A 220kV new-type tower with composite cross-arms is studied.
A 3D finite element model of the whole tower is established by finite element software to analyze the parameters of grading ring. In order to control the electric field strength,the structure parameters including pipe diameter,ring diameter and covering depth are adjusted to obtain an optimal design scheme for the grading ring. The computed results show that the electric field and potential distributions on the surface of horizontally post insulators and diagonally tension insulators can be improved effectively,and the maximum electric field strength on the end fitting surface can be reduced obviously.
However,the sharp edge of the metal flange leads to locally intensified electric field strength,which is slightly higher than the controlled value of 20kV/cm. After reasonable chamfering processing,the maximum electric field strength can be controlled within the desired scope.
