The working principle of the cable fault tester is to first measure the reflected waveform of the low-voltage pulse without breaking down the fault point of the cable under test, and then use the high-voltage pulse to break down the fault point of the cable to generate an arc, and the arc voltage drops to At a certain value, a medium voltage pulse is triggered to stabilize and extend the arc time, and then a low voltage pulse is sent out to obtain the reflected waveform of the fault point. After the two waveforms are superimposed, it can also be found that the divergence point is the corresponding position of the fault point. Because the medium voltage pulse is used to stabilize and extend the arc time, it is easier to obtain the fault point waveform than the two-pulse method. Compared with the two-pulse method, since the three-pulse method does not need to select the arc synchronization duration, it is easy to operate. The triple-pulse method uses the double-impact method to extend the arcing time and stabilize the arc, which can easily locate high-resistance faults and flashover faults. The triple-pulse method has advanced technology, simple operation, clear waveforms, fast and accurate positioning, and has become the mainstream positioning method for high-impedance faults and flashover faults. The three-pulse method is an upgrade of the two-pulse method. The overall length and the approximate location of the cable fault point from the test end. The cable fault locator is based on the cable fault tester host to determine the approximate location of the cable fault point to determine the precise location of the cable fault point. For buried cables with unknown directions, the working principle of the power cable fault tester The power cable fault tester is composed of three main parts: the power cable fault tester host, the cable fault locator, and the cable path tester. The cable fault tester host is used to measure the nature of cable faults. Need to use the path meter to determine the underground direction of the cable. The basic method of power cable fault testing is to apply high-voltage pulses to the faulty power cable, which will cause a breakdown at the cable fault point. When the cable fault breakdown point is discharged, electromagnetic waves and sound are generated to the outside. Let the high-resistance fault point of the cable puncture and 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 the appearance of the arc is reflected. Since the high-resistance fault becomes an instantaneous short-circuit fault during arcing, the low-voltage measurement pulse will have a significant impedance characteristic change, making the waveform of the flashover measurement into a low-voltage pulse short-circuit waveform, making the waveform discrimination particularly simple and clear. This is the so-called secondary pulse method. The reflected waveform of the received low-voltage pulse is equivalent to a waveform where the core is completely short-circuited to the ground. The low-voltage pulse waveform obtained when the high-voltage pulse is released and when the high-voltage pulse is not released are superimposed, 2 The waveform will have a divergence point. This divergence point is the reflected waveform point of the fault point. This method combines low-voltage pulse method and high-voltage flashover technology to make it easier for testers to determine the location of the fault point. Compared with traditional testing Compared with the method, the working principle of the application of arc reflection method (secondary pulse method) in cable fault location: First, a high voltage pulse with a certain voltage level and a certain energy is applied to the faulty cable at the test end of the cable. The second pulse method is advanced However, the complex waveform in the impulse high-voltage flashover method is simplified to the simplest low-voltage pulse short-circuit fault waveform, so the interpretation is extremely simple, and the fault distance can be accurately calibrated.
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