Study On Performance Of Insulating Paper Based On Multivariate Statistical Analysis Of Fiber Characteristics And Paper Structure

With the development of UHV power transmission and transformation,strict requirements are placed on the performance of insulating paper,and how to improve the performance of insulating paper faces huge challenges.In addition,due to the complexity of the oil-paper insulation system,whether it is possible to obtain a more accurate influence mechanism and calculation method to shorten the research and development cycle of electric equipment and reduce costs has been an important issue that researchers have faced for a long time.According to the influence of fiber characteristics and paper structure on the electrical performance of insulating paper,through the adjustment of the beating and papermaking process,design insulating paper with different fiber characteristics and paper structure,and use multivariate statistical analysis to build a model,study the "material-structure-performance" between of relevance.To provide theoretical and technical support for improving the performance of insulating paper and developing new products,which will help to improve the manufacturing technology and quality level of insulating paper products for China's UHV transformers.First,based on the orthogonal experimental design method,combined with range and variance analysis,the influence of the four preparation conditions on the breakdown strength was studied.At the same time,the Weibull distribution was used to construct the insulating paper failure model,and study the effect of calendered treatment on the breakdown strength.The results show that the degree of impact on the breakdown strength of insulating paper is beating degree>beating load>drying method>basis weight,and the degree of impact on the breakdown strength of oil-impregnated paper is beating degree>basis weight>beating load>drying method.Four factors there is a synergistic effect on the impact of penetration strength.The scale parameters of the failure model can be used to describe the breakdown strength of insulating paper and oil-impregnated paper.The dispersion of insulating paper's breakdown strength is less than that of oil-impregnated paper.Calendered can improve the breakdown strength and reduce the data dispersion of the breakdown strength.Secondly,the degree of impact of fiber characteristics and paper structure on the breakdown strength was studied,and a quantitative analysis model of the factors affecting the breakdown strength was constructed based on the grey relational analysis.The results show that the grey relational grade that affects the breakdown strength of insulating paper is fine>density>fiber length>length-width ratio>fiber width>porosity>thickness>air permeability.The grey relational grade that affects the breakdown strength of oil-impregnated paper is fiber length>length-width ratio>fine>fiber width>density>air permeability>porosity>thickness.Various factors have different effects on the breakdown strength of insulating paper and oil-impregnated paper,which is caused by the different oil absorption rate of oil-impregnated paper.In addition,a multivariate analysis method in statistics is introduced to construct a linear regression model of fiber characteristics and paper structure and breakdown strength to achieve the prediction of the breakdown strength.The principal component analysis shows that the three extracted principal components can explain 95.76%of the original seven parameters.The best subset selection method optimizes the seven parameters into three parameters,namely fine content,thickness and porosity.The relative deviation of the prediction results of the models obtained by the two methods is basically within 10%,with good predictive ability,and the accuracy of the prediction model of oil-impregnated paper is better than that of insulating paper.Finally,the effect of mix with different fibers on the mechanical and electrical performance of insulating paper was studied.Artificial fiber Tencel fiber and synthetic fiber polyester fiber are selected to mix with the insulating paper to prepare composite insulating paper.The results show that the addition of 10%Tencel or polyester fiber can improve the tearing degree,significantly reduce the dielectric constant and dielectric loss of insulating paper,and improve the thermal stability of insulating paper,effectively reduce the aging degree.