All Russian Electrotechnical Institute, Moscow, Russia

The high current triggered vacuum switch with a six-gap rod electrode system has ever-increasing utilization for pulse power switching in high-voltage circuits at currents to hundred kiloamperes and pulse duration of several milliseconds. The paper studies current-voltage characteristics of such electrode system versus scape and material of the electrodes and inter-electrode gap value. The investigation were carried out at a current amplitude up to 200 kA with the rate of its rise up to -5*10⁹ A/c. A number of features were observed concerning arc burning voltage dynamics depending on value and rate of the arc current and namely, a step-like voltage change at an initial discharge burning stage and excitation of high frequency voltage oscillations in a discharge current wave front. The duration and intensity of the unstable discharge-burning phase accompanied by high frequency voltage oscillations depend strongly on electrode system parameters. Dynamics of power dissipated in the vacuum gaps and full-dissipated energy were calculated in terms of the switching current amplitude. Results of the investigation gave possibility to design a sealed-off triggered vacuum switch having minimum power losses and prolonged service life evaluated by a transferred charge value > 10⁶ C.