Study on Dynamic Performance and Induced Breakdown of the Plasma-Triggered-Based Protective Gas Gap Switch

The plasma-triggered-based protective gas switch (PTGS) has obvious advantages in the control switch application of fast energy dissipation device used in the hybrid dc transmission projects. However, the high-pressure environment critically limits the plasma jet ability, easily leading to the trigger failure. Therefore, this article establishes a plasma-jet-triggered experimental platform to study the dynamic performance and induced breakdown laws of PTGS. It is shown that the evolution of plasma jet is divided into three stages: plasma jet of high-pressure, saturated stability, and dissipation. The induced breakdown mainly occurs in the high-pressure jet and saturated stability stage. The initial plasma jet velocity increases, as the energy storage capacitance and the charging voltage increase, making it faster to reach the jet length for induced breakdown, resulting in a significant reduction in switch-on time and improving the PTGS trigger stability. The increase in trigger gas pressure inhibits the plasma jet ability, but improves the electrical strength of PTGS. In order to achieve induce breakdown of PTGS, the plasma jet must reach the critical jet length. SF6 gas improves the insulation strength of PTGS and prevents the formation of plasma jet. To achieve stable trigger conduction, the trigger energy of PTGS must be increased. The findings can be used to develop theoretical guidance for improving the working performance of the high-voltage and large-capacity protective gas gap switches (GGSs).