A Multi-Microprocessor Based Travelling Wave Relay - Theory and Realization

A new travelling wave digital protection scheme to be used as an ultra high speed (UHS) EHV/ UHV transmission line relay is presented in this paper. Some of the potential problems and limitations associated with other travelling wave schemes are avoided. Verification of the relay operating principles is presented through digital computer numerical simulation using an electromagnetic transients program (EMTP) in conjunction with simulation of the proposed algorithm. Parallel digital processing is incorporated through multi-microprocessor implementation. Hardware and software of a multiprocessor prototype are managed in a way to fit the algorithm requirements in as simple a construction as possible. The resulting scheme achieves significantly improved security and dependability, in addition to the main features: fault classification and UHS phase selection in selective-pole schemes with minimum communication between the protected ends.