Non-communication protection of distribution feeders with tapped-off-loads

This paper presents a new technique for the accelerated protection of distribution systems with tapped-off-loads. In the technique, the sequence and superimposed signals are used to determine the remote circuit breaker operation, from which whether a fault is inside the protected section can be derived. Extensive simulation studies with respect to a typical double end feeder system with tapped-off-loads show that the proposed technique is able to significantly increase the speed of response of the conventional time grading based protection scheme.