IEEE 946-2004

IEEE 946-2004 is a technical standard for the design of DC auxiliary power systems used in generating systems. It addresses how direct-current auxiliary power is arranged to support critical plant functions, helping engineers apply consistent design practices for reliability and service continuity. As a superseded document in the power, energy, and industry applications area, IEEE 946-2004 remains useful as a reference for understanding established design expectations in generating facilities and related auxiliary power installations.

About IEEE 946-2004

This standard focuses on the recommended practice for designing DC auxiliary power systems that serve generating systems. In practical terms, it helps define how the DC supply should be planned to support control, protection, and other essential operating functions when normal AC supply is unavailable or needs backup support. IEEE 946-2004 is most relevant to engineers who need a structured approach to system layout, dependability, and integration of auxiliary DC equipment within power generation environments.

Where is IEEE 946-2004 used?

IEEE 946-2004 is commonly used in the design and review of DC auxiliary power arrangements for generating stations and associated power plant support systems. It is relevant where batteries, chargers, distribution panels, and related DC loads must work together to keep key equipment available. Typical use cases include planning for control power, protective relaying support, and dependable backup supply in generating-system environments. IEEE 946-2004 is also useful during specification writing, engineering review, and refurbishment of existing auxiliary power systems.

Importance in practice

In practice, this standard helps improve consistency in the design of DC auxiliary power systems, which can reduce risk during outages, switching events, or abnormal operating conditions. Using IEEE 946-2004 can support clearer procurement requirements, better coordination between equipment, and more reliable performance of essential plant functions. For projects involving generating systems, it provides a recognized technical reference for design control, helping teams align on expected practices and avoid avoidable weaknesses in auxiliary power architecture.

• DC auxiliary power system design
• Generating system support functions
• Backup supply for control and protection
• Battery and charger integration
• Design review and refurbishment reference