Evaluation of the GTO for 270 MVA Interrupter Applications

The fundamental problem of interrupting a direct, current is producing a current zero which will allow for the elimination of current flow. Historically, external circuits have been used to extinguish a plasma (arc) conducting medium by counterpulsing the arc current to zero. Preliminary results show that solid-state dc interrupters utilizing gale turnoff thyristors can provide for reduced capacitive energy storage requirements over vacuum interrupters and SCRs in creating a current zero. Additionally, the hardware required in the gate circuit of the GTO is significantly reduced over the counter-pulse circuits in vacuum interrupters and SCRs by taking advantage of the turn-off gain available in the GTO. Interrupters designed around the GTO can have applications in the power conditioning and protection circuits of particle accelerators and fusion reactors.