmax, the dimensions are matched according to the same spatial direction. If the direction of the maximum transient disengagement displacement is away from the yoke, the initial air gap and the maximum transient disengagement displacement are superimposed, and the target air gap size between the moving iron core and the yoke under resonance conditions is calculated using δ=δ0+Δδmax, where δ is the target air gap size.

[0047] S105. Obtain the pre-established law of electromagnetic attraction force changing with air gap size, and evaluate the transient magnetic holding force of the moving iron core under the target air gap size based on the law of change.

[0048] The target air gap size and the pre-established electromagnetic attraction force variation with the air gap size are obtained. This variation includes multiple air gap nodes of the same circuit breaker model in the closed-hold state, and the magnetic holding force record of the moving iron core corresponding to each air gap node. Based on the target air gap size, the air gap interval to which the air gap node belongs is determined. If the target air gap size is located between adjacent air gap nodes, a linear value is taken according to the magnetic holding force record of the moving iron core corresponding to the adjacent air gap node. Based on the magnetic holding force value obtained from the linear value, the transient magnetic holding force between the moving iron core and the yoke under the target air gap size is determined.

[0049] The variation of electromagnetic attraction force with air gap size was pre-established during the calibration phase of the pole-mounted circuit breaker. During calibration, for the same circuit breaker model and closing holding state, the magnetic holding force was recorded when the moving iron core and magnetic yoke were at different air gap sizes. The air gap size is the interval between the moving iron core's closing end face and the magnetic yoke's closing end face, and the magnetic holding force is the attraction and holding force generated by the electromagnetic mechanism on the moving iron core at that interval. During calibration, the air gap was gradually increased from 0.5 mm to 5.0 mm, and the corresponding magnetic holding force value was measured at 0.5 mm intervals to establish a complete force-gap correlation curve for subsequent mechanical analysis and fault diagnosis during operation. The air gap size is the interval between the moving iron core's closing end face and the magnetic yoke's closing end face, and the magnetic holding force is the attraction and holding force generated by the electromagnetic mechanism on the moving iron core at that interval.

[0050] Specifically, the variation pattern includes multiple air gap nodes and the corresponding magnetic holding force records of the moving iron core for each air gap node. The air gap nodes are pre-selected discrete intervals, and each air gap node corresponds to a magnetic holding force value obtained from calibration or simulation. Multiple air gap nodes are arranged in ascending order of air gap size, forming a queryable air gap node sequence. The magnetic holding force records are stored in the same order corresponding to this air gap node sequence.

[0051] For example, when establishing the aforementioned variation law, the moving iron core can be held at multiple air gap positions near the closed holding position, and the electromagnetic attraction force at each air gap position can be collected or calculated. The collection method can use tension / compression sensors to read the holding force of the moving iron core; the calculation method can use the finite element method to perform electromagnetic field simulation calculations to obtain the attraction force of the magnetic yoke contact surface on the moving iron core contact surface. After the collection or calculation results are standardized, a correspondence is formed between air gap nodes and moving iron core magnetic holding force records. The standardization includes normalizing the collected data and calculated data to the same dimension, performing curve fitting on discrete data points, and establishing a mapping relationship between air gap δ and magnetic holding force F. Further, after obtaining the target air gap size δ0, the position corresponding to the target air gap size is searched in the air gap node sequence. If the target air gap size is the same as a certain air gap node, the magnetic holding force record of the moving iron core corresponding to that air gap node is directly read. If the target air gap size is located between two adjacent air gap nodes, then the smaller air gap node δ1 and the larger air gap node δ2 are determined, and the magnetic holding force records F1 and F2 corresponding to the two air gap nodes are read respectively. The magnetic holding force F0 corresponding to the target air gap size is calculated by linear interpolation: F0 = F1 + (F2 - F1) × (δ0 - δ1) / (δ2 - δ1), where δ1 < δ0 < δ2.

[0052] Specifically, when the target air gap size is located between adjacent air gap nodes, it can be linearly valued according to its position within that interval. This linear value means that the closer the target air gap size is to the smaller air gap node, the closer the magnetic holding force value will be to the magnetic holding force record corresponding to that smaller air gap node; conversely, the closer the target air gap size is to the larger air gap node, the closer the magnetic holding force value will be to the magnetic holding force record corresponding to that larger air gap node. This value-taking method is only performed within the same interval between adjacent air gap nodes.

[0053] Preferably, when the target air gap size is smaller than the minimum air gap node, the magnetic holding force record of the moving iron core corresponding to the minimum air gap node is read as the magnetic holding force value result; when the target air gap size is larger than the maximum air gap node, the magnetic holding force record of the moving iron core corresponding to the maximum air gap node is read as the magnetic holding force value result, and it is recorded that the target air gap size exceeds the pre-established air gap node sequence range. This record only represents the value boundary state and does not change the target air gap size.

[0054] In one embodiment, the target air gap size is derived from the superposition of the initial air gap and the maximum transient disengagement displacement under resonant conditions. Once the target air gap size conforms to the aforementioned variation law, a corresponding magnetic holding force value is obtained. This magnetic holding force value represents the transient magnetic holding force between the moving iron core and the yoke under the target air gap size. This transient magnetic holding force characterizes the electromagnetic attraction and holding force experienced by the moving iron core at the current resonant disengagement position.

[0055] S106. Obtain the spring tension of the opening spring and the contact pressure spring, evaluate the static load under the closing holding condition based on the spring tension, and evaluate the remaining vibration resistance margin of the moving iron core based on the transient magnetic holding force and the static load.

[0056] Obtain the opening preload of the opening spring and the contact preload of the contact pressure spring, and convert them into opening load components and contact load components respectively, according to the direction away from the yoke of the moving iron core. Add the opening load component and the contact load component to obtain the static load under the closing holding condition. The static load represents the restoring force on the moving iron core in the direction away from the yoke. Subtract the static load from the transient magnetic holding force to obtain the remaining vibration resistance margin of the moving iron core to resist external vibration disengagement under resonance conditions.

[0057] The tripping preload of the tripping spring and the contact preload of the contact pressure spring are obtained through calibration measurements of the pole-mounted circuit breaker in the closed-holding state. This calibration process is completed during factory testing or initial field commissioning of the circuit breaker. The measurement data is stored in the non-volatile memory of the operating mechanism controller, forming a mechanism calibration record. This record, specific to a particular circuit breaker model and operating mechanism structure, records the relationship between the tripping spring compression and the corresponding spring tension, as well as the relationship between the contact pressure spring compression and the corresponding preload. For example, calibration data for a certain circuit breaker model shows a spring tension of 280 Newtons when the tripping spring compression is 15.0 mm and a preload of 150 Newtons when the contact pressure spring compression is 8.0 mm. Based on the stored calibration record and real-time spring displacement sensor data, the controller calculates the current tripping preload and contact preload values.

[0058] Specifically, the preload force is the spring force stored by the trip spring in the closed holding state and acting in the direction of tripping release. The contact preload force is the contact holding force formed by the contact pressure spring after the moving contact and stationary contact are pressed together. Both types of spring forces are related to the force on the moving iron core during closing and holding, but their action paths are transmitted to the moving iron core through the tripping transmission component and the contact transmission component, respectively. Further, after reading the preload force, the tripping load component is determined according to the force direction of the tripping transmission component relative to the moving iron core. The tripping load component is the force value converted from the preload force along the direction away from the magnetic yoke of the moving iron core. When the action direction of the tripping spring is consistent with the disengagement direction of the moving iron core, the preload force is directly used as the tripping load component; when there is an angle α between them, the tripping load component is calculated according to F. spring_f =F spring_pre ×cosα is calculated to obtain F spring_pre For the tripping preload, F_ spring_f α represents the tripping load component, and α is the angle between the direction of action of the tripping spring and the direction of separation of the moving iron core.

[0059] Specifically, read the contact preload F.contact Next, measure the angle β between the connecting rod and the axis of the moving iron core. Decompose the pressing force of the contact spring along the axial direction of the moving iron core to obtain the axial component force F. contact_a , where F contact_a =F contact ×cosβ. Determine the axial component force F. contact_a The direction of F, if F contact_a If the force points away from the yoke, the contact load component is included; if it points towards the yoke, the contact load component is not included. The contact load component is the sum of all axial components pointing away from the yoke.

[0060] In one possible implementation, both the tripping load component and the contact load component are treated using the same force direction reference, which is the direction in which the moving iron core moves away from the yoke from the closed holding position. Using the same force direction reference, the tripping load component and the contact load component have the same force direction, and their sum yields the static load under the closed holding condition.

[0061] It should be noted that the static load characterizes the restoring force on the moving iron core in the closed holding position, away from the yoke. It does not include the inertial force generated by housing vibration, nor does it include the additional instantaneous external force from subsequent fault impacts. The static load is calculated solely from the spring tension of the opening spring and contact pressure spring in the closed holding state, ensuring it is compared with the transient magnetic holding force using the same force comparison criteria. Furthermore, the transient magnetic holding force is the electromagnetic attraction and holding force between the moving iron core and the yoke at the target air gap size, and its direction is towards the yoke. The static load direction is the direction of the moving iron core away from the yoke. When subtracting the force values, the transient magnetic holding force is used as the attraction and holding force, and the static load is used as the reverse restoring force to obtain the remaining vibration resistance margin.

[0062] For example, the remaining vibration resistance margin is determined according to the formula: "Remaining vibration resistance margin = Transient magnetic holding force - Static load". The transient magnetic holding force is the magnetic holding force value corresponding to the target air gap size, and the static load is the sum of the opening load component and the contact load component. If the deduction result is positive, then this positive value is used as the remaining vibration resistance margin for the moving iron core to resist external vibration detachment under resonance conditions; if the deduction result is not greater than zero, then the remaining vibration resistance margin is recorded as zero.

[0063] In one embodiment, when the preload of the trip spring increases, the trip load component also increases; when the preload of the contact pressure spring increases, the contact load component also increases. The two types of load components are combined in the same direction and enter the static load, which is then subtracted by the transient magnetic holding force to obtain the remaining vibration resistance margin of the moving iron core under the current resonance condition.

[0064] S107. Evaluate whether the remaining vibration resistance margin is lower than the pre-established mechanical equilibrium critical point, identify whether dynamic instability has occurred, obtain an alarm trigger command after identifying dynamic instability, generate a jump risk warning signal and output it to the terminal device.

[0065] The remaining vibration resistance margin and a pre-established mechanical equilibrium critical point are obtained. The mechanical equilibrium critical point is the minimum vibration resistance margin that allows the moving iron core of the pole-mounted circuit breaker to maintain engagement in the closed-hold state. The remaining vibration resistance margin is compared with the mechanical equilibrium critical point. If the remaining vibration resistance margin is lower than the mechanical equilibrium critical point, dynamic instability is determined to have occurred, and an alarm trigger command is generated. Based on the alarm trigger command, a tripping risk warning signal containing the dynamic instability state is generated and output to the terminal device.

[0066] The mechanical equilibrium critical point is the minimum vibration resistance margin that allows the moving iron core of the pole-mounted circuit breaker to maintain its engagement in the closed-holding state. It can be obtained from the closing-holding calibration records of circuit breakers of the same model. The calibration records include the holding position of the moving iron core, the configuration of the opening spring, the configuration of the contact pressure spring, and the corresponding minimum holding margin. The minimum holding margin is measured by the following method as the basis for determining the mechanical equilibrium critical point: In the closed-holding state, gradually reduce the holding voltage until the moving iron core is released, and record the actual magnetic holding force at the moment of release; repeat this test on at least 20 circuit breakers of the same model, and take the mean of the minimum magnetic holding force among all test samples minus 1 standard deviation as the minimum holding margin. When comparing the remaining vibration resistance margin, it is necessary to ensure the consistency of the force unit and the direction of force. The remaining vibration resistance margin is usually expressed in Newtons (N) with the positive direction being downward along the axis of the moving iron core. If the calibration record of the mechanical equilibrium critical point uses kilograms (kgf) or other units, it needs to be converted to 1 kgf = 9.8 N. If the direction of force is defined as upward tension during calibration, the opposite number needs to be taken before comparison to ensure that the two are numerically judged under the same dimensions and direction reference.

[0067] Specifically, if the remaining vibration resistance margin is not lower than the mechanical equilibrium critical point, the margin comparison result indicates that no dynamic instability has occurred; if the remaining vibration resistance margin is lower than the mechanical equilibrium critical point, the margin comparison result indicates that dynamic instability has occurred. Dynamic instability indicates that the moving iron core has insufficient remaining engagement margin under the current resonance condition. The margin comparison result synchronously records the circuit breaker number, remaining vibration resistance margin, mechanical equilibrium critical point, and comparison time, where the circuit breaker number is obtained from the circuit breaker nameplate or the equipment information stored in the local controller. Further, when the margin comparison result indicates that dynamic instability has occurred, an alarm trigger command is generated from the margin comparison result. The alarm trigger command is written with the circuit breaker number, dynamic instability state, remaining vibration resistance margin, mechanical equilibrium critical point, and comparison time, and generates a tripping risk warning signal, which is output to the terminal equipment, including the pole-mounted circuit breaker local controller, distribution automation terminal, or maintenance monitoring terminal.

[0068] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for analyzing the opening and closing drive states of a pole-mounted circuit breaker, characterized in that, The method includes: The external vibration signal on the surface of the pole-mounted circuit breaker housing is acquired, the external vibration signal is frequency domain converted to obtain the vibration spectrum, and the target excitation frequency is extracted based on the vibration spectrum. Obtain the natural frequency of the moving iron core, evaluate whether the target excitation frequency falls into the resonant frequency band adjacent to the natural frequency, and identify whether the iron core resonance phenomenon has occurred. After identifying the occurrence of core resonance, the shell vibration acceleration in the external vibration signal is obtained. Based on the shell vibration acceleration and the target excitation frequency, the reciprocating motion amplitude of the moving core under resonance conditions is evaluated, and the maximum transient disengagement displacement of the moving core is extracted. Based on the maximum transient disengagement displacement and the pre-acquired initial air gap, the target air gap size of the moving iron core under resonance conditions is evaluated. Obtain the pre-established law of electromagnetic attraction force variation with air gap size, and evaluate the transient magnetic holding force of the moving iron core under the target air gap size based on the law of variation; Obtain the spring tension of the opening spring and the contact pressure spring, evaluate the static load under the closing holding condition based on the spring tension, and evaluate the remaining vibration resistance margin of the moving iron core based on the transient magnetic holding force and the static load. The remaining vibration resistance margin is assessed to determine whether it is lower than the pre-established mechanical equilibrium critical point. Dynamic instability is identified, and a jump risk warning signal is generated and output to the terminal device after dynamic instability is identified.

2. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 1, characterized in that, The process of acquiring external vibration signals from the surface of the pole-mounted circuit breaker housing, performing frequency domain transformation on the external vibration signals to obtain a vibration spectrum, and extracting the target excitation frequency based on the vibration spectrum includes: The external vibration signals collected by the sensors on the shell surface are arranged into an original vibration sequence according to the sampling time. The original vibration sequence is then subjected to zero-point drift subtraction and abnormal peak removal to obtain the shell vibration time sequence. The vibration time sequence of the shell is divided into continuous window segments, and the corresponding vibration spectrum is obtained by performing a fast Fourier transform on the acceleration waveform within each window segment. Remove spectral peaks that are consistent with the power frequency and its harmonics, eliminate spectral peaks that appear only in a single window segment, retain the frequency positions that maintain the main peak state in continuous window segments, and determine the target excitation frequency of the external vibration signal.

3. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 1, characterized in that, The process of obtaining the natural frequency of the moving iron core, evaluating whether the target excitation frequency falls within the resonant frequency band adjacent to the natural frequency, and identifying whether iron core resonance has occurred includes: The target natural frequency is obtained by reading the main oscillation frequency that is consistent with the current circuit breaker model and closing holding state from the pre-calibrated natural frequency record. The natural frequency record includes the circuit breaker model, closing holding state and the corresponding main oscillation frequency. The resonant frequency band is determined based on the target natural frequency and the bandwidth in the natural frequency record, and the upper and lower boundaries of the target excitation frequency and the resonant frequency band are compared. When the target excitation frequency falls within the resonant frequency band, it is determined that the core resonance phenomenon has occurred; when the target excitation frequency does not fall within the resonant frequency band, it is determined that the core resonance phenomenon has not occurred.

4. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 1, characterized in that, After identifying the occurrence of the core resonance phenomenon, the shell vibration acceleration in the external vibration signal is obtained, and the reciprocating motion amplitude of the moving core under resonance conditions is evaluated based on the shell vibration acceleration and the target excitation frequency. The maximum transient disengagement displacement of the moving core is extracted, including: After identifying the occurrence of the core resonance phenomenon, the shell vibration acceleration within the frequency band of the target excitation frequency is retained from the external vibration signal, and the target acceleration waveform is obtained by arranging them according to the sampling time. Based on the target acceleration waveform and the target excitation frequency, a pre-calibrated table corresponding to the shell acceleration and the iron core displacement is read. The iron core displacement table takes the target excitation frequency and acceleration amplitude as input parameters and outputs the corresponding moving iron core displacement amplitude to obtain the moving iron core displacement response curve.

5. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 4, characterized in that, The obtained displacement response curve of the moving iron core includes: The peak and valley times within a continuous reciprocating cycle are identified by the displacement response curve of the moving iron core. The peak and valley times correspond to the extreme positions of the moving iron core within the reciprocating cycle. The reciprocating motion amplitude of the moving iron core relative to the closing and holding position is determined, and the maximum transient disengagement displacement in the reciprocating motion amplitude is extracted.

6. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 1, characterized in that, The evaluation of the target air gap size of the moving iron core under resonance conditions based on the maximum transient disengagement displacement and the pre-obtained initial air gap includes: The initial air gap is the distance between the moving iron core and the magnetic yoke when the moving iron core is in the closed holding position, and the maximum transient disengagement displacement is the maximum displacement of the moving iron core away from the magnetic yoke. The target air gap size between the moving iron core and the magnetic yoke under resonance conditions is obtained by superimposing the initial air gap size and the maximum transient separation displacement in the direction away from the magnetic yoke of the moving iron core.

7. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 1, characterized in that, The process of obtaining a pre-established law governing the variation of electromagnetic attraction force with air gap size, and evaluating the transient magnetic holding force of the moving iron core under the target air gap size based on this law, includes: The variation pattern includes multiple air gap nodes of the same circuit breaker model in the closed holding state, as well as the magnetic holding force record of the moving iron core corresponding to each air gap node. The air gap interval to which the air gap node belongs is determined according to the target air gap size; When the target air gap size is located between adjacent air gap nodes, the value is linearly taken according to the magnetic holding force record of the moving iron core corresponding to the adjacent air gap node. The transient magnetic holding force between the moving iron core and the magnetic yoke under the target air gap size is determined based on the linear value results.

8. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 1, characterized in that, The process of obtaining the spring tension of the opening spring and the contact pressure spring, evaluating the static load under the closing holding condition based on the spring tension, and evaluating the remaining vibration resistance margin of the moving iron core based on the transient magnetic holding force and the static load includes: Obtain the opening preload of the opening spring and the contact preload of the contact pressure spring, and convert them into opening load components and contact load components respectively according to the direction of the moving iron core away from the magnetic yoke; The static load under the closing holding condition is obtained by adding the opening load component and the contact load component. The static load represents the restoring force on the moving iron core in the direction away from the yoke.

9. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 8, characterized in that, The obtained static load under the closing and holding condition includes: By subtracting the static load from the transient magnetic holding force, the remaining vibration resistance margin of the moving iron core under resonance conditions is obtained.

10. The method for analyzing the opening and closing drive state of a pole-mounted circuit breaker according to claim 1, characterized in that, The process of assessing whether the remaining vibration resistance margin is lower than the pre-established mechanical equilibrium critical point, identifying whether dynamic instability has occurred, and generating a jump risk warning signal and outputting it to the terminal device after identifying dynamic instability includes: The mechanical equilibrium critical point is the minimum vibration resistance margin that allows the moving iron core of the pole-mounted circuit breaker to maintain engagement in the closed-hold state. The remaining vibration resistance margin is compared with the mechanical equilibrium critical point. When the remaining vibration resistance margin is lower than the mechanical equilibrium critical point, dynamic instability is determined to have occurred and an alarm trigger command is generated. The alarm trigger command generates a jump risk warning signal containing dynamic instability and outputs it to the terminal device.

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