Equipment Life Extension and Modernization of Generator Circuit

Many hydro-electric generating facilities (Figure 1) built from the 1930’s to 1970’s have power circuit breakers installed between the generators and generator step up transformers that are well beyond their expected service life. Generator circuits also have unique characteristics that require circuit breakers specifically designed and tested for these conditions. To meet this need, the Switchgear Committee of the Institute of Electrical and Electronics Engineers (IEEE) developed and published a special industry standard to address these unique characteristics. Existing circuit breakers applied on generator circuits may use oil, compressed air, air-magnetic or SF6 technology for arc interruption. Some circuit breaker designs require more and more maintenance over time and if genuine replacement parts are not available, this can result in improper circuit breaker function that can cause catastrophic failure.