IEEE C57.153-2015

This paralleling guide describes and compares control methods of paralleling regulating transformers. The control methods include: master/follower, circulating current, power factor, circulating reactive current, and negative reactance methods. This guide presents operating philosophy descriptions, sample wiring diagrams, typical operational variations, the provision of adequate backup protection, and typical misapplication consequences. This guide does not apply to phase-shifting regulating transformers.