变压器式可控电抗器磁集成结构设计理论研究

发布时间：2018-03-14 19:58

本文选题：CRT　切入点：磁集成　出处：《兰州交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着电力系统向着超高压、大容量发展,对输电线路的安全、可靠性要求比以往更高,系统的安全可靠性可以通过无功补偿来提高。CRT(Controllable Reactor of Transformer Type,变压器式可控电抗器)作为一种无功补偿装置,对其进行研究具有十分重要的意义。CRT具有多个控制绕组,在各控制绕组中串联有反并联的晶闸管。为快速平滑调节CRT的容量,可以调节各反并联晶闸管的导通角以达到目的,变压器可以起到降低控制绕组电压的作用,因此在超高压大容量输电系统中有比较广阔的应用前景。本文在分析CRT工作原理的基础上,为了实现CRT“高阻抗、弱耦合”的设计原则,在CRT的结构设计中,以磁集成技术为基础,提出了CRT阵列式磁集成结构、多种导磁材料磁集成结构、分裂式磁集成结构。对阵列式磁集成结构分析了各控制绕组间磁通交链情况,建立了此结构的“变压器—电感”等效电路,推导了具有4个控制绕组结构的短路阻抗和短路电流的计算公式;对多种导磁材料磁集成结构不仅在建立等效电路的基础上推导了短路阻抗与短路电流的计算通式,而且在MATLAB中搭建了仿真模型,对工作绕组电流波形、控制特性、过渡过程等进行了仿真分析。仿真结果说明了CRT谐波含量小,能够实现容量的分级平滑调节,负载波动时能够快速响应;对分裂式磁集成结构基本结构单元建立了等效电路,分析了其实现“高阻抗”的原理,在ANSYS软件下建立了二维有限元仿真模型,采用“磁场—电路”耦合法计算了绕组电流分布以及各控制绕组依次短路时磁场分布情况。通过对以上三种结构的算例求解,说明了其均能够满足CRT“高阻抗、弱耦合”的设计原则,验证了这三种结构的正确性和有效性。以上3种结构中阵列式磁集成结构能够实现各控制绕组间的完全解耦,空载电流为0,但结构比较复杂,不易扩展;多种导磁材料磁集成结构很容易扩展,结构相对简单,但此结构空载电流不为0,不能实现各控制绕组间的完全解耦;分裂式磁集成结构易于扩展,结构简单,空载电流虽不为0,但仅为总电流的1.08%,说明分裂式结构更加接近于工程应用。据此,要实现CRT工作绕组与控制绕组间“高阻抗”的设计原则,可以给工作绕组与控制绕组间设置铁心柱或者铁饼;要实现CRT控制绕组间“弱耦合”的设计原则,可以在结构中设置分割铁心(低磁阻铁心)。
[Abstract]:With the development of power system towards ultra-high voltage and large capacity, the safety and reliability of transmission line are required higher than before. The safety and reliability of the system can be improved by reactive power compensation. CRT controllable Reactor of Transformer type can be used as a reactive power compensation device. There are antiparallel thyristors in series in each control winding. In order to adjust the capacity of CRT smoothly and quickly, the conduction angle of each antiparallel thyristor can be adjusted to achieve the purpose, and the transformer can play the role of reducing the voltage of the control winding. In order to realize the design principle of "high impedance and weak coupling" of CRT, this paper is used in the structure design of CRT, based on the analysis of the working principle of CRT. Based on the magnetic integration technology, CRT array magnetic integration structure, magnetic integration structure of various magnetic conductive materials and split magnetic integration structure are proposed. The magnetic flux intersection between the control windings is analyzed for the array magnetic integration structure. The equivalent circuit of "transformer inductor" with this structure is established, and the calculation formulas of short circuit impedance and short circuit current with four control windings are derived. On the basis of the equivalent circuit, the general formulas of short circuit impedance and short circuit current are derived for the magnetic integrated structure of various magnetic conductive materials, and the simulation model is built in MATLAB to control the current waveform and control characteristics of the working winding. The simulation results show that the CRT harmonics content is small, the capacity can be adjusted smoothly and the load fluctuates quickly, and the equivalent circuit is established for the basic structure unit of the split-type magnetic integrated structure. The principle of realizing "high impedance" is analyzed, and the two-dimensional finite element simulation model is established under ANSYS software. The current distribution of the winding and the magnetic field distribution of each control winding are calculated by using the coupling method of "magnetic field and circuit". By solving the above three kinds of structures, it is shown that they can meet the high impedance of CRT. The design principle of weak coupling verifies the correctness and validity of the three structures. Among the above three structures, the array magnetic integrated structure can realize the complete decoupling between the control windings, the no-load current is 0, but the structure is complex and difficult to expand. The magnetic integrated structure of many magnetic conductive materials is easy to expand, and the structure is relatively simple, but the no-load current of the structure is not zero, so it can not realize the complete decoupling between the control windings, and the split-type magnetic integrated structure is easy to expand and has a simple structure. Although the no-load current is not zero, it is only 1.08% of the total current, which shows that the split-type structure is closer to engineering application. According to this, the design principle of "high impedance" between CRT working winding and control winding should be realized. The core column or discus can be set between the working winding and the control winding, and in order to realize the design principle of "weak coupling" between the CRT control windings, the split core (low magneto-resistance core) can be set in the structure.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM47

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