The Impact of Surface Conditioning and Area on the Pulsed Breakdown Strength of Water

Experimental results are presented on the degree to which electrode surface conditioning and surface area impact the dielectric strength of water. The applied pulse to the test gap reached electric field levels greater than 1.5 MV/cm with risetimes around 200 and 50 ns, respectively. The test gap is composed of 304 stainless steel electrodes machined with a Bruce profile. Electrode surface roughness ranged from 0.34 to 1.41 and effective areas ranged from 0.5 to 75 . Additional results are presented on the pulsed breakdown strength of Rexolite with various surface finishes ranging from .025 to 5.715 . Conclusions are made as to the effect electrode surface area and surface roughness has on the holdoff voltage of water dielectric systems. Conclusions are also made as to the impact of the surface condition of Rexolite has on its bulk breakdown strength.