Relaying on sunbury transmission lines

IN PLANNING the development of the transmission facilities needed for the output of the initial installation of two 75,000-kw units at the new Sunbury plant of the Pennsylvania Power and Light Company, provision of “spare” lines has been avoided by placing full dependence on the ability of fast protective and reclosing relaying to reduce line outages to short durations for all except the relatively rare faults that are inherently persistent. Because of this dependence upon modern relaying, the number of lines has been limited to those already existent in close proximity, which are simply being extended into Sunbury, plus three new ones that are required for load-carrying capacity regardless of relaying. (See Figure 1.)