Effect of line model on experimental test results of travelling wave functions of a commercial relay

This article shows the effect of line model on experimental test results of travelling wave functions of a commercial relay (SEL-T400L). The test signals were obtained from an electromagnetic transient program (RSCAD), using Bergeron model and a frequency-dependent model for the faulted transmission line, and injected to the relays of both line ends using a real-time simulator (RTDS). The analyzed travelling wave functions are: a) directional, TW32; b) differential, TW87; c) fault location, TWFL. The tests were performed for different fault locations, fault types, inception angles and fault resistances. Only one pre-fault condition was simulated; thus, results for two conditions were obtained (since the sign of pre-fault power is different at each line-end). For single-line-to-ground faults, the travelling wave detectors only operated for Bergeron model. For line-to-line faults: a) the TW32 activation was not dependent on transmission line model; b) the TW87 only operated for internal faults with Bergeron model; c) the TWFL results were only different from simulated fault locations for some cases with Bergeron model.