Reliability analysis of 380V DC distribution in data centers

Data center downtime causes losses of millions of dollars. Maintaining high availability at all times is very critical to data centers. The distribution system with higher number of components is more likely to fail, resulting in increased downtime. This study presents a 380V DC powering option for data center distribution system, as the number of power conversion stages is less compared to the AC system. This study aims at comparing reliabilities of typical 480V AC distribution architecture against 380V DC architecture. Reliability assessment was done for both AC and DC sytems complying with Tier IV standard, as most of the data center uses Tier IV standard in their distribution system. The analysis was done for different level of redundancy (for eg. N, N+1, N+2) in the UPS system for both AC and DC systems. The reliability data was obtained from IEEE 493 Gold Book. Monte carlo simulation method was used to perform the reliability calculations. The simulation results showed that the 380V DC distribution system has higher level of reliability than conventional 480V ac distribution system in data centers but only up to certain level of redundancy in the UPS system. The reliability level of AC system will approach the reliability level of a DC system when a very high level of redundancy in the UPS system is considered, but this will increase the overall cost of the data center.