A cable aluminum sheath grounding fault location system, method and terminal equipment

Abstract

This invention discloses a cable aluminum sheath grounding fault location system, method, and terminal equipment, belonging to the field of electrical detection and fault diagnosis. The system includes a pulse source module and a contact sensor module. During fault detection and location: the cable segment to be tested is in a normally open grounding port state; the pulse source module emits a pulse current to the voltage-applied end of the cable segment; the contact sensor module detects the pulse signal of the cable segment and obtains the current signal detection result; when a sudden pulse change occurs in the current signal detection result, a fault point is determined in the cable segment, and the location of the sudden pulse change is identified as the fault point, thus achieving cable aluminum sheath grounding fault location. This invention solves the technical problems of inaccurate location and low efficiency of traditional detection methods, achieving efficient and accurate location of cable aluminum sheath grounding faults.

Description

Technical Field

[0001] This invention relates to the field of electrical testing and fault diagnosis, and in particular to a cable aluminum sheath grounding fault location system, method and terminal equipment. Background Technology

[0002] Against the backdrop of rapid urbanization, underground cable networks have become an important component of urban power distribution and transmission networks. 110kV and above high-voltage cross-linked polyethylene (XLPE) power cables, with their excellent electrical performance and environmental adaptability, are widely used in urban centers, critical load areas, and special power transmission scenarios such as those crossing rivers and seas. To ensure the safe and stable operation of the cable itself, the proper grounding and protection of the cable's metal sheath (usually aluminum or lead sheath) is a key technical aspect. The metal sheath not only serves as an electromagnetic shielding layer for the cable but also withstands fault short-circuit currents and provides waterproofing, moisture protection, and protection against mechanical damage. However, in actual operation, the cable's aluminum sheath (i.e., the polyethylene or polyvinyl chloride outer sheath used to protect the metal sheath) is prone to damage due to construction damage, soil chemical corrosion, external scraping, animal bites, etc., leading to abnormal grounding between the internal metal sheath and the ground, i.e., an outer sheath grounding fault. This type of fault poses a significant safety hazard. Therefore, developing precise location technology for cable aluminum sheath grounding faults has important practical significance and an urgent application need.

[0003] Currently, the location of grounding faults in aluminum sheathed cables mainly employs the bridge method and the voltage drop method. These two methods have significant technical limitations: when the fault point is in a high-resistance grounding state, or even when the grounding point is not completely broken down, the detection sensitivity of traditional methods drops drastically; the distributed capacitance of long cables generates interference signals, severely affecting the accuracy of fault testing; and both the bridge and voltage drop methods require a normal phase line as a reference, making them unusable when multiple phases of cables experience faults simultaneously. Due to the complex working conditions on site, conventional fault location methods suffer from high error rates and low efficiency, failing to meet the actual needs of cable maintenance. Specifically, the output signal strength of traditional bridge and voltage drop methods is low, while the complex environment of cable laying circuits easily generates strong interference signals, resulting in a high error rate in fault location due to the combined effects of these factors; traditional fault location signal detection uses Rogowski coils, requiring the entire cable to be inserted into the coil for signal measurement, a cumbersome and inconvenient installation method, and in some application scenarios, Rogowski coil installation is impossible, preventing detection operations from being carried out. Summary of the Invention

[0004] This invention provides a cable aluminum sheath grounding fault location system, method and terminal equipment, which solves the technical problems of inaccurate location and low efficiency of traditional detection methods, and realizes efficient and accurate location of cable aluminum sheath grounding faults.

[0005] This invention provides a cable aluminum sheath grounding fault location system, applied to a section of cable to be inspected, wherein the section of cable to be inspected includes an aluminum sheath. The system includes: a pulse source module and a fitted sensor module; wherein: The pulse source module is electrically connected to the pressure end of the cable section to be tested, and the pressure end of the aluminum sheath of the cable serves as the pressure end of the cable section to be tested. The bonding sensor module includes an arc-shaped sensing surface. When the bonding sensor module performs pulse signal detection, the arc-shaped sensing surface is used to bond to the outer surface of the aluminum sheath of the cable. When performing fault detection and location operations: The cable section to be tested is in a normal grounding port disconnected state; The pulse source module is used to emit pulse current to the pressurized end of the cable section to be tested; The fitted sensor module is used to detect the pulse signal of the cable section to be tested and obtain the current signal detection result; when the current signal detection result shows a pulse change, it is determined that there is a fault point in the cable section to be tested, and the location of the pulse change is located as the fault point, so as to realize the location of the grounding fault of the cable aluminum sheath.

[0006] This invention provides a cable aluminum sheath grounding fault location system. By disconnecting the normal grounding port during the detection process, the interference of the normal grounding circuit on the pulse current path is eliminated, allowing the pulse current to propagate only along the cable aluminum sheath. The arc-shaped sensing surface of the fitted sensor module can closely fit the cable aluminum sheath, improving the sensitivity and accuracy of pulse signal detection. When the pulse current flows through the fault point, the pulse signal changes abruptly due to the low resistance characteristics of the fault point. By detecting the pulse change, the fault location can be accurately located, achieving efficient and accurate location of cable aluminum sheath grounding faults. This solves the problems of inaccurate location and low efficiency of traditional detection methods.

[0007] Furthermore, the fitted sensor module includes an induction coil sampling circuit, a dual-T filter circuit, a signal amplification and processing circuit, and a data processing circuit, wherein: The output terminal of the induction coil sampling circuit is electrically connected to the input terminal of the double-T filter circuit, the output terminal of the double-T filter circuit is electrically connected to the input terminal of the signal amplification and processing circuit, and the output terminal of the signal amplification and processing circuit is electrically connected to the input terminal of the data processing circuit. The induction coil sampling circuit is used to detect pulse signals and output an induction signal so that the induction coil sampling circuit can convert the induction signal and output a pulse voltage signal. The dual-T filter circuit is used to filter out power frequency interference from the pulse voltage signal and output a filtered pulse voltage signal. The signal amplification and processing circuit is used to amplify the filtered pulse voltage signal with fixed gain and programmable gain, and output an amplified pulse voltage signal. The data processing circuit is used to perform voltage biasing and analog-to-digital conversion on the amplified pulse voltage signal, output a digital sampling signal, and obtain the current signal detection result based on the digital sampling signal.

[0008] The above scheme achieves effective acquisition, filtering, amplification, and digital processing of weak pulse signals. By setting up a dual-T filter circuit, power frequency interference is specifically filtered out, improving the signal-to-noise ratio. The signal amplification and processing circuit adapts to pulse signals of different intensities through a combination of fixed gain and programmable gain. The data processing circuit converts analog signals into digital signals, facilitating subsequent signal analysis and fault diagnosis, and further improving the accuracy and reliability of fault detection.

[0009] Further, the induction coil sampling circuit includes an induction coil, a series current-limiting resistor, a pull-down resistor, a bidirectional transient suppression diode, a filter capacitor, a first voltage divider resistor, a second voltage divider resistor, a first operational amplifier, a first feedback resistor, a second feedback resistor, a third feedback resistor, a first integrating capacitor, a second integrating capacitor, a first power supply decoupling capacitor, a second power supply decoupling capacitor, a power supply decoupling resistor, a current-limiting resistor, a low-pass filter resistor, and a low-pass filter capacitor, wherein: The first end of the series current-limiting resistor is electrically connected to the first end of the induction coil, the second end of the series current-limiting resistor is electrically connected to the first end of the pull-down resistor, and the second end of the induction coil is grounded. The first end of the pull-down resistor is electrically connected to the first end of the first voltage divider resistor, the first end of the pull-down resistor is electrically connected to the first end of the bidirectional transient suppression diode, the second end of the pull-down resistor is electrically connected to the second end of the bidirectional transient suppression diode, the second end of the pull-down resistor is electrically connected to the first end of the filter capacitor, and the second end of the pull-down resistor is grounded. The second end of the first voltage divider resistor is electrically connected to the second end of the filter capacitor, and the second end of the first voltage divider resistor is electrically connected to the first end of the second voltage divider resistor. The second end of the second voltage divider resistor is electrically connected to the negative input terminal of the first operational amplifier, the second end of the second voltage divider resistor is electrically connected to the first end of the first feedback resistor, and the second end of the second voltage divider resistor is electrically connected to the first end of the first integrating capacitor. The second end of the first feedback resistor is electrically connected to the first end of the second feedback resistor, and the second end of the first feedback resistor is electrically connected to the first end of the third feedback resistor. The second end of the third feedback resistor is electrically connected to the first end of the second integrating capacitor, and the second end of the second integrating capacitor is grounded. The second terminal of the first integrating capacitor is electrically connected to the second terminal of the second feedback resistor, the second terminal of the first integrating capacitor is electrically connected to the output terminal of the first operational amplifier, and the second terminal of the first integrating capacitor is electrically connected to the first terminal of the current limiting resistor. The second end of the current-limiting resistor is electrically connected to the first end of the low-pass filter resistor, the second end of the current-limiting resistor is electrically connected to the first end of the low-pass filter capacitor, and the second end of the low-pass filter capacitor is grounded. The first end of the low-pass filter resistor serves as the output end of the induction coil sampling circuit, used to output a pulse voltage signal. The positive input terminal of the first operational amplifier is electrically connected to the first terminal of the power supply decoupling resistor, the negative power supply terminal of the first operational amplifier is electrically connected to the first terminal of the first power supply decoupling capacitor, the negative power supply terminal of the first operational amplifier is electrically connected to a first negative voltage source, the positive power supply terminal of the first operational amplifier is electrically connected to the first terminal of the second power supply decoupling capacitor, the positive power supply terminal of the first operational amplifier is electrically connected to a first positive voltage source, the second terminal of the power supply decoupling resistor is grounded, the second terminal of the first power supply decoupling capacitor is grounded, and the second terminal of the second power supply decoupling capacitor is grounded.

[0010] In the above scheme, the induction coil is protected by a series current-limiting resistor and a pull-down resistor, the bidirectional transient suppression diode suppresses surge voltage, the filter capacitor and low-pass filter circuit filter out high-frequency noise, and the operational amplifier, together with the feedback resistor and the integrating capacitor, realizes the integration amplification of the signal, improves the stability and accuracy of the induction signal, and ensures the reliable output of the pulse voltage signal.

[0011] Further, the dual-T filter circuit includes a third voltage-dividing resistor, a fourth voltage-dividing resistor, a first voltage-dividing capacitor, a second voltage-dividing capacitor, a dual-T filter resistor, a first capacitor, a second capacitor, a dual operational amplifier, a third power supply decoupling capacitor, a fourth power supply decoupling capacitor, a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, and a seventh voltage-dividing resistor, wherein: The first end of the third voltage divider resistor serves as the input terminal of the double-T filter circuit. The first end of the third voltage divider resistor is electrically connected to the first end of the first voltage divider capacitor. The second end of the third voltage divider resistor is electrically connected to the first end of the fourth voltage divider resistor. The second end of the third voltage divider resistor is electrically connected to the first end of the first capacitor. The second end of the third voltage divider resistor is electrically connected to the first end of the second capacitor. The second end of the fourth voltage divider resistor is electrically connected to the second end of the second voltage divider capacitor, and the second end of the fourth voltage divider resistor is electrically connected to the non-inverting input of the first operational amplifier of the dual operational amplifier. The second terminal of the first voltage divider capacitor is electrically connected to the first terminal of the double-T filter resistor, and the second terminal of the first voltage divider capacitor is electrically connected to the first terminal of the second voltage divider capacitor. The second end of the dual-T filter resistor is electrically connected to the second end of the first capacitor, the second end of the dual-T filter resistor is electrically connected to the second end of the second capacitor, and the second end of the dual-T filter resistor is electrically connected to the inverting input terminal of the second operational amplifier of the dual operational amplifier. The first operational amplifier's inverting input terminal is electrically connected to the first operational amplifier's output terminal. The first operational amplifier's output terminal is electrically connected to the first terminal of the fifth voltage divider resistor. The first operational amplifier's output terminal is electrically connected to the first terminal of the sixth voltage divider resistor. The second operational amplifier's inverting input terminal is electrically connected to the second operational amplifier's output terminal. The positive power supply terminal of the dual operational amplifier is electrically connected to the first terminal of the third power supply decoupling capacitor. The positive power supply terminal of the dual operational amplifier is electrically connected to a first positive voltage source. The negative power supply terminal of the dual operational amplifier is electrically connected to the first terminal of the fourth power supply decoupling capacitor. The negative power supply terminal of the dual operational amplifier is electrically connected to a first negative voltage source. The second terminal of the third power supply decoupling capacitor is grounded, and the second terminal of the fourth power supply decoupling capacitor is grounded. The second terminal of the fifth voltage divider resistor serves as the output terminal of the dual-T filter circuit. The second end of the sixth voltage divider resistor is electrically connected to the first end of the seventh voltage divider resistor; The first end of the seventh voltage divider resistor is electrically connected to the non-inverting input of the second operational amplifier of the dual operational amplifier, and the second end of the seventh voltage divider resistor is grounded.

[0012] In the above scheme, the dual-T network structure is used to specifically suppress power frequency interference signals, dual operational amplifiers are used to improve the gain and stability of the filter circuit, and voltage divider resistors and capacitors are used to optimize the filtering characteristics. This effectively improves the quality of the pulse voltage signal, eliminates the impact of power frequency interference on fault detection, and ensures the accuracy of subsequent signal processing.

[0013] Furthermore, the signal amplification and processing circuit includes a second operational amplifier, a programmable gain amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, and a tenth capacitor, wherein: The positive input terminal of the second operational amplifier serves as the input terminal of the signal amplification and processing circuit. The negative input terminal of the second operational amplifier is electrically connected to the first terminal of the first resistor. The positive input terminal of the second operational amplifier is electrically connected to the first terminal of the second resistor. The negative power supply terminal of the second operational amplifier is electrically connected to the first terminal of the fourth capacitor. The positive power supply terminal of the second operational amplifier is electrically connected to the first terminal of the fifth capacitor. The output terminal of the second operational amplifier is electrically connected to the second terminal of the first resistor. The output terminal of the second operational amplifier is electrically connected to the first terminal of the third capacitor. The output terminal of the second operational amplifier is electrically connected to the first terminal of the third resistor. The second terminal of the third capacitor is grounded; The second end of the third resistor is electrically connected to the positive input terminal of the programmable gain amplifier; The negative input terminal of the programmable gain amplifier is grounded; the first correction terminal of the programmable gain amplifier is electrically connected to the first terminal of the fourth resistor; the second correction terminal of the programmable gain amplifier is electrically connected to the first terminal of the fifth resistor; the negative power supply terminal of the programmable gain amplifier is electrically connected to the first terminal of the sixth capacitor; the negative power supply terminal of the programmable gain amplifier is electrically connected to the first negative voltage source; the positive power supply terminal of the programmable gain amplifier is electrically connected to the first terminal of the seventh capacitor; the positive power supply terminal of the programmable gain amplifier is electrically connected to the first positive voltage source; the output terminal of the programmable gain amplifier is electrically connected to the first terminal of the eighth capacitor; and the output terminal of the programmable gain amplifier is electrically connected to the negative input terminal of the third operational amplifier. The second end of the fourth resistor is electrically connected to the first negative voltage source, and the second end of the fifth resistor is electrically connected to the first positive voltage source; The negative input terminal of the third operational amplifier is electrically connected to the output terminal of the third operational amplifier, the negative power supply terminal of the third operational amplifier is electrically connected to the first terminal of the ninth capacitor, the negative power supply terminal of the third operational amplifier is electrically connected to the first negative voltage source, the positive power supply terminal of the third operational amplifier is electrically connected to the first terminal of the tenth capacitor, the positive power supply terminal of the third operational amplifier is electrically connected to the first positive voltage source, and the output terminal of the third operational amplifier serves as the output terminal of the signal amplification and processing circuit. The second terminal of the sixth capacitor is grounded, the second terminal of the eighth capacitor is grounded, the second terminal of the ninth capacitor is grounded, and the second terminal of the tenth capacitor is grounded.

[0014] In the above scheme, a fixed-gain amplification is achieved through a second operational amplifier, a programmable gain amplifier adaptively adjusts the gain according to the signal strength, a third operational amplifier buffers the signal, and the combination of capacitors and resistors optimizes the frequency response of the signal, improves the adaptability to pulse signals of different intensities, ensures that the amplified signal meets the requirements of data processing, and further improves the sensitivity of fault detection.

[0015] Further, the data processing circuit includes a fourth operational amplifier, an analog-to-digital converter, a first data capacitor, a second data capacitor, a third data capacitor, a fourth data capacitor, a fifth data capacitor, a sixth data capacitor, a seventh data capacitor, a first data resistor, a second data resistor, a third data resistor, a fourth data resistor, a fifth data resistor, and a sixth data resistor, wherein: The first end of the first data resistor serves as the input terminal of the data processing circuit. The first end of the first data resistor is electrically connected to the first end of the first data capacitor. The second end of the first data resistor is electrically connected to the first end of the second data resistor. The second end of the first data resistor is electrically connected to the first end of the third data resistor. The second end of the first data resistor is electrically connected to the positive input terminal of the fourth operational amplifier. The second terminal of the first data capacitor is grounded, and the second terminal of the second data resistor is grounded. The second terminal of the third data resistor is electrically connected to the second positive voltage source; The negative input terminal of the fourth operational amplifier is electrically connected to the first terminal of the fourth data resistor, the negative output terminal of the fourth operational amplifier is electrically connected to the first terminal of the fifth data resistor, the output terminal of the fourth operational amplifier is electrically connected to the second terminal of the fifth data resistor, and the output terminal of the fourth operational amplifier is electrically connected to the first terminal of the sixth data resistor. The second terminal of the fourth data resistor is grounded; The second end of the sixth data resistor is electrically connected to the first end of the fourth data capacitor, the second end of the fourth data capacitor is grounded, and the second end of the sixth data resistor is electrically connected to the positive input terminal of the analog-to-digital converter. The negative input terminal and ground terminal of the analog-to-digital converter (ADC) are grounded. The power supply terminal of the ADC is electrically connected to a first positive voltage source. The power supply terminal of the ADC is electrically connected to the first terminal of the seventh data capacitor. The voltage reference terminal of the ADC is electrically connected to a second positive voltage source. The voltage reference terminal of the ADC is electrically connected to the first terminal of the fifth data capacitor. The output terminal of the ADC is electrically connected to a third positive voltage source. The output terminal of the ADC is electrically connected to the first terminal of the sixth data capacitor. The output terminal of the ADC serves as the output terminal of the data processing circuit. The second terminal of the fifth data capacitor is grounded, the second terminal of the sixth data capacitor is grounded, and the second terminal of the seventh data capacitor is grounded.

[0016] In the above scheme, voltage bias is achieved through a fourth operational amplifier to adjust the analog signal to the input range of the analog-to-digital converter. The analog-to-digital converter is then used to convert the analog signal into a digital signal. Data capacitors and data resistors are set to improve the stability and anti-interference capability of the signal and ensure the accuracy of the digital sampling signal.

[0017] Furthermore, the pulse source module includes an AC input circuit breaker, a transformer, a range selector switch, a switching power supply module, a large-capacity electrolytic capacitor, a fifth operational amplifier, a full-wave rectifier bridge, a large-capacity electrolytic capacitor, a DC shunt module, a first switching transistor, a first current-limiting resistor, and a second current-limiting resistor, wherein: The AC input circuit breaker receiver is used to receive power input. The first output terminal of the AC input circuit breaker is electrically connected to the first terminal of the switching power supply module. The second output terminal of the AC input circuit breaker is electrically connected to the second terminal of the switching power supply module. The first output terminal of the AC input circuit breaker is electrically connected to the first terminal of the transformer. The second output terminal of the AC input circuit breaker is electrically connected to the second terminal of the transformer. The third terminal of the transformer is electrically connected to the first terminal of the gear selector switch, the fourth terminal of the transformer is electrically connected to the second terminal of the gear selector switch, the fifth terminal of the transformer is electrically connected to the third terminal of the gear selector switch, the sixth terminal of the transformer is electrically connected to the third terminal of the gear selector switch, the seventh terminal of the transformer is electrically connected to the fourth terminal of the gear selector switch, and the third terminal of the transformer is electrically connected to the first terminal of the full-wave rectifier bridge. The fifth terminal of the gear selection switch is electrically connected to the second terminal of the full-wave rectifier bridge; The third terminal of the wave rectifier bridge is electrically connected to the first terminal of the large-capacity electrolytic capacitor, the fourth terminal of the wave rectifier bridge is electrically connected to the second terminal of the large-capacity electrolytic capacitor, the third terminal of the wave rectifier bridge is electrically connected to the first terminal of the DC shunt module, and the fourth terminal of the wave rectifier bridge is electrically connected to the first terminal of the first switching transistor. The first terminal of the first switching transistor is electrically connected to the first terminal of the fifth operational amplifier; The second terminal of the first switching transistor serves as the second power output port. The DC shunt module is provided with a first power output port; The first terminal of the fifth operational amplifier is electrically connected to the first terminal of the first current-limiting resistor, the second terminal of the fifth operational amplifier is electrically connected to the first positive voltage source, the third terminal of the fifth operational amplifier is electrically connected to the first terminal of the second current-limiting resistor, and the fourth terminal of the fifth operational amplifier is grounded. The second terminal of the first current-limiting resistor is grounded; The second end of the second current-limiting resistor serves as an input port for inputting a pulse control signal so that the pulse source module outputs a pulse current. The first power output port and the second power output port are electrically connected to the voltage-applied end of the cable segment to be tested, and are used to output the pulse current.

[0018] In the above scheme, overcurrent protection is achieved through an AC input circuit breaker, isolation and voltage reduction are achieved through a transformer, multi-level voltage output is achieved through a range selector switch, AC-DC conversion and filtering are achieved through a full-wave rectifier bridge and a large-capacity electrolytic capacitor, current sampling is achieved through a DC shunt module, and pulse current output is achieved through a pulse control signal by setting a first switching transistor, thereby improving the safety, stability and controllability of the pulse source module and achieving accurate pulse current output.

[0019] Furthermore, the switching power supply module includes a switching power supply, a switching power supply resistor, a sixth operational amplifier, a first interface, and a second interface, wherein: The first terminal of the switching power supply serves as the first terminal of the switching power supply module, the second terminal of the switching power supply serves as the second terminal of the switching power supply module, the third terminal of the switching power supply is electrically connected to the first terminal of the switching power supply resistor, the fourth terminal of the switching power supply is electrically connected to the first terminal of the first interface, the third terminal of the switching power supply is electrically connected to the first terminal of the second interface, the fourth terminal of the switching power supply is electrically connected to the second terminal of the second interface, the third terminal of the switching power supply is electrically connected to the first terminal of the sixth operational amplifier, and the fourth terminal of the switching power supply is electrically connected to the second terminal of the sixth operational amplifier. The second end of the switching power supply resistor is electrically connected to the second end of the first interface.

[0020] This invention also provides a method for locating grounding faults in aluminum sheathed cables, used to implement the aforementioned cable aluminum sheath grounding fault location system, wherein the system includes: a pulse source module and a bonding sensor module; the method includes: When performing fault detection and location operations: The cable segment to be tested is controlled to have its normal grounding port disconnected. A pulse current is emitted to the pressurized end of the cable section to be tested; The pulse signal is detected on the section of cable to be tested to obtain the current signal detection result; when the current signal detection result shows a pulse change, it is determined that there is a fault point in the section of cable to be tested, and the location of the pulse change is located as the fault point, so as to realize the location of the grounding fault of the aluminum sheath of the cable.

[0021] This invention provides a method for locating grounding faults in cable aluminum sheaths. By disconnecting the normal grounding port and eliminating interference from the normal grounding circuit, the pulse current is allowed to propagate along the cable aluminum sheath. The fault point is located by detecting pulse mutations, thereby achieving efficient and accurate location of grounding faults in cable aluminum sheaths and improving the efficiency and accuracy of fault detection.

[0022] The present invention also provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, it implements the cable aluminum sheath grounding fault location method as described above.

[0023] This invention provides a cable aluminum sheath grounding fault location system and method. Through the collaborative operation of a pulse source module and a fitted sensor module, it achieves precise location of cable aluminum sheath grounding faults. The pulse source module provides a stable and controllable excitation signal for fault detection through multi-level voltage output, precise pulse control, and reliable current sampling. The fitted sensor module improves the sensitivity and accuracy of pulse signal detection and eliminates the influence of noise such as power frequency interference through efficient signal acquisition, filtering, amplification, and digital processing. The fault location method eliminates loop interference by disconnecting the normal grounding port and then accurately locates the fault point by detecting pulse abrupt changes. This solves the problems of inaccurate location and low efficiency in traditional cable fault detection methods, achieving efficient, accurate, and reliable cable aluminum sheath grounding fault location, thereby effectively improving the efficiency and safety of power cable operation and maintenance. Attached Figure Description

[0024] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a cable aluminum sheath grounding fault location system provided in this embodiment; Figure 2 This is a schematic diagram of an induction coil sampling circuit provided in this embodiment; Figure 3 This is a schematic diagram of a dual-T filter circuit provided in this embodiment; Figure 4This is a schematic diagram of a signal amplification and processing circuit provided in this embodiment; Figure 5 This is a schematic diagram of a data processing circuit provided in this embodiment; Figure 6 This is a schematic diagram of a pulse source module circuit provided in this embodiment; Figure 7 This is a schematic diagram of a pulse current sampling circuit provided in this embodiment; In the diagram: 1. Cable section to be tested; 2. Cable aluminum sheath; 3. Pulse source module; 4. Fitted sensor module; 5. Fault point; 6. Normal grounding port disconnected before testing begins. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0028] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0031] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0032] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0033] This embodiment provides a cable aluminum sheath grounding fault location system, applied to a cable section to be inspected, wherein the cable section to be inspected includes an aluminum sheath. The system includes: a pulse source module and a fitted sensor module; wherein: The pulse source module is electrically connected to the pressure end of the cable section to be tested, and the pressure end of the aluminum sheath of the cable serves as the pressure end of the cable section to be tested. The bonding sensor module includes an arc-shaped sensing surface. When the bonding sensor module performs pulse signal detection, the arc-shaped sensing surface is used to bond to the outer surface of the aluminum sheath of the cable. When performing fault detection and location operations: The cable section to be tested is in a normal grounding port disconnected state; The pulse source module is used to emit pulse current to the pressurized end of the cable section to be tested; The fitted sensor module is used to detect the pulse signal of the cable section to be tested and obtain the current signal detection result; when the current signal detection result shows a pulse change, it is determined that there is a fault point in the cable section to be tested, and the location of the pulse change is located as the fault point, so as to realize the location of the grounding fault of the cable aluminum sheath.

[0034] In its implementation, this embodiment of the cable aluminum sheath grounding fault location system has been improved and optimized for tunnel conditions based on the existing step voltage method and pulse induction method. This embodiment applies a pulse current to the cable aluminum sheath through a pulse source module. Utilizing the characteristic that cable aluminum sheath defects in tunnels are low-resistance grounding faults, a grounding loop of pulse current is formed at the fault point. This results in a clear difference in signal presence and absence on the cable aluminum sheaths on both sides of the fault point, solving the problem that the step voltage method relies on ground voltage gradient detection and cannot be used on hardened tunnel surfaces. This embodiment optimizes the traditional insert-type signal detection structure into an arc-shaped fitting structure. Signal detection is completed by the arc-shaped sensing surface of the fitting sensor module fitting the cable aluminum sheath, eliminating the need to insert the sensor into the cable. This adapts to the detection scenario in tunnels. Furthermore, considering the characteristic that the unpressurized end is suspended when there is a grounding defect in the cable aluminum sheath, the pulse current propagates only on the cable aluminum sheath from the pressurized end to the fault point, ensuring that no pulse signal can be detected after the fault point, forming a reliable comparison from signal presence to absence.

[0035] Through the improvement and optimization of the above technologies, a technical solution is formed whereby the two ends of the metal sheath of the defective cable section are suspended, a high-power pulse source is applied from one end of the metal sheath, and the pulse flows through the ground via the defect point of the outer sheath. A pulse sensing device can detect a signal between the pressure-applied end and the defect point, and there is no signal after the defect point, forming a clear and reliable contrast from the presence to the absence of signal, thereby accurately and reliably locating the defect point. A positioning system is designed based on this solution. The positioning system of this embodiment adopts the inductive measurement principle. As long as the attached sensor module is close to the cable surface, reliable signal testing can be achieved. Installation and testing can be carried out in any scenario, improving work efficiency. At the same time, a high-current pulse source technology is used to change the continuous output signal source to a pulse mode, with a peak current of over 50A, improving the signal-to-noise ratio and increasing anti-interference capability. It can achieve accurate and efficient location of grounding faults in the aluminum sheath of cables in tunnels, greatly improving the accuracy of fault location and work efficiency.

[0036] In the specific implementation process, when performing fault detection and location operations on the cable section 1 to be tested, the cable aluminum sheath grounding fault location system mentioned in this embodiment is as follows: Figure 1As shown, at one end of the cable aluminum sheath 2 (as the pressure end), a pulse current is continuously emitted through the pulse source module 3. The inspector, either handheld or using a robotic arm, moves the highly sensitive, contact-type sensor module 4 along the surface of the section of cable 1 to be inspected in the tunnel cable for measurement. A signal is detected until it reaches fault point 5. After passing fault point 5, the signal suddenly disappears, and the signal from the contact-type sensor module shows a significant change from 1 to 0, thus accurately locating the fault. Here, r1 represents the grounding impedance of the fault point, r2 represents the contact resistance between the pressure end cable aluminum sheath and the ground, and the dashed box 6 represents the normal grounding port that was disconnected before the start of the inspection. To further improve measurement efficiency, multiple contact-type sensor modules can be used for distributed measurement simultaneously, further reducing the measurement time inside the tunnel.

[0037] Optionally, the fitted sensor module 4 includes an induction coil sampling circuit, a double-T filter circuit, a signal amplification and processing circuit, and a data processing circuit, wherein: The output terminal of the induction coil sampling circuit is electrically connected to the input terminal of the double-T filter circuit, the output terminal of the double-T filter circuit is electrically connected to the input terminal of the signal amplification and processing circuit, and the output terminal of the signal amplification and processing circuit is electrically connected to the input terminal of the data processing circuit. The induction coil sampling circuit is used to detect pulse signals and output an induction signal so that the induction coil sampling circuit can convert the induction signal and output a pulse voltage signal. The dual-T filter circuit is used to filter out power frequency interference from the pulse voltage signal and output a filtered pulse voltage signal. The signal amplification and processing circuit is used to amplify the filtered pulse voltage signal with fixed gain and programmable gain, and output an amplified pulse voltage signal. The data processing circuit is used to perform voltage biasing and analog-to-digital conversion on the amplified pulse voltage signal, output a digital sampling signal, and obtain the current signal detection result based on the digital sampling signal.

[0038] In this specific implementation, the pulse signal receiver used is a bonded sensor module 4, which internally employs a multi-turn induction coil coupled with magnetic lines of force to sense and detect current signals. It has a built-in battery, and an LCD screen can be added to display the detected signal magnitude. The measurement sensitivity can also be manually set, adapting to the needs of different applications.

[0039] Optionally, the induction coil sampling circuit includes an induction coil, a series current-limiting resistor, a pull-down resistor, a bidirectional transient suppression diode, a filter capacitor, a first voltage divider resistor, a second voltage divider resistor, a first operational amplifier, a first feedback resistor, a second feedback resistor, a third feedback resistor, a first integrating capacitor, a second integrating capacitor, a first power supply decoupling capacitor, a second power supply decoupling capacitor, a power supply decoupling resistor, a current-limiting resistor, a low-pass filter resistor, and a low-pass filter capacitor, wherein: The first end of the series current-limiting resistor is electrically connected to the first end of the induction coil, the second end of the series current-limiting resistor is electrically connected to the first end of the pull-down resistor, and the second end of the induction coil is grounded. The first end of the pull-down resistor is electrically connected to the first end of the first voltage divider resistor, the first end of the pull-down resistor is electrically connected to the first end of the bidirectional transient suppression diode, the second end of the pull-down resistor is electrically connected to the second end of the bidirectional transient suppression diode, the second end of the pull-down resistor is electrically connected to the first end of the filter capacitor, and the second end of the pull-down resistor is grounded. The second end of the first voltage divider resistor is electrically connected to the second end of the filter capacitor, and the second end of the first voltage divider resistor is electrically connected to the first end of the second voltage divider resistor. The second end of the second voltage divider resistor is electrically connected to the negative input terminal of the first operational amplifier, the second end of the second voltage divider resistor is electrically connected to the first end of the first feedback resistor, and the second end of the second voltage divider resistor is electrically connected to the first end of the first integrating capacitor. The second end of the first feedback resistor is electrically connected to the first end of the second feedback resistor, and the second end of the first feedback resistor is electrically connected to the first end of the third feedback resistor. The second end of the third feedback resistor is electrically connected to the first end of the second integrating capacitor, and the second end of the second integrating capacitor is grounded. The second terminal of the first integrating capacitor is electrically connected to the second terminal of the second feedback resistor, the second terminal of the first integrating capacitor is electrically connected to the output terminal of the first operational amplifier, and the second terminal of the first integrating capacitor is electrically connected to the first terminal of the current limiting resistor. The second end of the current-limiting resistor is electrically connected to the first end of the low-pass filter resistor, the second end of the current-limiting resistor is electrically connected to the first end of the low-pass filter capacitor, and the second end of the low-pass filter capacitor is grounded. The first end of the low-pass filter resistor serves as the output end of the induction coil sampling circuit, used to output a pulse voltage signal. The positive input terminal of the first operational amplifier is electrically connected to the first terminal of the power supply decoupling resistor, the negative power supply terminal of the first operational amplifier is electrically connected to the first terminal of the first power supply decoupling capacitor, the negative power supply terminal of the first operational amplifier is electrically connected to a first negative voltage source, the positive power supply terminal of the first operational amplifier is electrically connected to the first terminal of the second power supply decoupling capacitor, the positive power supply terminal of the first operational amplifier is electrically connected to a first positive voltage source, the second terminal of the power supply decoupling resistor is grounded, the second terminal of the first power supply decoupling capacitor is grounded, and the second terminal of the second power supply decoupling capacitor is grounded.

[0040] In specific implementation, the induction coil sampling circuit provided in this embodiment is as follows: Figure 2 As shown, the system includes an induction coil T21 (a non-closed induction coil, such as TRANS-1, is used in this embodiment), a series current-limiting resistor R21 (10kΩ), a pull-down resistor R22 (100kΩ), bidirectional transient suppression diodes D21 and D22 (model 1SS226 / C3 is used in this embodiment), a filter capacitor C21 (100nF), a first voltage divider resistor R23 (10kΩ), a second voltage divider resistor R24 ​​(10kΩ), an integration unit, a power supply decoupling unit, and an output filtering unit; the integration unit includes a first operational amplifier U1 (model O is used in this embodiment). The circuit consists of P07CD), a first feedback resistor R26 (1MΩ), a second feedback resistor R27 (1MΩ), a third feedback resistor R28 (1MΩ), a first integrating capacitor C22 (100nF), and a second integrating capacitor C23 (10uF); the power supply decoupling unit includes a first power supply decoupling capacitor C25 (100nF), a second power supply decoupling capacitor C26 (100nF), and a power supply decoupling resistor R25 (10kΩ); the output filtering unit includes a current limiting resistor R29 (10kΩ), a low-pass filter resistor R210 (10kΩ), and a low-pass filter capacitor C24 (100nF). Here, AG represents Analog Ground, serving as a common potential reference point; +5A represents a +5V analog power supply (i.e., the first positive voltage source), providing a positive 5V operating voltage to chip U1 and related analog circuits; -5A represents a -5V analog power supply (i.e., the first negative positive voltage source), providing a negative 5V operating voltage to the first operational amplifier U1 and related analog circuits.

[0041] In practical applications, Rogowski coils require repeated insertion, testing, and disassembly during the trial-and-error process, resulting in low efficiency. This embodiment designs a non-closed induction coil with adjustable sensitivity. To improve sensitivity, the detection surface is designed as an arc conforming to the cable body, forming the arc-shaped sensing surface. During use, it adheres closely to the outer surface of the cable's aluminum sheath 2, as close as possible to the area with the densest magnetic field lines, thereby increasing the detected signal strength. The signal sensed by the induction coil is the differential of the current change. After voltage division by resistors, it is integrated by an integrator circuit composed of OP07CD, converting it into a voltage signal representing the magnitude of the pulse current from the pulse source, which is then filtered.

[0042] Optionally, the dual-T filter circuit includes a third voltage-dividing resistor, a fourth voltage-dividing resistor, a first voltage-dividing capacitor, a second voltage-dividing capacitor, a dual-T filter resistor, a first capacitor, a second capacitor, a dual operational amplifier, a third power supply decoupling capacitor, a fourth power supply decoupling capacitor, a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, and a seventh voltage-dividing resistor, wherein: The first end of the third voltage divider resistor serves as the input terminal of the double-T filter circuit. The first end of the third voltage divider resistor is electrically connected to the first end of the first voltage divider capacitor. The second end of the third voltage divider resistor is electrically connected to the first end of the fourth voltage divider resistor. The second end of the third voltage divider resistor is electrically connected to the first end of the first capacitor. The second end of the third voltage divider resistor is electrically connected to the first end of the second capacitor. The second end of the fourth voltage divider resistor is electrically connected to the second end of the second voltage divider capacitor, and the second end of the fourth voltage divider resistor is electrically connected to the non-inverting input of the first operational amplifier of the dual operational amplifier. The second terminal of the first voltage divider capacitor is electrically connected to the first terminal of the double-T filter resistor, and the second terminal of the first voltage divider capacitor is electrically connected to the first terminal of the second voltage divider capacitor. The second end of the dual-T filter resistor is electrically connected to the second end of the first capacitor, the second end of the dual-T filter resistor is electrically connected to the second end of the second capacitor, and the second end of the dual-T filter resistor is electrically connected to the inverting input terminal of the second operational amplifier of the dual operational amplifier. The first operational amplifier's inverting input terminal is electrically connected to the first operational amplifier's output terminal. The first operational amplifier's output terminal is electrically connected to the first terminal of the fifth voltage divider resistor. The first operational amplifier's output terminal is electrically connected to the first terminal of the sixth voltage divider resistor. The second operational amplifier's inverting input terminal is electrically connected to the second operational amplifier's output terminal. The positive power supply terminal of the dual operational amplifier is electrically connected to the first terminal of the third power supply decoupling capacitor. The positive power supply terminal of the dual operational amplifier is electrically connected to a first positive voltage source. The negative power supply terminal of the dual operational amplifier is electrically connected to the first terminal of the fourth power supply decoupling capacitor. The negative power supply terminal of the dual operational amplifier is electrically connected to a first negative voltage source. The second terminal of the third power supply decoupling capacitor is grounded, and the second terminal of the fourth power supply decoupling capacitor is grounded. The second terminal of the fifth voltage divider resistor serves as the output terminal of the dual-T filter circuit. The second end of the sixth voltage divider resistor is electrically connected to the first end of the seventh voltage divider resistor; The first end of the seventh voltage divider resistor is electrically connected to the non-inverting input of the second operational amplifier of the dual operational amplifier, and the second end of the seventh voltage divider resistor is grounded.

[0043] In practical implementation, the 50Hz power frequency signal has a significant impact on signal acquisition and must be removed. This embodiment uses LM358 dual operational amplifiers to construct a dual-T band-stop (notch filter) active filter to filter out interference from external 50Hz power frequency signals. Specifically, this embodiment provides a dual-T filter circuit as follows: Figure 3 As shown, the resistors include a third voltage divider resistor R31 (10kΩ), a fourth voltage divider resistor R32 (10kΩ), a first voltage divider capacitor C31 (330nF), a second voltage divider capacitor C32 (330nF), a dual-T filter resistor R33 (5kΩ), a first capacitor C33 (330nF), a second capacitor C34 (330nF), a dual operational amplifier U31 (LM358D in this embodiment), a third power supply decoupling capacitor C35 (100nF), a fourth power supply decoupling capacitor C36 (100nF), a fifth voltage divider resistor R34 (10kΩ), a sixth voltage divider resistor R35 (10kΩ), and a seventh voltage divider resistor R36 (10kΩ).

[0044] Optionally, the signal amplification and processing circuit includes a second operational amplifier, a programmable gain amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, and a tenth capacitor, wherein: The positive input terminal of the second operational amplifier serves as the input terminal of the signal amplification and processing circuit. The negative input terminal of the second operational amplifier is electrically connected to the first terminal of the first resistor. The positive input terminal of the second operational amplifier is electrically connected to the first terminal of the second resistor. The negative power supply terminal of the second operational amplifier is electrically connected to the first terminal of the fourth capacitor. The positive power supply terminal of the second operational amplifier is electrically connected to the first terminal of the fifth capacitor. The output terminal of the second operational amplifier is electrically connected to the second terminal of the first resistor. The output terminal of the second operational amplifier is electrically connected to the first terminal of the third capacitor. The output terminal of the second operational amplifier is electrically connected to the first terminal of the third resistor. The second terminal of the third capacitor is grounded; The second end of the third resistor is electrically connected to the positive input terminal of the programmable gain amplifier; The negative input terminal of the programmable gain amplifier is grounded; the first correction terminal of the programmable gain amplifier is electrically connected to the first terminal of the fourth resistor; the second correction terminal of the programmable gain amplifier is electrically connected to the first terminal of the fifth resistor; the negative power supply terminal of the programmable gain amplifier is electrically connected to the first terminal of the sixth capacitor; the negative power supply terminal of the programmable gain amplifier is electrically connected to the first negative voltage source; the positive power supply terminal of the programmable gain amplifier is electrically connected to the first terminal of the seventh capacitor; the positive power supply terminal of the programmable gain amplifier is electrically connected to the first positive voltage source; the output terminal of the programmable gain amplifier is electrically connected to the first terminal of the eighth capacitor; and the output terminal of the programmable gain amplifier is electrically connected to the negative input terminal of the third operational amplifier. The second end of the fourth resistor is electrically connected to the first negative voltage source, and the second end of the fifth resistor is electrically connected to the first positive voltage source; The negative input terminal of the third operational amplifier is electrically connected to the output terminal of the third operational amplifier, the negative power supply terminal of the third operational amplifier is electrically connected to the first terminal of the ninth capacitor, the negative power supply terminal of the third operational amplifier is electrically connected to the first negative voltage source, the positive power supply terminal of the third operational amplifier is electrically connected to the first terminal of the tenth capacitor, the positive power supply terminal of the third operational amplifier is electrically connected to the first positive voltage source, and the output terminal of the third operational amplifier serves as the output terminal of the signal amplification and processing circuit. The second terminal of the sixth capacitor is grounded, the second terminal of the eighth capacitor is grounded, the second terminal of the ninth capacitor is grounded, and the second terminal of the tenth capacitor is grounded.

[0045] In practical implementation, the signal amplification and processing circuit provided in this embodiment is as follows: Figure 4As shown, it includes a second operational amplifier U2, a programmable gain amplifier U41, a third operational amplifier U3, a first resistor R42 (100kΩ), a second resistor R41 (10kΩ), a third resistor R43 (1kΩ), a fourth resistor R44 (300kΩ), a fifth resistor R45 (300kΩ), a third capacitor C41 (100nF), a fourth capacitor C42 (100nF), a fifth capacitor C43 (100nF), a sixth capacitor C44 (1uF), a seventh capacitor C45 (1uF), an eighth capacitor C46 (1uF), a ninth capacitor C47 (100nF), and a tenth capacitor C48 (100nF). The second operational amplifier U2 is a high-precision general-purpose operational amplifier, such as OP07CD, responsible for initial signal conditioning, voltage division, and biasing. The programmable gain amplifier U41 is a programmable gain instrumentation amplifier, such as PGA204AU. The third operational amplifier U3 is a high-precision general-purpose operational amplifier, such as OP07CD, responsible for secondary signal conditioning and low-pass filtering. Here, G represents digital ground. In this embodiment, a separate design architecture for digital ground G and analog ground AG is used during application. AG only serves the analog front-end (such as op-amps OP07 and PGA204) to ensure the sampling accuracy of weak pulse signals and is extremely sensitive to noise. G serves digital circuits (such as the communication terminal of the ADC and the main control chip), where transitions in digital signals generate high-frequency noise. The signal amplification and processing circuit provided in this embodiment uses an OP07 operational amplifier circuit and a PGA204 programmable amplifier to amplify the induced signal. The amplification factor is adjustable and has different sensitivities. The OP07 amplifier circuit amplifies the signal by 10 times, and the PGA204 has multiple amplification factors, such as 1x, 10x, or 100x.

[0046] Optionally, the data processing circuit includes a fourth operational amplifier, an analog-to-digital converter, a first data capacitor, a second data capacitor, a third data capacitor, a fourth data capacitor, a fifth data capacitor, a sixth data capacitor, a seventh data capacitor, a first data resistor, a second data resistor, a third data resistor, a fourth data resistor, a fifth data resistor, and a sixth data resistor, wherein: The first end of the first data resistor serves as the input terminal of the data processing circuit. The first end of the first data resistor is electrically connected to the first end of the first data capacitor. The second end of the first data resistor is electrically connected to the first end of the second data resistor. The second end of the first data resistor is electrically connected to the first end of the third data resistor. The second end of the first data resistor is electrically connected to the positive input terminal of the fourth operational amplifier. The second terminal of the first data capacitor is grounded, and the second terminal of the second data resistor is grounded. The second terminal of the third data resistor is electrically connected to the second positive voltage source; The negative input terminal of the fourth operational amplifier is electrically connected to the first terminal of the fourth data resistor, the negative output terminal of the fourth operational amplifier is electrically connected to the first terminal of the fifth data resistor, the output terminal of the fourth operational amplifier is electrically connected to the second terminal of the fifth data resistor, and the output terminal of the fourth operational amplifier is electrically connected to the first terminal of the sixth data resistor. The second terminal of the fourth data resistor is grounded; The second end of the sixth data resistor is electrically connected to the first end of the fourth data capacitor, the second end of the fourth data capacitor is grounded, and the second end of the sixth data resistor is electrically connected to the positive input terminal of the analog-to-digital converter. The negative input terminal and ground terminal of the analog-to-digital converter (ADC) are grounded. The power supply terminal of the ADC is electrically connected to a first positive voltage source. The power supply terminal of the ADC is electrically connected to the first terminal of the seventh data capacitor. The voltage reference terminal of the ADC is electrically connected to a second positive voltage source. The voltage reference terminal of the ADC is electrically connected to the first terminal of the fifth data capacitor. The output terminal of the ADC is electrically connected to a third positive voltage source. The output terminal of the ADC is electrically connected to the first terminal of the sixth data capacitor. The output terminal of the ADC serves as the output terminal of the data processing circuit. The second terminal of the fifth data capacitor is grounded, the second terminal of the sixth data capacitor is grounded, and the second terminal of the seventh data capacitor is grounded.

[0047] In specific implementation, the data processing circuit provided in this embodiment is as follows: Figure 5As shown, the system includes a fourth operational amplifier U4 (model OP07CD in this embodiment), an analog-to-digital converter U51 (model AD7685BRM in this embodiment), a first data capacitor C54 (100nF), a second data capacitor C52 (100nF), a third data capacitor C53 (100nF), a fourth data capacitor C54 (2.2nF), a fifth data capacitor C55 (10uF), a sixth data capacitor C56 (100nF), a seventh data capacitor C57 (100nF), a first data resistor R51 (5kΩ), a second data resistor R52 (10kΩ), a third data resistor R53 (10kΩ), a fourth data resistor R54 (10kΩ), a fifth data resistor R55 (10kΩ), and a sixth data resistor R56 (30Ω). Among them, the SDI interface of the analog-to-digital converter U51 is responsible for configuring the ADC, the SCK interface is responsible for synchronous communication, the SDO interface is responsible for outputting data, and the CNV interface is responsible for starting the conversion; +2.5 indicates a +2.5V precision reference voltage source, which is the second positive voltage source, and +3 indicates a +3V digital power supply, which is the power rail that supplies power to the digital interface section of the analog-to-digital converter U51 (AD7685BRM), which is the third positive voltage source.

[0048] Optionally, the pulse source module 3 includes an AC input circuit breaker, a transformer, a gear selector switch, a switching power supply module, a large-capacity electrolytic capacitor, a fifth operational amplifier, a full-wave rectifier bridge, a large-capacity electrolytic capacitor, a DC shunt module, a first switching transistor, a first current-limiting resistor, and a second current-limiting resistor, wherein: The AC input circuit breaker receiver is used to receive power input. The first output terminal of the AC input circuit breaker is electrically connected to the first terminal of the switching power supply module. The second output terminal of the AC input circuit breaker is electrically connected to the second terminal of the switching power supply module. The first output terminal of the AC input circuit breaker is electrically connected to the first terminal of the transformer. The second output terminal of the AC input circuit breaker is electrically connected to the second terminal of the transformer. The third terminal of the transformer is electrically connected to the first terminal of the gear selector switch, the fourth terminal of the transformer is electrically connected to the second terminal of the gear selector switch, the fifth terminal of the transformer is electrically connected to the third terminal of the gear selector switch, the sixth terminal of the transformer is electrically connected to the third terminal of the gear selector switch, the seventh terminal of the transformer is electrically connected to the fourth terminal of the gear selector switch, and the third terminal of the transformer is electrically connected to the first terminal of the full-wave rectifier bridge. The fifth terminal of the gear selection switch is electrically connected to the second terminal of the full-wave rectifier bridge; The third terminal of the wave rectifier bridge is electrically connected to the first terminal of the large-capacity electrolytic capacitor, the fourth terminal of the wave rectifier bridge is electrically connected to the second terminal of the large-capacity electrolytic capacitor, the third terminal of the wave rectifier bridge is electrically connected to the first terminal of the DC shunt module, and the fourth terminal of the wave rectifier bridge is electrically connected to the first terminal of the first switching transistor. The first terminal of the first switching transistor is electrically connected to the first terminal of the fifth operational amplifier; The second terminal of the first switching transistor serves as the second power output port. The DC shunt module is provided with a first power output port; The first terminal of the fifth operational amplifier is electrically connected to the first terminal of the first current-limiting resistor, the second terminal of the fifth operational amplifier is electrically connected to the first positive voltage source, the third terminal of the fifth operational amplifier is electrically connected to the first terminal of the second current-limiting resistor, and the fourth terminal of the fifth operational amplifier is grounded. The second terminal of the first current-limiting resistor is grounded; The second end of the second current-limiting resistor serves as an input port for inputting a pulse control signal so that the pulse source module 3 outputs a pulse current. The first power output port and the second power output port are electrically connected to the voltage-applied end of the cable segment 1 to be tested, and are used to output the pulse current.

[0049] Optionally, the switching power supply module includes a switching power supply, a switching power supply resistor, a sixth operational amplifier, a first interface, and a second interface, wherein: The first terminal of the switching power supply serves as the first terminal of the switching power supply module, the second terminal of the switching power supply serves as the second terminal of the switching power supply module, the third terminal of the switching power supply is electrically connected to the first terminal of the switching power supply resistor, the fourth terminal of the switching power supply is electrically connected to the first terminal of the first interface, the third terminal of the switching power supply is electrically connected to the first terminal of the second interface, the fourth terminal of the switching power supply is electrically connected to the second terminal of the second interface, the third terminal of the switching power supply is electrically connected to the first terminal of the sixth operational amplifier, and the fourth terminal of the switching power supply is electrically connected to the second terminal of the sixth operational amplifier. The second end of the switching power supply resistor is electrically connected to the second end of the first interface.

[0050] In specific implementation, the pulse source module 3 circuit provided in this embodiment is as follows: Figure 6As shown, the system includes an AC input circuit breaker U61 (in this embodiment, the circuit breaker model is AC-03-15A / 250V), a transformer T61 with isolation and step-down function (in this embodiment, the transformer model is TRANS-1-2-C), a range selector switch S61 (in this embodiment, the model is LW26-25), a switching power supply module, a fifth operational amplifier U5 (in this embodiment, the model is PC817), a full-wave rectifier bridge D61 (in this embodiment, the model is a single-phase bridge rectifier KBPC3510), a large-capacity electrolytic capacitor E61 (100uF / 450V), and a DC shunt module (in this embodiment, a DC shunt / Chaoguang FC-320W / 600V). The switching power supply module includes a first switching transistor Q61 (model FDP22N50N in this embodiment), a first current-limiting resistor R62 (1kΩ), and a second current-limiting resistor R63 (2kΩ); the first power output port J7 and the second power output port J8 are used to output pulse current; the input port PWM is used to input pulse control signals so that the pulse source module 3 outputs pulse current; the switching power supply module includes a switching power supply RS (model RS-25-12 in this embodiment, outputting 12V / 2.1V), a switching power supply resistor R61, a sixth operational amplifier U6 (model AD0812MS-A70GL in this embodiment), a first interface J9 (model 2510-3A) and a second interface J10 (model VH3.96-3A); Among them, the AC input circuit breaker serves as the main power switch of the whole machine, used to control the power-on and power-off of the entire pulse source module 3. When a short circuit or overload occurs in the downstream circuit and the current exceeds the rated value of 15A, the circuit breaker will automatically trip to cut off the power input, prevent the fault from spreading, and protect the equipment and personnel safety; the input port PWM (6) of the pulse source module 3 is used to input pulse control signals so that the pulse source module 3 outputs pulse current; J9 (2510-3A) is used to transmit the +12V and GND signals output by the switching power supply to the downstream circuit (such as U6). Its pin 1 is connected to the +12V power supply to provide the working voltage for the downstream module. Pin 2 is connected to GND as the reference ground of the power supply circuit. Pin 3 is left floating or used as a spare pin for extended functions or signal transmission; J10 (VH3.96-3A) serves as the external output interface of the switching power supply module, used to output stable +12V and GND to other modules of the whole system (such as sensors, control boards, etc.); its pin 1 is connected to + 12V power supply output, pin 2 is connected to GND ground output, and pin 3 is usually used as a spare pin or for transmitting control signals (such as power enable, fault indication, etc.).

[0051] In practical applications, this embodiment is configured with three output levels (25 / 50 / 100V), capable of outputting a maximum pulse current of 5A. The output is controlled by a high-power MOSFET, with an adjustable pulse width of 0-1000ms. It is powered by AC power or a portable power supply. The high-current pulse source is fed from the AC power input, which is then stepped down by transformer T61 and divided into three output levels, selectable via switch S61 to accommodate testing different ground fault impedances. The AC voltage is rectified by full-wave rectifier bridge D61, charging the large capacitor E61, and then the output is controlled by high-power MOSFET switch Q61, with an adjustable pulse width. A shunt resistor is connected in series in the output circuit to sample and measure the output pulse current.

[0052] In practical applications, this embodiment adds a fuse F1 (parameters 10A / 250V) at the AC input circuit breaker as backup protection for the circuit breaker. When the fault current is extremely high or the circuit breaker fails, the fuse will break the circuit by melting itself, providing a rapid response to severe short-circuit faults and preventing the main circuit from burning out. This embodiment also sets a current measurement interface J6 on the DC shunt module for pulse current detection of the pulse source module 3, so as to facilitate timely signal regulation.

[0053] In practical applications, the circuit in this embodiment adopts a partitioned grounding design, defining the ground of the main power circuit as G(1) and the ground of the control circuit as G(0). G(1) is specifically designed to carry the high-power pulse current flowing through the MOSFET and shunt, while G(0) serves as the logic reference ground for the optocoupler and switching power supply. This effectively prevents the high-current noise of the power circuit from coupling to the control circuit, ensuring the stability of the PWM pulse control signal and improving the accuracy of the pulse source output.

[0054] Optionally, this embodiment also provides a pulse current sampling circuit, such as... Figure 7As shown, the system includes a front-end filtering and voltage divider module. This module consists of an RC filter and surge absorption network composed of E71 (220μF / 50V), R71 (10kΩ), R72 (51Ω), and C71 (100nF). This network performs preliminary filtering on the voltage signal sampled by the shunt, suppressing high-frequency noise and surge voltage, and protecting the subsequent operational amplifier. A voltage divider network composed of R75 (51Ω) and R73 (500kΩ) adjusts the sampled voltage to the linear range of the high-precision operational amplifier U7 (OP07CD). The input range is provided, and DC bias is also provided. A high-precision operational amplifier U7 is used in conjunction with R74 (500kΩ) and C72 (100nF) to form an integrating amplifier circuit, which performs low-noise amplification and integration processing on the signal after voltage division at the front end, thereby improving the signal-to-noise ratio and stability of the signal. C73 (100nF) and C74 (100nF) are used as power supply decoupling capacitors for U7 to filter out the ripple noise of the positive and negative power supplies (+5(1) and -5(1)) and ensure the stable operation of the op-amp. A second-stage operational amplifier is used. Amplifier U8 (OP07CD), together with R75 (1kΩ) and R76 (1kΩ), forms a non-inverting amplifier circuit to amplify the signal output from U7 a second time, further increasing the signal amplitude to meet the input requirements of the microcontroller's AD sampling. C75 (1nF) is used in conjunction with U8 to form a low-pass filter network to filter out high-frequency interference and output a smooth VOUT signal. Voltage comparator U9 (LM393ND) is used to compare the analog signal output from U8 with the reference voltage. When the signal exceeds the threshold, the output flips to form the frequency signal FREQ. R77 (300kΩ) provides a reference voltage divider for U9 to set the comparison threshold. Pull-up resistor R78 (1kΩ) is set to pull the FREQ signal to +5 (1) to ensure stable output level. Bidirectional limiting diodes D71 (LL4148) and D72 (LL4148) are used to clamp the voltage range of the FREQ signal to protect the subsequent microcontroller IO port. V+ and V- are electrically connected to pin 1 and pin 3 of J9, respectively. The sampled pulse current and voltage signals are conditioned by signals U7 and U8, and the output signal VOUT is sent to the AD sampling terminal of the microcontroller to measure the magnitude of the output pulse current. Another path converts the signal into a frequency signal FREQ via comparator U10, calculates the frequency and pulse width of the pulse source output pulse, and adjusts the pulse control signal accordingly.

[0055] This embodiment also provides a method for locating grounding faults in the aluminum sheath 2 of a cable, used to implement the above-described system for locating grounding faults in the aluminum sheath 2 of a cable, wherein the system includes: a pulse source module 3 and a fitted sensor module 4; the method includes: When performing fault detection and location operations: The cable segment 1 to be tested is kept in the normal grounding port disconnected state; A pulse current is emitted to the pressurized end of the cable section 1 to be tested; The pulse signal is detected on the section of cable 1 to be tested, and the current signal detection result is obtained. When the current signal detection result shows a pulse change, it is determined that there is a fault point 5 in the section of cable 1 to be tested, and the location of the pulse change is located as the fault point 5, so as to realize the grounding fault location of the aluminum sheath 2 of the cable.

[0056] Based on the above embodiments of the cable aluminum sheath 2 grounding fault location system and cable aluminum sheath 2 grounding fault location method, this embodiment manufactures a fault location device consisting of a pulse source module 3 and multiple matching attached sensor modules 4. The fault location device was used in a simulated field test, and the following results were obtained: The fault location device designed in this embodiment located a 500-meter cable defect in 34 minutes, less than 60 minutes, achieving the first countermeasure objective of less than 60 minutes for defect location; 20 actual tests were conducted, with 20 successful and accurate locations, achieving 100% fault location reliability, greater than 95%, achieving the second countermeasure objective of over 95% reliability for the location method; The transmitter formed by the pulse source module 3 weighs 13 kg, and the sensor formed by the attached sensor module 4 weighs 0.3 kg, both less than 25 kg, achieving the third countermeasure objective of easy instrument transport in tunnels and a weight of less than 25 kg; The time to connect the transmitter to the cable outer sheath is 4 minutes, less than 10 minutes, achieving the fourth countermeasure objective of less than 10 minutes for instrument installation; The sensor's single measurement time is 5 seconds, less than 30 seconds, achieving the fifth countermeasure objective of sensitive instrument response and a single measurement time of less than 30 seconds. All five pre-defined countermeasure objectives were achieved, fulfilling the invention's purpose and enabling rapid and accurate location.

[0057] In summary, this embodiment employs a combined testing method of a high-current pulse current source and a bonded sensor. A high-current pulse source output is designed, increasing the maximum output current to over 50A, far exceeding the power frequency induction and other interference source signals in the field. Furthermore, a characteristic waveform mode is designed to effectively avoid various potential co-frequency interference problems. A bonded sensor has also been developed, which is extremely convenient to install and allows for simultaneous multi-point, segmented fault location operations, improving work efficiency several times over. The sensor incorporates a high-precision A / D converter and a high-performance 32-bit ARM processor, enabling it not only to record the received current pulse signal waveform but also to identify characteristic waveforms based on pulse shape, thus improving the accuracy of test results.

[0058] Based on the above embodiments of the cable aluminum sheath 2 grounding fault location method, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the cable aluminum sheath 2 grounding fault location method of any embodiment of the present invention.

[0059] For example, in this embodiment, the computer program can be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the terminal device.

[0060] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0061] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.

[0062] Based on the above-described method embodiments, another embodiment of the present invention provides a computer-readable storage medium, including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute the cable aluminum sheath 2 grounding fault location method described in any of the above-described method embodiments of the present invention.

[0063] The modules / units integrated in the device / terminal equipment, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0064] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A cable aluminum sheath grounding fault location system, applied to a section of cable to be inspected, wherein the section of cable to be inspected includes an aluminum sheath, characterized in that, The system includes: a pulse source module and a bonding sensor module; wherein: The pulse source module is electrically connected to the pressure end of the cable section to be tested, and the pressure end of the aluminum sheath of the cable serves as the pressure end of the cable section to be tested. The bonding sensor module includes an arc-shaped sensing surface. When the bonding sensor module performs pulse signal detection, the arc-shaped sensing surface is used to bond to the outer surface of the aluminum sheath of the cable. When performing fault detection and location operations: The cable section to be tested is in a normal grounding port disconnected state; The pulse source module is used to emit pulse current to the pressurized end of the cable section to be tested; The fitted sensor module is used to detect the pulse signal of the cable section to be tested and obtain the current signal detection result; when the current signal detection result shows a pulse change, it is determined that there is a fault point in the cable section to be tested, and the location of the pulse change is located as the fault point, so as to realize the location of the grounding fault of the cable aluminum sheath.

2. The cable aluminum sheath grounding fault location system as described in claim 1, characterized in that, The fitted sensor module includes an induction coil sampling circuit, a dual-T filter circuit, a signal amplification and processing circuit, and a data processing circuit, wherein: The output terminal of the induction coil sampling circuit is electrically connected to the input terminal of the double-T filter circuit, the output terminal of the double-T filter circuit is electrically connected to the input terminal of the signal amplification and processing circuit, and the output terminal of the signal amplification and processing circuit is electrically connected to the input terminal of the data processing circuit. The induction coil sampling circuit is used to detect pulse signals and output an induction signal so that the induction coil sampling circuit can convert the induction signal and output a pulse voltage signal. The dual-T filter circuit is used to filter out power frequency interference from the pulse voltage signal and output a filtered pulse voltage signal. The signal amplification and processing circuit is used to amplify the filtered pulse voltage signal with fixed gain and programmable gain, and output an amplified pulse voltage signal. The data processing circuit is used to perform voltage biasing and analog-to-digital conversion on the amplified pulse voltage signal, output a digital sampling signal, and obtain the current signal detection result based on the digital sampling signal.

3. The cable aluminum sheath grounding fault location system as described in claim 2, characterized in that, The induction coil sampling circuit includes an induction coil, a series current-limiting resistor, a pull-down resistor, a bidirectional transient suppression diode, a filter capacitor, a first voltage divider resistor, a second voltage divider resistor, a first operational amplifier, a first feedback resistor, a second feedback resistor, a third feedback resistor, a first integrating capacitor, a second integrating capacitor, a first power supply decoupling capacitor, a second power supply decoupling capacitor, a power supply decoupling resistor, a current-limiting resistor, a low-pass filter resistor, and a low-pass filter capacitor, wherein: The first end of the series current-limiting resistor is electrically connected to the first end of the induction coil, the second end of the series current-limiting resistor is electrically connected to the first end of the pull-down resistor, and the second end of the induction coil is grounded. The first end of the pull-down resistor is electrically connected to the first end of the first voltage divider resistor, the first end of the pull-down resistor is electrically connected to the first end of the bidirectional transient suppression diode, the second end of the pull-down resistor is electrically connected to the second end of the bidirectional transient suppression diode, the second end of the pull-down resistor is electrically connected to the first end of the filter capacitor, and the second end of the pull-down resistor is grounded. The second end of the first voltage divider resistor is electrically connected to the second end of the filter capacitor, and the second end of the first voltage divider resistor is electrically connected to the first end of the second voltage divider resistor. The second end of the second voltage divider resistor is electrically connected to the negative input terminal of the first operational amplifier, the second end of the second voltage divider resistor is electrically connected to the first end of the first feedback resistor, and the second end of the second voltage divider resistor is electrically connected to the first end of the first integrating capacitor. The second end of the first feedback resistor is electrically connected to the first end of the second feedback resistor, and the second end of the first feedback resistor is electrically connected to the first end of the third feedback resistor. The second end of the third feedback resistor is electrically connected to the first end of the second integrating capacitor, and the second end of the second integrating capacitor is grounded. The second terminal of the first integrating capacitor is electrically connected to the second terminal of the second feedback resistor, the second terminal of the first integrating capacitor is electrically connected to the output terminal of the first operational amplifier, and the second terminal of the first integrating capacitor is electrically connected to the first terminal of the current limiting resistor. The second end of the current-limiting resistor is electrically connected to the first end of the low-pass filter resistor, the second end of the current-limiting resistor is electrically connected to the first end of the low-pass filter capacitor, and the second end of the low-pass filter capacitor is grounded. The first end of the low-pass filter resistor serves as the output end of the induction coil sampling circuit, used to output a pulse voltage signal. The positive input terminal of the first operational amplifier is electrically connected to the first terminal of the power supply decoupling resistor, the negative power supply terminal of the first operational amplifier is electrically connected to the first terminal of the first power supply decoupling capacitor, the negative power supply terminal of the first operational amplifier is electrically connected to a first negative voltage source, the positive power supply terminal of the first operational amplifier is electrically connected to the first terminal of the second power supply decoupling capacitor, the positive power supply terminal of the first operational amplifier is electrically connected to a first positive voltage source, the second terminal of the power supply decoupling resistor is grounded, the second terminal of the first power supply decoupling capacitor is grounded, and the second terminal of the second power supply decoupling capacitor is grounded.

4. The cable aluminum sheath grounding fault location system as described in claim 2, characterized in that, The dual-T filter circuit includes a third voltage divider resistor, a fourth voltage divider resistor, a first voltage divider capacitor, a second voltage divider capacitor, a dual-T filter resistor, a first capacitor, a second capacitor, a dual operational amplifier, a third power supply decoupling capacitor, a fourth power supply decoupling capacitor, a fifth voltage divider resistor, a sixth voltage divider resistor, and a seventh voltage divider resistor, wherein: The first end of the third voltage divider resistor serves as the input terminal of the double-T filter circuit. The first end of the third voltage divider resistor is electrically connected to the first end of the first voltage divider capacitor. The second end of the third voltage divider resistor is electrically connected to the first end of the fourth voltage divider resistor. The second end of the third voltage divider resistor is electrically connected to the first end of the first capacitor. The second end of the third voltage divider resistor is electrically connected to the first end of the second capacitor. The second end of the fourth voltage divider resistor is electrically connected to the second end of the second voltage divider capacitor, and the second end of the fourth voltage divider resistor is electrically connected to the non-inverting input of the first operational amplifier of the dual operational amplifier. The second terminal of the first voltage divider capacitor is electrically connected to the first terminal of the double-T filter resistor, and the second terminal of the first voltage divider capacitor is electrically connected to the first terminal of the second voltage divider capacitor. The second end of the dual-T filter resistor is electrically connected to the second end of the first capacitor, the second end of the dual-T filter resistor is electrically connected to the second end of the second capacitor, and the second end of the dual-T filter resistor is electrically connected to the inverting input terminal of the second operational amplifier of the dual operational amplifier. The first operational amplifier's inverting input terminal is electrically connected to the first operational amplifier's output terminal. The first operational amplifier's output terminal is electrically connected to the first terminal of the fifth voltage divider resistor. The first operational amplifier's output terminal is electrically connected to the first terminal of the sixth voltage divider resistor. The second operational amplifier's inverting input terminal is electrically connected to the second operational amplifier's output terminal. The positive power supply terminal of the dual operational amplifier is electrically connected to the first terminal of the third power supply decoupling capacitor. The positive power supply terminal of the dual operational amplifier is electrically connected to a first positive voltage source. The negative power supply terminal of the dual operational amplifier is electrically connected to the first terminal of the fourth power supply decoupling capacitor. The negative power supply terminal of the dual operational amplifier is electrically connected to a first negative voltage source. The second terminal of the third power supply decoupling capacitor is grounded, and the second terminal of the fourth power supply decoupling capacitor is grounded. The second terminal of the fifth voltage divider resistor serves as the output terminal of the dual-T filter circuit. The second end of the sixth voltage divider resistor is electrically connected to the first end of the seventh voltage divider resistor; The first end of the seventh voltage divider resistor is electrically connected to the non-inverting input of the second operational amplifier of the dual operational amplifier, and the second end of the seventh voltage divider resistor is grounded.

5. A cable aluminum sheath grounding fault location system as described in claim 2, characterized in that, The signal amplification and processing circuit includes a second operational amplifier, a programmable gain amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, and a tenth capacitor, wherein: The positive input terminal of the second operational amplifier serves as the input terminal of the signal amplification and processing circuit. The negative input terminal of the second operational amplifier is electrically connected to the first terminal of the first resistor. The positive input terminal of the second operational amplifier is electrically connected to the first terminal of the second resistor. The negative power supply terminal of the second operational amplifier is electrically connected to the first terminal of the fourth capacitor. The positive power supply terminal of the second operational amplifier is electrically connected to the first terminal of the fifth capacitor. The output terminal of the second operational amplifier is electrically connected to the second terminal of the first resistor. The output terminal of the second operational amplifier is electrically connected to the first terminal of the third capacitor. The output terminal of the second operational amplifier is electrically connected to the first terminal of the third resistor. The second terminal of the third capacitor is grounded; The second end of the third resistor is electrically connected to the positive input terminal of the programmable gain amplifier; The negative input terminal of the programmable gain amplifier is grounded; the first correction terminal of the programmable gain amplifier is electrically connected to the first terminal of the fourth resistor; the second correction terminal of the programmable gain amplifier is electrically connected to the first terminal of the fifth resistor; the negative power supply terminal of the programmable gain amplifier is electrically connected to the first terminal of the sixth capacitor; the negative power supply terminal of the programmable gain amplifier is electrically connected to the first negative voltage source; the positive power supply terminal of the programmable gain amplifier is electrically connected to the first terminal of the seventh capacitor; the positive power supply terminal of the programmable gain amplifier is electrically connected to the first positive voltage source; the output terminal of the programmable gain amplifier is electrically connected to the first terminal of the eighth capacitor; and the output terminal of the programmable gain amplifier is electrically connected to the negative input terminal of the third operational amplifier. The second end of the fourth resistor is electrically connected to the first negative voltage source, and the second end of the fifth resistor is electrically connected to the first positive voltage source; The negative input terminal of the third operational amplifier is electrically connected to the output terminal of the third operational amplifier, the negative power supply terminal of the third operational amplifier is electrically connected to the first terminal of the ninth capacitor, the negative power supply terminal of the third operational amplifier is electrically connected to the first negative voltage source, the positive power supply terminal of the third operational amplifier is electrically connected to the first terminal of the tenth capacitor, the positive power supply terminal of the third operational amplifier is electrically connected to the first positive voltage source, and the output terminal of the third operational amplifier serves as the output terminal of the signal amplification and processing circuit. The second terminal of the sixth capacitor is grounded, the second terminal of the eighth capacitor is grounded, the second terminal of the ninth capacitor is grounded, and the second terminal of the tenth capacitor is grounded.

6. The cable aluminum sheath grounding fault location system as described in claim 2, characterized in that, The data processing circuit includes a fourth operational amplifier, an analog-to-digital converter, a first data capacitor, a second data capacitor, a third data capacitor, a fourth data capacitor, a fifth data capacitor, a sixth data capacitor, a seventh data capacitor, a first data resistor, a second data resistor, a third data resistor, a fourth data resistor, a fifth data resistor, and a sixth data resistor, wherein: The first end of the first data resistor serves as the input terminal of the data processing circuit. The first end of the first data resistor is electrically connected to the first end of the first data capacitor. The second end of the first data resistor is electrically connected to the first end of the second data resistor. The second end of the first data resistor is electrically connected to the first end of the third data resistor. The second end of the first data resistor is electrically connected to the positive input terminal of the fourth operational amplifier. The second terminal of the first data capacitor is grounded, and the second terminal of the second data resistor is grounded. The second terminal of the third data resistor is electrically connected to the second positive voltage source; The negative input terminal of the fourth operational amplifier is electrically connected to the first terminal of the fourth data resistor, the negative output terminal of the fourth operational amplifier is electrically connected to the first terminal of the fifth data resistor, the output terminal of the fourth operational amplifier is electrically connected to the second terminal of the fifth data resistor, and the output terminal of the fourth operational amplifier is electrically connected to the first terminal of the sixth data resistor. The second terminal of the fourth data resistor is grounded; The second end of the sixth data resistor is electrically connected to the first end of the fourth data capacitor, the second end of the fourth data capacitor is grounded, and the second end of the sixth data resistor is electrically connected to the positive input terminal of the analog-to-digital converter. The negative input terminal and ground terminal of the analog-to-digital converter (ADC) are grounded. The power supply terminal of the ADC is electrically connected to a first positive voltage source. The power supply terminal of the ADC is electrically connected to the first terminal of the seventh data capacitor. The voltage reference terminal of the ADC is electrically connected to a second positive voltage source. The voltage reference terminal of the ADC is electrically connected to the first terminal of the fifth data capacitor. The output terminal of the ADC is electrically connected to a third positive voltage source. The output terminal of the ADC is electrically connected to the first terminal of the sixth data capacitor. The output terminal of the ADC serves as the output terminal of the data processing circuit. The second terminal of the fifth data capacitor is grounded, the second terminal of the sixth data capacitor is grounded, and the second terminal of the seventh data capacitor is grounded.

7. The cable aluminum sheath grounding fault location system as described in claim 1, characterized in that, The pulse source module includes an AC input circuit breaker, a transformer, a range selector switch, a switching power supply module, a large-capacity electrolytic capacitor, a fifth operational amplifier, a full-wave rectifier bridge, a large-capacity electrolytic capacitor, a DC shunt module, a first switching transistor, a first current-limiting resistor, and a second current-limiting resistor, wherein: The AC input circuit breaker receiver is used to receive power input. The first output terminal of the AC input circuit breaker is electrically connected to the first terminal of the switching power supply module. The second output terminal of the AC input circuit breaker is electrically connected to the second terminal of the switching power supply module. The first output terminal of the AC input circuit breaker is electrically connected to the first terminal of the transformer. The second output terminal of the AC input circuit breaker is electrically connected to the second terminal of the transformer. The third terminal of the transformer is electrically connected to the first terminal of the gear selector switch, the fourth terminal of the transformer is electrically connected to the second terminal of the gear selector switch, the fifth terminal of the transformer is electrically connected to the third terminal of the gear selector switch, the sixth terminal of the transformer is electrically connected to the third terminal of the gear selector switch, the seventh terminal of the transformer is electrically connected to the fourth terminal of the gear selector switch, and the third terminal of the transformer is electrically connected to the first terminal of the full-wave rectifier bridge. The fifth terminal of the gear selection switch is electrically connected to the second terminal of the full-wave rectifier bridge; The third terminal of the wave rectifier bridge is electrically connected to the first terminal of the large-capacity electrolytic capacitor, the fourth terminal of the wave rectifier bridge is electrically connected to the second terminal of the large-capacity electrolytic capacitor, the third terminal of the wave rectifier bridge is electrically connected to the first terminal of the DC shunt module, and the fourth terminal of the wave rectifier bridge is electrically connected to the first terminal of the first switching transistor. The first terminal of the first switching transistor is electrically connected to the first terminal of the fifth operational amplifier; The second terminal of the first switching transistor serves as the second power output port. The DC shunt module is provided with a first power output port; The first terminal of the fifth operational amplifier is electrically connected to the first terminal of the first current-limiting resistor, the second terminal of the fifth operational amplifier is electrically connected to the first positive voltage source, the third terminal of the fifth operational amplifier is electrically connected to the first terminal of the second current-limiting resistor, and the fourth terminal of the fifth operational amplifier is grounded. The second terminal of the first current-limiting resistor is grounded; The second end of the second current-limiting resistor serves as an input port for inputting a pulse control signal so that the pulse source module outputs a pulse current. The first power output port and the second power output port are electrically connected to the voltage-applied end of the cable segment to be tested, and are used to output the pulse current.

8. The cable aluminum sheath grounding fault location system as described in claim 7, characterized in that, The switching power supply module includes a switching power supply, a switching power supply resistor, a sixth operational amplifier, a first interface, and a second interface, wherein: The first terminal of the switching power supply serves as the first terminal of the switching power supply module, the second terminal of the switching power supply serves as the second terminal of the switching power supply module, the third terminal of the switching power supply is electrically connected to the first terminal of the switching power supply resistor, the fourth terminal of the switching power supply is electrically connected to the first terminal of the first interface, the third terminal of the switching power supply is electrically connected to the first terminal of the second interface, the fourth terminal of the switching power supply is electrically connected to the second terminal of the second interface, the third terminal of the switching power supply is electrically connected to the first terminal of the sixth operational amplifier, and the fourth terminal of the switching power supply is electrically connected to the second terminal of the sixth operational amplifier. The second end of the switching power supply resistor is electrically connected to the second end of the first interface.

9. A method for locating grounding faults in the aluminum sheath of cables, characterized in that, A cable aluminum sheath grounding fault location system as described in any one of claims 1 to 8, wherein the system comprises: a pulse source module and a contact sensor module; the method comprises: When performing fault detection and location operations: The cable segment to be tested is controlled to have its normal grounding port disconnected. A pulse current is emitted to the pressurized end of the cable section to be tested; The pulse signal is detected on the section of cable to be tested to obtain the current signal detection result; when the current signal detection result shows a pulse change, it is determined that there is a fault point in the section of cable to be tested, and the location of the pulse change is located as the fault point, so as to realize the location of the grounding fault of the aluminum sheath of the cable.

10. A terminal device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, it implements the cable aluminum sheath grounding fault location method as described in claim 9.

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