Microstructure Evolution Analysis and Simulation of Self-healing Metallized Film Capacitor
王开正 1孔德照 1何渝霜 2孙鑫博 2潘蕾 2王飞鹏2
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作者信息
1. 昆明理工大学电力工程学院,昆明 650500
2. 输变电装备技术全国重点实验室(重庆大学电气工程学院),重庆 400044
折叠
摘要
金属化聚丙烯薄膜电容器(metallized polypropylene film capacitors,MPPFC)在充电条件下的自愈击穿可能造成电极和介质膜的永久性损伤,导致其电容减少和介电损耗增加.基于此,本文研究了 MPPFC 充电过程中的宏观特征量—自愈电压、自愈能量、电极损失面积等的演变规律并结合仿真分析了介质膜表面微观结构的变化特性.结果显示,自愈能量随自愈电压增加呈幂函数增长,与电极损失面积正相关,受电弧放电的影响,高压电极损失面积大于地电极且形状较地电极规则,其边界分形维数平均值(1.525)小于地电极(1.665).此外,电极孔洞缺口轴向边缘的电流密度高于切向边缘,致使金属化聚丙烯薄膜自愈击穿过程中金属化电极轴向损伤高于切向.了解这些特性对全面揭示多场耦合复杂工况下MPPFC物性演化规律具有重要意义.
Abstract
The self-healing breakdown of metallized polypropylene film capacitors(MPPFC)under charging conditions may bring about permanent damages to the electrodes and dielectric film,leading to decrease in capacitance and increase in dielectric loss.Therefore,we investigated the evolution characteristics of macroscopic parameters during the charging process of MPPFC,such as self-healing voltage,self-healing energy,electrode loss area,etc.Combining with simulation,we analyzed the changing characteristics of the microstructure on the surface of the dielectric film.The results show that the self-healing energy increases exponentially with the self-healing voltage,and is positively correlated with the elec-trode loss area.Influenced by arc discharge,the high-voltage electrode has a larger loss area compared to the ground electrode and exhibits a more irregular shape than the ground electrode.The average boundary fractal dimension of the high-voltage electrode(1.525)is lower than that of the ground electrode(1.665).Furthermore,the current density at the axial edge of the electrode hole defect is higher than that at the tangential edge,resulting in higher axial damage to the metallized electrode during the self-healing breakdown process of metallized polypropylene film capacitors.Understand-ing these characteristics is of significant importance for comprehensively revealing the evolution of material properties of MPPFC under multi-field coupled complex conditions.
关键词
金属化聚丙烯薄膜电容器/金属化聚丙烯薄膜/自愈击穿/电极损失/表面微观结构
Key words
metallized polypropylene film capacitor/metallized polypropylene film/self-healing breakdown/electrode loss/microstructure of the surface
维普
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