Lightning-induced overvoltages in overhead lines with shielded wires of medium voltage classes

Abstract

The monograph is devoted to the solution of an actual scientific and applied problem in the field of lightning protection of overhead power lines with protected wires of medium voltage classes from lightning-induced overvoltages that occur during lightning strikes near the power transmission line. Currently, shielded wires for overhead lines are becoming more and more widespread in Ukraine. The use of wires in a protective sheath has several significant advantages, namely: reliability, economic feasibility. Damage in distribution networks causes most of the damage associated with interruptions in the electricity supply to consumers. One of the main causes of accidents and disturbances is lightning overvoltages on overhead lines, which cause impulse overlaps and destruction of insulators and lead to arcing and disconnection of lines. Due to the low impulse strength, the insulation of distribution networks is prone to overlaps both during direct lightning discharges and from inductive overvoltages during lightning discharges near the line. The latter are the main cause of lightning shutdowns and equipment damage of 6-35 kV networks, making up to 90% in some cases. Thus, the reliability of electricity supply to consumers largely depends on the effectiveness of lightning protection measures.