INDUCEDBY THEFLOWOF OIL IN LARGEPOWER TRANSFORMERS

Staticelectrification phenomena inducedbytheflow of oilhavebeenstudiedusinga modelductof a forced oilcooledpower transformer.The dischargeobserved infullscale model transformers at an excessiveflow rate of oilwas reproduced in themodelduct.The leakage current to thegroundinducedby theflowofoilis a practicalmeasure of the static electrification process. Theformulaof theleakagecurrent obtainedfroma simpletheorybasedontheseparationand therelaxation ofchargescanbeappliedto explainthestaticelectrificationphenomenain fullscale modeltransformers as wellas themodelduct. Theresultsof thisstudy are appliedto assess andcontrolthestaticelectrification phenomena.They contribute to improvethe reliability of insulation in largepower transformers.