A Scalable, Reconfigurable, and Efficient Data Center Power Distribution Architecture

Introduction 2 Background 3 An optimized power distribution system 4 Alternative power distribution approaches 11 Conclusion 14 Resources 15 Click on a section to jump to it Contents White Paper 129 Significant improvements in efficiency, power density, power monitoring, and reconfigurability have been achieved in data center power distribution. The past techniques of massive transformer-based power distribution units feeding under-floor hardwired circuits via rigid or flexible conduit are shown to be obsolete. This paper explains some the newer approaches to power distribution including modular power distribution and overhead power busway, and shows their advantages when compared to the legacy approach. Most existing data centers utilize the same power distribution architecture that was developed for data centers approximately 40 years ago. This system is illustrated in Figure 1. In the traditional system, the main data center power is distributed to power distribution units (PDU-typically rated from 50 kW to 500 kW). The power distribution units may contain large power transformers to convert voltage or provide power conditioning. The power distribution units in turn distribute a quantity of branch circuits (typically rated from 1.5 kW to 15 kW) to the IT equipment. Each IT enclosure uses one or more branch circuits. The wiring to the IT enclosures is usually required to be in flexible or rigid conduit, typically located beneath the raised floor, as illustrated in Figure 2. Since the introduction of this system, there have been dramatic changes in how power is utilized in data centers that have challenged this architecture, specifically driven by increasing power density, the increasing number of separate IT devices within the data center, and the need to add and remove IT devices on a continuous basis.