Distance Protection Methodology for Detection of Faulted Phase and Fault Along With Power Swing Using Apparent Impedance

In this paper, a novel distance protection methodology that uses apparent impedance and concentric characteristics to identify faults and faulty phases along with power swing condition is proposed. The rate of change of apparent impedance is used to identify the fault or power swing condition. If a fault is detected, the relative location of the apparent impedance of the six distance elements with respect to their concentric characteristics is used to identify the faulty phases. The distance element(s) that compute the correct apparent impedance is(are) then enabled, which then issues the trip signal if the zone criterion is met. The proposed distance protection methodology is validated in Western System Coordinating Council (WSCC) Nine Bus System in MATLAB/Simulink by simulating various fault and power swing conditions. The results from the case studies proved that the proposed distance protection methodology could enable the right distance elements and issue trip signals during common faults and special kinds of faults like evolving and cross-country faults. Compared to others, the distinguishing feature of the proposed algorithm is its ability to identify the exact faulty phases even during special fault conditions like evolving and cross-country faults. The distance relay using the proposed methodology can issue the trip signal within one cycle for common faults and within one and half-cycle for evolving and cross-country faults.