2169 results about "Insulation resistance" patented technology

The invention discloses a photovoltaic inverter insulation resistance intelligent detection system and method, and particularly relates to the technical field of photovoltaic equipment operation safety monitoring, and the method comprises the following steps: generating frozen window shielding interference data through collecting a bus voltage in a state transition stage and constructing a dynamic convergence model; identifying an abnormal trend based on resistance derivative change in a stable state, inputting a dual-path decision process by combining environment and power grid parameters, and dynamically outputting an operation state level; control strategies such as remote prompt, power drop adjustment or output disconnection are executed according to the state grade, and accurate identification and grading response control of the insulation state are achieved; according to the invention, by constructing a voltage disturbance shielding mechanism, a trend derivative identification and delay confirmation strategy and a double-path safety state decision process with dynamic switching capability, high accuracy of insulation abnormity judgment, stability of trend identification and adaptability of a decision strategy are realized, and robustness and application range of a detection system are improved.

The invention discloses an insulation detection method for an electric automobile, belongs to the technical field of high-voltage safety monitoring of the electric automobile, and solves the problem that the insulation detection precision is reduced due to electromagnetic interference, impedance fluctuation and capacitive effect coupling in a dynamic load switching process. According to the scheme, a test sequence of discrete frequency points is applied to a high-voltage system; measuring a response current value through a current sensor and calculating a ground distributed capacitance value; connecting a test voltage source between positive and negative electrodes of the high-voltage system through a coupling circuit; applying a first pulse signal during no-load, dynamically setting the width according to the capacitance value, measuring a first response current value, and calculating an initial insulation resistance value; a second pulse signal with the same parameter is applied in the load state window, a second response current value is measured, and differential filtering is carried out in combination with the initial value to eliminate load noise; and comparing the filtered insulation resistance value with a threshold value, and outputting a fault signal when the insulation resistance value is lower than the threshold value. The method is used for monitoring the insulation state of the high-voltage system in real time and accurately early warning faults.

The invention discloses a box-type energy storage substation operation control method and system, a product and a medium. The method comprises the following steps: collecting gas concentration data in the box-type energy storage substation, comparing the gas concentration data with a preset threshold value, and judging whether gas leakage exists or not; if yes, recording related data, and detecting an insulation resistance value of the electrical contact component; based on the gas concentration data and the leakage time of the leakage area, judging whether a chemical reaction triggering condition is met or not; if yes, inert gas is sprayed to the leakage area; if the insulation resistance value is lower than a safety threshold value, electromagnetic isolation is carried out on the leakage area, and distribution of the electric load to the related energy storage unit is stopped; then, current is applied to the electrical contact component at a preset frequency, and an insulating property value is detected; when the insulating property is restored to within the safe range, the electrical load is redistributed to the leakage region. By implementing the technical scheme, the safety of the fault area after the insulation performance is reduced due to gas leakage in the operation process of the box-type energy storage substation is improved.

The invention provides a 110V transformer winding insulation resistance absorption ratio detection method, which belongs to the technical field of transformer windings, and is characterized in that transformer operation state parameters and environmental influence factors are acquired through a multi-channel synchronous acquisition system, and thermodynamic and electrical models are established. The research adopts methods of principal component analysis, numerical integration and the like, an insulation resistance change rule is analyzed under a standard test voltage, a weight coefficient matrix is constructed in combination with an operation state and an environmental factor, a measured value is corrected through multiple linear regression and a correction coefficient method, and finally, the insulation resistance is obtained through statistical average and standard deviation analysis. The accurate evaluation of the insulation resistance absorption ratio of the transformer winding is realized; according to the method, the influence of the complex working environment and the operation state of the transformer on the insulation performance is fully considered, and the problem that various complex factors in the operation process of the transformer cannot be comprehensively considered and compensated in the prior art is solved by adopting the means of mathematical modeling, data correction, statistical analysis and the like; therefore, the technical problem of large deviation of the measurement result is solved.

The invention relates to a low-voltage motor insulation resistance online monitoring and early warning method, system and device and a medium. The method comprises the following steps: firstly, acquiring multi-dimensional operation data through a data acquisition link to form an original monitoring data set; preprocessing the original monitoring data set, and focusing core information through dimension reduction processing to obtain a key parameter set; and then inputting the key parameter set into a dynamic correlation model constructed based on a long short-term memory network, and outputting a prediction result of the variation trend of the insulation resistance value along with time and the deterioration degree quantification. And finally, carrying out early warning analysis based on a prediction result, and generating early warning fault features in combination with a real degradation judgment process. According to the method, the insulation resistance trend and the degradation degree are accurately predicted, the defect of insufficient real-time performance of off-line detection is overcome, the accuracy and the pertinence of fault early warning are improved, and equipment shutdown and safety risks caused by insulation faults are effectively reduced.

The invention discloses a motor insulation breakdown voltage prediction method based on a continuous hidden Markov model, and the method comprises the steps: taking a plurality of groups of obtained experimental data of an insulating material of a motor in different motor operation time periods as a training set, and enabling the experimental data to comprise capacitance, insulation resistance, dielectric loss, maximum discharge capacity and breakdown voltage; constructing a continuous hidden Markov model by taking the test parameters as an observation sequence and taking the discretized breakdown voltage as a hidden state; performing iterative calculation on parameters of the continuous hidden Markov model through a Baum-Welch algorithm based on the training set, and determining optimal parameters of the continuous hidden Markov model; and based on the continuous hidden Markov model of the optimal parameters, determining a hidden state sequence with the maximum probability under the observation sequence at the current moment through a Viterbi algorithm, and determining the breakdown voltage at the current moment based on the hidden state sequence with the maximum probability. According to the invention, the breakdown voltage of the motor insulating material in the motor operation process can be effectively predicted.

The invention provides an insulation detection method and an insulation detection system, and the method comprises the steps: controlling a bridge measurement circuit to carry out two times of balance calibration when a complete insulation detection mode starting signal of a vehicle is detected, and obtaining measurement data; obtaining a first resistance value of a standard adjustable resistor in the bridge measurement circuit based on the initial balance state of the bridge measurement circuit, and calculating a first insulation resistance ratio; acquiring a second resistance value of the standard adjustable resistor based on a secondary balance state of the bridge measurement circuit, and calculating a second insulation resistance ratio; calculating an insulation resistance value corresponding to each insulation resistor by combining the first insulation resistance ratio and the second insulation resistance ratio; and judging whether the insulation resistance value accords with a preset safety threshold, and if not, generating alarm information. In the mode, through a two-time bridge balance calibration method and in combination with a vehicle state self-adaptive detection mode, the insulation detection mode can be dynamically adjusted under different working conditions, and the power consumption is reduced while the measurement precision is ensured.

The invention belongs to the technical field of low-voltage switch cabinet operation control, and particularly discloses an intelligent low-voltage switch cabinet system based on a building intelligent function, which comprises an operation sensing module, a spatial topology module, a fusion diagnosis module, a fault positioning module and a dynamic protection module, current and insulation resistance are synchronously detected at a circuit wiring terminal of the low-voltage switch cabinet, temperature and humidity distribution data of the surrounding environment are collected, and then coupling characteristics between the current and temperature rise are fused. And carrying out visual display of coupling and time sequence correlation in the built three-dimensional heat-electricity correlation topological graph in the switch cabinet by utilizing the time sequence correlation between the insulation resistance and the humidity change, so as to realize comprehensive identification of potential faults. According to the method, the sensitivity and the accuracy of fault identification are effectively improved, early fault symptoms such as poor contact and insulation degradation can be found earlier, the early warning capability of the system is enhanced, and the safety and the stability of operation of the switch cabinet are guaranteed.

The invention discloses a method for measuring the impedance of a grid-connected inverter, which relates to the technical field of impedance measurement of the grid-connected inverter and is characterized in that impedance types and measurement accuracy needing to be measured are determined, the impedance types comprise output impedance and ground insulation impedance, and according to the measurement method and equipment requirements, a data acquisition module is used for setting parameters for acquiring measurement data, the parameters comprise a frequency range, a current amplitude value and a voltage amplitude value, the data processing and analysis module processes and analyzes measured data, calculates an impedance value, compares a calculation result with an expected value and a previous measured value for verification, and in the measurement process, the control and safety module controls starting, stopping and parameter setting of measurement equipment, so that the measurement accuracy is improved. And the working state of the inverter and the safety condition in the measurement process are monitored in real time, and the measurement process, the measurement result and the analysis are written into a measurement report to be uploaded to a system terminal, so that the accuracy and the reliability of impedance measurement of the grid-connected inverter are improved.

The invention belongs to the technical field of electrical safety, and particularly discloses an insulation resistance intelligent detection system and method for an energy storage converter, and the system is based on a bridge balance structure, integrates a temperature and humidity sensor and a voltage sensor, and collects environment parameters and bridge unbalance signals in real time. A digital potentiometer and a resistor array are driven through a PID algorithm to dynamically adjust bridge balance, and environmental interference is eliminated in combination with a temperature and humidity compensation model; and carrying out intelligent analysis on the preprocessed multi-dimensional data by utilizing a band-pass filtering and detection model, and outputting a high-precision insulation resistance value. The method achieves full-automatic detection, is high in precision, is quick in response, is suitable for complex working conditions, and remarkably improves the reliability of the insulation performance evaluation of the energy storage converter.

The invention discloses a water pump motor fault detection method and system, and belongs to the technical field of detection, and the method comprises the steps: building an electrical operation state model based on current, voltage and three-phase balance degree, and outputting an electrical state coefficient; predicting a resistance degradation trend by using the historical winding / insulation resistance data set, and generating a resistance prediction coefficient; combining the electrical state, the amplitude under the load and the flow of the water pump to construct a vibration-flow matching coefficient; fusing the resistance prediction coefficient, the noise index and the temperature index, and outputting a fault evaluation coefficient through a fault evaluation model; and when the fault evaluation coefficient exceeds a threshold value, shutdown is triggered. The system correspondingly comprises an electrical analysis module, a resistance prediction module, a state evaluation module and a fault decision module. According to the invention, early fault accurate detection is realized by fusing multiple parameters, and the reliability of the water pump motor is improved.

The invention discloses an insulation resistance and capacitance measuring circuit and method based on monopulse double-edge analysis, and relates to the related field of the electrical insulation online monitoring technology, and the circuit comprises a detected object and an insulation detection circuit. The insulation detection circuit comprises a controlled pulse voltage source, a coupling resistance network, a current sensor, a switch control module, a signal modulation circuit and a processor. The measurement method implemented based on the circuit comprises the following steps: injecting a common-mode voltage pulse into a transmission line of the power transmission system by adopting a pulse transmitter; pulse current response is collected in real time, a current oscillogram is drawn, and a three-point sampling method is introduced to record a current value for insulation impedance parameter calculation; according to a load condition, a double-edge verification method is applied based on a pulse current attenuation characteristic, and insulation impedance parameters including a resistive component and a capacitive component are independently calculated by analyzing a pulse current rising edge and a pulse current falling edge. According to the invention, non-intrusive synchronous monitoring of resistive and capacitive components of line-to-ground impedance is realized, and the detection precision is improved.

The invention discloses a fan driving motor ground insulation evaluation method and device, and the method comprises the steps: inputting an effective value of a common-mode leakage current signal of a fan driving motor into a constructed fan driving motor ground insulation impedance evaluation model 1, and obtaining a first evaluation result; inputting a vibration speed signal of the fan driving motor into the constructed fan driving motor ground insulation impedance evaluation model 2 to obtain a second evaluation result; inputting the first evaluation result and the second evaluation result into a constructed fan driving motor ground insulation impedance fusion evaluation model to obtain a third evaluation result; and inputting the third evaluation result and a corresponding principal component obtained by the AC voltage signal into a constructed fan driving motor ground insulation decoupling model to obtain the resistance value of a fan driving motor ground insulation resistor and the capacitance value of a fan driving motor ground insulation capacitor. According to the invention, on-line monitoring of the ground insulation of the driving motor of the cooling tower fan of the phase modifier is realized, and the detection precision of the ground insulation of the driving motor of the cooling tower fan of the phase modifier is improved.

The invention discloses a dry-type transformer testing device, and relates to the technical field of testing devices, the dry-type transformer testing device comprises a workbench and a transformer main body, the transformer main body is installed on the workbench, the transformer main body is provided with a wiring terminal, and one side of the workbench is provided with a testing assembly for testing the transformer main body. According to the dry-type transformer testing device, when the brush is in contact with the outer wall of the wiring terminal and rotates, dirt, dust or other impurities on the outer wall of the wiring terminal can be effectively cleared away, through the clearing work, the insulation resistance tester body can check and measure the wiring terminal more accurately, and the testing efficiency of the dry-type transformer is improved. Therefore, potential connection problems, corrosion or abrasion and the like can be found easily, misjudgment or missing detection is avoided, and after interference factors of dirt and impurities are eliminated, the accuracy and reliability of a detection result can be improved.

Disclosed is a sensing block inspection device thermally fused and laser-welded to be mounted on a battery module to dispose a sensing block including a front and a near so that various inspections are performed through rotation, the sensing block inspection device including: a turntable for rotating a jig member mounted with a sensing block; an insulation resistance inspection unit for performing an insulation resistance inspection on the sensing block; a heat-fusion unit for heat-fusing the sensing block; a laser-welding unit for laser-welding the sensing block; an energization inspection unit for performing an energization inspection on the sensing block; a vision inspection unit for transmitting image information to a control unit; and a barcode adhesive unit for adhering a barcode printing paper to the sensing block, wherein the control unit controls the turntable to allow the jig member to sequentially move to the above components.

The invention discloses a comprehensive management system for intelligent power distribution, and the system comprises a sensing layer which is provided with a plurality of sensors, the sensors are disposed on power distribution equipment, and are used for collecting the operation data of a power distribution system in real time, and the operation data comprise a current I, a voltage U, a power P, an equipment temperature T, a power factor cos phi, and an insulation resistance R; the transmission layer is used for transmitting the operation data to a data layer; the data layer is used for preprocessing the operation data to generate standardized data, and preprocessing comprises data cleaning and normalization conversion; and the application layer comprises a fault early warning module, a predictive maintenance module, an energy consumption analysis module and a remote control module, and the application layer realizes collaborative management by calling the standardized data. Multi-dimensional data fusion, a dynamic intelligent algorithm and a module interaction mechanism are introduced, and full-process intelligence of power distribution management is achieved.

The invention relates to the technical field of power electronics, in particular to a direct-current charging pile insulation monitoring method and system, and the method comprises the following steps: monitoring the voltage deviation between a branch and a bus in real time, adjusting a measurement compensation parameter, correcting a branch insulation resistance measurement value, recognizing leakage current drift, positioning a leakage branch, triggering relay control, and sending alarm information. And generating a charging pile monitoring record. According to the method, the branch voltage deviation trend and the voltage compensation parameters are combined, the branch voltage measurement consistency is improved, the insulation resistance fluctuation is utilized to compare and correct the observation error, the measurement precision is optimized, the current deviation compensation in the no-load state is adopted to eliminate the zero drift interference of the sensor, and the measurement accuracy is improved. A current jump amplitude and a voltage direction are combined to identify an electric leakage branch, positioning accuracy is enhanced, a relay control and event information linkage mode is used, alarm response and equipment state records form a closed loop, and real-time performance and integrity of system monitoring are improved.

A fault detection system of a motor belongs to the technical field of motor fault detection, and aims to solve the problems that the existing motor fault detection device is high in detection difficulty and inaccurate in fault reason judgment. The fault detection system comprises the steps that a frequency converter is adopted as a motor starter, and the input voltage of the motor is gradually increased; a harmonic detection module is adopted to detect the harmonic component of a current signal output by the motor, and the harmonic detection module outputs a harmonic waveform; detecting whether the motor is in a normal operation state, a winding short-circuit fault state, a winding open-circuit fault state or a bearing fault state according to the harmonic waveform; a built-in insulation monitoring module of the frequency converter is adopted to detect the insulation resistance value of the motor; judging a motor leakage state according to the insulation resistance value; a torque measuring module arranged in the frequency converter is used for detecting the torque of the motor; judging a motor torque fault state according to the torque; a temperature sensor arranged in the frequency converter is used for detecting the temperature of the motor; and judging a motor fault state according to the temperature. The method is used for motor fault detection.

The invention provides a collision processing method of a vehicle battery, a control module, a device and a vehicle, the method is applied to the control module of the device, and when an elastic wave signal collected by any elastic wave detection module is received, it is determined that the vehicle battery is collided; based on the elastic wave signals collected by the elastic wave detection modules and a preset elastic wave analysis model, elastic wave information generated by collision in the vehicle battery is determined; acquiring the insulation resistance of the vehicle battery pack; if the insulation resistance is smaller than a preset minimum insulation resistance threshold value, determining that the vehicle battery insulation is invalid; determining a fault battery module corresponding to the target elastic wave detection module according to an elastic wave amplitude in the elastic wave information and a preset maximum elastic wave amplitude threshold; and generating a control signal to control the target cut-off module to cut off the corresponding high-voltage copper bar. The fault battery module in the battery pack is determined through elastic waves, and the connection between the fault battery module and other battery modules is cut off, so that short circuit and fire due to insulation failure are avoided, and the safety of the vehicle battery is improved.

The invention provides an insulation detection circuit of an energy storage system. A first sampling unit is used for forming a battery cluster voltage division sampling loop of a battery cluster in the energy storage system; the second sampling unit is used for forming an insulation voltage partial voltage sampling loop of a battery cluster to a casing equivalent insulation resistor in the energy storage system; the insulation resistance detection unit is used for obtaining a battery cluster partial voltage and an insulation voltage partial voltage by using the battery cluster partial voltage sampling loop and the insulation voltage partial voltage sampling loop; according to the battery cluster partial voltage, the insulation voltage partial voltage, the resistance of the first sampling unit and the resistance of the second sampling unit, constructing an electrical balance equation set about the equivalent insulation resistance of the battery cluster to the casing, and solving the electrical balance equation set to obtain the insulation resistance of the energy storage system. Sampling of battery cluster voltage division and insulation voltage division can be achieved only through one digital-to-analog converter or the digital-to-analog converter in the microcontroller, and only one change-over switch tube adopting a PhotoMOS tube is needed, so that the detection cost is low.

The invention relates to a high-voltage network for a motor vehicle, comprising at least the following components: - a first subnetwork; - a second subnetwork; - an isolation monitor; - at least one high-voltage switch per subnetwork. The high-voltage network is characterized primarily by the fact that the first subnetwork and the second subnetwork are arranged in a parallel switching arrangement, and The first subnetwork and the second subnetwork can each be separately connected to the insulation monitor by means of the high-voltage switches, so that the insulation resistance of the first subnetwork and the second subnetwork can each be detected separately by means of the insulation monitor. The proposed high-voltage network enables simple and accurate localization of insulation faults in subnetworks.

The invention relates to the technical field of direct current transmission detection, in particular to a device and method for testing power pipeline connection, and the device comprises a power parameter collection module which is used for collecting current signals and voltage signals in a power pipeline, measuring temperature values at a plurality of positions, obtaining insulation resistance at each node, and measuring grounding resistance of a plurality of grounding points; and summarizing the measurement data to generate an electric power parameter set. According to the invention, through integration and analysis of measurement data of current, voltage, temperature, insulation resistance and grounding resistance, comprehensive monitoring and evaluation of the state of the power pipeline are realized. After the data are integrated, by calculating the mean value, the variance and the peak value of the data and analyzing the spatial distribution of the temperature and the frequency characteristics of the grounding resistance, the understanding of the behavior of the power system is enhanced. According to the data analysis mode, the prediction capability of potential risks and the sensitivity of fault detection are improved, and serious equipment faults and service interruption are effectively avoided.

An insulation testing method for an electric vehicle, comprising: defining system parameters of an insulation monitoring module of a battery management system (BMS) (S110); starting an insulation test task of a powertrain domain control system (PDCS) on the BMS on the basis of the system parameters (S120); collecting the system parameters on the basis of a hardware part of the BMS (S130); determining calculation logic for an original insulation resistance value on the basis of a software part of the BMS, and calculating the original insulation resistance value on the basis of the calculation logic (S140); performing data processing on the original insulation resistance value (S150); and determining an insulation test result of the electric vehicle on the basis of the original insulation resistance value subjected to the data processing (S160). Data detection of the insulation resistance of the electric vehicle is realized by means of the domination of the BMS and the assistance of the PDCS. Also provided are an insulation testing system for an electric vehicle, and an electric vehicle.

The invention discloses a square lithium ion battery external insulation damage detection method, system, medium and equipment, and the method comprises the steps: carrying out the electrochemical impedance spectrum measurement of a square battery with an external insulation state to be detected, and obtaining an electrochemical impedance spectrum; building an equivalent circuit based on the electrochemical impedance spectrum to obtain each characterization electrical element parameter in the equivalent circuit; high-frequency insulation resistance and interface capacitance in the equivalent circuit are extracted, and the damage condition of the outer insulation film of the square lithium ion battery is detected through parameter differences.

The invention provides a fault detection method and device for a charging pile and electronic equipment, and relates to the technical field of detection. According to the method, operation data of a charging pile during working are obtained, the operation data comprise multiple sub-operation data, and the sub-operation data are any one of temperature, voltage, current, power factor, frequency, harmonic content and insulation resistance; inputting the operation data into a preset support vector machine model to obtain a detection result; if it is determined that the detection result indicates that abnormal sub-operation data exists in the multiple pieces of sub-operation data, it is determined that potential faults exist in the charging pile; determining a fault level based on the abnormal sub-operation data; and triggering an early warning mechanism according to the fault level. By implementing the technical scheme provided by the invention, the accuracy of fault detection of the charging pile is improved.

The embodiment of the invention discloses an insulation resistance detection circuit and an insulation resistance detection device of a battery module, and belongs to the technical field of resistance detection. Wherein the insulation resistance detection circuit comprises a detection port for detecting to-be-detected insulation resistance of the port to the ground, and the detection port of the insulation resistance detection circuit is connected to the positive electrode of any cell in the battery module; the processor is respectively connected with the first switch, the second switch and the voltage sampling unit, and is used for determining an impedance value of the to-be-detected insulation impedance and a voltage value of the detection port based on the voltage sampled by the voltage sampling unit in a process of controlling the connection or disconnection of the first switch and the second switch; when the insulation impedance of any cell is determined to be abnormal based on the impedance value of the to-be-detected insulation impedance, the number of cells to which any cell belongs in the battery module is determined based on the voltage value of the detection port, and the cells with abnormal insulation impedance in the battery module can be accurately determined.

The invention relates to an insulation detection method and related equipment thereof. The method comprises the following steps: according to the resistance values of a positive voltage sampling resistor R10, two positive detection resistors R13 and R14, a negative voltage sampling resistor R20 and two negative detection resistors R23 and R24, and a first voltage value Ux1, a second voltage value Uy1, a third voltage value Ux2 and a fourth voltage value Uy2, calculating the resistance values of the positive voltage sampling resistor R10, the two positive detection resistors R13 and R14, the negative voltage sampling resistor R20 and the two negative detection resistors R23 and R24; and calculating an insulation resistance value Rx of the DC bus positive electrode DC + to the protective grounding PE and an insulation resistance value Ry of the DC bus negative electrode DC-to the protective grounding PE. According to the invention, the problem of large insulation detection error in the prior art is solved, and the accuracy of insulation detection is improved.

The invention provides an insulation detection method, device and equipment of an energy storage system, a medium and a program product. The method comprises the step of performing insulation detection on the first battery cluster in the at least two battery clusters by adopting a balanced bridge method and an unbalanced bridge method. For any battery cluster except the first battery cluster in the at least two battery clusters, under the condition that the insulation detection of the previous battery cluster is passed, the resistance value of the positive electrode side insulation resistor and the resistance value of the negative electrode side insulation resistor obtained during the insulation detection of all the battery clusters before the battery cluster are utilized to obtain the resistance value of the positive electrode side insulation resistor and the resistance value of the negative electrode side insulation resistor. And carrying out insulation detection on the battery cluster through an unbalanced bridge method. According to the method, the time of insulation detection of the energy storage system is shortened, and the accuracy of insulation detection of the energy storage system is improved.

The invention relates to the technical field of on-line monitoring, in particular to an insulation fault on-line monitoring method and system for a medical IT system control cabinet. The method comprises the following steps: selecting a non-integer frequency multiplication detection frequency according to equivalent ground distributed capacitance in a previous monitoring period, and superposing the non-integer frequency multiplication detection frequency with a fundamental frequency to form a composite signal injection system; collecting signals to calculate a voltage instantaneous harmonic distortion rate change gradient, and selecting a time window to split the leakage current according to the change gradient; on the basis of dispersion estimation signal-to-noise ratio weighted fusion current vectors, insulation resistance and distributed capacitance are calculated; constructing a four-dimensional original feature vector composed of the insulation parameter, the phase difference and the intermodulation component energy; constructing a diagonal weighting matrix based on the resistance-capacitance ratio and the gradient to transform a feature vector, and determining the fault attribution through the Mahalanobis distance calculation with the fault template library. According to the scheme, harmonic interference can be avoided, calculation stability can be improved, insulation instantaneous sudden change can be quickly responded, and different fault types can be accurately distinguished to guide maintenance.

A first insulation resistance monitoring circuit includes a first resistor connected between a positive terminal of a battery pack and a node, and connected between the positive terminal of the battery pack and a ground terminal of an external device, and has a first monitoring terminal. A second insulation resistance monitoring circuit is connected between the ground terminal and the negative terminal of the battery pack, and has a second monitoring terminal. A voltage monitoring circuit is connected between the node and the negative terminal of the battery pack, and has a third monitoring terminal. A processor measures the voltage of the battery pack.