Probabilistic evaluation of impacts of high-resistance faults on digital distance relays

摘要

The presence of high resistances in the fault path-occurrence of high-resistance faults-is well known in the literature as a serious situation giving rise to the misoperation of distance relays. The literature, however, lacks an investigation determining quantitatively the extent to which the distance relays are influenced by the situation. This matter is addressed in this paper by adopting two probabilistic indices. The indices take advantage of ideal tripping regions to determine the probability that high fault resistances will lead to the under/overreaching of the relays in various operating conditions. The paper presents valuable results clearly pointing to the high underreaching probability of commercial distance relays, and also to the inefficiency in non-adaptive setting of them in high fault resistance conditions.