Directional relaying using parameter estimation approach

Selectivity and sensitivity of the relay have been enhanced using the phasor estimation based directional algorithms. However, accurate phasor estimation is affected due to the inherent presence of spurious components in the fault signal and causes ambiguity in determination of fault direction. In this paper, a new technique is proposed to ascertain the direction by estimating line parameters in between relay and end source bus using least square technique and the sign of the resistance confirms the direction of fault (i.e. forward or reverse). Similar approach can be applied for all type of faults even with high fault resistance. A 400 kV two source equivalent system is considered to test the proposed technique using PSCAD/EMTDC and MATLAB tools and results shows the accuracy of method and provides faster decision than the phasor-based technique.