Short-Circuit Calculating Procedure for D-C Systems with Motors and Generators [includes discussion]

Additional background information made available in the last 5 years now permits the approximate time-current characteristics of fault currents in d-c systems to be calculated with the assurance of more realistic results. The need for this information has increased as the concentrations of d-c power sources have grown. Some older systems may also benefit from a short-circuit study. The object of this work is to assemble information and methods which will permit the reader readily to determine fault characteristics of d-c systems. This paper is limited to a discussion of d-c systems containing only motors and generators. The information presently available regarding the fault characteristics of other sources of short-circuit current is not sufficiently advanced to permit its inclusion in this paper. The other sources of short-circuit current are rectifiers, synchronous converters, electrolytic cells, and batteries, and it is expected that as further information concerning the fault characteristics of these sources becomes available, it will also be simplified and presented in a readily usable form.