A novel method for measuring residual flux density of the single-phase transformer core based on phase difference

A serious inrush current may occur when a power transformer is re-energized, which will cause many adverse effects on equipment and the grid. The corresponding potential hazards can be reduced if existing residual flux density (Br) accurately measured. Combined with field-circuit coupling analysis method, novel method for measuring Br based phase difference between applied AC voltage resulting transient proposed in this paper. When same to winding, affects current. calculated by cross-correlation technique. Based finite element (FEM), empirical formula quantitative measurement of core determined. Finally, an experimental study performed square single-phase transformers. results reveal that high accuracy.