Author: Noyafa–Cable Tester Suppliers
The detection of cable faults generally goes through four steps: diagnosis, distance measurement, path finding and fixed point. 1. Diagnosis Diagnosis of the nature of the cable fault, that is, to determine the type and severity of the fault, so that the tester can prescribe the right medicine and select the appropriate cable fault location and fixed-point method. Use a megohmmeter and a multimeter to measure the fault resistance to determine whether the cable fault is high resistance or low resistance; whether it is a flashover or a closed fault; whether it is grounding, short circuit, disconnection, or a combination of them; whether it is single-phase, two-phase, or three-phase. Phase failure.
2. Distance measurement of cable fault tester During the test, first use the low-voltage pulse function of the flash tester to test the full length of each phase of the cable separately to see if the test waveforms are consistent when the three-phase armor is tested. For most high-impedance faults, the test waveforms for each phase are consistent. For low-resistance faults and high-resistance faults with open-phase faults, the test waveform of the faulty phase is inconsistent with the full length of the tested cable, so that the fault distance can be directly tested with low-voltage pulses.
3. Path testing When looking for the cable path, connect the opposite end of the cable or the armor to the ground, then connect the cable path test type generator at the test end, and clamp the two test clamps to the opposite end. Between the phase of the loop or the armor and the ground, after turning on the power, you can hold the signal receiver to find the cable path. 4. Determine the precise point. When testing by the high-voltage flashover method, no matter whether the cable fault is a high-resistance fault or a low-resistance fault, the high-voltage flashover method can be used for testing. For low-resistance or disconnection faults that can directly test the fault distance with low-voltage pulses, generally high-voltage flashovers are also used for verification testing and accurate determination of the fault point.
When testing the high-voltage flashover method, it should be noted that no matter whether the cable has a single-phase fault or a multi-phase fault, when testing a faulty phase, the other cable phase wires should be short-circuited with the cable armor to reduce the interference of other cables and improve the performance of the cable. Test accuracy. After the high-voltage flashover method test is completed, the fault distance is determined, and the fault can be accurately determined. When using the acousto-magnetic synchronous locator, fault locating and path detection can be carried out synchronously.
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