A Strategy for Refining Fault Zone Identification of Distance Relays.

Document Type : Research Studies

Author

Elect. Eng. Dept., Mansoura University, Mansoura, 35516, Egypt

Abstract

A modified setting strategy for deciding the correct fault zone in distance relays is introduced, It depends on exchanging information between local relays in the same station in addition to a command from the remote end relay. As a start point, the conventional setting strategy is applied to initially determine which distance relays should operate and their zones of operation. Based on this preliminary information, the proposed system locates the faulty line. Then, the set of relays with suspected preliminary operation zones, that needs to be examined, is identified using some rules. This limited set of relays is solely considered in the next validation stages to save the processing time. The scheme verifies the relay zone reach in two steps. In the first step, a rule-base is applied to determine a modified zone for the relay. In the second step, another rule-base is applied to determine the final zone for the relay based on its modified zone. The governing rules for the proposed strategy are presented. The strategy is examined against a wide range of setting problems of a real part of a high-voltage network. The results confirm that the prop < em>osed strategy achieves the required accurate, sensitive, and selective relay operation. 

Main Subjects