According to the structures of both grading shield and grading ring on top of 2 400 k V DC voltage generator for the areas at altitude of 2 500 m

the control value of electric field intensity is specifically given. The finite element software COMSOL is used to simulate and calibrate the electric field of 2 400 k V DC voltage generator

finding that the maximum electric field intensity of the grading shield on the top is8.12 kV/cm

and the maximum surface electric field intensity of the grading ring is 9.58 kV/cm. In order to improve the insulation performance of the 2 400 kV DC voltage generator

it is necessary to optimize the structure of the grading ring. After many attempts

the curvature radius of several grading rings with large surface electric field intensity is increased and positions of grading rings are adjusted. After optimization

the maximum surface electric field intensity of the grading ring is reduced to 8.12 kV/cm

a reduction of about 15.2%

and the insulation performance of the 2 400 kV DC voltage generator has been improved.