Department of Electrical Engineering, Indian Institute of Science, Bangalore-12.
This paper describes the design and construction of a transistorised statitc distance relay based on the sampling technique developed by P.G. Mc Laren(1) to allow a comparison of instantaneous values of system voltage and current derived at different instants of time. This, in effect, dispenses with the need to phase shift and mix signals derived from the power system and thereby achieves a considerable saving in both space and cost. The construction of a current polarised relay is discussed with main reference to a quadrilateral pick up characteristic surrounding the probable fault area of a transmission line.
