The Fundamentals of Industrial Distribution Systems

The intensive manufacturing activity accompanying the present defense program has stimulated interest in industrial electric power distribution. The ultimate objective is one of effectively satisfying electric power requirements with reasonable first cost consistent with a fair standard of safety and service reliability. This paper presents the fundamental aspects of industrial power distribution, with particular reference to low-voltage power supply to distributed electrical machinery, and compares various basic system designs, including large concentrated substations and distributed load-center substations with radial and secondary network modifications, as to safety, service reliability, simplicity, and so on, relative to estimated installed cost. The comparative analysis comprehends the complete electrical system between high-voltage supply bus and utilization terminal of low-voltage feeders. The ideal size of unit substation as influenced by operating voltage and load density is covered. Principles of system design here disclosed are applicable not only to new plant construction but to expansion or modernization of existing plants as well.