Protection selectivity analysis in electric system for hospital application. Part I: Radial and loop distribution

This paper deals with the protection coordination in particular distribution system, such as hospitals, characterized by the need of high quality energy supply. In the paper a brief description of the network schemes and the grounding systems, referring to the recent updating of the standard for the hospital application is presented. The selectivity concept is also introduced, with particular care to the selectivity analysis in the ring networks. Moreover the real case of a hospital whose systems had big selectivity problems is discussed.