IDEAL OPERATING REGION OF DIGITAL DISTANCE RELAY UNDER HIGH-RESISTANCE EARTH FAULT

Remote end infeed has caused a lot of problems to distance relay measu rement especially under high resistance earth fault conditions. The me asured impedance may be larger or smaller than the actual value. This paper describes the main factors which affect the ideal distance relay operating region and how it is related to the active and reactive pow er flow in the line. This would help to solve the problems in the deve lopment of an intelligent adaptive digital distance relay which does n ot need communication links from the remote end of the line or the sys tem control centre. (C) 1997 Elsevier Science S.A.