A Simple Method for Tree Fall Detection on Medium Voltage Overhead Lines With Covered Conductors

Covered conductors are an alternative to aluminum core steel reinforced medium voltage overhead lines in forested terrains. The covered conductors are highly reliable due to the XLPE insulation system, which prevents the short-circuit current in case of contact of phases with the surrounding vegetation. However, the disadvantage of the covered conductor operation is the problematic detection of high impedance faults. Such type of faults is usually caused by the surrounding vegetation. The covered conductor may get ruptured or damaged due to the destructive degradation of the insulation system during the high impedance fault. This article contains a description and results of a new fault detection system for medium voltage overhead lines with covered conductors. The method of insulation fault identification is based on partial discharge activity detection. Our aim is to develop cheap and reliable online detector, which could be installed in large quantities for optimal high impedance fault detection and localization. Common partial discharges detectors are too expansive for this purpose.