Frequency Response Analysis for Phase-Shifting Transformers in Oil Field Facilities

Phase-shifting transformers for variable frequency drives (VFDs) are usually specialty designed, and their applications become more common in oil field facilities. The 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 the FRA method. In this paper, the FRA baseline measurement is conducted on a healthy delta-polygon-polygon winding phase-shifting transformer for a 12-pulse VFD system in a laboratory. The test data are presented and analyzed, which could serve as the baseline reference and provide valuable information for the maintenance of phase-shifting transformers with similar design.