How To Safely Island A Chemical Facility

In a chemical plant facility with excess generation, it is not only beneficial to export excess power, but essential to support the utility’s load by maintaining a certain minimum power export. A chemical plant’s electrical stability is of highest importance because downtime and unplanned events pose potential risks to the plant, personnel, and environment.This paper describes how rate-of-change of frequency (ROCOF) detection is used to safely island a chemical plant from a utility. This is followed by runback and generation shedding. Decoupling protection design, benefits, and limitations are explored with results from hardware-in-the-loop (HIL) testing. The ping-pong effect between sheddable loads and generators is discussed and underfrequency-based load shedding as back up is also introduced.