Using of FEM method for design and prediction of static behavior of three electrode mid-plane spark gap

In many Pulsed Power applications, three electrode mid-plane spark gap switches are used to discharge of capacitive energy. Therefore, the prediction of the influence of spark gap design parameters on its performance is critical. A Three electrode mid-plane spark gap has been numerically and experimentally investigated and designed. ANSYS finite element package used for static analyzing of the electric field distribution in the dielectric medium for designing spark gap switch with self-breakdown voltage 20% upper than desired operational voltage. In addition, we used FEM analysis at operational voltage to become assured that, before applying the trigger voltage, the electric field stress is under the self-breakdown electric field. Using this analysis at specific trigger voltage, we will be certain that the breakdown will occur. We have used this static model for numerically prediction of the influence of trigger shape, trigger position, trigger voltage and main electrode voltage on the electrical field distribution. These analyses enable us to determine the switch operating voltage range. The spark gap switched energy of a 6 muF, 20 kV capacitor on explosive wire which has been used for production of nano powder. Experimental delay time of the switch has been compared with the empirical formula of Martin. Also, the influence of main electrode voltage on the delay time of the switch has been investigated. Experimental self-Breakdown voltage of switch has been compared with analytical results. The numerical results agree with the experimental results.