Erco Worldwide is a chemical manufacturing plant that owns a 138 kV substation feeding multiple polyphase rectifier transformers, which connect to rectifiers on the secondary side. As part of a contract maintenance crew, responsibilities included inspecting thyristors, performing full-function testing of DCS controls, and monitoring alarming and measurements during regularly scheduled plant outages. While the plant was online, duties involved Dissolved Gas Analysis (DGA) for the transformers and InfraRed (IR) imaging of the entire plant’s electrical system.