Calculation of complex electric field along insulators of UHV transmission lines with domain-decomposition and iterative method

We put forward a new calculation method for unbounded field problem concluding complex parts by introducing the domain-decomposition and iterative processes. Firstly, the field domain should be decomposed to two parts. One is the concerned part with finer meshes for calculation, the other is the big space part with coarser meshes, and the two parts have a common domain between them. Secondly, the two parts are calculated by the iterative process on the common domain until the result become stable. This method uses less time to calculate the complex field model and has more accuracy on the concerned domain. It also makes the asymptotic boundary condition to get more accuracy by a further boundary without too much computation time. The calculations on the 800 kV composite insulator show that the electric field distribution is contacted with the sheds configuration on the insulatos, and the electric field on the surface of sheds is 50%~60% higher than the electric field on the surface of the pole in the nearby gaps.