直流输电线路电晕放电的微观物理过程及离子流场分析

发布时间：2018-07-05 17:23

本文选题：电晕放电 + 混合数值模型　；参考：《重庆大学》2014年博士论文

【摘要】：特高压直流输电线路由于运行电压极性固定，电晕放电导致的空间电荷使得离子流场问题尤为严峻。开展电晕放电微观物理过程研究对于探求电晕放电的演化规律、指导输电线路离子流场计算具有重要理论价值。电晕放电微观过程中会产生大量激发态粒子、带电粒子、自由基等微观粒子，动理学规律极其复杂。由于缺乏有效的等离子体诊断手段，电晕放电的很多关键微观参数无法通过试验获得，国内外开展了大量电晕微观机理的数值研究，至今未取得突破性进展。可定量分析电晕放电微观物理过程的模型尚缺，对其影响因素的微观分析也未能深入。本文在流体动力学电晕放电模型的基础上，提出研究电晕放电微观物理过程的混合数值模型。采用棒-板电极最简模型对电晕放电脉冲电流进行了计算分析，研究电晕放电微观特征量在单次放电脉冲持续过程中的时空发展规律。建立了直流输电线路电晕放电宏观离子流场计算模型，讨论了输电线路结构对离子流场的影响，着重分析相对空气密度对离子流场的影响规律。本文的主要内容为： ①首次提出了可量化研究电晕放电微观物理过程的混合数值模型。模型中利用流体动力学控制方程描述电晕放电的宏观物理规律；采用等离子体化学反应过程电晕放电微观过程中粒子的产生和消散过程；Boltzmann方程求解模块给流体动力学模型提供详细的电子输运参数和能量传递系数，同时给等离子体化学模型提供化学反应速率；通过试验得到的正负电晕放电单次脉冲波形和UI特性曲线证明了该模型的有效性。 ②计算分析了正负电晕的脉冲形成机制，在此基础上研究得到了负电晕放电的电子特性(平均电子能量、电子密度、电子的生成/消散速率等)和负电晕放电的重粒子特性(净空间电荷、等离子体化学反应速率、重粒子的成分及密度)在单次脉冲持续过程中的时空发展规律。 ③采用上流有限元法建立了直流输电线路电晕放电的宏观离子流场计算模型，利用单/双极试验导线的地面合成场强和离子流密度证明了模型的有效性，，讨论了输电线路结构对离子流场的影响，着重分析了相对空气密度对离子流场的影响。对±800kV和±1100kV直流输电线路离子流场的计算结果表明，在跨越高海拔、高温度区域时，需要对输电线结构进行校验，确保其合成场强满足国家标准。
[Abstract]:Due to the fixed polarity of the operating voltage, the space charge caused by corona discharge makes the ion flow field more serious. The research on the microscopic physical process of corona discharge is of great theoretical value in exploring the evolution law of corona discharge and guiding the calculation of ion flow field in transmission lines. In the microscopic process of corona discharge, a large number of excited particles, charged particles, free radicals and other micro-particles will be produced, and the kinetic laws are extremely complex. Due to the lack of effective plasma diagnostic methods, many key microscopic parameters of corona discharge can not be obtained through experiments. A large number of numerical studies on the microscopic mechanism of corona have been carried out at home and abroad, but no breakthrough has been made so far. There is still no model for quantitative analysis of corona discharge microphysical process, and the microcosmic analysis of its influencing factors is not thorough. Based on the hydrodynamic corona discharge model, a hybrid numerical model is proposed to study the microscopic physical process of corona discharge. The corona discharge pulse current was calculated and analyzed by using the simplest model of rod-plate electrode, and the temporal and spatial development of the microscopic characteristic quantity of corona discharge in the continuous process of single discharge pulse was studied. The calculation model of macroscopic ion flow field in corona discharge of DC transmission line is established. The influence of transmission line structure on ion flow field is discussed, and the influence law of relative air density on ion flow field is analyzed. The main contents of this paper are as follows: 1 for the first time, a mixed numerical model for quantifiable study of microscopic physical processes of corona discharge is proposed. In the model, the macroscopic physical law of corona discharge is described by hydrodynamic governing equation, and the generation and dissipation of particles in corona discharge microcosmic process by plasma chemical reaction are described. The Boltzmann equation solution module provides detailed electron transport parameters and energy transfer coefficients for the hydrodynamic model and chemical reaction rate for the plasma chemical model. The validity of the model is proved by the single pulse waveform and UI characteristic curve of positive and negative corona discharge. 2 the pulse formation mechanism of positive and negative corona is calculated and analyzed. On this basis, the electron characteristics of negative corona discharge (average electron energy, electron density, electron generation / dissipation rate, etc.) and the heavy particle characteristics of negative corona discharge (net space charge, plasma chemical reaction rate, etc.) are obtained. The temporal and spatial development of heavy particles in the process of single pulse duration. (3) the calculation model of macroscopic ion flow field of DC transmission line corona discharge is established by means of upflow finite element method. The effectiveness of the model is proved by the ground synthetic field strength and ion current density of a single / bipolar test wire. The influence of transmission line structure on ion flow field is discussed, and the influence of relative air density on ion flow field is analyzed. The calculation results of ion flow field in 卤800kV and 卤1100kV HVDC transmission lines show that when crossing the high altitude and high temperature regions, it is necessary to check the transmission line structure to ensure that the composite field strength meets the national standard.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM721.1

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