Optimization of a Triggered Vacuum Switch With Multirod Electrodes System

The breakdown and triggering characteristics of triggered vacuum switch (TVS) are very important features, and they affect the operation reliability of TVS. Both of them mainly depend on the electrode material, electrode shape, gap distance, and surface condition. For an optimized electrode´s geometry, finite-element method 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 multirod system (MTVS) is calculated by the finite method. The simulation results show that the geometric enhancement factor (GEF) is decreased with the increase of the fillet radius of the edge of the rod. In case of the fillet radius for the side face of rod 3 mm and the fillet radius of the top face of the rod is 5 mm, the GEF is decrease to a minimum value of 3. The breakdown voltage of MTVS was measured by the high-voltage direct current generator after switch currents with amplitude of 63 kA and width of 13 ms with the interval time of 10-15 min. The influences of electrode materials and operation times on the breakdown voltage and trigger characteristics are also studied. The experimental results show that the breakdown voltage of the optimized MTVS is higher than that of the non-optimized MTVS. The breakdown voltage of CuCr30 is higher than that of oxygen-free copper. In addition to, the trigger characteristics of MTVS are influenced mainly by the electrode materials, the fillet radius of electrode has a little effect on the triggering characteristics of MTVS.