Transactions papers and discussions comprising pages 611–74 of the 1939 volume: Economical loading of high-voltage cables installed in underground subway systems

AN underground high-voltage cable system is made up of two major components: the cable with its joints and accessories and the underground duct and manhole structure. The question of what size of conductor should be chosen ground facilities already exist and when only a few additional feeders are being considered it might seem logical to make use of them. A study of the annual charges may show, however, in some cases, that it will be more economical to for a particular transmission feeder or as a general standard for distribution feeders has confronted every planning group. The voltage for the system is frequently limited to one or to relatively few different values already existing as a system standard, deviations from which would result in increased cost to obtain terminal facilities. Frequently some under-build additional new underground facilities rather than further to congest already existing structures.