Research on the Insulation Characteristics of Nitrogen Insulated Ring Main Unit

Nitrogen (N2) or dry air as the gas insulation media in medium voltage switchgear to replace SF6 is the hot-spot study in the development process of environment-friendly switchgear. To develop the smaller size, researchers need to control the electrical field in the new gas. This article researched the insulated properties of N2 from the respects of different field uniformities, pressures (p), and electrode gaps distance (d), and as the result we obtained the empirical equations of N2 insulation for the instruction of N2 switchgear designing. According to the simulation and test data, the nonuniform electric field characteristics as the designing criterion concluded that d is the key point of the new gas insulation.