Abstract:Based on studying an existing 1250A busbar socket assembly design feature and verified its dielectric performance, a new insulated silicon was designed to upgrade the busbar socket rated voltage to 40.5kV and passed dielectric test. And then redesigned a new busbar socket contact terminal to make sure its rated current up to 1250A and passed temperature-rise test. The new design insulated silicon and the new design busbar socket are installed together to compose as a 40.5kV-1250A busbar socket assembly. This busbar socket assembly has been applied on 40.5kV-1250A gas insulated switchgears. Its main features are safe and reliable, compact and low cost.