Study On The Infuluence Of Multiplesulfur Corrosion On The Development Of Partail Discharge Of Transformer Oil-Paper Insulation

A small amount of sulfide remains in the oil during the refining process,which is more or less corrosive to oil-immersed metal components.The corrosive action of sulfide may change the electric field distribution around the winding,induce the inter-turn discharge of the winding,the slight inter-turn discharge is not easy to be recognized,so the protection will not work,and the discharge is likely to further develop into interlayer discharge or even interphase discharge.Even burning the transformer to cause serious consequences.The above procedure are considered to be the culprit of many transformer accidents at home and abroad.In actual operation,the transformer insulating oil contains a variety of sulfides,and the effects of each sulfide on the partial discharge of the transformer have certain differences.Therefore,the research on the influence of multiple sulfur corrosion on partial discharge of oil paper and on its development,have important theoretical research value and practical significance.A series of insulating oils containing different concentrations and kinds of sulfides were prepared for testing.The sulfur corrosion test of the transformer windings was carried out,and the aging state of the wound samples after corrosion was evaluated.The influence of corrosive sulfides on aging properties of oil-paper insulation was analyzed.Subsequently,a test platform for observing partial discharge of oil-paper insulation samples after multiple sulfur corrosion was built.The principle of partial discharge measurement,the significance of each characteristic parameter and the stage division of the discharge process were introduced.Based on the analysis of discharge patterns and experimental phenomena,the process of oil-paper insulation partial discharge is divided into four stages: initial,slow development,rapid development and pre-breakdown.Among them,the initial and slow development stages last longer and the discharge is less severe,Discharge type is mainly the discharge of insulating oil and the surface of the insulating paper near the electrode;the discharge is intense during the rapid development stage,indicating that the discharge enters the destructive stage;The pre-breakdown stage indicates that a penetrating breakdown of the oil-paper insulation is about to occur.By analyzing the variation of characteristic parameters of each group of samples during partial discharge,the influence of corrosive sulfide on partial discharge of oil-paper insulation was investigated.The results show that the combination of different sulfides has different effects on partial discharge.The effect of the various sulfides is not equal to the sum of the effects of their individual effects.Finally,by exploring the difference between the performance degradation rules of different parts of the windings under the action of different concentrations and types of sulfides,and combining with the theory of partial discharge,the change rules of the above partial discharge characteristic parameters are further explained...