流-电耦合场中金属颗粒群的荷电计算及影响因素研究  

Study on the Charge Calculation and Influencing Factors of Metal Particle Groups in Fluid-Electric Coupling Field

作　　者：张宁 王鹏[1] 刘智捷 刘恭智 贺博[1] Zhang Ning;Wang Peng;Liu Zhijie;Liu Gongzhi;He Bo(School of Electrical Engineering Xi’an Jiaotong University,Xi’an 710049 China)

机构地区：[1]西安交通大学电气工程学院,西安710049

出　　处：《电工技术学报》2024年第17期5534-5544,共11页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51977170)。

摘　　要：绝缘油中金属颗粒的荷电量分布是研究颗粒运动特性以及绝缘油中局部放电与击穿行为的关键。该文搭建了油道模拟观测系统,采用动力学分析的方法,构建了液固耦合系统中金属颗粒的运动模型,并在此基础上提出通过粒子图像测速(PIV)来计算颗粒荷电量;分析了不同油流速度、电压等级以及电压类型对颗粒荷电量的分布影响以及作用机理。结果表明,基于PIV计算出的油中颗粒的荷电量与传统模型的计算结果数量级相近,绝缘油中金属颗粒荷电量占比分布曲线接近高斯分布,这是由于颗粒与颗粒之间碰撞也会发生电荷转移或中和。在直流电压下流速增加会阻碍颗粒之间的电荷传递,增加颗粒与极板碰撞概率,导致颗粒荷电量减小。电压等级增加则会使颗粒群的流线由平缓变为振荡,颗粒荷电量普遍增加。相比于直流电压,在交流电压下,荷电量大的颗粒占比较多。In the life cycle of power equipment,the insulating oil is easy to mix with various solid impurity particles such as metal and fiber,which will cause electric field distortion and insulation balance failure of equipment.Therefore,considering that compared with non-metallic particles,metal particles have a greater impact on partial discharge and arc breakdown of oil,this paper proposes a method to derive the charge of particles by analyzing the force model of metal particles on the basis of discrete particle model,and reveals the influence of electric field intensity,voltage type and flow velocity on the charge distribution of metal particles.Firstly,the internal oil channel environment of power transformer was simulated and the experimental observation platform for particles in oil was built.Secondly,the force model of metal particles in the fluid electric coupling system was established combined with fluid dynamics.The formula for calculating the charge of metal particles under experimental conditions was derived through the formula.Thirdly,the particle image velocimetry(PIV)system was used to capture the cloud picture of particle swarm velocity and streamline,and the velocity and acceleration of metal particles were calculated through the streamline of particles and the finite difference method,so as to calculate the charge of particles,which was close to the charge of particles calculated by the traditional model.Finally,by changing the applied voltage,oil flow rate and voltage type,the charge value and distribution of metal particles in the oil flow were calculated and counted.The experimental results show that when the flow rate of insulating oil is 0.15 m/s,the maximum charge of particles is 0.17 pC,and the proportion of particles with the absolute value of charge greater than 0.01 pC is 36%,while when the flow rate is 0.3 m/s,the maximum charge of particles is-0.13 pC,and the proportion of particles with the absolute value of charge greater than 0.01 pC is 29%,which may be due to the increase of horizontal

关 键 词：粒子图像测速 金属颗粒 绝缘油 液固耦合 荷电分布 

分 类 号：TM855[电气工程—高电压与绝缘技术]