Relaying of High Voltage Interconnection Transmission Lines

This paper presents an operating engineer's point of view of the practical and theoretical problems presented in applying relays for the protection of high voltage open wire interconnection transmission lines. It points out that the relaying of such lines involves problems which are not ordinarily present in the relaying of intra-system lines. These problems are enumerated and the extent to which modern relaying meets them is discussed. It is shown that the most satisfactory schemes are very expensive and the cheaper schemes are not entirely effective. The limitations of available schemes are discussed and their economics compared. A theoretical solution is proposed.