“Multiplex” scheme in urban distribution

THE ELECTRIC DISTRIBUTION SYSTEM of the the Consolidated Gas Electric Light and Power Company of Baltimore extends over 2,269 square miles in the State of Maryland with a population of 1,400,000. Approximately 70 per cent of this population is in the city of Baltimore, which covers an area of about 73 square miles, and the bulk of electric load is concentrated within the territory of the city and immediate suburbs. Service for residential and commercial use is provided there by a 4-kv radial distribution system, with feeders generally underground. Only the most heavily loaded business section is served by a secondary a-c network and a d-c network which is being gradually changed over to alternating current. In this area, at the end of the war, the ratio between peak load and installed transformer capacity had reached the limits which should not be exceeded to assure firm power supply at all locations. Temporary provisions, like the use of portable fans during emergencies, were put into effect, but the need for new facilities became urgent and a decision had to be made as to the best method for expansion.