NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–CCTV Tester
The method of cable fault tester to test the cable fault The first step: first measure the distance with a distance meter. In fact, it is necessary to first judge whether the cable fault is high resistance or low resistance or grounding, and different test methods are used according to this condition. If it is a ground fault, the method of testing the cable fault with the cable fault tester The first step: first measure the distance with a distance meter.
In fact, it is necessary to first judge whether the cable fault is high resistance or low resistance or grounding, and different test methods are used according to this condition. If it is a ground fault, use the low-voltage pulse method of the distance meter to measure the distance directly; if it is a high-resistance fault, use the high-voltage impulse discharge method to measure the distance, and use the high-voltage impulse discharge method to measure the distance. Auxiliary equipment, such as high-voltage pulse capacitors, discharge balls, current-limiting resistors, inductor coils and signal samplers, etc., are troublesome and unsafe to operate, and have certain dangers. What is more cumbersome is to analyze the sampling waveform. The knowledge requirements of the testers are relatively high. The second step: is to find the path (if the path is clear, this step can be omitted).
When searching for a path, add a signal to the cable (path signal generator), then use the receiver to receive the signal, and walk along the path with the signal to determine the path of the cable. However, the range of this path is roughly between 1-2 meters, which is not particularly accurate. The third step is to accurately locate according to the measured distance.
It is based on the sound produced by the spark discharge. When the loudest sound is heard from the earphone of the pointing device, the location of the fault point is found. However, because it is listening to the sound, it takes a lot of time to find it due to the influence of the ambient noise, and sometimes it can only be done at night. When it comes to cross-linked cables, it takes more time, because cross-linked cables are generally internally discharged, and the sound is very small, almost inaudible, and finally only measurement.
Therefore, this method can solve most of the faults of power cables with oil-impregnated paper as insulating materials. For the faults of cables with cross-linked materials and polyethylene materials as insulating materials in recent years, the test results are not very ideal. The reason is that the sound produced by the spark discharge is often very small (the outer sheath of the cable is not damaged, but the inner part of the cable is discharged). When this happens, other methods can only be used to solve it.
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