Voltage transient propagation in AC and DC datacenter distribution architectures

Global industries, governments, organizations, and institutions rely on the operation of datacenters in order to successfully meet their day-to-day objectives. The increased reliance on datacenters combined with the growth of the industry sector has led to more careful considerations for datacenter design. Stakeholders in the datacenter industry have begun to consider alternative electrical distribution systems that provide greater reliability and operating efficiency, as well as lower capital costs and ease-of-installation. Among the many alternatives proposed, facility-level DC distribution has emerged as the option providing the highest operating efficiency. A number of studies have shown that DC distribution provides savings, in terms of energy efficiency, space utilization, and required cooling within a datacenter. However, the propagation of transient and their impact on equipment protection have not been fully quantified [2]. This study compares voltage transients, originating from the utility distribution grid and propagating throughout the datacenter facility, using both an AC and DC distribution architecture. The goal is to identify future requirements for protection in DC datacenter facilities. As an initial study in this subject area, the analysis is performed via simulation. Each distribution architecture has been modeled using PSCAD/EMTDC. A voltage transient is generated from a capacitor bank switching event. The transient is analyzed as it propagates through both the AC and DC architectures. It is shown that the AC architecture provides inherent protection against transients, at the cost of low efficiency, a high parts count, and poor space utilization. The DC system is vulnerable to transients. More research is required in order to fully characterize the protection needs for DC distribution systems.