IEEE 946-2004

This recommended practice provides guidance for the design of the dc auxiliary power systems for nuclear and non-nuclear power generating stations. The components of the dc auxiliary power system addressed by this recommended practice include lead-acid storage batteries, static battery chargers, and distribution equipment. Guidance for selecting the quantity and types of equipment, the equipment ratings, interconnections, instrumentation, control, and protection is also provided. The ac power supply to the battery chargers; the loads served by the dc systems, except as they influence the dc system design; and dedicated engine starting (cranking) battery systems are beyond the scope of this recommended practice.