Influence of co-field and cross field flow of mineral oil with andwithout additives on conduction current and breakdown voltage in highlynonuniform fields

摘要

The paper presents the results of the effect of enforced co-fieldand cross-field oil flow on the conduction current and breakdown voltageof degassed oil, oil saturated with O₂ and withSF₆ and oil containing 1-methylnaphthalene (MN) anddimethylaniline (DMA) as additives. Direct voltage and a point-to-planeelectrode geometry were used and results were obtained for bothpolarities of the point electrode. A general conclusion from allexperiments is that oil flow, whether co-field or cross-field, raisesthe breakdown voltage and lowers the conduction current. The resultsalso show that with the exception of DMA, all additives both gaseous (O₂ and SF₆) or solid (MN) raised the breakdownvoltage and reduced conduction current, compared with degassed oil, forboth polarities of the point electrode. These effects are attributed tothe electron-trapping properties of the additives