Partial Discharges Pattern Analysis of Various Covered Conductors

Covered conductors represents an alternative to the reinforced aluminum conductors. The E.ON Distribuce company aims to replace some of the reinforced aluminum conductors in its overhead distribution network with covered conductors. To make this distribution network as reliable as possible, the overhead powerlines will be equipped with online insulation fault detector. Problematic insulation fault detection is one of the biggest disadvantages of medium voltage covered conductors, because of the very low fault current. But during this type of faults, partial discharges activity is usually presented. Based on this knowledge, on-line partial discharges monitor was deigned at VSB - TUO to detect such insulation faults on medium voltage overhead power lines. This article describes the testing of various covered conductors from the point of partial discharge activity during high impedance faults.