Research on sympathetic interaction between transformers

Abstract

The phenomenon of sympathetic interaction between transformers is discussed in this paper. A mathematical model is developed for two transformers in parallel and in series operation to analyze the origin mechanism of sympathetic interaction. At the same time, its characteristics are further analyzed by numerical simulation. The sympathetic inrush current could influence the transformer differential protection. The physical dynamic simulation experiment results are analyzed, which prove the second harmonic restrain method could restrain the sympathetic inrush and the CT saturation criterion should be used for the differential protection.