Fuzzy Location Algorithm for Cross-Country and Evolving Faults in EHV Transmission Line

Abstract

Fault protection is an important issue as it adversely affects the performance of conventional relays, particularly for cross-country and evolving faults in transmission lines. In this paper, a novel fault location algorithm for cross-country and evolving faults in extra high voltage transmission (EHVT) line using the fuzzy expert system (FES) is presented. The algorithm is based on the impedance values of relaying terminal fundamental component. In addition, the proposed FES is independent of communication links. It was designed using input variables via the IF-THEN rules and developed with the fuzzy MAMDANI structure. A triangular membership function was used to estimate the degree of inputs. MATLAB software was used to evaluate the error in the fault location for a 100-km, 400-kV, 50-Hz EHVT line. The FES algorithm yielded precise values. The test results were independent of the fault inception time, location, and type. The experimental results illustrate that the FES performed better than the other algorithms.