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What is drainage wire?

May 08, 2021

Drainage wire is a kind of lightning protection facilities, which is mainly used for directly buried cables to prevent induced lightning current. That is to say, when there is lightning damage, the induced lightning may enter the cable (mainly the cable) in the way of induction. This is to lay the drainage line in the cable construction. It can be said that the induced current is guided into the ground, so as to protect the personal and equipment safety.

The drainage wire has three functions

A. Generally speaking, if the peak value of direct lightning current hitting the drainage line is not higher than 15ka, there is almost no counterattack to the cable. With the help of the lightning current flowing on the drainage line, the induced current on the cable is opposite to the lightning current directly discharged from the lightning point to the cable, so that the total current on the cable is significantly reduced, So as to reduce the overvoltage between the cable core and the metal sheath.

B. Even if the soil between the drain line and the cable is broken down and discharged to the cable, the drain line can reduce the degree of lightning damage and the lightning current flowing into the cable.

C. It can reduce the energy produced by the thermal and mechanical effects of lightning stroke on the cable.