404 / 2017-04-26 13:42:44

Study on Insulation Characteristics of Composite Insulation in Nitrogen Insulated Ring Main Unit

gas insulation; eco-friendly switchgear; insulation coordination; electric field distribution; compound insulation

Using nitrogen (N2) or dry air replace SF6 as medium voltage switchgear insulation medium is the hot spot in the environmental protection switch equipment development. To ensure the characteristics of compact structure and small size, engineers need to fully control the insulation characteristics of the new gas and compound insulation. This article studies the fundamental properties of N2 as the insulation medium from the respects of different field uniformities, pressures and electrodes gaps, where we obtained the empirical equations of N2 insulation as a direction of N2 insulated switchgear designing. According to the simulation calculation and the insulation coordination experiments, we conclude that the non-uniform electric field characteristics should be the designing criterion, and the sufficient gap is the key point of the solid-gas compound insulation.