Electric Field Calculation of 800kV Composite Insulator with Domain-decomposition and Iterative Method

Based on finite element method and the asymptotic boundary condition, the paper presents a new calculation method for unbounded field problem with complex parts by the domain-decomposition and iterative processes. Firstly, the field domain should be decomposed to two parts. One is the concerned domain with finer meshes, the other is the unbounded space domain with coarser meshes. And the two parts have a common domain. Secondly, the concerned domain and the unbounded space domain are calculated separately by the iterative process on the common domain based on the finite element method until the result become stable. This method uses less time to calculation the complex field model and has more accuracy on the concerned domain. It also makes the asymptotic boundary condition to get more accuracy than a further boundary without too much computing time. The paper calculates a 3D model of 800 kV composite insulator with tower conductors and shielding wires. Calculation on the composite insulator of plusmn800 kV UHV DC transmission lines proves the advantage of the method. In the end, the verification tests show good agreement between calculations and measurements.