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 Length Tester
In the process of using high-voltage power cables, due to external force damage, moisture and other reasons, cable failures will be caused, which will seriously affect the safe operation of cables. It is necessary to quickly find the fault point of the cable in a short time, repair the fault point of the cable in time, and quickly restore the power supply. In the process of using high-voltage power cables, due to external force damage, moisture and other reasons, it will cause cable failures, which will seriously affect the safe operation of cables.
It is necessary to quickly find the fault point of the cable in a short time, repair the fault point of the cable in time, and quickly restore the power supply. Therefore, a cable fault tester is required. This article will briefly introduce the operation steps of the cable fault tester.
According to the transmission line theory and the radar ranging principle, the cable fault tester will produce a reflected waveform in the middle of the faulty cable due to the impedance change during the propagation of the radio wave from the beginning to the terminal in the cable. In this way, if a low voltage pulse or a high voltage pulse is sent to the cable. Use a high-speed collector to collect the trajectory data of the pulse wave propagating in the cable, display it on the screen, and use the dual cursor card to measure the time for the radio wave to travel back and forth between the transmitting end and the fault point according to its characteristic inflection point. The speed of propagation in the cable, calculate the distance from the cable fault point to the launch point.
Before the on-site fault test, you should first check whether the power of the instrument is sufficient. If the power is insufficient, you should connect an external power supply before the instrument can be used normally. turn on“switch”, after the system starts, the instrument enters the Windows desktop system, and automatically enters the cable fault test system setting interface. According to the type of the tested cable, the actual length and the nature of the fault, use the touch pen to click the relevant touch keys of the cable meter to perform initial parameter settings.
Parameter setting is complete (default“Low pressure pulse method”), connect the red and black clips of the instrument test line to the faulty phase of the faulty cable under test and the other good phase or the ground wire of the cable respectively, click“sampling”key, the instrument automatically enters the data acquisition state, and the waveform is displayed on the screen at the same time. click again“sampling”key, the instrument will enter“continuous”sampling status. The operator can continuously adjust the amplitude and position of the waveform displayed on the screen“Position adjustment”and“Amplitude adjustment”knob.
Adjust until the waveform is easy to analyze, then click“Cancel sampling”Touch the key to stop sampling. If set“high pressure flashover”, click“sampling”After pressing the key, the instrument enters“sampling”Waiting state, when the faulty cable is flashed with high voltage, it will automatically“sampling box”The acquired signal is displayed on the screen. and enter again“sampling”The waiting state is ready to collect the signal of the next high-voltage flash.
Adjusted during continuous high pressure flash sampling“Displacement adjustment”“Amplitude adjustment”knob, adjust until the waveform is easy to analyze, and then click“Cancel sampling” Touch the key to stop sampling, and then perform cursor operation to obtain the cable length from the fault point to the test end. The cable fault tester is a kind of equipment that is rarely used at ordinary times, but once it is used, it is necessary to quickly use the equipment to find the fault point.
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