Failure mode analysis on capacitor energy banks

Capacitor energy banks can be considered as power converters in which the energy storage is charged within a long time (some tenths of seconds) and the energy released within a short time (from microseconds to milliseconds). The converter function is provided by a capacitor, which has to withstand two constraints: 1. high stored energy which relates to electrostatics: a high electric field is applied to the dielectric of the capacitor. 2. high output current which relates to electrodynamics: stress is applied to the galvanic circuit of the capacitor. The evolution of the requirement in terms of stored energy (both increase of and density of) necessitates the most exhaustive analysis of the induced risks and consequences. This analysis has been conducted for the MegaJoule Laser Project. Its energy bank will store within one minute 450 MJ at 24 kV. Then, the bank should be able to deliver a 135 MA pulse current within 360 /spl mu/s. This study will analyze the failure modes of the capacitors and their effects will be experimentally verified.