Consolidation within the healthcare industry and the rise of regional medical centers has led to larger facilities, often spread over a large area in a campus environment. These facilities require more standby power due to size alone, and the impracticality of evacuating a large patient census during an extended utility outage means capacity to permit normal or near-normal operation of the facilities may be required.
Higher power demand leads to use of larger generators at higher voltages to allow for practical and economical distribution of power throughout the facility. While traditional systems have usually used generators rated at 480 Volts and 1,000 kW or less, large systems typically use units rated from 4,160-13,800 Volts (a range referred to as “medium voltage”) and up to 2,500 kW. These installations are typically centrally located with other major utility systems to permit efficient operation and maintenance. This article will discuss the differences between large central systems and traditional single-facility systems from design, code compliance, and reliability standpoints and then offer advice on implementation based on lessons learned over the course of many projects.