A mine heavy truck generator insulation leakage on-line detection device and method

Abstract

The application provides a kind of mine heavy truck generator insulation leakage on-line detection device and method, device includes signal acquisition unit, signal processing unit, control unit and communication unit, signal acquisition unit adopts capacitive coupling voltage sensor, with non-contact way adheres to generator outer insulation layer or machine box wall, real-time induction leakage signal, signal processing unit passes through adaptive filter and inhibits mine area strong electromagnetic interference, control unit executes leakage calculation, trend analysis and three-level early warning.The application aims to solve the problem that the prior art cannot realize on-line, accurate and reliable insulation monitoring in harsh environment of mine area, realizes 24 hours uninterrupted monitoring and early fault warning of generator insulation state in-40 DEG C extremely cold, high dust, strong vibration working condition, has the advantages of compact size, strong anti-interference ability, convenient installation, high safety, significantly improves the operation safety and maintenance efficiency of mine heavy truck.

Description

Technical Field

[0001] This invention relates to the field of mining equipment technology, and in particular to an online detection device and method for insulation leakage current of a heavy-duty mining truck generator. Background Technology

[0002] Heavy-duty mining trucks are the core equipment of open-pit mine transportation systems. Their power systems typically consist of a diesel engine driving a main generator, which produces high-voltage alternating current (up to 2000V or more). After rectification, this current drives an electric wheel motor, enabling the vehicle to move. As a high-voltage power source, the insulation performance of the generator directly affects the safety of vehicle operation and the lives of personnel.

[0003] In the harsh working conditions of open-pit coal mines, generators face the following unique challenges: 1. High dust environment: The dust concentration in mining sites and spoil heaps is high. Dust may enter the generator and adhere to the winding surface, forming a conductive channel and reducing the resistance and insulation performance. 2. Damp mud and water: In rainy or snowy weather, or when washing vehicles, water may enter the generator, causing insulation deterioration or even a short circuit; 3. Vibration and impact: The roads in the mining area are uneven and potholed, and vehicles generate strong random vibrations and impact loads during operation. Long-term vibration may cause the insulation layer to wear and crack. 4. Dramatic temperature changes: Extremely cold winters of -40℃ and extremely hot summers (temperatures can reach over 80℃ inside the cabin), thermal expansion and contraction accelerate insulation aging.

[0004] These factors can accelerate the aging and damage of the generator's internal insulation, leading to leakage and potentially causing equipment damage or even electric shock accidents. Therefore, real-time monitoring of the generator's insulation status is crucial.

[0005] Currently, the main technical solutions and corresponding shortcomings for leakage current detection of generators used in mining heavy-duty trucks are as follows: 1. Manual handheld periodic inspection: This method requires manual operation while the machine is stopped, which poses safety hazards, and it cannot provide real-time monitoring and early warning. The inspection data is also difficult to record and analyze systematically. 2. Fixed Insulation Monitoring Devices: These devices, installed on some industrial equipment, monitor insulation resistance by injecting DC or low-frequency AC signals. However, they are prone to false alarms in the strong electromagnetic interference environment of mining areas, their performance degrades in extremely cold environments of -40℃, affecting measurement accuracy, and they are also bulky, making them difficult to install in the compact engine compartment of mining trucks, and their cost is also high. 3. Indirect monitoring by on-board diagnostic system (OBD): Some new mining trucks indirectly determine the insulation status by monitoring parameters such as voltage and current. However, this method has low sensitivity and slow response, cannot directly measure insulation resistance, and is difficult to locate whether the fault comes from the generator body or the line.

[0006] In summary, none of the existing technologies can provide a comprehensive solution that can simultaneously address issues such as online real-time monitoring, adaptability to harsh mining environments (extreme cold, strong vibration, dust), suppression of strong electromagnetic interference, compact installation, and cost control. Summary of the Invention

[0007] The purpose of this invention is to provide an online detection device and method for insulation leakage of generators in heavy-duty mining trucks, which can realize non-contact real-time online monitoring and meet the reliable operation requirements of harsh environments such as strong electromagnetic interference, -40℃ extreme cold, high dust, and strong vibration in mining areas.

[0008] This invention provides an online detection device for insulation leakage current of a heavy-duty mining truck generator, comprising: The signal acquisition unit includes at least one capacitively coupled voltage sensor, which includes electrodes and an insulating layer for attaching to the surface of the outer insulating layer of the generator lead wire or the outer wall of the generator chassis to sense the alternating electric field signal generated by leakage current through the capacitive coupling principle. A signal processing unit, connected to the signal acquisition unit, includes a preamplifier circuit and an adaptive filter circuit, used to amplify the acquired leakage current signal and filter out electromagnetic interference. The control unit, connected to the signal processing unit, is used to calculate leakage parameters and estimate insulation resistance values ​​based on the processed leakage signal, and to perform insulation resistance change trend analysis and early warning judgment. A communication unit, connected to the control unit, is used to upload detection results and early warning information to the vehicle monitoring system or remote management platform.

[0009] Preferably, the capacitively coupled voltage sensor further includes a shielding layer, which adopts a double-layer shielding structure, wherein the inner shielding layer is connected to the signal ground and the outer shielding layer is connected to the device housing ground.

[0010] Preferably, the signal acquisition unit further includes a zero-sequence current transformer and a temperature sensor, which are used to be installed on the three-phase leads or neutral grounding wire of the generator to detect leakage current. The control unit can determine whether the leakage current originates from the generator body or the lead line based on the combination of the detection signals from the capacitively coupled voltage sensor and the zero-sequence current transformer. The control unit is connected to the temperature sensor to acquire generator temperature data and perform temperature compensation on the estimated value of insulation resistance based on the temperature data.

[0011] Preferably, the signal processing unit further includes a digital-to-analog converter, the start and stop of which are controlled by the control unit, and the adaptive filtering circuit is an adaptive filter based on the minimum mean square error algorithm, used to dynamically track and filter out specific frequency harmonic interference generated by the frequency converter.

[0012] Preferably, the control unit includes a data acquisition and control module, a leakage current calculation module, a trend analysis module, an early warning judgment module, and a self-diagnosis module. The data acquisition and control module is used to control the sampling timing of the signal acquisition unit; the leakage current calculation module is used to calculate the leakage current voltage value based on the leakage current signal and estimate the insulation resistance value in combination with known system parameters; the trend analysis module is used to record the insulation resistance measurement value, establish a historical database, and perform trend analysis of insulation resistance changes to identify slow degradation processes and predict remaining lifespan; the early warning judgment module can set three-level early warning thresholds, determine the early warning level, and issue corresponding early warning signals; the self-diagnosis module is used to issue fault prompts when a device fault is detected.

[0013] Preferably, the trend analysis module has a built-in insulation degradation prediction model, which is used to predict the time when the insulation resistance drops to a dangerous threshold based on historical insulation resistance data and using linear regression or exponential smoothing algorithms.

[0014] Preferably, the communication unit includes a CAN bus interface that supports the J1939 protocol and is used to upload leakage status and warning information to the vehicle central controller or instrument panel.

[0015] Preferably, it also includes a power supply unit for providing operating power to the device, with an input voltage of DC12~36V.

[0016] Preferably, the device is encapsulated in a sealed metal housing with a protection rating of at least IP65, the bottom of which is mounted on a mounting bracket, and the mounting bracket is provided with rubber vibration damping pads.

[0017] In addition, the present invention also provides a method for online detection of generator insulation leakage based on the above-mentioned device, characterized by comprising the following steps: The alternating electric field signal of the generator leads or the surface of the chassis is sensed in real time in a non-contact manner using the capacitively coupled voltage sensor. The acquired signal is pre-amplified and adaptively filtered to eliminate electromagnetic interference; The processed analog signal is converted into a digital signal, and the leakage voltage value is calculated. The insulation resistance value is estimated by combining the generator phase voltage. Continuously record insulation resistance data, analyze its changing trends, compare it with preset multi-level thresholds, and issue corresponding level of early warning information; The detection results and early warning information are uploaded through the communication unit.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Achieve 24 / 7 real-time online monitoring: Adopting a non-contact capacitive coupling sensor, it does not require shutdown and does not damage the original insulation structure of the generator. It continuously monitors the insulation status 24 hours a day during vehicle operation, solving the problems of lag and safety risks associated with manual inspection. 2. Excellent adaptability to harsh environments: By selecting industrial-grade wide-temperature components (-40℃~+85℃), conformal coating on circuit boards, IP65 protection-rated housing, and rubber vibration damping installation, the device ensures long-term stable and reliable operation in mining environments with extreme cold, high temperature, high humidity, dust, and strong vibration. 3. High-precision anti-electromagnetic interference performance: The adaptive filtering algorithm dynamically filters out wideband harmonic interference generated by devices such as frequency converters. Combined with an amplifier circuit with high common-mode rejection ratio, the power frequency leakage signal is accurately extracted from complex electromagnetic noise, which significantly reduces the false alarm rate. 4. Intelligent Early Warning and Fault Location: Based on historical trend analysis of insulation resistance, a three-level early warning system is implemented, issuing alerts in the early stages of faults to avoid unplanned downtime. Simultaneously, through multi-sensor information fusion, it can distinguish between generator body leakage and leakage in the lead-out lines, providing clear guidance for rapid repair. 5. Compact structure and easy installation: The device is small in size and can be flexibly installed in the generator junction box or the narrow space of the engine compartment, adapting to the compact layout of mining trucks and solving the problem that existing fixed monitoring instruments are too large to be installed. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a block diagram of the overall structure of the device of the present invention; Figure 2 This is a schematic diagram of the installation of the capacitively coupled voltage sensor in this invention; Figure 3 This is a schematic diagram of the outer casing structure and installation position of the device of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figure 1-3As shown, the online insulation leakage detection device for heavy-duty mining truck generators of the present invention includes a signal acquisition unit, a signal processing unit, a control unit, a communication unit, and a power supply unit. Each functional unit is integrated onto the same circuit board assembly, which is embedded in a sealed metal housing. The signal acquisition unit includes at least one capacitively coupled voltage sensor, which includes electrodes and an insulating layer. This sensor is attached to the outer insulation layer of the generator leads or the outer wall of the generator chassis to sense the alternating electric field signal generated by leakage current through capacitive coupling. The signal processing unit, connected to the signal acquisition unit, includes a preamplifier circuit and an adaptive filter circuit to amplify the acquired leakage current signal and filter out electromagnetic interference. The control unit, connected to the signal processing unit, calculates leakage current parameters and estimates insulation resistance values ​​based on the processed leakage current signal, and performs trend analysis and early warning judgment on insulation resistance changes. The communication unit, connected to the control unit, uploads the detection results and early warning information to the vehicle monitoring system or a remote management platform.

[0025] In this embodiment, a capacitively coupled voltage sensor is used for non-contact acquisition of generator leakage current signals. The sensor senses the alternating electric field signal generated by the leakage current through capacitive coupling, and its sensitivity can detect electric field changes corresponding to leakage currents exceeding 1 mA. The capacitively coupled voltage sensor uses a 10*20mm sensor. 2 ~20*40mm 2 The copper foil electrodes are used. The capacitively coupled voltage sensor also has a shielding layer, which employs a double-layer shielding structure. The inner shielding layer is connected to the signal ground, and the outer shielding layer is connected to the device housing ground. The capacitively coupled voltage sensor is fixed by binding or adhesive without damaging the original insulation structure.

[0026] The signal acquisition unit also includes a zero-sequence current transformer and a temperature sensor. The zero-sequence current transformer uses a toroidal iron core with external secondary windings, has a range of 0-5A (leakage current), and an accuracy of ±1%. It is used to be installed on the three-phase leads or neutral grounding wire of the generator to detect the vector sum of the three-phase currents and determine whether there is leakage current. The control unit can determine whether the leakage current originates from the generator body or the leads based on the combination of detection signals from the capacitively coupled voltage sensor and the zero-sequence current transformer. The temperature sensor uses a PT100 resistance temperature detector (RTD) or a digital temperature sensor, installed inside or on the surface of the generator chassis to monitor the generator temperature. The control unit is connected to the temperature sensor to acquire generator temperature data and performs temperature compensation on the estimated insulation resistance based on this temperature data, in case the generator overheats.

[0027] In addition to conditioning the acquired leakage current signal, the signal processing unit also performs digital processing. The preamplifier circuit provides an adjustable amplification factor for the leakage current signal between 10 and 100 times, with an input impedance ≥10MΩ to minimize its impact on the tested circuit. Its common-mode rejection ratio (CMRR) is ≥80dB, effectively suppressing common-mode interference. The adaptive filter circuit uses a bandpass filter with a center frequency of 50Hz / 60Hz and a bandwidth of ±5Hz. Its built-in adaptive algorithm enables adaptive filtering based on minimum mean square error, dynamically tracking interference frequencies and filtering out harmonic interference generated by the inverter and motor (within a specific frequency range of 100Hz-10kHz). The signal processing unit performs digital processing through a digital-to-analog converter (DAC). The DAC has a resolution of 2-bit or 16-bit and a sampling rate ≥1kS / s, meeting the real-time acquisition requirements of the leakage current signal. The DAC's start and stop are controlled by a control unit.

[0028] The signal processing unit can also be equipped with an adaptive notch filter, which can dynamically track and filter out specific frequency harmonics (such as 2kHz-8kHz) generated by the frequency converter, making it suitable for the strong interference environment of electric drive mining trucks (such as electric wheel dump trucks).

[0029] The control unit is the core of the device's control system, employing an industrial-grade microcontroller. Specifically, it includes a data acquisition and control module, a leakage current calculation module, a trend analysis module, an early warning judgment module, a self-diagnosis module, and a fault location module. The data acquisition and control module controls the sampling timing of the signal acquisition unit and manages the start and stop of the analog-to-digital converter. The leakage current calculation module calculates the leakage voltage value based on the leakage signal and estimates the insulation resistance value by combining known system parameters (generator voltage level, line distributed capacitance, etc.). The calculation formula is as follows: R_ins = V_leak / I_leak (based on the equivalent circuit model).

[0030] The trend analysis module records insulation resistance measurements, establishes a historical database, and analyzes the changing trends of insulation resistance. It identifies slow degradation processes and predicts remaining lifespan. Its built-in insulation degradation prediction model, based on historical insulation resistance data, uses linear regression or exponential smoothing algorithms to predict when the insulation resistance will drop to a dangerous threshold, providing a basis for planned maintenance. The early warning judgment module can set three levels of early warning thresholds, determine the warning level, and issue corresponding warning signals. The self-diagnosis module periodically checks the operating status of sensors and circuits, issuing fault prompts when a device malfunction is detected. The fault location module has a fault location function, capable of determining whether leakage originates from the generator itself or the lead-out lines by comparing signals from different measuring points.

[0031] The three-level warning thresholds include attention thresholds, alarm thresholds, and danger thresholds: 1) Warning value: A yellow warning is issued when the insulation resistance drops by 20%, alerting equipment management personnel to pay attention; 2) Alarm value: When the insulation resistance drops by 50%, an orange alarm will be issued, and it is recommended to arrange maintenance in the near future; 3) Dangerous value: When the insulation resistance is lower than the safety threshold (e.g., 1MΩ), a red alarm will be issued and it is recommended to stop the machine immediately for inspection.

[0032] The communication unit is used to upload detection data to the vehicle monitoring system or remote management platform. It includes a CAN bus interface, supports the J1939 protocol, and uploads leakage status and warning information to the vehicle's central controller or instrument panel. The uploaded data mainly includes leakage voltage, estimated insulation resistance, warning level, and sensor status, displayed as icons, numerical values, or alarm lights. The device is equipped with a self-test button (or can perform a remote self-test via the CAN bus), which can periodically trigger simulated leakage signals to verify the normal functioning of the detection device.

[0033] In addition, the communication unit is equipped with an RS485 / Modbus interface as a backup interface and a wireless communication module. The backup interface is used to connect portable debugging equipment or an external display screen. The wireless communication module adopts 4G / 5G DTU or Bluetooth to upload data to the mine intelligent management platform to realize remote monitoring, generate historical trend curves, and facilitate analysis and decision-making by equipment management personnel.

[0034] The power supply unit provides operating power to the device. It adopts a wide-voltage input power module with an input voltage of DC 12~36V, which can adapt to the power fluctuations of the mining truck. The output voltage is DC 5V and 3.3V, and it has overvoltage protection, overcurrent protection, and reverse connection protection functions. In addition, a backup battery is also configured. The backup battery uses lithium batteries or supercapacitors to maintain the operation of the device when the vehicle loses power and record the state before the power failure.

[0035] The wiring relationships of the functional units in this device are as follows: A capacitively coupled voltage sensor is mounted on the outer insulation layer of the generator leads or on the outer wall of the generator chassis. Its output is connected to the preamplifier circuit of the signal processing unit via a shielded cable. A zero-sequence current transformer is fitted onto the three-phase leads or neutral grounding wire of the generator, and its secondary winding is connected to the signal processing unit. A temperature sensor is installed inside or on the surface of the generator chassis, and its output is connected to the temperature acquisition port of the control unit. The signal processing unit is connected to the control unit via an SPI or I2C bus to transmit the digitized leakage current signal to the control unit. The control unit is connected to the vehicle's CAN network via a CAN bus interface to send the detection results to the vehicle's instrument panel. The input of the power supply unit is connected to the output of the vehicle's battery or generator, and its output supplies power to each unit of the device.

[0036] In this embodiment, all circuit units of the device are encapsulated within a sealed metal housing with a protection rating of at least IP65. The housing is constructed from cast aluminum alloy with sealing rings, and also serves a heat dissipation function. The bottom of the sealed metal housing is mounted on a mounting bracket, which is equipped with rubber vibration damping pads to isolate vehicle vibrations. The mounting bracket is installed in a suitable location within the generator compartment. The sealed metal housing is detachable and has external interfaces including a CAN interface, a power interface, and sensor interfaces.

[0037] In addition, the present invention also provides a method for online detection of generator insulation leakage based on the above-mentioned device, characterized by comprising the following steps: Step 1: Signal Acquisition: The alternating electric field signal of the generator leads or chassis surface is sensed in real time in a non-contact manner through a capacitively coupled voltage sensor, the three-phase current vector sum (leakage current) is detected by a zero-sequence current transformer, and the generator temperature is monitored by a temperature sensor. Step 2: Signal Conditioning and Digitization: The weak leakage current signal is pre-amplified by the pre-amplifier circuit, the electromagnetic interference generated by the frequency converter and motor is filtered out by the adaptive filter, and the analog signal is converted into a digital signal by the analog-to-digital converter. Step 3: Leakage Parameter Calculation: Convert the processed analog signal into a digital signal and calculate the leakage voltage value. Combine this with the generator phase voltage to estimate the insulation resistance value. The calculation time is as follows: Leakage voltage calculation: V_leak = K × V_sensor (K is the sensor calibration coefficient); Leakage current calculation: I_leak = K_I × I_CT (directly measured through zero-sequence current transformer); Insulation resistance estimation: R_ins = V_ph / I_leak (V_ph is the generator phase voltage, which can be obtained through the vehicle CAN bus); The insulation resistance measurement value is compensated and corrected based on the generator temperature. Step 4: Trend Analysis and Early Warning Judgment: Continuously record insulation resistance data, analyze its changing trends, compare the current measured value with the historical database, calculate the rate of decrease in insulation resistance, and compare it with the preset three-level threshold to issue corresponding level of early warning information, specifically: Measured value > warning value: Normal condition; Note that if the measured value is greater than or equal to the alarm value, a yellow warning will be issued (early stage of insulation deterioration). Alarm value ≥ Measured value > Danger value: Orange alarm (recommend immediate maintenance); Measured value ≤ Dangerous value: Red alarm (immediate shutdown recommended); In addition, for fault location, if the zero-sequence current transformer measures leakage current but the capacitance sensor does not detect leakage in the chassis, it can be determined that the leakage is in the line rather than in the generator itself.

[0038] Step 5: Data Upload and Display: The detection results and early warning information are uploaded through the communication unit. Specifically, the detection results are sent to the vehicle's instrument panel via the CAN bus and displayed as icons, values, or alarm lights. The data is also uploaded to the mine's intelligent management platform via the wireless communication module to form historical trend curves, which facilitates analysis and decision-making by equipment management personnel.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An online detection device for insulation leakage current of a heavy-duty mining truck generator, characterized in that, include: The signal acquisition unit includes at least one capacitively coupled voltage sensor, which includes electrodes and an insulating layer for attaching to the surface of the outer insulating layer of the generator lead wire or the outer wall of the generator chassis to sense the alternating electric field signal generated by leakage current through the capacitive coupling principle. A signal processing unit, connected to the signal acquisition unit, includes a preamplifier circuit and an adaptive filter circuit, used to amplify the acquired leakage current signal and filter out electromagnetic interference. The control unit, connected to the signal processing unit, is used to calculate leakage parameters and estimate insulation resistance values ​​based on the processed leakage signal, and to perform insulation resistance change trend analysis and early warning judgment. A communication unit, connected to the control unit, is used to upload detection results and early warning information to the vehicle monitoring system or remote management platform.

2. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 1, characterized in that, The capacitively coupled voltage sensor also includes a shielding layer, which adopts a double-layer shielding structure, wherein the inner shielding layer is connected to the signal ground and the outer shielding layer is connected to the device housing ground.

3. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 1, characterized in that, The signal acquisition unit also includes a zero-sequence current transformer and a temperature sensor, which are used to be installed on the three-phase leads or neutral grounding wire of the generator to detect leakage current. The control unit can determine whether the leakage current originates from the generator body or the lead line based on the combination of the detection signals from the capacitively coupled voltage sensor and the zero-sequence current transformer. The control unit is connected to the temperature sensor to acquire generator temperature data and perform temperature compensation on the estimated value of insulation resistance based on the temperature data.

4. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 1, characterized in that, The signal processing unit also includes a digital-to-analog converter, the start and stop of which are controlled by the control unit. The adaptive filtering circuit is an adaptive filter based on the minimum mean square error algorithm, used to dynamically track and filter out specific frequency harmonic interference generated by the frequency converter.

5. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 1, characterized in that, The control unit includes a data acquisition and control module, a leakage current calculation module, a trend analysis module, an early warning judgment module, and a self-diagnosis module. The data acquisition and control module is used to control the sampling timing of the signal acquisition unit; the leakage current calculation module is used to calculate the leakage current voltage value based on the leakage current signal and estimate the insulation resistance value in combination with known system parameters. The trend analysis module is used to record insulation resistance measurements, establish a historical database, and perform insulation resistance change trend analysis to identify slow degradation processes and predict remaining lifespan. The early warning judgment module can set three-level early warning thresholds, determine the early warning level, and issue corresponding early warning signals. The self-diagnosis module is used to issue fault prompts when a device fault is detected.

6. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 5, characterized in that, The trend analysis module has a built-in insulation degradation prediction model, which is used to predict the time when the insulation resistance drops to a dangerous threshold based on historical insulation resistance data and using linear regression or exponential smoothing algorithms.

7. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 1, characterized in that, The communication unit includes a CAN bus interface that supports the J1939 protocol and is used to upload leakage status and warning information to the vehicle central controller or instrument panel.

8. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 1, characterized in that, It also includes a power supply unit to provide operating power to the device, with an input voltage of DC12~36V.

9. The online detection device for insulation leakage current of heavy-duty mining truck generators according to claim 1, characterized in that, The device is encapsulated in a sealed metal housing with a protection rating of at least IP65. The bottom of the sealed metal housing is mounted on a mounting bracket, which is provided with rubber vibration damping pads.

10. A method for online detection of generator insulation leakage current based on the device according to any one of claims 1 to 9, characterized in that, Includes the following steps: The alternating electric field signal of the generator leads or the surface of the chassis is sensed in real time in a non-contact manner using the capacitively coupled voltage sensor. The acquired signal is pre-amplified and adaptively filtered to eliminate electromagnetic interference; The processed analog signal is converted into a digital signal, and the leakage voltage value is calculated. The insulation resistance value is estimated by combining the generator phase voltage. Continuously record insulation resistance data, analyze its changing trends, compare it with preset multi-level thresholds, and issue corresponding level of early warning information; The detection results and early warning information are uploaded through the communication unit.

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