scope:

This document provides guidance in the protection of stationary battery systems. For the purposes of this guide, stationary battery systems include the battery and dc components to and including the first protective device downstream of the battery terminals. The recommendations provided are not intended to set requirements; rather, they present options to the designer of the battery system concerning the types of protection available.

This guide provides discussions and recommendations regarding the forms of stationary battery protection as well as characteristics, sizing, application, and ratings of protective devices used in dc circuits and the short-circuit characteristics of batteries and battery chargers. A discussion of physical protection of battery systems as well as electrical protection is provided within this guide. Discussions are also presented in Annexes B and C regarding dc system time constants.

A discussion of coordination of protective devices for selective tripping is not treated within this guide and is considered beyond its scope. The user of this guide is referred to IEEE Std 242-1986¹ for guidance concerning coordination of protective devices.

Both grounded and ungrounded dc battery systems are used widely in different industry applications. The philosophy employed in the protection of stationary battery systems shall take into consideration whether the dc system is a grounded or ungrounded system. This guide provides guidance in the protection of both grounded and ungrounded stationary battery systems.

¹Information on references can be found in Clause 2.