20 kV overhead lines with covered conductors

The experiences of an Austrian utility, an overhead line fittings producer and a conductor company are reported in this paper. Aerial bundled conductor systems for 400 V are in use with good results by the Lower Austrian Utility EVN and the next step was the introduction of covered conductors for 20 kV. Despite the extreme winter conditions in the Year 95/96 and in subsequent years, breakdowns occurred to a less degree. Faults by snow, hoarfrost, by wind and storm or by iceshedding were minimal. Following permission from the relevant Government ministry, a test line was erected with reduced distances phase to phase. In this project, called Hackbichl, smaller lanes through the forests were permitted. Experiences with regard to protection against overvoltage and partial discharges are discussed