Induced Lightning Stroke Identification on Protection Relays

Abstract

It is well known that lightning strokes produce mal-operation of transmission line protection relays. Where, protection devices cannot identify correctly between lightning stroke that generates or not permanent faults. Thus, when a flash produces a permanent fault, the protection relay sends a trip order, and the Transmission Line (TL) is disconnected correctly. However, when a lightning stroke does not produce a permanent fault, the protection devices also send the trip order, and the TL is disconnected unnecessary. In this context, these phenomena can produce unnecessary electric power outages, producing damage for the society and economic. Therefore, it is necessary to correctly identify between these lightning stroke signals. Besides that, direct lightning strokes, which hit directly on TLs or transmission towers, have usually been analyzed. However, induced lightning strokes, which hit on ground, have not been considered in previous analyzed. In this paper, in order to identify these induced lightning strokes, an algorithm based on a deterministic focus is proposed.