【作者】 宋宇；

【导师】 林莘；

【作者基本信息】 沈阳工业大学 ， 电气工程， 2018， 硕士

【摘要】 随着我国高压和超、特高压输电工程的建设,高压SF₆断路器作为输电线路中应用最广泛的重要保护和控制设备也势必向着更高电压等级、更大容量的方向发展。我国高压开关生产厂家在迎来巨大发展机遇的同时也面临着空前的挑战,设计、研发开断性能更好、绝缘能力更强的高压SF₆断路器,已成为各个企业在国内甚至是国际高压开关领域拥有核心竞争力、提升话语权的首要任务。以往国内高压SF₆断路器生产企业主要依靠引进国外技术,在进行一定程度改进后凭借经验与试验进行设计、研发,这导致研发成本高、研发周期长,且无法形成一套拥有自主知识产权的高压SF₆断路器研发体系。随着计算机性能与数值仿真技术的不断发展,国内外众多专家学者将研究重点转移到采用数值仿真技术指导断路器设计研发。鉴于此,本文以一台高压SF₆断路器为研究对象,建立了适用于断路器开断过程的电弧数学模型,对高压断路器空载开断、小电流开断、短路大电流开断三种开断工况进行了深入的计算研究,详细分析了断路器开断过程中介质恢复特性、电弧特性和压气特性。研究方法与研究成果将为高压SF₆断路器设计、研发提供坚实的理论基础,实现高压断路器产品研发国产化、自主化。首先结合SF₆电弧等离子体物理特性计算分析结果,耦合气流场、温度场、电磁场和辐射场之间的相互作用,基于局部热力学平衡态假设和磁流体力学（MHD）理论,联立流体力学三大守恒方恒与电磁场方程,考虑了洛伦兹力对电弧形态的影响,以及电弧的欧姆发热和热辐射输运部分,较以往电弧辐射数学模型,创新性的提出了五波段P-1辐射模型,建立了较为完善的SF₆等离子体电弧数学模型。为实现高压SF₆断路器空载开断过程中气流场与电场的同时计算,首先联立气流场控制方程、气体状态方程和湍流方程对空载开断气流场进行计算。在此基础上,使用同一套网格在计算域内求解拉普拉斯方程,完成了高压断路器空载开断过程电场计算。计算得到灭弧室内压强、密度、电场强度和击穿电压分布。分析断路器触头间介质临界击穿电压变化曲线,给出高压SF₆断路器介质恢复的变化规律。建立断路器开断过程多物理场耦合计算模型,完成断路器小电流与短路大电流开断过程仿真计算,得到灭弧室内的压强、温度、密度和气流速度等参数分布及变化趋势,分析不同开断过程的电弧动态变化以及灭弧室内压气特性与气流特性。更多还原

【Abstract】 With the construction of HV、EHV and UHV transmission projects,HV SF₆ circuit breakers,as the most widely used protection and control equipment in transmission lines,are bound to develop toward higher voltage levels and larger capacities.China’s HV switch companies are facing unprecedented challenges while facing huge development opportunities.In order to have core competitiveness and improve their discourse power in China and even in the world,the primary task is to design,research and develop the HV SF₆ circuit breaker with better interrupting performance and insulation performance。In the past,domestic HV SF₆ circuit breaker companies mainly relied on the introduction of foreign technology.After a certain degree of improvement,HV circuit breakers were designed and developed based on experience and experimentation.It results in high R&D costs and a long research and development cycle,and it’s unable to form a set of HV SF₆circuit breaker R&D system with independent intellectual property rights.With the continuous development of computer performance and numerical simulation technology,many experts and scholars have shifted their research focus to the use of numerical simulation techniques to guide the design and development of circuit breakers.In view of this,a HV SF₆ circuit breaker is considered as a research object,and an arc mathematical model suitable for the circuit breaker interrupting process is established in this paper.The HV circuit breakers have been studied in detail by means of no-load interrupting,small-current interrupting,and short-circuit interrupting,and the dielectric recovery characteristics,arc characteristics and pressure characteristics have been analyzed in detail during the interrupting process.The research methods and research results will provide a solid theoretical basis for the design and development of HV SF₆ circuit breakers,and realize the localization and autonomy of HV circuit breaker product development.Firstly,combined with the SF₆ arc plasma physical property calculation results,the interaction between the flow field,temperature field,electromagnetic field and radiation field are coupled.Based on the assumption of local thermodynamic equilibrium state,the magneto-hydro-dynamic（MHD）mathematical theory is used,a more complete two-dimensional dynamic theoretical model is established.The ohmic heat and heat radiation are considered in the energy equation.Compared with the previous arc mathematical model,a five-band P-1 radiation model is innovatively established in this paper.Secondly,in order to realize the simultaneous calculation of flow field and electric field during no-load interrupting process,the same grid is used in the simulation software to calculate the flow field combining flow field control equations,gas state equations and turbulence equations.On this basis,the UDS（User Defined Scalar）transport equation is used to solve the potentialφ,and the electric field is calculated.The distribution of pressure,density,electric field strength and breakdown voltage are calculated,the change rule of dielectric recovery is given by analyzing the curve of breakdown voltage between the arc contacts.Lastly,a multi-physics-field coupling calculation model of arc is established,the pressure characteristics,gas flow characteristics,and arc characteristics during small-current and short-circuit current interrupting process are calculated by coupling the flow field and the temperature field.The distribution and the trend of changes of pressure,temperature and density are obtained to analyze the dynamic changes of the arc in different current interrupting processes.更多还原