Distance Protection For Parallel And Double-Circuit HV = Lines Chránění Paralelních A Souběžných Vedení Vvn Distanční Ochranou.

Abstract

The protection of parallel and double-circuit lines is actually challenging due to the effect of mutual coupling impedance, fault resistance and the current reversal phenomenon which distort the single-phase fault impedance ‘’seen’’ by the distance protection. However, numerical distance protections currently used provide compensation functions which can be used for the characteristic correction and computation of distance-to-fault location, because of their locator characteristics with enough resistive reserve and the possibility of setting an adequate tripping mode. This work explores the problems faced by the distance protection locator while measuring and calculating the location distance of a single-phase fault, and the current state of solutions adopted in solving those problems. Owing to the parameter calculations for the given transmission line, possible errors when localizing single-phase faults were evaluated, and a setting design was proposed for the effective line protection, including settings of parameters which compensate the above mentioned negative phenomena. It was found that the earth-wire and the line transposition, improve the accuracy of the locators, because the least error was found in the transposed line with earth wire.