Main transformer neutral point lightning arrester test auxiliary device and control method thereof

Abstract

The invention relates to a main transformer neutral point lightning arrester test auxiliary device and a control method thereof, the main transformer neutral point lightning arrester test auxiliary device comprises a high-voltage isolation execution mechanism connected in series with a discharge gap branch and a ground terminal used for remote control, and the high-voltage isolation execution mechanism comprises an execution unit, a driving unit, a sensing monitoring unit and an energy management unit; the execution unit is electrically connected with the driving unit, the sensing monitoring unit and the energy management unit. The energy management unit is used for managing release and cut-off of power supply energy in real time; after the execution unit receives an opening instruction, the energy management unit judges that the driving unit is allowed to drive and execute the opening action only when the residual energy is greater than the preset multiple of the closing demand energy, so that the high-voltage isolation execution mechanism always has enough energy to complete the subsequent closing recovery.

Description

TECHNICAL FIELD

[0001] The application relates to a main transformer neutral point arrester test auxiliary device and a control method thereof, and belongs to the field of arrester test devices. BACKGROUND

[0002] When a main transformer neutral point arrester is subjected to high-voltage tests such as a direct-current reference voltage or a leakage current, it must be ensured that it is electrically isolated from a parallel discharge gap to prevent the discharge gap from breaking down or discharging before the arrester, resulting in distorted test data. The existing technology usually relies on maintenance personnel to remove the discharge gap lead or install a temporary insulation partition to achieve isolation. This method not only has a serious risk of falling from a high altitude, but also is complicated and time-consuming to operate, and frequent disassembly and assembly can easily cause loose connections and other poor contact hazards.

[0003] Although some remote-controllable isolation devices have appeared, their control logic mainly focuses on simple mechanical switch actions, and lacks deep perception and closed-loop safety evaluation of the energy state of the device itself. For example, the existing technology cannot accurately quantify the real load capacity of the battery under complex environmental temperatures, nor can it dynamically predict the additional energy consumption of the mechanical mechanism due to increased resistance under low-temperature working conditions, which can easily cause a stuck failure after switching off due to energy depletion, resulting in a long-term loss of protection for the main transformer neutral point. In addition, the confirmation of the closed state usually relies on a single signal, and lacks multi-dimensional comparison of the health of the action process. Therefore, there is an urgent need for a main transformer neutral point arrester test auxiliary device and a control method thereof, which can establish an energy supply and demand analysis model based on multi-condition data calibration, have active optimization capability of the break electric field, and have double verification of the whole process state. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a main transformer neutral point arrester test auxiliary device and a control method thereof.

[0005] A main transformer neutral point arrester test auxiliary device comprises a high-voltage isolation execution mechanism in series with a discharge gap branch and a ground terminal for remote control. The high-voltage isolation execution mechanism comprises an execution unit, a driving unit, a sensing and monitoring unit, and an energy management unit. The execution unit is electrically connected to the driving unit, the sensing and monitoring unit, and the energy management unit. The energy management unit is used to manage the release and cut-off of power supply energy in real time. When the execution unit receives a switching-off instruction, the energy management unit is used to determine whether the remaining energy is greater than a preset multiple of the closing demand energy, and only when the remaining energy is greater than the preset multiple of the closing demand energy is the driving unit allowed to drive the switching-off action, so that the high-voltage isolation execution mechanism always has sufficient energy to complete the subsequent closing recovery.

[0006] Further, the sensing and monitoring unit comprises a temperature sensor for collecting ambient temperature, a micro-resistance measurement module for collecting contact resistance, and a waveform capture module for collecting driving current; and the driving unit is an electric drive mechanism comprising a position feedback module.

[0007] Further, an electric field optimization insulation shield is arranged at the periphery of the moving and static contact breaking gap of the high-voltage isolation actuator.

[0008] The application also provides a control method of the auxiliary device for testing the main transformer neutral point lightning arrester, which is applied to any of the above devices and comprises the following steps: S1, an energy supply and demand analysis model is established, and an electric quantity safety threshold value for a single cycle from breaking to reclosing is set; S2, a breaking instruction is received, and a pre-breaking self-checking program is started; S3, real-time environmental parameters and battery state data are collected, and input into the energy supply and demand analysis model, to calculate the supply-demand ratio of the effective energy that can be released by the battery under the current working condition and the energy required for the cycle from breaking to reclosing; S4, when the supply-demand ratio meets the electric quantity safety threshold value, the driving device performs a breaking action to isolate the discharge gap, and automatically starts a test time window monitoring program; S5, a reclosing recovery program is started when the time window is timed out or a reclosing instruction is received within the test time window; S6, a reclosing action is performed, and multi-dimensional feature data in the action process are collected, and the reclosing result is determined by using state checking logic.

[0009] Further, the energy supply and demand analysis model established in step S1 specifically comprises the following steps: in a preset full temperature range, the battery is subjected to multi-rate discharge test, to establish an electric quantity supply side database reflecting the mapping relationship between environmental temperature, open circuit voltage of the battery and cumulative use frequency and the current available effective energy of the battery; in the preset full temperature range, the power consumption data of the driving unit driving the contact to complete the full process of breaking and reclosing are tested, to establish an electric quantity demand side fitting curve reflecting the change law between environmental temperature change and minimum action energy required to overcome mechanical resistance; the effective energy evaluated by the electric quantity supply side database is compared with the minimum action energy calculated by the electric quantity demand side fitting curve, and a redundant safety factor is introduced, and only when the effective energy is greater than the minimum action energy weighted by the safety factor, a determination result of allowing action is output.

[0010] Further, the step S1 of establishing the energy supply and demand analysis model further comprises a mechanical aging compensation mechanism, specifically: by continuously recording and analyzing the evolution trend of the action time consumption and the drive current peak value in the device historical operation data, an aging correction coefficient dynamically adjusted with the increase of the action number is generated; the aging correction coefficient is used to correct the power demand side fitting curve in a positive direction to compensate for the additional energy consumption demand caused by the increase of mechanical wear and tear or the aging of lubricating grease due to long-term outdoor operation.

[0011] Further, the step S6 of determining the closing result by using the state verification logic specifically comprises: in the initial calibration stage, the drive current time domain waveform of the device during multiple reliable closing under standard working conditions is collected, a standard current waveform template is generated after feature extraction and smoothing processing, and an allowed waveform similarity tolerance range is set; during the actual closing process, on the one hand, the static impedance value of the contact circuit is read and compared with the pre-set qualified impedance threshold value, and on the other hand, the drive current waveform is collected in real time and dynamically matched with the standard current waveform template; only when the impedance value is qualified and the waveform matching degree falls within the similarity tolerance range, the closing is determined to be successful and the protection is confirmed to be restored.

[0012] Further, the real-time collection of the drive current waveform and the dynamic matching analysis with the standard current waveform template specifically comprises: the real-time collected drive current waveform is divided into a start-up acceleration segment, a steady-state running segment and a braking contact segment in the time domain by using a segmented feature mapping method; key feature values are extracted for each segment, including a start-up peak current, a running average current and a contact oscillation time, and difference degrees are calculated for the corresponding segmented features in the standard current waveform template; if the difference degree of any segment exceeds the set tolerance range, the state verification logic will determine the corresponding mechanical fault type according to the specific waveform segment whose difference degree exceeds the standard, and output a fault diagnosis code at the same time as outputting a closing failure signal.

[0013] Further, when the supply and demand ratio meets the power safety threshold in the step S4, the drive device performs an opening action to isolate the discharge gap, and automatically starts a test time window monitoring program, specifically comprising: the device automatically starts a countdown after opening, and sends the remaining permitted time to the ground terminal in real time; if no closing instruction is received before the countdown ends, or the communication connection is interrupted for more than a pre-set time length, the device will trigger a forced homing logic and automatically perform a closing action.

[0014] Further, the step S4 of driving the device to perform the isolation action to isolate the discharge gap specifically comprises: performing a gap electric field active regulation step, that is, controlling the driving unit to drive the internal contact to move to a preset electric field shielding residence position, so that the contact gap is located in the effective range of the electric field optimization insulation shield; using the electric field optimization insulation shield capacitor coupling effect, linearly adjusting the potential distribution between the gaps, and limiting the surface field strength of the contact tip below the air corona starting threshold, so that the gap insulation does not occur along the surface flashover during the application of the DC test high voltage.

[0015] The beneficial effects of the present application are as follows: the energy management unit monitors the power supply energy state in real time, and determines the energy supply-demand ratio before the opening, to ensure that the device always retains sufficient energy for subsequent closing recovery, and the electric field optimization and multi-dimensional state verification mechanism effectively solve the closing function failure problem caused by the lack of energy management in the prior art, and have the advantages of ensuring the timely recovery of the protection state of the main transformer neutral point, and improving the safety and reliability of the power grid operation. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings obtained according to these drawings without creative labor are still within the scope of the present application.

[0017] Figure 1 is the logic diagram of the control method in the present application; Figure 2 is the wiring principle diagram of the device in the main transformer neutral point arrester test in the present application; Figure 3 is the energy supply-demand analysis model logic diagram; Figure 4 is the dynamic characteristic curve of the driving motor current changing with time in the closing process. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present application more clear, the following will further describe the present application in combination with the drawings.

[0019] It should be noted that all the expressions of "first" and "second" in the embodiments of the present application are used to distinguish two same name different entities or different parameters, and it can be seen that "first" and "second" are only for the convenience of description, and should not be understood as a limitation of the embodiments of the present application. The subsequent embodiments will not be described one by one.

[0020] The terms of direction and position mentioned in the present application, such as "up", "down", "front", "back", "left", "right", "inner", "outer", "top", "bottom", "side", and the like, are only the direction or position of reference to the drawings. Therefore, the terms of direction and position used are used to illustrate and understand the present application, and are not a limitation on the scope of protection of the present application.

[0021] In the high voltage test process of the existing main transformer neutral point arrester, in order to ensure the accuracy of the direct current reference voltage or leakage current measurement data, the electrical isolation of the arrester and the parallel discharge gap must be realized. However, the existing remote control isolation device lacks deep perception of energy state and closed-loop safety evaluation mechanism, cannot accurately quantify the real load capacity of the battery under complex environmental temperature, and cannot dynamically predict the additional energy consumption demand of the mechanical mechanism due to the increase of movement resistance under low temperature working condition, so that the power supply energy is exhausted after the opening operation and the closing reset action cannot be performed, causing the interruption of the main transformer neutral point protection function, and further affecting the continuity and reliability of the system overvoltage protection.

[0022] To this end, the present application proposes, as shown in Figures 1-4 An embodiment of a main transformer neutral point arrester test auxiliary device of the present application, including a high voltage isolation execution mechanism in series with the discharge gap branch and a ground terminal for remote control, the high voltage isolation execution mechanism includes an execution unit, a driving unit, a sensing and monitoring unit and an energy management unit; The execution unit is electrically connected with the driving unit, the sensing and monitoring unit and the energy management unit respectively; The energy management unit is used for real-time management of the release and cut-off of the power supply energy; When the execution unit receives the opening instruction, it is judged by the energy management unit that only when the remaining energy is greater than the preset multiple of the closing demand energy, the driving unit is allowed to drive the opening action, so that the high voltage isolation execution mechanism always has enough energy to complete the subsequent closing recovery.

[0023] In practical application, the high voltage isolation execution mechanism refers to a mechanical device in series with the discharge gap branch for realizing electrical isolation, which can be realized by vacuum arc extinguishing chamber or magnetic blowout circuit breaker structure, for example, by physically separating the moving contact and the static contact to block the current path, which is mainly to isolate the discharge gap branch during the test to ensure the accuracy of the arrester test data.

[0024] The execution unit can be implemented by a programmable logic controller or a microprocessor module, for example, receiving instructions through a digital input / output interface and coordinating the work of each unit, which is mainly to realize the centralized control of the opening and closing actions. The energy management unit refers to a module that monitors the power supply energy state in real time and controls the energy on-off, which can be implemented by a battery management system combined with a voltage sampling circuit and a current integration unit, for example, calculating the remaining power by periodically measuring the battery terminal voltage and load current, which is mainly to dynamically evaluate the energy reserve and prevent power interruption.

[0025] Specifically, when the execution unit receives the opening instruction, the energy safety judgment is implemented by the energy management unit, and the opening action is allowed to be executed only when the remaining energy is greater than the preset multiple of the closing demand energy, which can be set to a value range of 1.2 to 2.0, for example, comparing the real-time energy value with the pre-stored threshold value through a software algorithm, which is mainly to ensure that sufficient energy margin is reserved after the opening operation to complete the subsequent closing recovery.

[0026] As a preferred embodiment, the ground terminal is configured as a remote control interface, which can be implemented by a wireless communication module or a wired Ethernet interface, for example, ensuring operation safety through encrypted instruction transmission, which is mainly to eliminate the safety hazards of manual climbing operation.

[0027] The execution unit can be specifically implemented as a microcontroller based on the ARM Cortex-M4 core, which integrates an analog-to-digital conversion interface and a communication module for coordinating data interaction between units; the energy management unit includes a lithium ion battery pack and a supporting power monitoring integrated circuit, which dynamically tracks the remaining energy through voltage sampling and coulomb counting technology. In actual operation, the device verifies the energy supply-demand relationship in a closed loop before opening, ensuring that the high-voltage isolation execution mechanism still has sufficient closing energy margin after completing the opening action.

[0028] Through the technical scheme, the environmental fluctuations and energy uncertainties are fully considered, so that the device always has the energy reserve required for subsequent closing recovery, thereby effectively ensuring the continuity of the main transformer neutral point protection function. The safety hazards of manual climbing operation are eliminated, and the protection failure problem caused by the lack of energy management is avoided, ensuring the reliable switching of the main transformer neutral point protection state during the test process.

[0029] In some embodiments of the present application, a sensing monitoring unit and a driving unit are provided to support energy management. However, in the implementation process, the sensing monitoring unit lacks accurate collection capability of environmental temperature, contact resistance and driving current, which leads to the inability to accurately quantify the real load capacity of the battery under complex environmental temperature and dynamically predict the mechanical resistance change.

[0030] To this end, the application further proposes that the sensing and monitoring unit comprises a temperature sensor for collecting ambient temperature, a micro-resistance measurement module for collecting contact resistance, and a waveform capture module for collecting driving current; and the driving unit is an electric drive mechanism comprising a position feedback module.

[0031] The temperature sensor is used to obtain the ambient temperature parameter in real time, which can be realized by using a thermistor, a thermocouple or an integrated digital temperature sensor, and the purpose is to provide an environmental temperature compensation basis for energy management; the micro-resistance measurement module is a circuit system for accurately measuring the contact resistance, which can be realized by using a four-wire measurement technology or a Kelvin clamping method, and the purpose is to eliminate the influence of test lead resistance to accurately reflect the contact connection state; the waveform capture module is a collection unit for recording the dynamic change of driving current, which can be realized by using a high-speed analog-to-digital converter in combination with a data buffer memory, and the purpose is to capture the current waveform characteristics for action process analysis; and the position feedback module is a sensing component for monitoring the movement position of the driving unit, which can be realized by using a rotary encoder, a Hall effect sensor or a potentiometer, and the purpose is to provide real-time feedback of the contact position to ensure accurate action.

[0032] The temperature sensor can be a DS18B20 type digital temperature sensor; the micro-resistance measurement module can be realized based on a four-wire Wheatstone bridge circuit; the waveform capture module can include a 16-bit resolution high-speed ADC and a non-volatile storage unit; and the position feedback module can integrate an incremental rotary encoder on the output shaft of the electric drive mechanism.

[0033] Through the above scheme, the application realizes accurate collection of ambient temperature, contact resistance and driving current, significantly improves the accuracy of battery energy evaluation, and ensures that there is enough energy to complete the closing restoration after the opening; at the same time, through the multi-dimensional state checking mechanism, the reliability of the closing confirmation is enhanced, and the risk of closing failure caused by single signal failure is effectively avoided.

[0034] In some embodiments of the application described above, a high-voltage isolation actuator is proposed to realize the electrical isolation of the discharge gap. However, in this process, the moving and static contact breaking gap is prone to form uneven electric field distribution when a high voltage of direct current test is applied, which causes the surface field strength of the contact tip to exceed the air corona starting threshold, triggers the surface flashover phenomenon, and causes the test data to be distorted or the equipment insulation to fail, posing a safety hazard.

[0035] To this end, the application further proposes that the sensing and monitoring unit comprises a temperature sensor for collecting ambient temperature, a micro-resistance measurement module for collecting contact resistance, and a waveform capture module for collecting driving current; and the driving unit is an electric drive mechanism comprising a position feedback module.

[0036] The electric field optimization insulation shield is an insulation structure for regulating the electric field distribution of a high-voltage fracture, which can be realized by a metal shield body, a ring-shaped shield made of composite insulation material or a coating structure with gradient conductivity, and aims to reduce the local field strength concentration effect of the contact tip by physically intervening the electric field path, avoid the air corona initiation condition being triggered, and thus maintain the insulation stability of the fracture in a DC high-voltage environment.

[0037] Through the above scheme, the technical problem of uneven electric field distribution of the moving and static contact breaking gap under DC test high voltage is effectively solved, the surface flashover phenomenon caused by the excessive surface field strength of the contact tip is avoided, the insulation reliability and data accuracy of the lightning arrester test process are ensured, and the insulation failure risk of the equipment caused by flashover is eliminated.

[0038] In another embodiment, the application also discloses a control method of a main transformer neutral point lightning arrester test auxiliary device, which is applied to any of the devices and includes the following steps: S1, an energy supply and demand analysis model is established, and an electric quantity safety threshold value of a single cycle from breaking to reclosing is set; S2, a breaking instruction is received, and a pre-breaking self-checking program is started; S3, real-time environmental parameters and battery state data are collected, input into the energy supply and demand analysis model, and the supply-demand ratio of the effective energy that can be released by the battery under the current working condition and the energy required for the cycle from the breaking to the reclosing is calculated; S4, when the supply-demand ratio meets the electric quantity safety threshold value, the device is driven to perform a breaking action to isolate the discharge gap, and a test time window monitoring program is automatically started; S5, a reclosing recovery program is started when the test time window is timed out or a reclosing instruction is received in the test time window; S6, a reclosing action is performed, and multi-dimensional feature data in the action process is collected, and the reclosing result is determined by using state checking logic.

[0039] Through the above scheme, the energy closed-loop management mechanism is embedded in the breaking instruction receiving stage, the supply-demand ratio is dynamically calculated based on real-time environmental parameters and battery state data, and the breaking action is only performed when the remaining energy meets the safety threshold value, so that the protection failure risk caused by energy depletion is fundamentally avoided. In addition, the test time window monitoring program and the reclosing recovery program are cooperatively designed, the main transformer neutral point is effectively prevented from losing protection for a long time, and the multi-dimensional state checking logic significantly improves the reliability of the reclosing determination by dynamically matching double data and standard templates.

[0040] In some embodiments of the above application, an energy supply and demand analysis model is established to ensure that the device has sufficient energy to complete the subsequent closing after the opening operation, however, in the implementation process, the model lacks dynamic quantification ability for environmental temperature changes and battery aging state, cannot accurately evaluate the real available energy of the battery under different working conditions, and also fails to accurately reflect the additional energy consumption required by the mechanical mechanism due to increased resistance under adverse conditions such as low temperature, resulting in incorrect energy judgment before opening, which may cause the closing operation to fail due to insufficient energy after opening, and the main transformer neutral point loses protection for a long time.

[0041] To this end, the application further proposes to establish an energy supply and demand analysis model in step S1, specifically including: performing multiple rate discharge tests on the battery within a preset full temperature range, establishing an electricity supply side database reflecting the mapping relationship between environmental temperature, battery open circuit voltage, and cumulative use number and current available effective energy of the battery; testing the power consumption data of the driving unit driving the contact to complete the opening and closing process within the preset full temperature range, establishing an electricity demand side fitting curve reflecting the change law between environmental temperature change and minimum action energy required to overcome mechanical resistance; comparing the effective energy evaluated through the electricity supply side database with the minimum action energy calculated through the electricity demand side fitting curve, and introducing a redundancy safety factor, and only when the effective energy is greater than the minimum action energy weighted by the safety factor, the determination result of allowing action is output.

[0042] Among them, the electricity supply side database is a structured collection of battery characteristic data, which can be implemented by using a multi-dimensional lookup table or a parameterized regression model, the purpose is to systematically characterize the comprehensive influence of environmental temperature fluctuation, battery open circuit voltage attenuation and cumulative use number on available energy, avoiding the evaluation distortion caused by the traditional method relying only on nominal capacity; the electricity demand side fitting curve can be understood as a mathematical expression describing the correlation between mechanical action energy consumption and environmental temperature, which can be implemented by using a polynomial fitting or a piecewise linear interpolation model, the purpose is to dynamically quantify the additional mechanical resistance caused by aging of lubricating grease or shrinkage of parts under low temperature working conditions; the redundancy safety factor is specifically a conservative coefficient set to cover measurement uncertainty, which can be configured as a fixed threshold or a dynamic adjustment value based on historical operation data, the purpose is to compensate for working condition fluctuations and sensor errors, and ensure the reliability of energy judgment.

[0043] Specifically, the scheme of the application constructs a closed-loop energy verification mechanism by calling the power supply side database and fitting the power demand side curve in real time before the opening. When receiving the opening instruction, the system synchronously collects parameters such as ambient temperature, open-circuit voltage of the battery and cumulative use frequency, evaluates the effective energy that the battery can release under the current working condition based on the power supply side database, calculates the minimum action energy required for the driving contact to complete the opening and closing cycle according to the real-time ambient temperature through the power demand side fitting curve, and then dynamically compares the effective energy with the minimum action energy weighted by the redundancy safety factor, and only when the effective energy fully covers the weighted demand, the determination result of allowing action is output. This double verification logic takes the dynamic changes of battery characteristics and mechanical energy consumption into the quantitative evaluation system, upgrades the energy judgment from a static threshold to a dynamic decision based on multi-condition data, and fundamentally avoids the energy evaluation misalignment problem caused by environmental mutations or aging accumulation.

[0044] The power supply side database can be constructed based on the multi-rate discharge test data of lithium ion batteries in the industrial temperature range, and the available energy values corresponding to different temperature, voltage and use frequency combinations are stored in the form of a three-dimensional data table. The power demand side fitting curve can be a quadratic polynomial fitting the power consumption test data of the driving unit in the same temperature range to represent the nonlinear relationship between temperature and minimum action energy. The redundancy safety factor can be set as an empirical constant to cover the measurement uncertainty.

[0045] In actual operation, when the system detects a low-temperature environment, the temperature-compensated battery effective energy value is obtained by querying the power supply side database, and the increased mechanical resistance demand at low temperature is calculated according to the power demand side fitting curve, and the energy supply and demand ratio is determined after being weighted by the safety factor, so as to ensure that the opening action is only executed when sufficient closing energy is reserved.

[0046] Through the above technical scheme, the application can accurately quantify the real available energy of the battery under complex environment, dynamically adapt to the additional energy consumption demand of the mechanical mechanism due to temperature change, effectively avoid the energy judgment error before opening, and ensure that the high-voltage isolation execution mechanism always has sufficient energy to complete the subsequent closing recovery after opening, thereby guaranteeing the continuity and reliability of the main transformer neutral point protection function.

[0047] In some embodiments of the application described above, an energy supply and demand analysis model is proposed to ensure the energy safety of opening and closing, however, during the implementation process, the additional energy consumption demand caused by the increase of mechanical wear and tear and the aging of lubricating grease due to long-term outdoor operation, and the existing model does not consider the aging factor, which may lead to insufficient energy after aging and unable to complete the closing action.

[0048] To this end, the application further proposes that the establishment of the energy supply and demand analysis model in the step S1 further comprises a mechanical aging compensation mechanism, specifically: by continuously recording and analyzing the evolution trend of the action time consumption and the drive current peak value in the device historical operation data, an aging correction coefficient dynamically adjusted with the increase of the action number is generated; the aging correction coefficient is used to positively correct the power demand side fitting curve to compensate for the additional energy demand caused by the increase of mechanical wear and tear or the aging of lubricating grease due to long-term outdoor operation.

[0049] Among them, continuously recording and analyzing the evolution trend of the action time consumption and the drive current peak value in the device historical operation data is a long-term quantitative monitoring of the device running state, which can be realized by using a non-volatile memory to periodically sample and store the action parameters with a microprocessor, and can be specifically configured to automatically record the timing data and current waveform characteristic values after each opening and closing operation, the purpose is to establish a traceable aging process database; generating an aging correction coefficient dynamically adjusted with the increase of the action number can be understood as an adaptive parameter fitted based on historical data, and a linear regression algorithm or an exponential decay model is used to dynamically calculate the correction value according to the action number, the purpose is to convert the degree of mechanical wear into a quantifiable energy compensation factor; positively correcting the power demand side fitting curve with the aging correction coefficient is specifically a gain adjustment of the basic energy demand model, which can be realized by multiplying or adding the correction coefficient into the demand side curve calculation process, so as to make the predicted minimum action energy value increase synchronously with the aging degree, thereby covering the actual increased energy demand.

[0050] Through the above-mentioned scheme, the application can dynamically adjust the energy demand evaluation benchmark based on the actual evolution of mechanical wear during long-term outdoor operation of the device, ensure that the remaining energy can still accurately meet the closing demand before opening under the working condition that the resistance increases due to the aging of lubricating grease or the wear of contacts, effectively avoid the closing failure caused by the failure to compensate for the aging energy consumption, and ensure the continuous reliability of the main transformer neutral point protection function.

[0051] In some embodiments of the application, the use of state verification logic to determine the closing result is proposed, however, in the implementation process, only a single signal (such as the static impedance value of the contact circuit) is used for determination, which lacks multi-dimensional comparison of the action process health, resulting in that the closing result is easily misjudged by accidental factors.

[0052] To this end, the application further proposes to use state verification logic to determine the closing result, specifically including: in the initial calibration stage, the acquisition device collects the drive current time domain waveform during multiple reliable closing under standard working conditions, generates a standard current waveform template after feature extraction and smoothing processing, and sets an allowable waveform similarity tolerance range; during the actual closing process, on the one hand, the static impedance value of the contact circuit is read and compared with the pre-set qualified impedance threshold value, and on the other hand, the drive current waveform is collected in real time and dynamically matched with the standard current waveform template; only when the impedance value is qualified and the waveform matching degree falls within the similarity tolerance range, the closing is determined to be successful and the protection is confirmed to be restored.

[0053] Among them, the standard current waveform template is a reference waveform formed by collecting the drive current waveform during reliable closing multiple times and processing it, which can use signal processing techniques such as principal component analysis or wavelet transform to extract stable core features, thereby accurately representing the mechanical motion state of normal closing; the waveform similarity tolerance range is the allowable waveform deviation threshold, which is determined based on the statistical distribution of historical operation data, for example, by calculating the dispersion degree of multiple normal closing waveforms to set a reasonable boundary, so as to avoid misjudgment due to environmental fluctuations.

[0054] Specifically, the scheme of the application provides a high-reliability reference basis for the closing process by establishing a standard current waveform template and setting a tolerance range in the initial calibration stage. In the actual closing process, the system simultaneously performs static impedance detection and dynamic current waveform analysis: static impedance detection quickly verifies the integrity of electrical connection, while dynamic waveform matching quantifies the similarity between real-time current waveform and standard template to sensitively capture abnormalities in the contact motion trajectory (such as acceleration segment jamming or braking segment oscillation). Since the drive current waveform is directly related to the mechanical motion state, its dynamic change can effectively reflect the health of the contact closing process. Only when both indicators meet the pre-set conditions, the system determines that the closing is successful, and this double verification mechanism ensures the double verification of electrical contact quality and mechanical action process, fundamentally avoiding the protection failure problem caused by single signal misjudgment.

[0055] Through the above scheme, the application effectively solves the closing misjudgment problem caused by single signal determination, ensures the reliable restoration of the main transformer neutral point protection function, avoids the protection failure risk caused by abnormal mechanical action (such as incomplete contact closing or motion jamming), and thus guarantees the timely and accurate restoration of system protection function after high voltage test.

[0056] In some embodiments of the application described above, the use of state verification logic to determine the closing result is proposed, however, in the implementation process, when the waveform matching degree is unqualified, only the closing failure can be determined and the specific fault type cannot be identified, which makes it difficult for operation and maintenance personnel to quickly locate the mechanical fault source, increasing the complexity and time cost of equipment maintenance.

[0057] To this end, the application further proposes to collect the driving current waveform in real time and dynamically match it with the standard current waveform template, specifically including: using a segmented feature mapping method to divide the real-time collected driving current waveform into a start-up acceleration segment, a steady-state running segment, and a braking contact segment in the time domain; for each segment, extract the key feature values, including the start-up peak current, the running average current, and the contact oscillation time, and calculate the difference degree with the corresponding segmented features in the standard current waveform template; if the difference degree of any segment exceeds the set tolerance range, the state verification logic will determine the corresponding mechanical fault type according to the specific waveform segment that exceeds the difference degree, and output a fault diagnosis code while outputting a closing failure signal.

[0058] Among them, the start-up acceleration segment is the interval of rapid current rise in the initial stage of closing action, which can be understood as a characteristic interval reflecting the initial response capability of the driving mechanism, and can be defined by detecting the current rise slope change point to capture motor start-up load abnormalities; the steady-state running segment refers to the interval of relatively stable current during the closing process, which embodies the characteristic interval of stable resistance in the movement process, which can be identified by the current fluctuation amplitude threshold, and monitors the resistance change caused by mechanical wear; the braking contact segment is the interval of current oscillation when the contact is about to contact, which is the characteristic interval related to the contact quality of the contact, which can be defined by the current oscillation frequency and amplitude, and the purpose is to evaluate the problem of contact contamination or poor contact.

[0059] Difference degree calculation is a mathematical method to quantify the deviation degree of real-time feature values from standard template feature values, which is realized by using Euclidean distance, Mahalanobis distance or dynamic time warping algorithm, and the purpose is to objectively evaluate the deviation degree of each stage state; fault diagnosis code is the encoding information representing a specific mechanical fault type, which can be represented in binary encoding, hexadecimal encoding or text encoding form, and the purpose is to enable operation and maintenance personnel to quickly identify the fault type.

[0060] Through the above technical solutions, the application can accurately identify the mechanical fault type according to the segmented feature difference of the driving current waveform in the closing process, so that the operation and maintenance personnel can quickly locate the fault root without complex troubleshooting, significantly shortening the fault diagnosis time and reducing the maintenance complexity.

[0061] The application further proposes that when the supply-demand ratio meets the power safety threshold in step S4, the driving device performs the opening action to isolate the discharge gap, and automatically starts the test time window monitoring program, specifically including: the device automatically starts the countdown after opening, and sends the remaining permitted time to the ground terminal in real time; if no closing instruction is received before the countdown ends, or the communication connection is interrupted for more than a preset time, the device will trigger the forced homing logic and automatically perform the closing action.

[0062] The countdown is a time monitoring mechanism, which can be realized by using a real-time clock module of an embedded system or a software timer, and is used to accurately control the duration of the open state and prevent the protection function from being long-term invalid due to the absence of external instructions; the real-time sending of the remaining permitted time to the ground terminal can be understood as a state feedback process, which is realized by periodically sending data packets by using a wireless communication module such as a LoRa or 4G module, and the purpose is to enable the operator to remotely master the remaining operation window and timely adjust the test rhythm; the determination of the absence of a closing instruction refers to the timeout detection logic, which can be realized by comparing the current timing value with a preset threshold, and the purpose is to automatically identify the instruction delay and avoid the device being long-term retained in the open position without instructions; the communication connection interruption detection refers to the link stability monitoring, which is realized by periodically sending heartbeat packets and detecting the timeout of the response, timely discovering the signal transmission abnormity and ensuring that the device can still respond independently when the remote control fails; the forced homing logic can be understood as a safety recovery mechanism, which is realized by calling a preset closing control program, and the purpose is to immediately start the autonomous recovery process according to the abnormal determination result without relying on external input, and fundamentally guarantee the rapid reset of the protection function.

[0063] Through the above technical solution, the device can autonomously manage the test time window after opening, and automatically restore the closed state when the instruction is missing or the communication fails, effectively avoiding the long-term invalidation of the main neutral point protection function, and significantly improving the safety and reliability of the test process.

[0064] The step of driving the device to perform the opening action to isolate the discharge gap comprises: performing a step of actively regulating the electric field at the break, that is, controlling the driving unit to drive the internal contact to move to a preset electric field shielding residence position, so that the contact break is located within the effective range of the electric field optimization insulation shielding cover; and linearly adjusting the potential distribution between the breaks by using the capacitive coupling effect of the electric field optimization insulation shielding cover, so as to limit the surface field strength of the contact tip to be below the air corona starting threshold, thereby keeping the breakage insulation from surface flashover during the application of the DC test high voltage.

[0065] The electric field shielding residence position is a specific positioning point set after the contact breaks to achieve electric field optimization, which is realized by using a mechanical limiting stopper or an electronic positioning method based on encoder feedback, and the purpose is to ensure that the break is stably located within the electric field regulation region of the electric field optimization insulation shielding cover; the electric field optimization insulation shielding cover refers to an insulation protection structure with a specific curved surface profile and dielectric properties, which is made of silicone rubber composite material or epoxy resin molding process, and the electric field distribution is guided by structural design; the capacitive coupling effect can be used to balance the potential gradient by using the distributed capacitance characteristics between the shielding cover and the contact, and the geometric size and material dielectric constant of the shielding cover are adjusted to realize the elimination of the electric field concentration phenomenon in the break area.

[0066] By the technical scheme, the electric field distortion at the fracture can be effectively inhibited during application of the DC test high voltage, the air ionization phenomenon caused by the field intensity exceeding the standard of the contact tip is avoided, the insulation integrity of the discharge gap branch is ensured, and the accurate acquisition of the test data of the surge arrester and the reliable recovery of the protection function of the main transformer neutral point are ensured.

[0067] 1. Device configuration and environmental conditions The main transformer neutral point surge arrester test auxiliary device is applied to the main transformer neutral point of a 220 kV substation in East China in this embodiment.

[0068] Environmental conditions: ambient temperature +20℃, relative humidity 40%, wind speed 2 (normal working condition).

[0069] Device configuration: Battery: 24V / 5Ah lithium iron phosphate battery (standard type) Drive motor: rated power 60W, stroke 100mm Controller: STM32F407 Communication mode: LoRa 433MHz Shielding cover: silicon rubber umbrella skirt structure, inner diameter 120mm 2. Initial calibration and model parameters (1) Database data on the power supply side The effective energy of the battery at 20℃ is about 95% (about 114Wh).

[0070] (2) Demand side calculation The fitting formula established in the laboratory is adopted: When T = 20℃: (3) Aging correction coefficient The device accumulates about 50 actions, so the aging coefficient is small: K age =1.02 The corrected action demand energy: 3. Field test process (1) Energy self-check before switching off The current temperature is 20℃, and the battery voltage is 26.0V (SOC 92%).

[0071] Supply side energy: Demand side energy + redundancy reservation: a redundancy safety factor of 2.0 is adopted Determination of energy sufficiency, allowing action.

[0072] (2) Breaking and electric field shielding The drive unit operates, and the contact drops 100 mm. The moving contact enters the inner cavity of the shield 80 mm, forming a stable electric field shielding area. A 60 kV DC test voltage is applied to the arrester.

[0073] There is no corona spot around the fracture, and weak corona appears at about 45 kV when not shielded.

[0074] (3) Closing recovery and double check The contact resistance is measured to be 120 μΩ, and it is determined to be qualified. The collected current waveform characteristics are as follows: All feature differences are within the tolerance range, and the closing check is passed. The device reports an operation success signal, and the terminal green light is on.

[0075] 4. Comparison of abnormal working conditions To verify the diagnosis capability, the guide rod lubrication is reduced to simulate mild wear: the starting peak current rises to 3.0 A, and the steady-state operating current rises to 1.2 A, determining that the "steady-state section difference exceeds the threshold value", prompting: ERR_01: Mechanical friction is too high (needs to be repaired), but the action is not stuck, and the closing can still be completed, prompting the operation and maintenance personnel to carry out preventive maintenance.

[0076] The above only discloses the preferred embodiments of the present application, and of course cannot limit the scope of the rights of the present application, so equivalent changes made according to the claims of the present application still fall within the scope of the present application.

[0077] Although the present application has been described with reference to several specific embodiments, it should be understood that the present application is not limited to the disclosed specific embodiments. The present application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A testing auxiliary device for a main transformer neutral point surge arrester, characterized in that: It includes a high-voltage isolation actuator connected in series in the discharge gap branch and a ground terminal for remote control. The high-voltage isolation actuator includes an execution unit, a drive unit, a sensing and monitoring unit and an energy management unit. The execution unit is electrically connected to the drive unit, the sensing and monitoring unit and the energy management unit respectively; The energy management unit is used to manage the release and cutoff of power supply in real time; After receiving the tripping command, the execution unit determines through the energy management unit that the drive unit is allowed to perform the tripping action only when the remaining energy is greater than a preset multiple of the energy required for closing, so that the high-voltage isolation actuator always has sufficient energy to complete the subsequent closing and restoration.

2. The auxiliary testing device for the neutral point surge arrester of the main transformer as described in claim 1, characterized in that: The sensing and monitoring unit includes a temperature sensor for acquiring ambient temperature, a micro-resistance measurement module for acquiring contact resistance, and a waveform capture module for acquiring drive current; the drive unit is an electric transmission mechanism that includes a position feedback module.

3. The auxiliary testing device for the neutral point surge arrester of the main transformer as described in claim 1 or 2, characterized in that: It also includes an electric field optimized insulation shield, which is located around the periphery of the separation gap between the moving and stationary contacts of the high-voltage isolation actuator.

4. A control method for an auxiliary testing device for a main transformer neutral point surge arrester, characterized in that: Applied to any of the apparatuses of claims 1-3, the method comprises the following steps: S1. Establish an energy supply and demand analysis model and set the power safety threshold for a single cycle from circuit breaker opening to circuit breaker closing. S2. Receive the tripping command and start the pre-tripping self-test program; S3. Collect real-time environmental parameters and battery status data, input them into the energy supply and demand analysis model, and calculate the supply and demand ratio of the effective energy that the battery can release under the current operating conditions and the energy required for this tripping to reclosing cycle. S4. When the supply-demand ratio meets the power safety threshold, the drive device performs a tripping action to isolate the discharge gap and automatically starts the test time window monitoring program. S5. Receive the closing command within the test time window or start the closing recovery procedure when the time window expires; S6. Execute the closing action and collect multi-dimensional feature data during the action process, and use the status verification logic to determine the closing result.

5. The control method for the auxiliary testing device of the main transformer neutral point surge arrester as described in claim 4, characterized in that: The step S1, which establishes an energy supply and demand analysis model, specifically includes: Within a preset full temperature range, the battery is subjected to multi-rate discharge tests to establish a power supply-side database that reflects the mapping relationship between ambient temperature, battery open-circuit voltage, cumulative number of uses, and the battery's current available effective energy. Within the preset full temperature range, the power consumption data of the drive unit driving the contacts to complete the entire opening and closing process is tested, and a power demand-side fitting curve reflecting the change law between ambient temperature change and the minimum operating energy required to overcome mechanical resistance is established. The effective energy assessed by the power supply-side database is compared with the minimum action energy calculated by the power demand-side fitted curve. A redundancy safety factor is introduced, and the decision result of allowing action is output only when the effective energy is greater than the minimum action energy weighted by the safety factor.

6. The control method for the auxiliary testing device of the main transformer neutral point surge arrester as described in claim 5, characterized in that: The energy supply and demand analysis model established in step S1 also includes a mechanical aging compensation mechanism, specifically: By continuously recording and analyzing the evolution trend of action time and peak drive current in the historical operation data of the device, an aging correction coefficient is generated that dynamically adjusts with the increase of the number of actions. The aging correction coefficient is used to positively correct the power demand-side fitting curve to compensate for the additional energy consumption caused by increased mechanical wear or aging of lubricating grease due to long-term outdoor operation.

7. The control method for the auxiliary testing device of the main transformer neutral point surge arrester as described in claim 4, characterized in that: Step S6 uses state verification logic to determine the closing result, specifically including: During the initial calibration phase, the time-domain waveform of the drive current during multiple reliable closing operations under standard operating conditions is collected. After feature extraction and smoothing, a standard current waveform template is generated, and an allowable waveform similarity tolerance range is set. During the actual closing process, on the one hand, the static impedance value of the contact circuit is read and compared with the preset qualified impedance threshold; on the other hand, the drive current waveform is collected in real time and dynamically matched and analyzed with the standard current waveform template. Only when the impedance value is qualified and the waveform matching degree falls within the similarity tolerance range can the closing be determined as successful and the protection be confirmed to have been restored.

8. The control method for the auxiliary testing device of the main transformer neutral point surge arrester as described in claim 7, characterized in that: Real-time acquisition of the drive current waveform and dynamic matching analysis with the standard current waveform template specifically includes: The segmented feature mapping method is used to divide the real-time acquired drive current waveform into three segments in the time domain: the start-up acceleration segment, the steady-state operation segment, and the braking contact segment. For each segment, key feature values ​​are extracted, including the starting peak current, the average operating current, and the contact oscillation time, and the difference between these features and the corresponding segment features in the standard current waveform template is calculated. If the difference in any segment exceeds the set tolerance range, the status verification logic will determine the corresponding mechanical fault type based on the specific waveform segment with the excessive difference, and output a fault diagnosis code while outputting a closing failure signal.

9. The control method for the auxiliary testing device of the main transformer neutral point surge arrester as described in claim 4, characterized in that: In step S4, when the supply-demand ratio meets the power safety threshold, the drive device performs a tripping action to isolate the discharge gap and automatically starts the test time window monitoring program, specifically including: The device automatically starts a countdown after the circuit breaker is tripped and sends the remaining permitted time to the ground terminal in real time. If no closing command is received before the countdown ends, or if the communication connection is interrupted for more than the preset time, the device will trigger the forced reset logic and automatically execute the closing action.

10. The control method for the auxiliary testing device of the main transformer neutral point surge arrester as described in claim 4, characterized in that: In step S4, the driving device performs a tripping action to isolate the discharge gap, specifically including: The active control step of the electric field at the break point is to control the driving unit to drive the internal contact to move to the preset electric field shielding dwell position, so that the contact break point is within the effective range of the electric field optimized insulation shield. By utilizing the capacitive coupling effect of the electric field-optimized insulating shield, the potential distribution between the breaks is linearly adjusted, limiting the surface field strength at the contact tip to below the air corona initiation threshold, thereby preventing surface flashover of the break insulation during the application of DC test high voltage.

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