Frequency response analysis for phase-shifting transformers in oil field facilities

The phase-shifting transformers for variable frequency drives (VFD) are usually specialty designed and their applications become more common in oil field facilities. Frequency response analysis (FRA) method has been recognized as a useful maintenance tool for transformers; however, very limited work has been done on phase-shifting transformers for maintenance and troubleshooting using FRA method. In this paper, the lab testing is conducted on a healthy phase-shifting transformer for a 12-pulse VFD system. The test data are presented and analyzed, which could serve as the baseline reference and will provide valuable information for maintenance of phase-shifting transformers with similar design.