Split-conductor cable — Balanced protection

Primarily, this paper is intended to be a brief history of the principal experiences of the Edison Electric Illuminating Company of Boston in the design and application of selective balanced-protection schemes to parallel connected transmission conductors. Split-conductor cables are discussed at considerable length, both as to design and operation. Paired ordinary conductors also are discussed, and their relation to so-called split-conductors pointed out. Special apparatus and devices required in connection with current-balancing schemes are illustrated and discussed. A partial nomenclature is proposed, to assist in clearing the way for intelligent discussion and a uniform understanding of the general subject of current-balance protection for paired conductors. A schedule of installations in the Boston system is given in order that the extent of the work described may be visualized, supplemented by a description of the results obtained in actual operation. No general conclusions are drawn since the paper is of the nature of a report on progress; specific conclusions are drawn, however, in a number of cases where the evidence or experience appears to be reasonably conclusive. A mathematical discussion of a number of reactive end-impedance devices, by Professor C. A. Adams, is appended.