Reliability considerations for data centers power architectures

To meet the on-going challenges of uninterrupted service, the traditional voice-telecommunications have developed throughout the years a very reliable -48VDC power architecture. Having a standardized -48VDC power interface simplifies reliability considerations to a few engineering decisions like battery sizing, A&B DC bussing, AC backup scheme (generator, fuel cells, etc.). The explosion of the data communication industry and the strong dependency of the modern world economy have brought unforeseen reliability design issues: reliability design has now taken another twist as loss of service is translated into more vital loss of revenues then ever. Unfortunately, the established principles for DC powered equipment can no longer be applied as modern data centers are using a multitude of different equipment that can be powered by either AC or DC input voltages. The power architect is now faced with endless possibilities and combinations to achieved the desired reliability objective. AC power, DC power, battery location, dual line feed equipment, heat management, building & space constraints are all new elements which must now be taken into consideration. This paper reviews simple power architectures and reviews reliability, availability and cost differentials.