ELECTRODE SURF ACE EFFECTS ON UNIPOLAR CHARGE INJECTION IN COOLED LIQUID DIELECTRIC MIXTURES by

Previous investigations at NSWC, Dahlgren Laboratory, have established that anomalous voltage decay curves are observed for capacitors filled with cooled ethylene glycolwater dielectric mixtures. A unipolar charge injection model developed in conjunction with M. Zahn, et a!, at MIT correctly predicted experimental waveforms and yielded information on the quantity of charge injection and the mobility of the transported species. Experiments are described demonstrating the effects . of surface materials on the charge injection phenomenon, specifically electropolished, passivated stainless steel vs. untreated 304 stainless steel and cuprous oxide coatings vs. electrolytic copper. Analysis of the electrode surface effect is accomplished with the assistance of a computer model of the charge injection process that uses a hill climber routine to adjust physical parameters until the model matches the experimental behavior of the voltage decay curve.