A high voltage cable earth return fault simulation device

Abstract

The application discloses a high-voltage cable grounding loop fault simulation device, comprising a device main body, wherein a standard cross-connection grounding loop module, a fault simulation module, a signal coupling injection module, a parameter acquisition module, a data analysis module and a man-machine interaction and control module are integrated on the device main body. Through the innovative design of high integration, precise adjustment and intelligent analysis, the application realizes the closed loop of 'high-fidelity reproduction' and 'automatic detection' of the high-voltage cable grounding loop fault in the laboratory environment, and significantly improves the authenticity of fault simulation, the automation degree of testing and the accuracy of diagnosis.

Description

Technical Field

[0001] This invention relates to the field of high-voltage cable testing technology, and specifically to a high-voltage cable grounding circuit fault simulation device. Background Technology

[0002] High-voltage cables, especially 110kV and above transmission cables, typically employ cross-interconnection grounding for their metallic sheaths (such as aluminum or copper sheaths). This method effectively reduces induced voltage and circulating current in the sheath, and is a key technology for ensuring the safe and economical operation of cables. However, due to complex site environments, construction processes, material aging, and external damage, various faults may occur in the cable grounding circuit.

[0003] For example, poor contact due to corrosion or loosening of connection points in grounding boxes and interconnection boxes can increase contact resistance; damage to cable sheath insulation or water ingress can lead to multi-point grounding of the sheath, forming a grounding loop and causing overheating; and a broken grounding wire or connecting conductor can break the grounding path. If these faults are not detected and addressed in time, they may cause serious accidents such as damage to the main cable insulation, localized overheating, or even fire. Therefore, developing efficient and accurate grounding loop fault detection and location technologies is crucial for the safe operation and maintenance of power systems.

[0004] Existing simulation methods are too simplistic and have certain technical limitations:

[0005] First, existing laboratory simulations use fixed resistors to simulate grounding faults, which cannot reproduce the complex three-phase cross-interconnected grounding network structure on site, nor can they accurately simulate the continuous changes in fault resistance, inductance, and ground admittance, as well as their distribution characteristics in long cable loops. This results in the detection algorithms or equipment developed performing well in laboratory tests, but their performance degrades on site due to environmental differences.

[0006] Second, existing simulation methods may only be able to simulate a single type of fault (such as simulating only an increase in resistance), and the adjustment accuracy is low and the range is narrow. When simulating different types of faults or combinations of faults, it is necessary to manually change the wiring, which is a complicated and inefficient process and makes it difficult to achieve automated test sequences. Summary of the Invention

[0007] To address this issue, the present invention provides a high-voltage cable grounding circuit fault simulation device to solve the problem that the prior art cannot accurately simulate the continuous changes in fault resistance, inductance, and ground admittance, as well as their distribution characteristics in long cable circuits.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A high-voltage cable grounding circuit fault simulation device includes a main body, on which a standard cross-interconnected grounding circuit module, a fault simulation module, a signal coupling injection module, a parameter acquisition module, a data analysis module, and a human-machine interaction and control module are integrated.

[0010] The standard cross-connection grounding loop module is used to construct a three-section cross-connection grounding electrical structure consistent with the 110kV and above high-voltage cables on site;

[0011] The fault simulation module is connected in series or in parallel with the standard cross-interconnected grounding loop module to output adjustable fault resistance, fault inductance, and fault admittance, thereby simulating poor contact, multi-point grounding, wire breakage, insulation damage, and sheath corrosion.

[0012] The signal coupling injection module is used to inject heterogeneous AC signals, wideband sweep signals, power frequency superposition signals into the grounding circuit and to provide excitation sources for fault detection.

[0013] The parameter acquisition module is used to synchronously acquire circuit voltage, current, impedance, harmonics, and phase parameters;

[0014] The data analysis module is used to perform decoupled calculations, broadband impedance spectrum plotting, and fault feature extraction on the parameters acquired by the parameter acquisition module.

[0015] The human-computer interaction and control module is used to set fault parameters, signal parameters, and acquisition modes, and to output fault simulation reports and detection verification results.

[0016] Furthermore, the standard cross-interconnection grounding loop module includes a three-phase standard sheath simulated conductor, two sets of cross-interconnection connection units, a direct grounding unit, and a protective grounding unit;

[0017] The three-phase standard sheath simulation conductor is used to proportionally reproduce the resistance, inductance, capacitance to ground and electromagnetic coupling characteristics of the high-voltage cable metal sheath, provide a fault-free reference path, and undertake the basic functions of fault access, signal coupling and parameter measurement.

[0018] The cross-connection unit is used to construct a three-phase cross-connection topology consistent with the field, connecting the three simulated conductors into a complete closed-loop grounding loop that conforms to the field topology, and providing a clear access endpoint for segmented fault location;

[0019] The direct grounding unit is used to form the main grounding discharge path of the sheath, provide a zero potential reference, form a complete current loop for signal injection and acquisition, and at the same time ensure the normal operation of the loop and the safety grounding requirements during the test process.

[0020] The protective grounding unit is used to simulate the field protective grounding or current-limiting grounding structure, serving as an auxiliary grounding interface for the circuit, limiting grounding circulation current, monitoring the insulation status of the sheath, and linking with the device protection logic to improve test safety.

[0021] Furthermore, the fault simulation module includes a precision adjustable resistor unit, a precision adjustable inductor unit, an adjustable leakage admittance unit, a fault switching switch array, and a fault location interface.

[0022] The precision adjustable resistor unit is used to simulate faults such as poor contact, corrosion, and loose joints, and outputs a continuously adjustable contact resistance to quantitatively characterize the degree of circuit continuity defects.

[0023] The precision adjustable inductor unit is used to simulate faults such as local deformation of the sheath, abnormal magnetic circuit, and changes in the equivalent inductance of the connection structure, and to restore the deviation of the loop inductance parameters caused by the fault.

[0024] The adjustable leakage admittance unit is used to simulate sheath insulation damage, water ingress and moisture, and multi-point grounding faults, providing a controllable leakage path to ground and reproducing abnormal leakage current characteristics.

[0025] The fault switching array is used to quickly switch between different fault types, supports one-click switching between normal and fault conditions, and meets the needs of automated simulation of multiple faults and combined faults.

[0026] The fault location interface is used to access a specified segment of the standard cross-connected grounding loop module to simulate fault location in the first, middle, and last segments.

[0027] Furthermore, the resolution of the precision adjustable resistor unit is better than 0.1mΩ, and the adjustment range is 0.1mΩ-100Ω.

[0028] Furthermore, the signal coupling injection module includes a different frequency signal source, a wideband sweep frequency source, a coupling injection coil, an auxiliary measurement coil, and a signal power amplification unit;

[0029] The heterogeneous frequency signal source is used to output a stable AC excitation signal that is not in the power frequency range, avoiding power frequency interference on site and providing a high signal-to-noise ratio injection signal for circuit fault detection;

[0030] The wideband sweep frequency source is used to output a continuous wideband sweep frequency signal to construct a wideband impedance spectrum of the circuit, thereby realizing fault location and circuit characteristic analysis.

[0031] The coupling injection coil is used to inject the excitation signal into the grounding circuit in a non-contact electromagnetic coupling manner without damaging the original wiring structure.

[0032] The auxiliary measurement coil is used to synchronously acquire the induced electromotive force signal and calculate the actual injected signal strength, providing a benchmark for parameter calculation and calibration.

[0033] The signal power amplification unit is used to amplify and drive the excitation signal to ensure that the signal injection depth and amplitude meet the requirements of long loop simulation.

[0034] Furthermore, the parameter acquisition module includes a high-precision voltage transformer, a high-precision current transformer, a signal conditioning unit, and a high-speed ADC acquisition unit;

[0035] The high-precision voltage transformer is used to isolate, collect, and accurately measure the voltage at each node of the circuit, providing voltage reference data for impedance calculation and fault analysis.

[0036] The high-precision current transformer is used to perform non-contact and precise acquisition of the three-phase current and grounding current of the circuit, and to obtain fault characteristic current and response signal.

[0037] The signal conditioning unit is used to filter, amplify, boost, and reduce noise in the acquired voltage and current signals to improve signal quality and signal-to-noise ratio.

[0038] The ADC acquisition unit is used to convert analog signals into digital signals at high speed, realize synchronous waveform sampling, and provide digital data support for subsequent decoupling calculations, impedance analysis, and fault identification.

[0039] Furthermore, the data analysis module includes a decoupling calculation unit and a broadband impedance spectrum analysis unit;

[0040] The decoupling calculation unit is used to perform mathematical processing on the collected three-phase voltage and current data. Based on the symmetrical component method and the impedance matrix inversion algorithm, it removes the comprehensive interference of electromagnetic induction coupling, sheath-ground capacitance coupling and cross-interconnection topology coupling between the three-phase conductors, thereby calculating the independent impedance, resistance, inductance and ground admittance parameters of each phase.

[0041] The broadband impedance spectrum analysis unit is used to convert frequency domain impedance data into spatial domain impedance curves, identify fault types and fault locations through waveform abrupt change points, and complete automatic fault location and feature extraction.

[0042] Furthermore, the human-computer interaction and control module includes a touch screen display, a fault parameter configuration unit, a signal control unit, a data storage unit, and a result output unit;

[0043] The touch screen is used to provide a visual operating interface to display parameters, monitor status, and input manual commands;

[0044] The fault parameter configuration unit is used to set simulation parameters such as fault type, fault value, and fault location to complete the precise configuration of fault conditions.

[0045] The signal control unit is used to adjust the output frequency, amplitude, power and operating mode of the signal source to ensure that the excitation signal is stable and controllable;

[0046] The data storage unit is used to store and record test data, waveform curves, calculation results, and configuration parameters, and supports historical data traceability and comparative analysis.

[0047] The result output unit is used to output detection reports, fault location results, and parameter calculation values, and to realize data export, display, and printing output.

[0048] Furthermore, it also includes a safety protection module, which includes overcurrent protection, overvoltage protection, overheat protection, and ground fault protection, and automatically cuts off signal output and fault circuit under abnormal conditions.

[0049] The present invention has the following advantages:

[0050] 1. A three-section cross-connection grounding electrical structure, completely identical to that used in 110kV and above high-voltage cables in the field, was constructed in the laboratory. This included three-phase sheathed simulated conductors, cross-connection units, direct grounding units, and protective grounding units. This provided a fault-free reference path highly consistent with the field, ensuring the authenticity and comparability of the simulated environment.

[0051] 2. The signal coupling injection module uses heterogeneous frequency signals to avoid power frequency interference and combines them with wideband sweep signals to provide a high-quality excitation source for fault detection. The parameter acquisition module achieves high-precision synchronous acquisition of multiple parameters such as circuit voltage, current, and impedance through high-precision current transformers and high-speed synchronous ADCs, providing a reliable data foundation for analysis. The data analysis module eliminates electromagnetic cross-coupling interference between the three-phase circuits through the decoupling calculation unit, separating out pure circuit parameters. Through the wideband impedance spectrum analysis unit, the frequency domain data is converted into spatial domain impedance curves, and the fault type is automatically identified and the fault point is accurately located based on the waveform abrupt change points, greatly improving the intelligence and accuracy of diagnosis.

[0052] 3. The human-computer interaction and control module provides a visual touch interface, allowing users to easily set fault parameters, signal parameters, and acquisition modes, achieving "one-click" test process control and greatly improving test efficiency. It integrates data storage and result output functions, automatically saving all test data, waveforms, and configuration parameters, and generating structured test reports. It supports historical data traceability and comparative analysis, providing a systematic data support platform for algorithm research, equipment calibration, and personnel training.

[0053] 4. By integrating fault simulation, signal excitation, data acquisition, intelligent analysis, and human-computer interaction into a single device, the entire process from fault setting to result output is integrated, reducing reliance on external devices and wiring complexity. The independent safety protection module has multiple protections against overcurrent, overvoltage, overheating, and grounding faults. In case of abnormality, it automatically cuts off the signal output and fault circuit, effectively preventing equipment damage and safety accidents, and ensuring the safe conduct of high-risk simulation experiments in the laboratory.

[0054] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0055] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0056] Figure 1 This is a schematic diagram of the structure of a high-voltage cable grounding circuit fault simulation device according to the present invention.

[0057] Figure 2 This is a system block diagram of a high-voltage cable grounding circuit fault simulation device according to the present invention.

[0058] Figure 3 This is a system block diagram of the standard cross-connection grounding loop module of the present invention.

[0059] Figure 4 This is a system block diagram of the fault simulation module of the present invention.

[0060] Figure 5 This is a system block diagram of the signal coupling injection module of the present invention.

[0061] Figure 6 This is a system block diagram of the parameter acquisition module of the present invention.

[0062] Figure 7 This is a system block diagram of the human-computer interaction and control module.

[0063] In the diagram: 10. Main body of the equipment;

[0064] 101. Standard cross-connection grounding loop module; 1011. Three-phase standard sheath simulated conductor; 1012. Cross-connection unit; 1013. Direct grounding unit; 1014. Protective grounding unit;

[0065] 102. Fault simulation module; 1021. Precision adjustable resistor unit; 1022. Precision adjustable inductor unit; 1023. Adjustable leakage admittance unit; 1024. Fault switching switch array; 1025. Fault location interface;

[0066] 103. Signal coupling injection module; 1031. Different frequency signal source; 1032. Wideband sweep frequency source; 1033. Coupling injection coil; 1034. Auxiliary measurement coil; 1035. Signal power amplification unit;

[0067] 104. Parameter acquisition module; 1041. High-precision voltage transformer; 1042. High-precision current transformer; 1043. Signal conditioning unit; 1044. High-speed ADC acquisition unit;

[0068] 105. Data Analysis Module; 1051. Decoupling Calculation Unit; 1052. Broadband Impedance Spectrum Analysis Unit;

[0069] 106. Human-computer interaction and control module; 1061. Touch screen display; 1062. Fault parameter configuration unit; 1063. Signal control unit; 1064. Data storage unit; 1065. Result output unit;

[0070] 107. Safety protection module. Detailed Implementation

[0071] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these embodiments are merely for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Technical engineers in the field can make some non-essential improvements and adjustments to the present invention based on the above-described content. 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.

[0072] Please see Figure 1-7 A high-voltage cable grounding circuit fault simulation device includes a main body 10, on which a standard cross-interconnected grounding circuit module 101, a fault simulation module 102, a signal coupling injection module 103, a parameter acquisition module 104, a data analysis module 105, and a human-machine interaction and control module 106 are integrated.

[0073] The standard cross-connection grounding loop module 101 is used to construct a three-section cross-connection grounding electrical structure consistent with that of 110kV and above high-voltage cables in the field;

[0074] The fault simulation module 102 is connected in series or in parallel with the standard cross-interconnected grounding loop module 101 to output adjustable fault resistance, fault inductance and fault admittance, so as to realize the simulation of poor contact, multi-point grounding, wire breakage, insulation damage and sheath corrosion.

[0075] The signal coupling injection module 103 is used to inject heterogeneous AC signals, wideband sweep signals, power frequency superposition signals into the grounding circuit and to provide excitation sources for fault detection.

[0076] The parameter acquisition module 104 is used to synchronously acquire circuit voltage, current, impedance, harmonics, and phase parameters;

[0077] The data analysis module 105 is used to perform decoupled calculations, broadband impedance spectrum plotting, and fault feature extraction on the parameters acquired by the parameter acquisition module 104.

[0078] The human-machine interaction and control module 106 is used to set fault parameters, signal parameters, and acquisition modes, and to output fault simulation reports and detection verification results.

[0079] In this embodiment, during operation, firstly, the standard cross-interconnected grounding loop module 101 establishes a fault-free three-section cross-interconnected grounding electrical structure that is completely consistent with the field 110kV and above high-voltage cables as a reference. Next, the user sets the required fault type, value, and location through the human-machine interaction and control module 106. According to the settings, the fault simulation module 102 connects adjustable resistors, inductors, or admittances at designated locations in the grounding loop to accurately simulate various fault states such as poor contact and insulation damage. Subsequently, the signal coupling injection module 103 injects heterogeneous, broadband, or power frequency superimposed signals into the fault-set loop as excitation. The parameter acquisition module 104 synchronously and with high precision acquires the loop's voltage, current, and other response parameters under excitation. Finally, the data analysis module 105 processes the acquired data, eliminates mutual interference through decoupling calculations, plots a broadband impedance spectrum, extracts fault characteristics, locates the fault point, and ultimately generates a detection report.

[0080] This device integrates the accurate laboratory reproduction and testing verification of high-voltage cable grounding circuit faults. It solves the problem that traditional methods cannot equivalently reproduce complex field grounding circuits and their faults in a laboratory environment. It provides a safe, controllable, and repeatable high-fidelity experimental platform for the development of fault diagnosis algorithms, the calibration of testing equipment, and the technical training of maintenance personnel. Through integrated design, it integrates fault simulation, signal excitation, data acquisition, and intelligent analysis functions, significantly improving R&D and testing efficiency.

[0081] In a further preferred embodiment of the present invention, the standard cross-interconnected grounding loop module 101 includes a three-phase standard sheath simulation conductor 1011, two sets of cross-interconnection connection units 1012, a direct grounding unit 1013, and a protective grounding unit 1014;

[0082] The three-phase standard sheath simulation conductor 1011 is used to proportionally reproduce the resistance, inductance, capacitance to ground and electromagnetic coupling characteristics of the metal sheath of high-voltage cables, provide a fault-free reference path, and undertake the basic functions of fault access, signal coupling and parameter measurement.

[0083] The cross-connection unit 1012 is used to construct a three-phase cross-connection topology consistent with the field, connecting the three simulated conductors into a complete, closed-loop grounding loop that conforms to the field topology, and providing a clear access endpoint for segmented fault location.

[0084] The direct grounding unit 1013 is used to form the main grounding discharge path of the sheath, provide a zero potential reference, form a complete current loop for signal injection and acquisition, and at the same time ensure the normal operation of the loop and the safety grounding requirements during the test process.

[0085] The protective grounding unit 1014 is used to simulate the field protective grounding or current-limiting grounding structure, serving as an auxiliary grounding interface for the circuit, limiting grounding circulation current, monitoring the insulation status of the sheath, and linking with the device protection logic to improve test safety.

[0086] In this embodiment, the three-phase standard sheath simulated conductor 1011 accurately simulates the resistance, inductance, capacitance to ground, and electromagnetic coupling characteristics of the actual cable's metal sheath, forming an equivalent electrical path. Two sets of cross-interconnection units 1012 connect the three simulated conductors into a complete closed-loop circuit according to the actual cross-interconnection method used on-site, providing clear electrical segmentation points. The direct grounding unit 1013 establishes the main grounding path, providing a zero-potential reference point for the entire circuit and ensuring a complete current loop during signal injection, while also meeting safety grounding requirements. The protective grounding unit 1014 simulates the auxiliary grounding or low-resistance grounding method used on-site to limit possible circulating currents and is linked with the internal protection logic of the device to continuously monitor the circuit insulation status.

[0087] This module establishes a standard circuit in the laboratory that closely matches the electrical characteristics of the field, providing a reliable, fault-free (initial) reference environment for subsequent fault simulation and parameter measurement. Its accurate proportional reproduction ensures the authenticity and comparability of fault simulation and test results. The clearly defined segmented design provides a physical basis for subsequent precise fault location at the "first, middle, and last stages." The dual grounding (direct grounding and protective grounding) structure not only replicates the field grounding method but also greatly enhances the safety of the entire device testing process.

[0088] In a further preferred embodiment of the present invention, the fault simulation module 102 includes a precision adjustable resistor unit 1021, a precision adjustable inductor unit 1022, an adjustable leakage admittance unit 1023, a fault switching switch array 1024, and a fault location positioning interface 1025.

[0089] The precision adjustable resistor unit 1021 has a resolution better than 0.1mΩ and is used to simulate faults such as poor contact, corrosion, and loose joints. It outputs a continuously adjustable contact resistance to quantitatively characterize the degree of circuit continuity defects.

[0090] The precision adjustable inductor unit 1022 is used to simulate faults such as local deformation of the sheath, abnormal magnetic circuit, and changes in the equivalent inductance of the connection structure, and to restore the deviation of the loop inductance parameters caused by the fault.

[0091] The adjustable leakage admittance unit 1023 is used to simulate sheath insulation damage, water ingress and moisture, and multi-point grounding faults, providing a controllable leakage path to ground and reproducing abnormal leakage current characteristics.

[0092] The fault switching switch array 1024 is used for rapid switching between different fault types, supports one-click switching between normal and fault conditions, and meets the automated simulation needs of multiple faults and combined faults.

[0093] The fault location interface 1025 is used to connect to a specified segment of the standard cross-interconnected grounding loop module 101 to realize the simulation of fault location in the first segment, middle segment, and last segment.

[0094] In this embodiment, the precision adjustable resistor unit 1021 provides a high-resolution continuously adjustable resistor ranging from 0.1mΩ to 100Ω to accurately simulate changes in contact resistance caused by corrosion and loosening. The precision adjustable inductor unit 1022 simulates abnormal loop inductance parameters caused by cable sheath deformation by changing the inductance value. The adjustable leakage admittance unit 1023 simulates leakage current faults caused by insulation damage and moisture by providing a controllable leakage path to ground. The fault switching switch array 1024 can quickly and automatically switch between different fault units or combinations. The fault location interface 1025 physically connects the aforementioned fault units to designated segment points (such as the connection points of the first, middle, or last segment) of the standard loop module 101.

[0095] This module enables quantitative and programmable simulation of typical faults in high-voltage cable grounding systems. Its high resolution (better than 0.1mΩ) and wide range of adjustable resistance can precisely characterize various conduction defects ranging from slight contact to complete open circuit. Adjustable inductance and admittance functions cover the simulation of faults involving both inductance and insulation to ground. Through the switch array and positioning interface, users can flexibly and quickly configure single faults, compound faults, and their precise locations, greatly meeting the automation needs of various testing scenarios and providing a key means for studying the characteristic patterns of different faults.

[0096] In a further preferred embodiment of the present invention, the signal coupling injection module 103 includes a different frequency signal source 1031, a wideband sweep frequency source 1032, a coupling injection coil 1033, an auxiliary measurement coil 1034, and a signal power amplification unit 1035;

[0097] The heterogeneous frequency signal source 1031 is used to output a stable AC excitation signal that is not in the power frequency range, avoiding power frequency interference on site and providing a high signal-to-noise ratio injection signal for circuit fault detection;

[0098] The wideband sweep frequency source 1032 is used to output a continuous wideband sweep frequency signal to construct a wideband impedance spectrum of the circuit, thereby realizing fault location and circuit characteristic analysis.

[0099] The coupling injection coil 1033 is used to inject the excitation signal into the grounding circuit in a non-contact electromagnetic coupling manner without damaging the original wiring structure.

[0100] The auxiliary measurement coil 1034 is used to synchronously acquire the induced electromotive force signal and calculate the actual injected signal intensity, providing a reference for parameter calculation and calibration.

[0101] The signal power amplification unit 1035 is used to amplify and drive the excitation signal to ensure that the signal injection depth and amplitude meet the requirements of long loop simulation.

[0102] In this embodiment, a different frequency signal source 1031 generates a stable sinusoidal signal with a frequency different from the 50 / 60Hz power frequency to avoid strong on-site power frequency electromagnetic interference. A wideband sweep source 1032 generates a signal with continuously varying frequency to excite the circuit's response at different frequencies. A signal power amplification unit 1035 amplifies the signal generated by the above signal sources to ensure sufficient energy is injected into the long circuit. A coupling injection coil 1033 couples the amplified excitation signal to the grounding circuit conductor in a non-contact manner through the principle of electromagnetic induction, without damaging the conductor structure. An auxiliary measurement coil 1034 synchronously monitors the induced signal to calibrate the actual signal strength injected into the circuit.

[0103] This module effectively avoids power frequency interference by using heterogeneous frequency signals, significantly improving the signal-to-noise ratio of the detection signal. Wideband sweep excitation provides a data foundation for subsequent plotting of wideband impedance spectra reflecting the frequency characteristics of the circuit. The non-contact electromagnetic coupling injection method avoids physical cutting or wiring changes to the standard circuit, maintains the integrity of the circuit structure, simplifies operation, and improves reliability. Power amplification ensures that the signal has sufficient transmission depth and detection amplitude in the simulated long-distance cable circuit.

[0104] In a further preferred embodiment of the present invention, the parameter acquisition module 104 includes a high-precision voltage transformer 1041, a high-precision current transformer 1042, a signal conditioning unit 1043, and a high-speed ADC acquisition unit 1044.

[0105] The high-precision voltage transformer 1041 is used for isolated acquisition and accurate measurement of voltage at each node of the circuit, providing voltage reference data for impedance calculation and fault analysis;

[0106] The high-precision current transformer 1042 is used for non-contact and accurate acquisition of three-phase current and grounding current in a circuit, and to obtain fault characteristic current and response signal.

[0107] The signal conditioning unit 1043 is used to filter, amplify, boost, and reduce noise in the acquired voltage and current signals to improve signal quality and signal-to-noise ratio.

[0108] The ADC acquisition unit 1044 is used to convert analog signals into digital signals at high speed, realize synchronous waveform sampling, and provide digital data support for subsequent decoupling calculations, impedance analysis, and fault identification.

[0109] In this embodiment, high-precision voltage transformer 1041 and high-precision current transformer 1042 perform isolated measurements of the voltage and conductor current at key nodes of the circuit in a non-contact manner, acquiring raw voltage and current waveform data. Signal conditioning unit 1043 filters these raw signals to remove high-frequency noise, amplifies them to match the acquisition range, and performs voltage boosting and noise reduction. The processed high-quality analog signal is sent to high-speed ADC acquisition unit 1044 for synchronous, high-speed analog-to-digital conversion to obtain an accurate digital waveform sequence.

[0110] This module enables high-precision, synchronous, and wide-bandwidth acquisition of loop response signals. High-precision current transformers ensure the accuracy of the measurement reference, signal conditioning significantly improves the quality and signal-to-noise ratio of the useful signal, and the high-speed synchronous ADC provides complete, high-fidelity digital waveform data for subsequent analysis, forming the data foundation for accurate impedance calculation, harmonic analysis, and phase analysis.

[0111] In a further preferred embodiment of the present invention, the data analysis module 105 includes a decoupling calculation unit 1051 and a broadband impedance spectrum analysis unit 1052;

[0112] The decoupling calculation unit 1051 is used to perform mathematical processing on the collected three-phase voltage and current data. Based on the symmetrical component method and impedance matrix inversion algorithm, it removes the comprehensive interference of electromagnetic induction coupling, sheath-ground capacitance coupling and cross-interconnection topology coupling between the three-phase conductors. Using the impedance matrix inversion and symmetrical component method algorithm, it calculates the independent impedance, resistance, inductance and ground admittance parameters of each phase.

[0113] The broadband impedance spectrum analysis unit 1052 is used to convert frequency domain impedance data into spatial domain impedance curves, identify fault types and fault locations through waveform abrupt change points, and complete automatic fault location and feature extraction.

[0114] Specifically, the circuit frequency domain impedance is obtained through wideband sweep frequency excitation → converted into spatial domain impedance distribution → impedance abrupt change points are identified → fault type and location are determined.

[0115] First, the formula for calculating the input impedance at a single frequency point is as follows:

[0116] f is the frequency point;

[0117] ;

[0118] To collect voltage, For current, For input impedance, For resistance components, Assuming the reactance component, the broadband impedance spectrum is obtained as follows:

[0119] ;

[0120] Second, the cross-connection grounding loop can be equivalent to a uniform transmission line, as shown in the following formula:

[0121] ;

[0122] ;

[0123] in, Let be the propagation constant. Characteristic impedance, impedance per unit length The impedance per unit length;

[0124] Let the distance from the fault point to the injection terminal be d, then the input impedance satisfies:

[0125] ;

[0126] Divide the entire line into segments (first segment / middle segment / last segment), establish mappings for each segment, and obtain the impedance curve Z(x) distributed along the length.

[0127] Third, the fault location uses a sudden change point detection algorithm to calculate the gradient G(x) of the spatial impedance curve Z(x):

[0128] ;

[0129] Set threshold To satisfy The location (x=d) is the location of the fault point;

[0130] Fourth, the fault type is automatically classified and determined based on the impedance change pattern:

[0131] 1. Poor contact / corrosion (high resistance);

[0132] 2. Insulation damage / multiple grounding points (increased leakage admittance);

[0133] 3. , disconnection (open circuit);

[0134] 4. Sheath deformation / abnormal inductance.

[0135] In this embodiment, the decoupling calculation unit 1051 performs mathematical processing on the collected three-phase voltage and current data, using algorithms to remove the mutual coupling effects between the three-phase conductors caused by electromagnetic induction, thereby calculating the independent impedance, resistance, and inductance parameters of each phase. The broadband impedance spectrum analysis unit 1052 uses impedance data obtained from frequency sweep testing at different frequencies to plot a curve showing the impedance changing with frequency or propagation distance (converted through transmission line theory), i.e., the impedance spectrum. By analyzing the characteristics and locations of reflection points, abrupt change points, or resonant points on this curve, the fault type is identified and the fault point is accurately located. The decoupling calculation of this module eliminates the inherent electromagnetic coupling interference in cross-connected loops, ensuring that the extracted resistance, inductance, and other parameters accurately reflect the fault point, significantly improving the accuracy of parameter calculation. Broadband impedance spectrum analysis transforms the fault location problem into the identification of characteristic patterns in the impedance curve, enabling automatic fault location and type identification, significantly improving the intelligence and accuracy of diagnosis.

[0136] In a further preferred embodiment of the present invention, the human-computer interaction and control module 106 includes a touch screen display 1061, a fault parameter configuration unit 1062, a signal control unit 1063, a data storage unit 1064, and a result output unit 1065.

[0137] The touch display screen 1061 is used to provide a visual operating interface to realize parameter display, status monitoring and manual command input;

[0138] The fault parameter configuration unit 1062 is used to set simulation parameters such as fault type, fault value, and fault location to complete the precise configuration of fault conditions.

[0139] The signal control unit 1063 is used to adjust the output frequency, amplitude, power and operating mode of the signal source to ensure that the excitation signal is stable and controllable.

[0140] The data storage unit 1064 is used to store and record experimental data, waveform curves, calculation results, and configuration parameters, and supports historical data traceability and comparative analysis.

[0141] The result output unit 1065 is used to output test reports, fault location results, and parameter calculation values, and to realize data export, display and print output.

[0142] In this embodiment, the user performs all operations through a graphical interface on the touch screen 1061. The fault parameter configuration unit 1062 provides an interface for the user to set the fault type, impedance value, fault location, etc. The signal control unit 1063 allows the user to adjust parameters such as the frequency and amplitude of the excitation signal. The data storage unit 1064 automatically saves all configuration parameters, raw waveform data during the test, intermediate analysis data, and final results. The result output unit 1065 organizes the fault location information and parameter calculation results generated by the data analysis module 105 into a structured test report, supporting screen display, printing, or electronic file export.

[0143] This module provides an intuitive and convenient integrated operation and control interface, lowering the barrier to entry for equipment use and enabling fully digital control of fault simulation, testing processes, and data management, thereby improving the automation and repeatability of experiments. Complete data storage capabilities support historical data backtracking and comparative analysis, facilitating long-term research and accumulation of fault characteristics. Standardized report outputs facilitate the recording, sharing, and archiving of test results.

[0144] In a further preferred embodiment of the present invention, a high-voltage cable grounding circuit fault simulation device further includes a safety protection module 107, which includes overcurrent protection, overvoltage protection, overheat protection, and grounding fault protection, and automatically cuts off the signal output and fault circuit under abnormal conditions.

[0145] In this embodiment, the module operates as an independent monitoring and protection system. It continuously monitors the current, voltage, temperature of critical points in the circuit, and grounding status. Upon detecting any abnormality such as overcurrent, overvoltage, overheating, or grounding fault, the protection logic immediately activates, automatically disconnecting the fault access circuit of the fault simulation module 102 and simultaneously commanding the signal coupling injection module 103 to stop signal output, allowing the system to quickly return to a safe state; providing comprehensive active safety protection for the entire device. It effectively prevents equipment damage or safety accidents that may result from fault setting errors, short circuits, or equipment malfunctions, ensuring operator safety and the reliability of the device itself, making high-risk simulation tests such as high-voltage cable grounding faults in the laboratory safe and feasible.

[0146] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-voltage cable grounding circuit fault simulation device, comprising a main body (10), characterized in that, The main body (10) of the equipment integrates a standard cross-interconnection grounding loop module (101), a fault simulation module (102), a signal coupling injection module (103), a parameter acquisition module (104), a data analysis module (105), and a human-machine interaction and control module (106). The standard cross-connection grounding loop module (101) is used to construct a three-section cross-connection grounding electrical structure consistent with the field 110kV and above high voltage cables; The fault simulation module (102) is connected in series or in parallel with the standard cross-interconnected grounding loop module (101) to output adjustable fault resistance, fault inductance and fault admittance, so as to simulate poor contact, multi-point grounding, wire breakage, insulation damage and sheath corrosion. The signal coupling injection module (103) is used to inject heterogeneous AC signals, wideband sweep signals, power frequency superposition signals and provide excitation sources for fault detection into the grounding circuit; The parameter acquisition module (104) is used to synchronously acquire circuit voltage, current, impedance, harmonics, and phase parameters; The data analysis module (105) is used to perform decoupled calculations, broadband impedance spectrum plotting, and fault feature extraction on the parameters acquired by the parameter acquisition module (104). The human-machine interaction and control module (106) is used to set fault parameters, signal parameters, acquisition mode, and output fault simulation reports and detection verification results.

2. The high-voltage cable grounding circuit fault simulation device according to claim 1, characterized in that, The standard cross-interconnection grounding loop module (101) includes a three-phase standard sheath simulation conductor (1011), two sets of cross-interconnection connection units (1012), a direct grounding unit (1013), and a protective grounding unit (1014). The three-phase standard sheath simulation conductor (1011) is used to proportionally reproduce the resistance, inductance, capacitance to ground and electromagnetic coupling characteristics of the high-voltage cable metal sheath, provide a fault-free reference path, and undertake the basic functions of fault access, signal coupling and parameter measurement. The cross-connection unit (1012) is used to construct a three-phase cross-connection topology consistent with the field, connecting the three simulated conductors into a complete, closed-loop grounding loop that conforms to the field topology, and providing a clear access endpoint for segmented fault location; The direct grounding unit (1013) is used to form the main grounding discharge path of the sheath, provide a zero potential reference, form a complete current loop for signal injection and acquisition, and at the same time ensure the normal operation of the loop and the safety grounding requirements during the test process. The protective grounding unit (1014) is used to simulate the field protective grounding or current-limiting grounding structure, serving as an auxiliary grounding interface for the circuit, limiting the grounding circulation current, monitoring the insulation status of the sheath, and linking with the device protection logic to improve test safety.

3. The high-voltage cable grounding circuit fault simulation device according to claim 1, characterized in that, The fault simulation module (102) includes a precision adjustable resistor unit (1021), a precision adjustable inductor unit (1022), an adjustable leakage admittance unit (1023), a fault switching switch array (1024), and a fault location interface (1025). The precision adjustable resistor unit (1021) is used to simulate faults such as poor contact, corrosion, and loose joints, and outputs a continuously adjustable contact resistance to quantitatively characterize the degree of circuit continuity defects. The precision adjustable inductor unit (1022) is used to simulate faults such as local deformation of the sheath, abnormal magnetic circuit, and changes in the equivalent inductance of the connection structure, and to restore the deviation of the loop inductance parameters caused by the fault. The adjustable leakage admittance unit (1023) is used to simulate sheath insulation damage, water ingress and dampness, and multi-point grounding faults, providing a controllable leakage path to ground and reproducing abnormal leakage current characteristics. The fault switching array (1024) is used to quickly switch between different fault types, supports one-click switching between normal and fault conditions, and meets the automated simulation requirements of multiple faults and combined faults. The fault location interface (1025) is used to access a specified segment of the standard cross-connection grounding loop module (101) to realize the simulation of fault location in the first segment, middle segment and last segment.

4. The high-voltage cable grounding circuit fault simulation device according to claim 3, characterized in that, The precision adjustable resistor unit (1021) has a resolution better than 0.1mΩ and an adjustment range of 0.1mΩ-100Ω.

5. A high-voltage cable grounding circuit fault simulation device according to claim 1, characterized in that, The signal coupling injection module (103) includes a different frequency signal source (1031), a wideband sweep frequency source (1032), a coupling injection coil (1033), an auxiliary measurement coil (1034), and a signal power amplification unit (1035). The heterogeneous frequency signal source (1031) is used to output a stable AC excitation signal that is not a power frequency signal, avoiding power frequency interference on site, and providing a high signal-to-noise ratio injection signal for circuit fault detection; The wideband sweep frequency source (1032) is used to output a continuous wideband sweep frequency signal to construct a wideband impedance spectrum of the circuit, thereby realizing fault location and circuit characteristic analysis. The coupling injection coil (1033) is used to inject the excitation signal into the grounding circuit in a non-contact electromagnetic coupling manner without damaging the original wiring structure. The auxiliary measurement coil (1034) is used to synchronously acquire the induced electromotive force signal and calculate the actual injected signal strength, providing a reference for parameter calculation and calibration; The signal power amplification unit (1035) is used to amplify and drive the excitation signal to ensure that the signal injection depth and amplitude meet the requirements of long loop simulation.

6. The high-voltage cable grounding circuit fault simulation device according to claim 1, characterized in that, The parameter acquisition module (104) includes a high-precision voltage transformer (1041), a high-precision current transformer (1042), a signal conditioning unit (1043), and a high-speed ADC acquisition unit (1044). The high-precision voltage transformer (1041) is used to isolate, collect, and accurately measure the voltage at each node of the circuit, providing voltage reference data for impedance calculation and fault analysis. The high-precision current transformer (1042) is used to perform non-contact and precise acquisition of the three-phase current and grounding current of the circuit, and to obtain fault characteristic current and response signal; The signal conditioning unit (1043) is used to filter, amplify, boost, and reduce noise in the acquired voltage and current signals to improve signal quality and signal-to-noise ratio. The ADC acquisition unit (1044) is used to convert analog signals into digital signals at high speed, realize synchronous waveform sampling, and provide digital data support for subsequent decoupling calculation, impedance analysis and fault identification.

7. The high-voltage cable grounding circuit fault simulation device according to claim 1, characterized in that, The data analysis module (105) includes a decoupling calculation unit (1051) and a broadband impedance spectrum analysis unit (1052). The decoupling calculation unit (1051) is used to perform mathematical processing on the collected three-phase voltage and current data. Based on the symmetrical component method and the impedance matrix inversion algorithm, it removes the comprehensive interference of electromagnetic induction coupling, sheath-ground capacitance coupling and cross-interconnection topology coupling between the three-phase conductors, thereby calculating the independent impedance, resistance, inductance and ground admittance parameters of each phase. The broadband impedance spectrum analysis unit (1052) is used to convert frequency domain impedance data into spatial domain impedance curves, identify fault types and fault locations through waveform abrupt change points, and complete automatic fault location and feature extraction.

8. The high-voltage cable grounding circuit fault simulation device according to claim 1, characterized in that, The human-computer interaction and control module (106) includes a touch screen (1061), a fault parameter configuration unit (1062), a signal control unit (1063), a data storage unit (1064), and a result output unit (1065). The touch screen (1061) is used to provide a visual operation interface to realize parameter display, status monitoring and manual command input; The fault parameter configuration unit (1062) is used to set simulation parameters such as fault type, fault value, and fault location to complete the precise configuration of fault conditions. The signal control unit (1063) is used to adjust the output frequency, amplitude, power and working mode of the signal source to ensure that the excitation signal is stable and controllable; The data storage unit (1064) is used to store and record test data, waveform curves, calculation results, and configuration parameters, and supports historical data tracing and comparative analysis. The result output unit (1065) is used to output detection reports, fault location results, and parameter calculation values, and to realize data export, display and print output.

9. A high-voltage cable grounding circuit fault simulation device according to claim 1, characterized in that, It also includes a safety protection module (107), which includes overcurrent protection, overvoltage protection, overheat protection, and ground fault protection, and automatically cuts off the signal output and fault circuit under abnormal conditions.

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