【作者】 徐军；

【导师】 姜惠兰； 陈明喜；

【作者基本信息】 天津大学 ， 电气工程， 2011， 硕士

【摘要】 谐波是目前电力系统中存在的最普遍的现象,是电能质量的最主要指标。近年来,随着电气化铁路建设速度的不断加快,电气化铁路机车逐渐成为了电力系统中主要的大型谐波源之一,对电气化铁路和电力电网的安全运行带来了很大的危害。为了减轻电铁系统产生的谐波对电力系统所造成的危害,当前通常采取的办法主要是在电铁系统和电网的接入点处安装无源或有源滤波器来抑制谐波,使之满足国家所制定的谐波标准。传统的无源补偿装置是采用LC无源滤波器。这种方法的装置结构和原理简单,维护方便,运行可靠,成本较低,主要缺点是其补偿特性受电网阻抗和运行状态影响,容易和系统发生并联谐振,补偿效果也差强人意。相比之下,有源滤波器能够实现谐波和无功的动态补偿,克服了传统LC滤波器补偿效果较差的缺点,它对大小和频率都变化的谐波以及变化的无功都可进行动态实时的补偿,补偿响应快,受电网参数影响较小,不易引起系统谐振,但投资费用过高等因素是目前阻碍有源滤波器得以推广的主要障碍。SVC是一种新型无源型无功补偿及谐波抑制装置,投资费用较低、控制相对简单,而且也能较好的实现无功的动态补偿。考虑到电铁系统是单相负荷,系统功率因数较低,而SVC又能很好的进行无功补偿提高其功率因数,所以采用SVC进行电铁的谐波抑制和无功补偿是个很好的选择。本文首先对谐波的基本概念等进行了详细的阐述,并分析了电气化铁路谐波产生的原理,着重阐述了基于快速傅里叶变换法的谐波分析法。在Simulink平台下搭建了电铁牵引负荷的谐波源模型,并对系统接入点处的电流进行了谐波分析。分析结果表明电铁负荷注入电网的谐波含量很大,必须进行相应的抑制措施。然后本文给出了两种基于SVC的谐波抑制方案,通过对比分析选取了其中可行性较好的一种,并结合呼东牵引变的实际情况进行了验证。最后对装设SVC后的系统接入点及电网其它节点和支路的采样数据进行了谐波分析,结果表明本文采用的SVC谐波抑制方案是有效的。更多还原

【Abstract】 At present harmonic is the most prevalent phenomenon in the power system. It is the most main power quality indicator. In recent years, with the accelerating of electrified railway construction, electric locomotive is gradually becoming one of the main sources of the harmonic in power system. It has brought great harm to the safe operation of the electrified railway and power grid.In order to reduce the harm of harmonic caused by electrified railway to power system, the currently using method is to install passive or active filter at the junction of electrified railway systems and power grid to restraint harmonic, making sure it meets the national standard for harmonic. The traditional passive compensation device is the LC filters. Its structure and principle is simple, maintenance is also convenient, and its operation is reliable and costs low. Its main drawback is that compensation characteristic is easily influenced by system impedance and the operation state of grid. It easily occurs parallel resonant with power system, and the compensation effect is also inferior. Active filter can realize dynamic compensation of harmonic and reactive power. It overcomes the shortcomings that traditional LC filters compensation effect is poor. Active filter can realize dynamic and real-time compensation of harmonic that varies in size and frequency and changing reactive power. Active filter has a fast compensation response, and it’s not easily influenced by power system parameters and it’s not easily to cause system resonance. But active filter costs so much that it’s not widely used now.SVC is a new type of passive reactive power compensation and harmonic control device. Its investment cost is low, control simply. And it can better realize the dynamic compensation of reactive power. Considering the electrified railway system is single-phase load, and system power factor is low. While SVC can be very good for reactive compensation and improving power factor. So using SVC for electric locomotive reactive power compensation and harmonic control is a very good choice.Firstly this paper expatiates the basic concept of harmonic, and analyzes the principle of electrified railway harmonics. The harmonic analysis method that based on fast Fourier transform is emphatically elaborated. Electric locomotive load harmonic source model is built in the platform of Matlab/Simulink. Then do the harmonic analysis on the current at system junction. Analysis results indicate that the electrified railway infuse great harmonic to the grid, so corresponding control measures must be taken. Then the paper gives two kinds of harmonic control scheme based on SVC. Through comparing the two solutions this paper selected the one that has better feasibility. Then this paper verified the feasibility of the solution connecting with traction substation of Hudong. Finally this paper analyzed the sampling data of junction and other nodes of the system furnishing with SVC. The results show that the SVC harmonic control scheme is effective.更多还原