Critical Process Loads: Defining and Incorporating Them Into a Reliable Power System

Every facility, regardless of its size, has process loads that are considered to be critical. However, what does the term critical mean? A process engineer's definition of a critical load may differ from that of an electrical engineer; a health, safety and environmental engineer; or a plant engineer. This article defines critical loads and discusses a methodology that evaluates whether a load should be classified as critical. The methodology considers personnel and equipment safety, process immunity time, and electrical system reliability. We provide an overview of the associated design process and technical solutions to address critical load needs.