In gas insulated substations

very fast transient overvoltages will impair transformer insulation.Consequently

we calculated the interturn capacitance

the section-to-section capacitance and the ground capacitance of the transformer windings by the finite element method

and established an ATP-EMTP model for the propagation of the very fast transient overvoltages in the transformer windings. The results show that the model of transformer windings based on one turn as an element can simulate the propagation properties of VFTO precisely. The improved interleaved connection mode can decrease the interturn voltage and section-to-section voltage. Inner shield coil can be further used to improve the voltage distribution of VFTO. Reducing the ground capacitance or increasing longitudinal capacitance can improve the VFTO distribution

and the attenuation of VFTO in the transformer windings will be slower if conductance is not considered.