基于气液两相及光电离的酯基绝缘油流注放电模拟  

Simulation of Ester Based Insulating Oil Streamer Discharge Based on Gas-Liquid Two-Phase and Photoionization

作　　者：王开正 王帅旗 俞瑞龙 李露露 王飞鹏[2] Wang Kaizheng;Wang Shuaiqi;Yu Ruilong;Li Lulu;Wang Feipeng(Faculty of Electric Power Engineering Kunming University of Science and Technology,Kunming 650500 China;State Key Laboratory of Power Transmission Equipment Technology Chongqing University,Chongqing 400044 China)

机构地区：[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),重庆400044

出　　处：《电工技术学报》2024年第21期6896-6907,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金青年项目(52107017);云南省科技厅基础研究专项青年项目(202201AU070172);国家自然科学基金面上项目(52177016);国家自然科学基金重点项目(52130707)资助。

摘　　要：流注放电是一个非常复杂的多尺度、多物理场耦合过程,目前尚无准确的模型能描述其发展过程。相变及光电离是影响流注演变的重要因素,但现有流注放电模型很少将其影响考虑到模型内。为分析二者对流注放电的影响,该文在COMSOL中建立针/板放电几何模型,以酯基绝缘油为研究对象,基于电流体动力学模型,以相变温度为临界点,分别构建气相和液相下的电离机制。此外,建立了与电场阈值相关的光电离数学模型。结果表明,光电离的引入促使优势流注分支的产生,且光电离主要发生在优势流注头部区域。由于高温区域主要集中在针尖处,气相区域会随着局部温度的升高而产生,在电场作用下,气相区域发生碰撞电离,在针尖处产生更多的小流注分支。气相区域对主流注的传播速度几乎没有影响,主流注的传播速度主要受场致电离和光电离的控制。光电离在流注头部产生了更多的载流子,促使改进模型的主流注以更快的速度传播,从而易实现传播模式从慢速到快速的转换。该文可为酯基绝缘油快速流注的产生机理提供新的研究思路,为提高其击穿电压提供指导依据。In recent years,biodegradable and environmentally friendly synthetic ester insulation oils with high ignition points have received attention and extensive research,and have been applied to in-service power transformers.However,in long oil gaps,synthetic ester insulation oil is more prone to rapid streamer compared to mineral insulation oil,and rapid streamer has been proven to be one of the most critical factors leading to insulation faults in oil-immersed transformers,which limits its application in transformers at higher voltage levels.At present,research on the dielectric properties of synthetic ester insulating oils mainly focuses on experimental observation,making it difficult to observe their microscopic processes under high electric fields.In this study,based on the electrohydrodynamic model,a gas phase impact ionization term with phase transition temperature as the critical point and an ester based insulating oil streamer discharge model considering molecular ionization energy,temperature,and electric field photoionization terms were established.The streamer discharge process of ester based insulating oil was simulated,and the streamer morphology characteristics,streamer channel temperature distribution,propagation characteristics,and space charge distribution were investigated.Firstly,the mechanism of the generation and capture of positive ions,electrons,and negative ions was explained using the convection diffusion equation.By coupling the Poisson equation with the convection diffusion equation,the process of charge movement and spatial charge distribution in synthetic ester insulating oil under the action of an electric field can be described.Secondly,collision ionization was established using the phase transition temperature of synthetic ester insulating oil as the critical point.Thirdly,a photoionization model was established that considers the correlation between molecular ionization energy,temperature,and electric field.Finally,all oil parameters are derived from the previously prepared synthetic e

关 键 词：酯基绝缘油 光电离 气相 流注放电 

分 类 号：TM214[一般工业技术—材料科学与工程]