Cable Fault Path Detector

Product Usage

Precision location of underground cable fault points, accurate determination of the burial path and depth of underground cablesPrecision Detection。

Point Principle

Utilizing the principle of acoustic-magnetic synchronous positioning to precisely locate fault points. The specific implementation method is as follows:

By applying a pulse high voltage to one end of an underground power cable, a discharge arc is generated at the fault point of the cable, producing electromagnetic waves and vibration sound waves—acoustic-magnetic signals. The digital synchronous positioning instrument synchronously receives the acoustic-magnetic signals emitted by the discharge arc, and converts the time difference between the electromagnetic waves and sound waves received by the digital synchronous positioning instrument into the straight-line distance from the receiver's fixed probe to the fault point in digital form. Simultaneously, along the path of the cable burial, the size of the fault point's discharge vibration sound is judged by the earphones based on the received sound waves by the probe. The reading on the digital display is lower and the sound of the vibration wave is louder directly above the fault point, thereby accurately determining the precise location of the fault point.

Upon initial power-up, the two-digit digital displays on the surveyor's panel show the internal battery voltage (e.g., 8.0) as 8.0 volts; they then automatically switch to "0.0" (meters). During the transition between survey and path functions, the displayed value is also the internal battery voltage. During the surveying process, if no vibration waves are heard, each time the starting end discharges, the high-voltage electromagnetic field radiated on the cable is refreshed on the digital display screen, starting a count with a large number, 100. Each refresh of the display's digits indicates a normal discharge from the starting end, with the blinking rate in sync with the discharge cycle. During the survey, the ground probe moves forward along the path at approximately 50 cm intervals, listening carefully for the vibration sound waves of the discharge from the fault point deep in the ground. When seismic waves are heard at a certain intensity, a number is displayed. If this number is in sync with the discharge cycle and repeats, it represents the straight-line distance from the ground sensor probe to the underground cable fault point. As the sensor probe approaches the fault point, this number decreases gradually. Above the fault point, the discharge sound is loud, and the displayed reading is small. When the sensor probe passes the fault point, the displayed reading increases again. At this point, the sensor probe should be moved slowly forward and backward, observing the digital display's reading carefully. The reading is small below where the discharge sound is loud, indicating the fault point. At this moment, the displayed number represents the approximate burial depth of the cable at the fault point.

During the pinpointing process, irregular values may occasionally appear randomly. These are interferences from environmental noise and should be disregarded. The sound is the true signal from the fault point only when the underground vibration waves heard by the sensing probe synchronize with the high-voltage discharge (synchronizing with the refresh of the digital display). This effectively eliminates the interference from environmental noise.

The theodolite should be recharged as soon as the internal voltage drops below approximately 7 volts after a certain period of use. Failure to do so may result in reduced accuracy or increased noise, affecting normal operation.