Maintaining transformer reliability requires more than a single test or diagnostic method. A recent project at a New England generation plant demonstrated how oil diagnostics, electrical testing, engineering evaluation, and experienced field services can work together to identify developing problems and protect critical equipment.
During a planned outage, oil testing performed by MVA indicated that the plant’s 226-MVA generator step-up transformer was internally healthy. However, comprehensive electrical testing by Sigma C Power Services revealed significant deterioration in all three high-voltage bushings, an issue that routine dissolved gas analysis alone would not have detected.
After the most critical bushing was identified, MVA Services quickly mobilized to perform the high-voltage bushing replacement and fully re-gasket the transformer. The expanded transformer repair scope also included oil processing, a heat run under vacuum, final vacuum filling, and post-repair electrical diagnostic testing. Despite the additional work, MVA completed the entire project within the plant’s scheduled outage window, helping the customer avoid extended downtime and return the transformer to service on schedule.
By combining proactive testing, oil diagnostics, repair planning, and rapid field execution, Sigma C and MVA helped the customer avoid a potentially catastrophic transformer failure and prolonged unplanned outage. The project reinforces a simple reliability principle: Testing identifies problems. Diagnostics help explain them. Field services solve them.
Read the full article in NETAWORLD Journal
