Design and Testing of a Multi-Microprocessor Travelling Wave Relay

This paper describes the design and testing of a digital ultra high speed (UHS) travelling wave based protective relay. It shows how a prototype has been realized by a simple and fairly low cost (a few hundred dollars for parts) dedicated multi-microprocessor system. The paper presents also the results of the tests carried out on the prototype by using a microprocessor based complex waveform signal generator (CWSG) which displays the output of a mainframe computer-based electromagnetic transients program (EMTP) in real time. The relay showed good practical behaviour, especially with regard to the UHS feature and faulted phase selection and fault classification capability.