A new approach to fast distance protection with adaptive features

Distance relays are one of the most important components of protection available to power system protection engineers. Distance relays can benefit from ideas in the newly developed field of adaptive protection, and can offer an even more selective and sensitive form of protection, under a variety of power system configurations. A new fast adaptive distance protection scheme for single line to ground faults and multi-phase faults for EHV transmission lines is described in this paper. This scheme also performs well on series compensated lines. The new complementary fast tripping algorithms together with the earlier experienced algorithm and multiprocessor-based distance algorithm, have led to the development to an adaptive hybrid scheme. This scheme is implemented into a well-proven hardware platform with moderate requirements on the communication. The protection scheme provides high speed tripping (less than one cycle) and high speed signalling