Why is it difficult to find the reason after the failure of the low-voltage cable?

The difficulty in finding the fault distance of a low-voltage cable is often caused by the following reasons:

1. The three-end wiring process of the low-voltage cable is not standardized. The main reason is that the ground wire or neutral line is not properly handled, resulting in unsatisfactory test waveform. The specific performance is:

A. Discontinuous steel armor of the middle joint;

B. Steel armor is not grounded.

2, test wiring error. Multi-fingered, unshielded, and unshielded multi-core LV cables will result in unsatisfactory waveforms, and even reflected waves will not cause crude test failure. The specific performance is as follows:

A. The non-test phase is not grounded;

B. Test ground;

C. The test line is inversely connected with the shielding line;

D. The shield wire shall be connected with ungrounded phase or steel stern;

E. The shielded wire is directly connected to the ground column unrelated to the LV cable under test.

Therefore, when we regulate the operation in the construction, maintenance and overhaul of the low-voltage cable, the situation is much better, and the rough measurement of the fault distance reduces the uncertainty. In addition, fault localization is a problem because it has many determinants. This is mainly due to the fault of the fixed-point low-voltage cable, the impulse voltage is generally not high, the energy is not large, and the placement state of the construction long point is not ideal. However, the mechanical vibration wave and electromagnetic wave at the fault point are relatively weak. Coupled with the sensitivity of the detection equipment, the interference of the monitoring environment, the testing technology and experience, the fixed-point work in the city is even more difficult than the medium and high pressure.

Fortunately, the contrast test equipment has been using acoustic magnetic positioning technology, which greatly alleviates the problem of locating men. It is difficult to locate the low-voltage cable fault. Improvements should be made in the following aspects:

To improve the discharge state of the fault point;

Select and use appropriate testing equipment;

Avoid the interference of environmental factors

Well, the above is about "why is it difficult to find the cause after the failure of the low-voltage cable?" The introduction, hope to help you! It is recommended to continue to pay attention to Ruiyang Cable for more information about low-voltage cables.

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