Electric Field Analysis of the 230 kV AC Transmission Line System for an Limited Area

In recent years, the composite cross-arm is used in the transmission line system. The electric field analysis at the composite cross-arm is very important for the high voltage system. The electric field at corona rings and grading rings must be confirmed that can withstand the corona threshold field. But the geometry of cross-arm is very complicated for computing. Therefore, the objective of this paper is to compute the 3 phase electric field by using ANSYS Maxwell software base on the finite element method (FEM). We separately calculate in each phase in order to reduce the computation time. Firstly, the 3-dimensional (3D) model of composite crossarm is simulated in a close domain. Then the average potential from the 2-dimensional (2D) model is defined as a boundary condition in case of the 3-dimensional model. Finally, the maximum electric field values in each phase are compared. From the results, the highest electric field occurs at phase B, and the electric field of tension-type grading ring is slightly higher than other types of ring. However, all values are lower than the electric field criteria.