A New Fault Resistance Compensation Scheme for Distance Relaying Application

Protective distance relays, which make use of impedance measurements in order to determine the presence and location of faults. The resistance introduces an error in the fault distance estimate, and hence may create an unreliable operation of a distance relay. A new compensation method based on fault resistance calculation is presented. The fault resistance calculation is based on monitoring the active power at the relay point. The compensated fault impedance measures accurately the impedance between the relay location and the fault point. This new compensation method avoids the under-reach problem in ground distance relays. MATLAB/SIMULINK‟S Power System Block set (PSB) is used for detailed modeling of a power system network and fault simulation. A 400 KV, 300 km transmission line is selected as example for fault simulation and suggested approach is tested using different fault types and proven successful identification for the type of fault.