IEEE
IEEE 946-2020 is a recommended practice published by the Institute of Electrical and Electronics Engineers for the design of direct-current auxiliary power systems in generating stations. It addresses the batteries, chargers, distribution equipment and protection that supply control, protection and emergency loads when alternating-current power is not available.
Editions cited: IEEE 946-2020
The practice is aimed at designers of station direct-current systems and at the engineers who specify, review and commission them. It discusses system architecture and redundancy, the sizing of batteries and chargers against the connected loads, voltage and fault-current considerations, protective devices, grounding and ground detection, and the monitoring that tells operators when something has gone wrong. Although it is written around generating stations, the same concepts are applied in substations and industrial plants that depend on a battery-backed supply. Testing firms and owners refer to it for the expected behavior of chargers, rectifiers and ground detection schemes, and for the installation conditions that field checks should confirm. The pages in this encyclopedia that cite IEEE 946-2020 explain battery charger performance and direct-current ground detection in general terms and point the reader to the document for design intent and governing criteria.