IEEE P946 DRAFT

Description / Abstract: This recommended practice provides guidance for the design of stationary dc power systems. The components of the stationary dc power system addressed by this recommended practice include:

- Storage batteries

- Static battery chargers/rectifiers (including sizing)

- Distribution equipment

- Protection equipment

- Control equipment

- Interconnections

- Instrumentation

Guidance for selecting the quantity, types and ratings of equipment is also provided.

The considerations of each of these different components and the issue of load voltage and other load specifies are discussed in terms of their effect on thedesign of the whole system. Guidance on short circuit calculation and contribution of different dc system components are also offered to improve reliability, performance and safety of the installation.

Exclusions

Electrically self-contained ac-ac equipment and the following of the dc system, with the exception of how they influence the dc system design, are specifically excluded from the scope of this recommended practice:

- The ac power supply to the battery charger/rectifiers

- Photovoltaic, wind, and other alternative dc power sourcesystem design

- Loads served by the dc system's dedicated engine starting (cranking) battery systems

- Applications requiring dc voltage supply above 1000V nominal

- Motor generator sets

Separate systems are usually recommended for the following special service applications, and are not within the scope of this document:

- Engine (cranking) starting

- Emergency lighting

- Fire detection and annunciation

- Fire protection actuation