A Novel Travelling Waves Based Ultra-High Speed Ratio Directional Protection

This paper proposes a novel travelling wave based directional pilot protection scheme for EHV/UHV transmission line. The directional relay determines fault direction by a ratio of two integrations. The first one is based on forward voltage travelling wave, and the second one is based on backward voltage travelling wave. To evaluate the validity of the proposed scheme, a variety of fault conditions and system configurations have been simulated. Theoretical analysis and simulation results have shown that the proposed ratio directional protection can overcome most of the drawbacks existing in traditional travelling wave protections.