磁控电抗器的谐波特性及其抑制研究

发布时间：2018-08-22 19:31

【摘要】：无功功率是电力系统正常运行的必要条件,随着经济的不断发展,更高的输电电压等级、更长的输电距离、更大的容量是电力系统的发展方向,电压控制和无功平衡的问题也相对突出。磁控电抗器作为一种无功输出连续可调、控制简单、耐压等级高的无功补偿电力设备,在电压稳定和无功补偿方面具有很好的应用前景。但由于磁控电抗器工作在饱和状态,不可避免的产生谐波电流,造成谐波污染。为了研究磁控电抗器的谐波特性以及抑制谐波电流。本文首先对磁控电抗器的结构特点与工作原理进行分析,根据晶闸管和电力二极管的导通情况,建立磁控电抗器在不同阶段下的数学模型。同时,基于10kV/2500kVar油浸式磁控电抗器的试验系统,介绍磁控电抗器的调节器与光纤触发磁控箱的硬件组成,阐述成套无功补偿设备的基本硬件设计思路与运作原理。接着,使用图解方法分析直流偏磁与激磁电流畸变的关系,探讨磁控电抗器产生谐波的原理。在Matlab编程环境下,建立磁控电抗器的神经网络直流偏磁磁滞模型,模拟磁控电抗器的偏磁特性,计算磁控电抗器在不同触发角下的激磁电流,对比实验波形,验证模型的可靠性。然后,利用快速傅立叶变换对激磁电流的谐波特性进行分析,绘制不同偏磁条件下磁控电抗器的各次谐波幅频特性与含量图。针对磁控电抗器低磁饱和度工况下,谐波电流含量较大的特点,本文采用分级磁阀的设计方法,建立分级磁阀结构的等效数学模型,使用基于粒子群的优化算法对磁控电抗器的磁阀参数进行优化,令部分谐波在内部可以相互抵消,能有效减小电抗器激磁电流中的各次谐波含量。对于三相磁控电抗器,则通过改变其接线方式,加入移相线圈改变各相谐波的相位,抵消部分次谐波,达到谐波抑制的目的。最后,使用有限元分析方法,基于ANSYS软件对磁控电抗器进行二维建模,分析其交直流磁场分布特点,绘制磁控电抗器的激磁电流和不同工作时刻下的磁密分布云图。
[Abstract]:Reactive power is a necessary condition for the normal operation of power system. With the development of economy, higher transmission voltage level, longer transmission distance and larger capacity are the development direction of power system. The problems of voltage control and reactive power balance are also relatively prominent. As a kind of reactive power compensator with simple control and high voltage class, magnetic controlled reactor has a good application prospect in voltage stability and reactive power compensation. However, because the magnetron reactor works in saturation state, harmonic current is inevitable and harmonic pollution is caused. In order to study the harmonic characteristics of magnetron reactor and restrain harmonic current. In this paper, the structure characteristics and working principle of magnetron reactor are analyzed firstly. According to the conduction of thyristor and power diode, the mathematical model of magnetron reactor in different stages is established. At the same time, based on the test system of 10kV/2500kVar oil-immersed magnetic reactor, the hardware composition of the regulator of magnetic reactor and the fiber-optic trigger magnetic control box is introduced, and the basic hardware design idea and operation principle of the complete set of reactive power compensation equipment are expounded. Then, the relationship between DC bias and exciting current distortion is analyzed by graphic method, and the principle of harmonic generation in magnetically controlled reactor is discussed. In the Matlab programming environment, the neural network DC bias magnetic hysteresis model of magnetically controlled reactor is established, the magnetic bias characteristic of magnetic controlled reactor is simulated, the excitation current of magnetic controlled reactor under different trigger angles is calculated, and the experimental waveforms are compared. Verify the reliability of the model. Then, the harmonic characteristics of magnetic current are analyzed by fast Fourier transform, and the amplitude-frequency characteristics and contents of each harmonic of magnetically controlled reactor under different magnetic bias are plotted. In view of the large harmonic current content under the condition of low magnetic saturation of the magnetic reactor, the equivalent mathematical model of the structure of the graded magnetic valve is established by adopting the design method of the graded magnetic valve. The particle swarm optimization algorithm is used to optimize the magnetic valve parameters of the magnetically controlled reactor, which makes some harmonics cancel each other in the inner part, which can effectively reduce the harmonic content in the exciting current of the reactor. For the three-phase magnetron reactor, the phase shifting coil is added to change the phase of the phase harmonics by changing its wiring mode, thus canceling some of the subharmonics to achieve the purpose of harmonic suppression. Finally, using finite element analysis method, based on ANSYS software, the two-dimensional modeling of magnetron reactor is carried out, and the characteristics of AC / DC magnetic field distribution are analyzed, and the magnetic current of magnetron reactor and the magnetic density distribution cloud diagram at different working time are plotted.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM47

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