Impedance-Based Fault Location Experience

Accurate fault location reduces operating costs by avoiding lengthy and expensive patrols. Accurate fault location expedites repairs and restoration of lines, ultimately reducing revenue loss caused by outages. In this paper, we describe one- and two-ended impedance-based fault location experiences. We define terms associated with fault location and describe several impedance-based methods of fault location (simple reactance, Takagi, zero-sequence current with angle correction, and two-ended negative-sequence). We examine several system faults and analyze the performance of the fault locators given possible sources of error (short fault window, non-homogeneous system, incorrect fault type selection, etc.). Finally, we show the laboratory testing results of a two-ended method, where we automatically extracted a two-ended fault location estimate from a single end.