ADAPTIVE DISTANCE RELAY SETTING FOR PARALLEL TRANSMISSION LINES CONNECTING A WIND FARM

Abstract

An ideal trip characteristic of distance relay is significantly affected as the apparent impedance seen by the relay is affected in the presence of mutual inductance and shunt capacitance. Reach setting of distance relay is also affected when a wind farm is connected to one end of a parallel transmission line because of continuous fluctuation in relay voltage due to continuous variation in wind speed of a wind farm. Thus proposed scheme focus on design an adaptive relay setting for a parallel transmission network which is supplied by a one wind farm and other end is connected to a constant voltage source. In proposed scheme we also include variety in working states of wind farms and effect of mutual inductance and shunt capacitance of parallel transmission lines. The proposed relay algorithm is extensively tested on two terminal network with wide variety in parameters of a system like receiving end to sending end voltage ratio, variation in source impedance and variation in load angle. The performance of the proposed adaptive relay is tested for SLG fault because it is the most frequent fault although this scheme can also be extended for other types of fault like 3-phase fault, LL fault, LLG fault. The change in characteristics according to change in system parameter shows the ability of a proposed scheme to handle distance relaying in a parallel transmission system.