Bushing Replacement

IEEE C57.93, the guide for The Installation and Maintenance of Liquid Immersed Power Transformers, recommends that substation transformers be electrically tested every three to five years, and to inspect and clean the bushings.  Behind LTCs, bushings are another leading cause of transformer failure.  Proactively performing power factor testing of the bushings is important to identify unknown issues before failure.  After testing, MVA will replace the bad bushing and vacuum-fill the transformer so it can be placed back in service.