不同接线牵引变压器负序特性及补偿方案研究

发布时间：2018-08-03 06:56

【摘要】：电气化铁路作为一种波动剧烈的大功率单相不平衡负荷,长期存在着功率因数低、注入电力系统的谐波与负序较大等问题。随着近年来电气化铁路的快速发展,电力牵引引发的电能质量问题引起人们越来越多的关注。交-直-交机车的大量使用,大大改善了谐波和功率因数问题,但随着牵引功率的大幅增加,负序问题却变得更加严重。本文给出了目前我国常用的几种牵引变压器的空载电压关系,负载电流关系,负序电流与一二次侧电流关系以及电压输出方程。得到了不同接线牵引变压器对三相电力系统的负序影响。通过神朔重载电气化铁路的现场实测数据,比较了三相V/v接线与Scott接线牵引变压器的负序电流特性,说明了在山区重载电气化铁路使用平衡变压器的实际效果。同时根据牵引负荷在波动剧烈时,会在短时间内引起电流、电压幅值突变且变化很大的特点,提出利用基波正序(或负序)分量的变化量来估算系统阻抗和短路容量的方法。杭甬客专沿线的新上虞变电所采用了新型的二次侧中抽式Scott接线变压器,推导出该新型变压器的电气特性并进行验证,通过与相邻的牛汇桥变电所采用的V/X接线变压器相比较,得到了这种新型牵引变压器对负序电流的抑制效果。介绍了目前针对负序的治理技术及常用的无源补偿装置SVC与有源补偿装置SVG的基本工作原理,提出了同相供电的概念。在无功补偿原理的基础上,提出了分别在系统侧与牵引侧安装补偿装置的治理方案并对牵引侧安装补偿装置的方案进行验证。可见要减小牵引负荷注入电力系统的负序电流,安装补偿装置是必不可少的。
[Abstract]:As a highly fluctuating single-phase unbalanced load, electrified railway has many problems, such as low power factor, large harmonic and negative sequence injected into power system and so on. With the rapid development of electrified railway in recent years, more and more attention has been paid to the power quality problem caused by electric traction. With the extensive use of AC-DC-AC locomotives, the harmonic and power factor problems are greatly improved, but with the increase of traction power, the negative sequence problem becomes more serious. In this paper, the relationship between no-load voltage, load current, negative sequence current and primary and secondary side current and voltage output equation of several traction transformers commonly used in China are given. The negative sequence effect of different wiring traction transformers on three-phase power system is obtained. Based on the field measured data of Shenshuo heavy duty electrified railway, the negative sequence current characteristics of three-phase V / v connection and Scott traction transformer are compared, and the actual effect of using balance transformer in mountain area heavy duty electrified railway is explained. At the same time, according to the characteristics that the traction load can cause the sudden change of the current and voltage amplitude in a short time when the load fluctuates violently, a method to estimate the impedance and short-circuit capacity of the system by using the variation of the fundamental positive sequence (or negative sequence) component is proposed. The new Shangyu substation along the route of Hangyong passenger College adopts a new type of secondary side pumping Scott connection transformer. The electrical characteristics of the new transformer are deduced and verified, and compared with the V / X connection transformer adopted by the adjacent Niuhuiqiao substation. The effect of the new traction transformer on the negative sequence current is obtained. This paper introduces the control technology of negative sequence and the basic working principle of passive compensation device SVC and active compensation device SVG, and puts forward the concept of in-phase power supply. On the basis of the principle of reactive power compensation, the control scheme of installing compensator on the system side and the traction side is put forward, and the scheme of installing the compensator on the traction side is verified. Therefore, it is necessary to install compensator to reduce the negative sequence current of traction load injected into power system.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM922.73

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