Design and verification of insulation system for valve side outlet device of converter transformer based on multi-index optimization

The valve side outlet device is like the ‘neck’ of the converter transformer. It is located at the position where the electric field and current of the converter transformer are most concentrated. The size deviation control requirements are strict. It also needs to consider the coordination with the electric field at the tail of the bushing. It has many insulation interfaces, diverse materials, complex dielectric characteristics and great design difficulty. In this study, multi index optimization design is carried out for the insulation structure of valve side outlet device of converter transformer, and the optimal design scheme is proposed. The research results are applied to engineering products and verified by insulation margin test.