Numerical analysis and measuring for The potential distribution of 800 kV MOA are introduced in the paper.Firstly

the potential distribution of 800 kV MOA with no parallel connection of capacitors

is studied with the finite element method（FEM）and ANSYS software.All of MOR voltage deviation and MOR voltage share ratios in each unit are obtained.The partial capacitance between every flange and the capacitance to the earth of each flange are also calculated at the same time.After connecting parallel capacitor

MOA "electrostatic field" issue will be transformed into "circuit" problem.We can get the partial capacitance by ANSYS

and then calculate the potential distribution of MOA and the voltage deviations of MOR using node potential method（NPM）

when there is parallel connection of capacitors.Then

the potential distribution test of 800 kV MOA has been done by using the designed optic-electric measuring system.The current distribution curve of MOR is gotten

and then the potential distribution is obtained.The results show that the measuring results relative accurately reflect the potential distribution of MOA

and the calculating results accurately obtain the voltage deviations of MOR.Both trends reflect the potential distribution achieve consistency.