Optimization of a triggered vacuum switch with multi-rod electrodes system

One of the most important characteristic of triggered vacuum switch (TVS) is the breakdown voltage affecting the operation reliability of TVS. It depends on features, such as electrode material, electrode shape, gap distance and surface condition. For an optimized electrode's geometry, FEM electrostatic field simulations were conducted to evaluate the effect of geometric parameters on the electrostatic field strength and distribution. The distribution of electrostatic field of the TVS with multi-rod system is calculated by the finite method. The simulation results show that the geometric enhancement factor (GEF) is decrease with the increase of the fillet radius of the edge of the rod. In case of the fillet radius of the side face of rod 3mm and the fillet radius of the top face of the rod is 5mm, the GEF is up to the minimum value of 3. A lot of experiments are carried out. And the breakdown voltage of TVS with multi-rod system was measured by the high voltage direct current generator after switch currents with amplitude of 63kA and width of 13ms with the interval time of 10~15min. The influences of electrode materials and operation times on the breakdown voltage are also studied. The experimental results show that the first breakdown voltage increased with the increasing of the operation times. And the breakdown voltage of CuCr (30%Cr) is higher than that of oxygen-free copper.