ABSTRACT
The calculations of short-circuit currents in direct current (DC) systems is essential for the design and application of distribution and protective apparatuses used in these systems. The DC systems include DC motor drives and controllers, battery power applications, emergency power supply systems for generating stations, data-processing facilities, and computer-based DC power systems and transit systems. Maximum short-circuit currents should be considered for selecting the rating of the electrical equipment like cables, buses, and their supports. The high-speed DC protective devices may interrupt the current, before the maximum value is reached. It becomes necessary to consider the rise in the rate of current, along with interruption time to determine the maximum current that will be actually obtained. Lower speed DC protective devices may permit the maximum value to be reached, before current interruption.
