Stand alone intelligent digital distance relay

Remote end infeed causes problems in distance relay measurement, especially under high resistance earth fault conditions. Although a distance relay set to an ideal operating region can cover the fault resistance at one particular load condition, the operating region is affected by changes in load condition. Hence a distance relay may overreach or underreach when load changes. From the main factors which affect the ideal digital distance relay operating region, a stand alone intelligent digital distance relay which can adapt to these changes is presented, This approach does not need communication links from the remote end of the line or the system control center. Numerous computer simulations have been carried out on realistic system configurations and the results show that there is a high potential for developing an intelligent digital distance relay.