DETERMINATION OF LEAKAGE CURRENT THROUGH INSULATED COATING OF 10 KV OVERHEAD DISTRIBUTION LINE WIRES WHILE CONTACTING TREES AND OTHER EARTHED OBJECTS IN RAINY WEATHER

Abstract

Investigations that were conducted with the help of overhead distribution line model reflected such situations as wire swinging cross, their contact with fallen trees and other earthed objects have shown that the overhead lines may operate rather long under such conditions. However leakage current may lead to dangerous high potentials on these objects and around them.The results of calculations and experimental research have revealed that in the rain leakage current on an earthed object and insulation resistance depends on the width of moistened zone and practically does not depend on an object size and shape. Leakage current does not exceed 3 mA at an operating voltage and 15mA at possible internal overvoltage and full insulation resistance is not less than 3…4 MW for actual overhead distribution line spans