Research Status Quo and Trend of Transformer Inrush Current Identification Technology

This paper states producing mechanism of excitation inrush current and sympathetic inrush current of transformer.By establishing related model,it analyzes flux relationship of transformers when no-load closing happens and points out existence of sympathetic inrush current may cause reduction of decay speed of excitation inrush current while the basic reason for producing sympathetic inrush current is bias magnet produced by excitation inrush current.It studies merits and demerits and applicability of present main inrush current identification technologies.In addition,it points out that for improving action accuracy of transformer protection,it is necessary to improve traditional method or use new inrush current identification technologies.