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–Cable Tester Manufacturer
Question: How Power Cable Fault Tester Works Answer: How Power Cable Fault Tester Works Power Cable Fault Tester is mainly composed of three parts: Power Cable Fault Tester Host, Cable Fault Locator and Cable Path Test Question: Power Cable The working principle of the fault tester Answer: The working principle of the power cable fault tester The power cable fault tester is mainly composed of three parts: the power cable fault tester host, the cable fault locator and the cable path tester. The main unit of the cable fault tester is used to measure the nature of the cable fault, the full length and approximate location of the cable fault point from the test end. The cable fault locator determines the precise position of the cable fault point according to the approximate position of the cable fault point determined by the host of the cable fault tester.
For underground cables whose direction is unknown, a path meter is required to determine the underground direction of the cable. The basic method of testing power cable faults is to apply a high voltage pulse to the faulty power cable to create a breakdown at the fault point of the cable. At the same time, cable faults are eliminated while generating external electromagnetic waves and sound.
The working principle of the arc reflection method (second pulse method) at the fault location of the cable: First, apply a high voltage pulse with a certain voltage level and a certain energy to the faulty cable at the test end of the cable, so that the high resistance fault point of the cable is touched. Cross arc. At the same time, a low voltage pulse for measurement is added to the test terminal.
When the measurement pulse reaches the high-resistance fault point of the cable, it encounters an arc and reflects off the surface of the arc. Since the high-impedance fault becomes an instantaneous short-circuit fault during arcing, the low-voltage measurement pulse will have a significant change in impedance characteristics, which will cause the waveform of the flashover measurement to become a low-voltage pulse short-circuit waveform, making the waveform identification particularly simple and clear. This is what we call"second pulse method". The received low-voltage pulse reflection waveform is equivalent to the waveform of the core completely grounded.
Superimpose the low-voltage pulse waveform obtained when the high-voltage pulse is released and the low-voltage pulse waveform obtained when the high-voltage pulse is not released. The two waveforms will have a divergence point, which is the point of the reflected waveform at the fault point. This method combines the low voltage pulse method with the high voltage flashover technique to make it easier for the tester to locate the fault point.
Compared with the traditional test method, the advantage of the secondary pulse method is that the complex waveform in the shock high voltage flashover method is simplified to the simplest low voltage pulse short circuit fault waveform, so the interpretation is very simple and the fault distance can be accurately calibrated .
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