Sizing Batteries for Generating Stations

Sizing of storage batteries is straightforward using the formulas in IEEE 485; however, the key to proper sizing is the determination of the duty cycle. This paper will discuss voltage considerations, loads, and the duty cycle as they relate to battery sizing. Illustrative examples are provided as required. Although the emphasis of this paper will be on batteries for generating station stationary applications, uninterruptible power supply (UPS) system batteries are also discussed. A UPS system is a constant kVA load, and battery sizing, using the kW method discussed, is preferable in this case. The guidance provided will enable the user to determine the requirements for a specific application and properly size the battery. Although this paper discusses generating stations, the material presented is applicable to other installations, including substations, industrial control, and communications systems.