Design and Prototype Implementation of an Adaptive Mho Distance Relay by the KU Method

This paper presents the design, simulation and implementation of an adaptive mho distance relay to compensate during a phase-to-phase fault with fault resistance using the KU method. The phaseto-phase fault with fault resistance occasionally produces a trajectory of impedance outside the zone of the distance relay protection. Therefore, in this case, the distance relay will not send the trip command to the circuit breaker. This paper presents an analysis of three zones with adaptations to the mho distance relay to compensate during a phase-to-phase fault with fault resistance in a single circuit (radial) transmission line. This new concept was simulated using Matlab/Simulink and implemented using Dspace (DS11104). The prototype adaptive distance relay was tested in the laboratory using the relay equipment, Freja300 and the results analyzed and discussed.