Characteristic analysis of zero-mode inrush current of high-impedance transformer

•Proposed equivalent circuit of zero-mode inrush current.•Calculated parameters of high-impedance transformer according to winding arrangement.•Compared and analysed the zero-mode inrush current characteristics of high-impedance transformer.•The zero-sequence protection is more likely to misoperate when T-Hin is energized.•Constructed physical models to verify the theory.