Consideration of Requirements and Limitations of Relaying and High-Speed Reclosing on Long and Heavily-Loaded Transmission Lines

Present-day large interconnected power systems have many problems in common with regard to economical line loading, optimum placement of generating capacity, and satisfactory solution of protective relaying and line-reclosing requirements to provide the best over-all system performance. This paper suggests some of the engineering considerations which necessarily must be given incident to the planning and specification of the protective relaying and high-speed reclosing to be applied to transmission lines of considerable length which may serve as stabilizing ties between generating stations of an extensive system. For purposes of discussion, a hypothetical transmission system is analyzed. Companion papers^1,2 deal with the problems in the selection of relaying of the short and medium-length transmission lines of the same typical system.