Dielectric breakdown characteristics of environment-friendly insulating fluids

SF₆ gas is not environmental friendly and it is leading to global warming effect. SF₆ is used as the external insulation medium of transmission voltage lever vacuum circuit breakers (VCBs) recently. In order to decrease the SF₆´s annual emission and leakage, the dielectric breakdown characteristics of silicone oil is tested and it is found that silicone oil´s great insulation ability is good enough, which can be used as a SF₆ substitute in the external insulation protection of the VCBs. So the VCBs will be not only suitable for application but also friendly to the environment. Silicone oil can be applied in other switchgear´s external insulation system due to its nonflammable and nontoxic characteristics, environmentally friendly superiority and discarded silicone oil can be absorbed by environment without damage. The objective of this paper is to use silicone oil to take the place of SF₆ in the external insulation protection of VCBs. Investigation contents contain basic characteristics, dielectric breakdown characteristics and chemical analysis of insulating oils and insulators.