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
Under normal circumstances, the radiation path of the high voltage cable is easy to determine, but the high voltage cable needs to fill the sand bricks to deeply buried, and it is difficult to find the short-voltage cable length, the radiation is free, and the path is unclear. In the following small series, the radiode path of the high-voltage cable is easily determined, but the high-voltage cable needs to fill the sand bricks to deeply buried, and it is difficult to find the low voltage cable of the low-voltage cable. The radiation is free, the path Unclear. The following small series gives you a short-voltage cable fault search detection method.
Everyone can learn from it. In order to solve the problem of low-voltage cable failure, research and development of scientific research and development has produced“Blink”Principle cable fault tester. To make a low-voltage cable failure lookup, you must first use the rangefinder to measure distance.
In fact, first, it is necessary to judge that the cable fault is a high impedance or a low-impedance or ground, and different test methods are used according to this condition. If it is a ground fault, the distance is measured directly with the low pressure pulse method of the rangefinder; if it is a high-resistance failure, the method of high-voltage impact discharge is used to measure the distance, and the distance is measured by the method of high voltage impact discharge. Equipment: such as high pressure pulse capacitors, discharge balls, current limiting resistors, inductors, and signal samplers, etc., operate both trouble and unsafe, have certain hazards, more cumbersome is to analyze sampling waveforms, tested The knowledge of knowledge is relatively high. The second step is to find the path (if the path can be saved).
When looking up the path, you want to add a signal (path signal generator) to the cable, re-use the receiver, and take the path along the path to the signal, it determines the path of the cable. However, this path ranges from 1-2 meters, not particularly accurate. The third step is to accurately position according to the measured distance.
It is based on the sound generated by the flame discharge, and when he heard the sound from the headset, it is the location of the fault point. Because it is listening to sound, it is a considerable time, sometimes waiting until the evening. When encountering a cross-linked cable, it takes more time. The cross-linking cable is generally the internal discharge sound is very small, and it is only almost impossible to hear.
Therefore, in this way, most of the power cable faults that use the oil invasion-free insulation material. For cable failures in cross-linking materials and polyethylene materials in recent years, the test effect is not too Ideally, the reason is that the sound produced by fire discharge is often small (the outer skin is not damaged, but the cable inside is discharged). When this is encountered, only other methods are solved. We know that the low-voltage cable insulation requires a low demand, and the current is large during operation. There is a significant feature after the failure, the specific class is as follows: a class of faults: the whole cable is blown or a certain phase is blown, such The fault causes the current relay operation on the power distribution cabinet, and the cable is damaged in the fault. Second class fault: The cable is short, and like this failure has a motor relay and voltage relay on the power distribution cabinet. The cable is also serious in the failure point (may be caused by external force).
Three types of faults: there is only one changing circuit, the current relay operation, the failure point is less than the expression. It may be that the phase current is too large or caused by cable quality. Four types of faults: short circuit inside the cable, the appearance does not see marks, such faults are generally relatively rare due to cable quality.
The above is the method of low-voltage cable fault detection detection, I hope to give some help to people need.
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