采用分子模拟法分析变压器油纸绝缘材料的相互作用  

Analysis of Interaction Between Transformer Oil and Cellulosic Insulation Paper Using Molecular Simulation Method

作　　者：廖瑞金[1] 朱孟兆[1] 杨丽君[1] 周欣[1] 严家明[1] 孙才新[1] 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030

出　　处：《高电压技术》2011年第2期268-275,共8页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2009CB724505-1);中央高校基本科研业务费资助(CDJXS11152235)~~

摘　　要：油纸绝缘是变压器的重要绝缘方式,油纸的相互作用和影响对其复合绝缘状态有着重要的影响。为此,利用分子动力学方法,对变压器油纸材料的相互作用和影响进行了研究。通过计算发现,油与绝缘纸的主要成分纤维素的相互作用从大到小依次为纤维素Iβ晶体的(110)表面、(1-10)表面和纤维素无定形区的表面。通过对油和纤维素的相互作用能的分析得到,晶体界面处可能是产生油流带电主要区域。分析油在纤维素不同表面的分子构象发现,在纤维素晶体表面,油分子大多数以平行于纤维素表面的分子构象分布,而在纤维素的无定形区表面油分子更多的是采用竖直构象,而无定形纤维素与油的界面处最易产生空间电荷。最后分析了不同油纸界面的密度分布,发现在纤维素晶体表面油的密度会变大;而纤维素无定形区表面油的密度变化不大;晶体表面处油密度的变化将使纸中水分的扩散受到阻隔,加速纸的老化。Oil-paper insulation is an important insulation mode in transformer,and the interaction between oil and cellulosic paper strongly affects the oil-paper compound insulation.Consequently,the interaction between cellulose,which is the main component of transformer insulation paper,and power transformer oil is studied using the molecular dynamics simulation.The interaction energies between the oil and cellulose decreases in sequence of the（110） face,the（1-10） face,and the amorphous phase of cellulose,indicating that the interface of crystals may be the main area that the oil flow electrification appears.Thus,the molecular conformation of the oil on the different cellulosic surfaces is analyzed.On the surface of the cellulose Iβ crystal,the conformation of the oil is mainly parallel to the surfaces,however,on the surface of cellulose amorphous phase,the conformation of the oil is mainly perpendicular to the interface.The space charge will appear most easily at the surface of the amorphous cellulose and oil.Finally,the density distributions of three models in the Z direction are calculated,and the results show that the density of the oil will increase but it hardly changes on the interfaces between oil and cellulose amorphous phase.The change of density may prevent the diffusion of water in paper,and accelerates aging of paper.

关 键 词：分子动力学 油纸绝缘材料 相互作用 分子构象 密度分布 油流带电 空间电荷 

分 类 号：TM855[电气工程—高电压与绝缘技术]