Experimental Investigation on the Interruption Performance of Vacuum Interrupters in a Quench Protection Switch

The quench protection switch (QPS) is an indispensable unit to transfer the energy, which is stored in the magnet coils, to the discharge resistor when a quench occurs in a superconducting Tokamak. In this paper, a QPS based on the artificial current zero is involved. A vacuum circuit breaker (VCB), which is driven by a high-speed electromagnetic repulsion mechanism, is used as the main circuit breaker (MCB). Commercial vacuum interrupters (VIs) with electrodes generating axial magnetic field (AMF) are adopted. An LC oscillating circuit is applied to generate oscillating current to simulate the direct current near its peak. The countercurrent with frequency of 500Hz~2500Hz is provided by a commutation branch. The interruption performance of the VI under different frequencies of countercurrent is investigated. The impacts of stray inductance near the MCB on the interruption performance are analyzed.