基于有限元法的变压器式可控电抗器的电磁场分析

发布时间：2018-03-31 10:56

本文选题：变压器式可控电抗器　切入点：电磁场　出处：《兰州交通大学》2014年硕士论文

【摘要】：CRT(Controllable Reactor of Transformer Type,变压器式可控电抗器)是一种新型的可控电抗器。它能够宽范围快速平滑的调节输出感性无功，并且可以通过级数的合理设置，将谐波减小到要求的水平。它的这些优点，使其满足补偿电网无功，控制电网电压稳定的要求，因此国内外有越来越多的学者对其展开了深入的研究。本文以变压器式可控电抗器CRT为主要研究对象，研究分析CRT的一些基本理论问题，如CRT的等效电路、工作特性、谐波分析、功率级数的计算等。通过使用FEM(FiniteElement Method,有限元法)分析CRT的电磁场分布和铁心磁通分布，得到额定功率时控制绕组的电流，并且计算CRT的阻抗参数，为CRT后续更加深入的研究和结构的优化提供实用的资料。介绍CRT的基本工作原理，根据其结构，，建立CRT的多边形等值电路模型、梯形等值电路模型和射线形等值电路模型。分析CRT的谐波特性、控制特性、有功消耗和响应时间，得到谐波含有率与控制级数的关系和控制特性表达式（即晶闸管触发角与电流的关系式），给出有功消耗的计算方法，用matlab仿真分析CRT的过渡过程。通过对CRT这些性能的分析，得到CRT有谐波小和响应速度快等诸多优点，对它有一个全面的了解。由于CRT的控制级数与谐波有着密切的联系，因此要对CRT的谐波进行深入的分析。根据谐波的标准，给出三种谐波含有率的定义，对三种情况下谐波含有率与其控制级数之间的关系表达式进行推导。通过比较分析和算例计算得到的结果可知，已有文献关于CRT谐波的计算方法会导致过多的控制级数。在满足谐波电流有效值要求的前提下，使用新的计算方法可以将CRT的控制级数减小到两级，这可以大大简化CRT的结构，并且简化控制，降低制造成本。介绍有限元方法在电磁场计算中的一般分析方法，给出CRT的有限元数学模型。介绍ANSYS有限元分析软件，以及它在二维和三维电磁场分析中的应用。阐述它的使用方法和分析有限元问题的一般步骤，最后介绍场路耦合分析方法在CRT电磁场分布问题中的分析步骤。以ANSYS为仿真分析平台，采用场路耦合的有限元电磁场分析方法，建立6绕组CRT的实体模型，对CRT的谐波磁场进行分析。结果表明在额定负载时，CRT的主磁场主要分布于工作绕组和控制绕组之间以及它们各自所占的空间中，铁心柱中几乎没有磁通通过。在此基础上，利用ANSYS的后处理功能得到通过铁心和绕组的磁通，计算各个控制绕组的电流分配。介绍使用磁场能量法计算绕组电感的原理，并且使用APDL(ANSYS Parameters Design Language,ANSYS参数化设计语言)编程计算得到CRT的自互阻抗和短路阻抗矩阵。
[Abstract]:CRT(Controllable Reactor of Transformer type (transformer controllable reactor) is a new type of controllable reactor. It can adjust inductive reactive power quickly and smoothly in a wide range, and can be set reasonably by series. The harmonic wave is reduced to the required level. These advantages make it meet the demand of compensating reactive power and controlling the voltage stability of the power network, so more and more scholars at home and abroad have carried out in-depth research on it. In this paper, the transformer controllable reactor (CRT) is taken as the main research object, and some basic theoretical problems of CRT are studied and analyzed, such as equivalent circuit of CRT, working characteristics, harmonic analysis, etc. By using FEM(FiniteElement method, the electromagnetic field distribution and core flux distribution of CRT are analyzed, the current of control winding is obtained when the rated power is rated, and the impedance parameters of CRT are calculated. It provides practical data for further research and structural optimization of CRT. The basic working principle of CRT is introduced. According to its structure, the polygonal equivalent circuit model, trapezoidal equivalent circuit model and radial equivalent circuit model of CRT are established. The harmonic characteristics, control characteristics, active power consumption and response time of CRT are analyzed. The relation between harmonic content rate and control series and the expression of control characteristic are obtained. The calculation method of active power consumption is given, and the transition process of CRT is simulated by matlab. Through the analysis of these properties of CRT, the calculation method of active power consumption is given. It is concluded that CRT has many advantages, such as low harmonic and fast response, and has a comprehensive understanding of it. Since the control series of CRT is closely related to harmonics, it is necessary to analyze the harmonics of CRT deeply. According to the standard of harmonics, the definition of three kinds of harmonic containing rate is given. The expression of the relationship between the harmonic content rate and its control series is deduced in three cases. The calculation method of CRT harmonics in existing literature will lead to too many control series. On the premise of satisfying the requirements of the effective value of harmonic current, the control series of CRT can be reduced to two levels by using the new calculation method, which can greatly simplify the structure of CRT. It also simplifies control and reduces manufacturing cost. The general analysis method of finite element method in electromagnetic field calculation is introduced, and the finite element mathematical model of CRT is given. The ANSYS finite element analysis software is introduced. And its application in two-dimensional and three-dimensional electromagnetic field analysis. The application method and general steps of finite element analysis are described. Finally, the analysis steps of field-circuit coupling analysis method in CRT electromagnetic field distribution problem are introduced. Taking ANSYS as the simulation platform, the solid model of 6-winding CRT is established by using the field-circuit coupled finite element electromagnetic field analysis method. The harmonic magnetic field of CRT is analyzed. The results show that the main magnetic field of CRT is mainly distributed between the working winding and the control winding and the space occupied by them, and there is almost no flux passing through the core column. Using the post processing function of ANSYS, the current distribution of each control winding is calculated through the flux of iron core and winding. The principle of calculating winding inductance by magnetic field energy method is introduced. And the self-mutual impedance and short-circuit impedance matrix of CRT are calculated by using APDL(ANSYS Parameters Design language and ANSYS parametric design language.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM47

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