Operating Experience With Reactance Type Distance Relays

In view of the fact that reactance type distance relays have been in service in this country less than a year, operating experience should be of general interest to the industry at this time. This paper presents the performance record during the 1930 lightning season of two new types of reactance relays. One of these types is a high-speed American built relay, using a stepped time-distance characteristic. The other relay, using a sloped time-distance characteristic is European built, but designed for a more conventional speed of operation. These relays have performed satisfactorily on long transmission lines with wide variation in short-circuit conditions. The correctness of the reactance principle has been demonstrated. Certain difficulties with these relays have arisen on interconnections operating near the stability limit. Both definite and tentative conclusions from this year's operating experience are included in the paper.