Study On The Influence Of Corrosive Sulfur To The Propertiesof Transformer Oil-paper Insulation

The transformer is the core equipment for energy delivery and distribution inpower system.it’s own fault not only can lead to damage of itself, but alsobring hugeeconomic loss to the community.In recent years, many power transmission andtransformation equipment insulation faults causedby sulfur corrosionattracted theattention of researchers at home and abroad, although the related statutes forlimit thesulfur content of insulation oils have been developed, used to control winding erosionbycorrosive sulphurininsulation oil.But the insulation performance degradation causedby sulfur corrosion of oil and result in equipment failure are emerging in an endless.Although by far the generation mechanism of corrosive sulfur in oil-paper insulationalready get early insights, the influence ofcorrosive sulfur to thepropertiesoftransformer oil-paper insulation has not yet been fully studied.Therefore,exploringtheinfluence of corrosive sulfur to the insulation performance in oil-paper insulationwillbe of great academic significance and application valuable.Firstly,thispapercarry out thermal agingexperimentby means of puttingwindingmodelsimpregnate intoinsulation oil with different concentration of dibenzyl disulfide(DBDS). The samples were taken regularly toobtain insulation oil and winding modelwith different sulfur corrosion degree.Secondly,some basic parameters such asinsulation parameters and partial discharge have been tested, in order to study thesulfur corrosion of oil influence of the DBDS concentration, as well as the rules ofwinding model with different degree of corrosion. The main research resultsof thispapers are presented as follows:①Through qualitative and quantitative analysis ofthe corrosion on copper andinsulation paper surfaceby a combination of macro and micro methods,it can beconcluded that the deposition weight on insulation paper surface and copper wirecorrosion degree are all in proportion to corrosive sulfur concentration in oil,inversely proportional to surplus of corrosive sulfur concentration after ageing.②Through the test result of resistivity of insulation windings and frequencydomain dielectric spectroscopy with different degrees of corrosion, deposition ofcorrosive sulfur caused a decline in the volume and surface resistivity of theinsulation winding,and the volume resistivity drop even more obvious. Comparedwith the blank samples, the volume resistivity reduced47.56percent by Corrosive sulfur, but the surface resistivity reduced at most11percent. The dielectric loss ofinsulation winding increases gradually with the increasing corrosive sulfur.③The test results of insulation oil volume resistivity and breakdown voltageshow that corrosive sulfur deposited in windings permeate to insulation oil, Comparedwith the blank samples, the breakdown voltage decline3.8kV. The formation ofcorrosive sulfur need expend oxygen gas and acid in oil, it can lead to the volumeresistivity drop rate become faster than the blank oil sample.④Based the partial discharge test results on insulation windings of the differentcorrosive degree, the research has get the PDIVand phase resolved partial dischargeof samples throughout the ageing process，Achievedextract theinfluenceof sulfidecorrosive deposition to characteristics ofwinding partial discharge form the PRPDpattern...