A 2D-axisymmetric model of 1000 kV MOA was established based on the special structure of MOA

and the electric field and potential distribution of MOA was calculated by using the numerical analysis software ANSYS to improve the reliability of power system.The electric field and potential distributions of the resistors and inside porcelain with and without shunting capacitors were compared.The result shows that discharge or flashover most possibly occurs at the resistor or inside porcelain in first or forth section leaving the up flange for about 1/6～1/5 of section.The field and potential distribution of resistors in each section tends to be uniform with the shunting capacitors paralleled.However

the radial field and potential difference in some sections are enhanced

which should be taken into account in the design and manufacture of arrester.