直流电压下油纸绝缘纤维杂质迁移运动特性及动力分析模型  

Movement Characteristics and Kinetic Analysis Model of Cellulose Impurities in Oil-paper Insulation Under DC Voltage

作　　者：杨森鸿 李原 林思衍 袁豪 周凯[1] 伍亚萍 YANG Senhong;LI Yuan;LIN Siyan;YUAN Hao;ZHOU Kai;WU Yaping(College of Electrical Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学电气工程学院,成都610065

出　　处：《高电压技术》2024年第4期1714-1722,共9页High Voltage Engineering

基　　金：国家自然科学基金(52107159);四川省自然科学基金(2022NSFSC1872)。

摘　　要：换流变压器阀侧绕组运行过程中长期承受直流电场分量,其内部纤维杂质易积聚成桥,严重影响复合绝缘性能。为此,探究了直流电压下油纸绝缘纤维杂质迁移运动特性,对其轨迹、速度、偏移距离等特征参数进行了定量分析。在此基础上,建立了直流电压下纤维杂质动力分析模型,还原了纤维杂质的整个运动轨迹,并定量解释了其运动过程中速度及偏移距离变化的动力学机制。结果表明:球板电极下,单个纤维杂质在电极间往复运动,同时向强场区域水平迁移。其单次运动周期分为“抬升”、“上升”、“下降”3个阶段,最大运动速度可达10^(2)mm/s量级。随加压时间增加,油中纤维杂质在强场区域积聚为杂质小桥,小桥间因同号电荷相斥最终呈现中间密集而边缘稀疏的形态特征。仿真研究纤维杂质迁移运动特性,发现其“上升”阶段运动速度先急速增大再缓慢增加,“下降”阶段速度则先急剧增大至极大值而后逐渐减小,最大加速度可达10^(2)m/s^(2)量级。进一步地,纤维杂质运动过程中水平方向偏移距离随碰撞次数增加逐渐减小,其关系服从指数函数。以上研究可明确直流电压下纤维杂质全运动过程,实现杂质动力学特征定量计算,为后续纤维杂质绝缘危害性评估工作提供理论依据。The valve side winding of a converter transformer bears DC electric field continuously during operation.Its internal cellulose impurities are easy to accumulate and form bridges,which seriously impairs the performance of the composite insulation.In this paper,the migration and accumulation characteristics of cellulose impurities in oil-paper in-sulation under DC voltage were investigated.The trajectory,speed,offset distance and other characteristic parameters of impurities were quantitatively analyzed.The kinetic analysis model of cellulose impurities under DC electric field was established thereafter,the whole motion trajectory of fiber impurities was reduced,and the kinetic mechanism of the vari-ation of velocity and offset distance was explained quantitatively.The results show that a single cellulose impurity reciprocates between sphere electrodes and plate electrodes,and moves horizontally to the stronger electric field region at the same time.The single motion cycle can be divided into three stages:‘lifting’,‘rising’and‘falling’,and the maximum speed reaches over 10^(2)mm/s during this process.As time increases,the cellulose impurities in the oil form impurity bridges in the stronger electric field region.The micro bridges present the characteristics of dense morphology in the cen-ter and sparse morphology in the edges due to the repulsion of charges with the same polarity.By simulation of the migration characteristics of cellulose impurities,it is found that the growth rate of particle velocity is fast firstly and then slow in the‘lifting’stage,while the velocity increases sharply to the maximum at first,and then decreases gradually in the‘falling’stage.Meanwhile,the maximum acceleration can reach over 10^(2)m/s^(2).In addition,the horizontal offset distance decreases with the increase of collision times in the process of cellulose impurity movement.Offset distance and collision times have an exponential relation.This study clarifies the whole moving process of cellulose impurities under

关 键 词：油纸绝缘 纤维杂质 迁移运动 有限元 动力学模型 

分 类 号：TM855[电气工程—高电压与绝缘技术]