Ground Relay Protection for Transmission Systems

The relay problems of an electric power system are most important, and are very vital to the successful operation of the system. More and more consideration is being given to the relay engineers´ point of view with resultant improvement in system operation. Several large, successful companies undertake no project having any bearing on the primary electric system without due regard to the relay engineer´s recommendation. With the transmission networks becoming more and more interconnected, and with the injection into the problem the interconnections with other power companies, the absolute necessity of isolating a faulty line, (or a faulty piece of equipment), is essential and is becoming more clearly recognized by all large companies. Since this article was written, other 66-kv., ground relay tests have been made with a resistor grounded neutral and with a solidly grounded neutral, and some very interesting and unexpected points were discovered. It is hoped these points will be brought out during the discussion of this paper.