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 se t to an ideal operating region can cover the fault resistance at one partic ular load condition, the operating region is affected by changes in load co ndition. Hence a distance relay may overreach or underreach when load chang es. From the main factors which affect the ideal digital distance relay ope rating region, a stand alone intelligent digital distance relay which can a dapt to these changes is presented, This approach does not need communicati on links from the remote end of the line or the system control center. Nume rous computer simulations have been carried out on realistic system configu rations and the results show that there is a high potential for developing an intelligent digital distance relay.