As the core carrier of power transmission, the fault diagnosis efficiency of power cables directly affects the reliability of power supply. The cable fault testing instrument has become the core equipment for power operation and maintenance by providing accurate technical solutions to achieve full process testing such as fault nature diagnosis, distance measurement, and precise positioning. This article will focus on mainstream testing instruments and analyze them from two aspects: core technical principles and industry adaptation technology advantages, providing reference for operation and maintenance selection.

1、 Core Testing Instruments: Technical Principles and Advantages Analysis

The core testing instrument is the "core center" for cable fault diagnosis, covering three core functions: fault diagnosis, distance measurement, and positioning. Its technical level directly determines the efficiency and accuracy of fault diagnosis.

（1） Cable Fault Tester (Host) - Fault Diagnosis and Ranging Core

1. Core technical principles

Adopting the composite technology route of "multi pulse detection+intelligent signal analysis", the core includes two major core modules:

Signal generation module: switchable output of low-voltage pulses (for low resistance/open circuit faults) and multiple pulses (secondary/tertiary pulses, for high resistance/flashover faults), injecting stable test signals into the tested cable through coaxial cables, with a rising edge of ≤ 10ns, ensuring signal penetration and identification;

Signal analysis module: equipped with a high-speed data acquisition chip (sampling rate ≥ 100MHz), it captures the signal waveform reflected by the fault point, combines with the built-in intelligent waveform recognition algorithm, automatically filters the on-site electromagnetic interference (such as frequency converter, high-voltage equipment interference), and compares it with the preset cable parameters (wave speed, length) to calculate the fault distance.

2. Core technological advantages

Full fault type adaptation, strong compatibility: Through pulse mode switching, it can accurately diagnose all common cable faults such as low resistance (≤ 100 Ω), high resistance (>100 Ω), open circuit, flashover, etc., without the need for additional specialized instruments, suitable for all scenarios of 10kV-110kV medium and high voltage cables;

High ranging accuracy and controllable error: Intelligent algorithms can automatically correct wave velocity deviation, ranging accuracy ≤ 1% ± 1m, and can still maintain accuracy for long-distance cables (>10km), greatly reducing the subsequent fixed-point range and avoiding blind excavation;

Outstanding anti-interference ability, suitable for complex sites: adopting shielded signal transmission design and interference filtering algorithm, it can work stably in scenarios with severe electromagnetic interference such as cable trenches and substations, with waveform recognition accuracy of ≥ 95%;

Easy to operate, lowering the threshold: equipped with a high-definition touch screen, built-in cable parameter database (covering mainstream cable types such as cross-linked polyethylene and oil paper), supports automatic waveform storage and playback, and beginners can independently complete distance measurement operations after simple training.

（2） Acoustic magnetic synchronous fixed-point instrument - key equipment for precise fault location

1. Core technical principles

Based on the "fault discharge sound light synchronous induction" technology, positioning is achieved using two core signals generated during the discharge of the fault point:

Electromagnetic signal induction: By using a built-in coil sensor to capture the electromagnetic pulse signal generated during fault discharge, the signal response frequency range is 100Hz-1MHz, which can accurately pinpoint the approximate range of the fault point;

Acoustic signal acquisition: By using a high-sensitivity microphone to collect mechanical waves (sound signals) generated by fault discharge, combined with acoustic electric synchronous triggering technology, the time difference between electromagnetic signals and acoustic signals is converted into distance difference to achieve precise positioning.

2. Core technological advantages

High positioning accuracy, directly hitting the fault point: synchronized comparison of acoustic and magnetic signals, positioning accuracy ≤ 0.1m, can accurately lock the fault point of buried cables, avoid excessive excavation, and reduce operation and maintenance costs;

Strong environmental adaptability, fearless of noisy scenes: Built in acoustic filtering algorithm, can filter environmental noise such as vehicles and personnel on site, and can still clearly identify fault discharge sound in noisy scenes such as urban roads and industrial parks;

Suitable for multi scenario installation: supports both handheld and bracket usage, equipped with high fidelity headphones, and can be flexibly operated in complex installation environments such as narrow cable trenches and high-altitude cable trays;

Safety redundancy design: Adopting an inherently safe circuit design, it is resistant to high voltage impact and can ensure the safety of operators in the event of high-voltage cable fault discharge scenarios.

（3） Step voltage fixed-point instrument - specialized equipment for cable outer sheath faults

1. Core technical principles

In response to the damage of the outer sheath of a single core high-voltage cable, the "DC high voltage excitation+step voltage induction" technology is adopted: DC high voltage is injected into the outer sheath of the cable through a high-voltage signal generator, and the fault point will generate leakage current and form a potential gradient on the ground. The instrument senses the step voltage difference between two points on the ground through a double probe. When the probe approaches the fault point, the voltage difference will show a significant sudden change, thereby locking the fault location.

2. Core technological advantages

Specialized treatment for specific diseases, precise positioning of outer sheath faults: targeted solutions for difficult faults such as damaged outer sheath and grounding of single core cables, with a positioning error of a ≤ 0.5m, and a technical gap in conventional fixed-point instruments;

High voltage compatibility, suitable for high voltage scenarios: supports up to 35kV excitation voltage input, can penetrate the outer sheath insulation layer, and can generate stable leakage current even in minor damage faults, with a detection rate of ≥ 98%;

Intuitive operation and clear indication: equipped with digital voltage display and fault direction indicator lights, operators can quickly determine the fault direction based on the trend of voltage changes, without the need for complex data analysis.

2、 Auxiliary identification instrument: technology empowers operation and maintenance efficiency improvement

Although auxiliary identification instruments do not directly participate in fault location, they can solve the pre problem of "finding the right cable and understanding the path", avoiding the risk of misoperation. Their technical advantages are mainly reflected in anti-interference, accurate identification, and safe adaptation.

（1） Electric cable identification device

1. Core technical principles

Using the "phase induction+encoded signal recognition" technology, the transmitting end injects a unique encoded low-frequency electromagnetic signal into the target cable, and the receiving end captures the electromagnetic signal around the cable through an induction coil. Combined with phase comparison technology, the signal difference between the target cable and adjacent parallel cables is distinguished to achieve accurate recognition.

2. Core technological advantages

Both live and power outages can be identified, suitable for all scenarios: no need to cut off cable power supply, identification can be completed in live operation to avoid affecting normal power supply;

Strong anti-interference ability, multiple cables parallel without pressure: For complex scenarios where multiple cables are parallel in cable trenches, encoded signals can effectively resist signal interference from adjacent cables, with a recognition accuracy of ≥ 99%;

Safe and convenient, easy to operate: Non contact induction design, no need to directly contact cable conductors, equipped with sound and light alarm indicators, operators can quickly judge the recognition results.

（2） Underground pipeline detector

1. Core technical principles

Based on the "electromagnetic induction+signal attenuation analysis" technology, the transmitting end injects electromagnetic signals of a specific frequency into the buried cable, and the receiving end captures the electromagnetic signals radiated by the cable by adjusting the receiving frequency. The cable path direction is determined by changes in signal strength; At the same time, combined with the signal attenuation model, calculate the cable burial depth.

2. Core technological advantages

Deep detection depth, covering mainstream scenarios: capable of detecting buried cables with a depth of 0-3m, suitable for mainstream buried cable laying scenarios such as urban roads and industrial parks;

Synchronized acquisition of path and burial depth, with strong planning capability: not only can it accurately locate the cable path (positioning accuracy ≤ 5cm), but it can also display the burial depth in real time, providing accurate depth reference for subsequent excavation points and avoiding cutting off adjacent pipelines;

Multi frequency adaptation, strong penetration: supports switching between multiple frequencies (1kHz-100kHz), can adjust the frequency according to soil moisture and cable shielding layer type, ensuring stable detection even under complex geological conditions.

3、 Supporting equipment: Safety and efficiency guarantee of technological advantages

Although the supporting equipment is an auxiliary tool, it provides safety redundancy and efficiency support for the testing process through technological optimization. Its core technological advantages are focused on safety protection and scene adaptation.

（1） Integrated high-voltage signal generator

Core technological advantages: Adopting modular design, the output voltage is continuously adjustable from 0-35kV, and can be linked with the fault tester host to automatically match the pulse mode; Equipped with dual protection against overcurrent and overvoltage, it automatically shuts down when the current exceeds the threshold to avoid damaging cables and instruments; Compact in size, supports portable mobility, and is suitable for outdoor on-site testing.

（2） Dual gun cable safety stabbing device

Core technological advantages: adopting remote control operation design, operators can complete piercing at a safe distance (≥ 5m), avoiding direct contact with high-voltage cables; Double gun double bond interlock prevents misoperation, and after piercing, the live status of the cable can be visually judged through discharge indication; Suitable for 10kV-35kV cables, the shell is made of insulation material and resistant to high voltage impact.

4、 Summary of overall technological advantages and industry value

The Leande power cable fault testing instrument has achieved three core industry values through technological upgrades of "precision, intelligence, safety, and portability":

Improve troubleshooting efficiency: Traditional manual troubleshooting takes several days, but with the help of precise testing instruments, it can be shortened to several hours, significantly reducing power outage time and improving power supply reliability;

Reduce operation and maintenance costs: precise positioning to avoid blind excavation, reduce manpower and material investment; Intelligent operation reduces reliance on professionals and lowers training costs;

Ensuring operation and maintenance safety: Essentially safe design, non-contact operation, multiple protection functions, avoiding safety risks such as high-voltage electric shock and misoperation from a technical perspective, and ensuring the personal safety of operation and maintenance personnel.

In the future, with the integration of the Internet of Things and AI technology, the Leiente cable fault testing instrument will be upgraded towards "remote control, intelligent prediction, and data traceability", further enhancing the intelligence level of industry operation and maintenance.