MATHEMATICAL FORMULATION OF 2D AND 3D FINITE AND BOUNDARY ELEMENT MODEL FOR TRANSIENT ELECTRIC-FIELDS IN HIGH-PERFORMANCE CAPACITORS

Capacitors and their pulse-forming networks deliver very high currents in the millisecond time frame to electromagnetic (EM) and electrothermal chemical (ETC) guns. The spatial distribution of electrical fields in high-performance capacitors and their variation in time are fundamental in developing and optimizing new advanced capacitor modules. This paper outlines the principles of 2D and 3D finite and boundary element method codes for calculating electric field strength distribution in high-voltage capacitor insulation systems in arrangements with complex boundaries. A very accurate representation of the space distribution of electric fields, varying in time during discharge as the combined effect of the circuit parameters, modulated by diffusion and time-changing parameters as properties of the dielectric materials, corona effects, and accelerated aging, can be the basis for a global performance criterion for the system. This criterion should be large enough to represent the complexity of the phenomena in heavy-duty capacitors but still simple to be meaningful.