A Compact Parallel Plate Water Capacitor

A low inductance high energy density parallel plate water capacitor has been designed for driving currents through an inductive load. The design is an extension of the ZFX parallel plate water capacitor (350 kJ, 750 kV) in which the field enhancement at the edge of the plates is eliminated by using thick structures that are fully radiused at the ends. The new concept uses thin plates with the enhancement reduced by placing a plastic field attractor (PFA) at the edge of the plate. This approach has been successfully tested on a small scale (250 J, 890 kV) module, and a full scale system (340 kJ, I MV) has been designed and is under construction. This water capacitor is inexpensive, mechanically simple, easy to maintain, and very compact. In fact it would be almost nine times smaller than a single coaxial line with the same performance.