High power Tesla transformer is widely used in the area of pulsed power technology

but its secondary coils is in a non-uniform electric field

and the uneven distribution of inter-turn voltage of the coils is likely to lead to inter-turn insulation breakdown. In this paper

a set of dual magnetic core Tesla transformer is designed

an electric field simulation model of the secondary coil is set up by finite element method and the inter-turn electric field distribution is analyzed. Aiming at the problem of uneven distribution of inter-turn voltage

the two ends of the secondary coil are double-wired and a shielding ring is added to improve the electric field distribution so to keep the maximum field strength be less than the breakdown field strength of the tiny oil gap and assure insulation safety of the secondary coil of the transformer. It is found through simulation analysis that the double-wired winding of head and tail terminals can improve electric field distribution

but the number of double-wired turns shall not be too much. After addition of the shielding ring to the high-voltage terminal

the field strength distribution is more uniform

the maximum field strength is reduced by 62.9%

the maximum field strength is much lower than the breakdown field strength of the oil gap under the pulse condition

which can meet the insulation design requirements.