风电场汇流站SVG并联系统谐波环流机理及其负面影响分析  

Analysis on mechanism of harmonic circular current in wind farm conflux station parallel-SVG system and its negative impact

作　　者：陈继开[1] 成毅平 李国庆[1] 王振浩[1] CHEN Jikai;CHENG Yiping;LI Guoqing;WANG Zhenhao(School of Electrical Engineering,Northeast Electric Power University,Jilin 132012,China)

机构地区：[1]东北电力大学电气工程学院,吉林吉林132012

出　　处：《电力自动化设备》2018年第12期53-58,共6页Electric Power Automation Equipment

基　　金：吉林省教育厅"十三五"科学技术研究项目(JJKH-20170098KJ)~~

摘　　要：针对风电场汇流站并联静止无功发生器(SVG)可能发生机间谐波环流的问题,以级联型H桥SVG并联系统为研究对象,依托系统等效电路分析机间谐波环流发生机理,并推导谐波环流解析式。基于单极倍频载波移相调制原理分析谐波环流与低频扰动产生之间的内在联系,利用离散迭代映射方程研究谐波环流幅度与H桥SVG直流电压分岔的因果关系;通过建立控制系统传递函数模型,研究谐波环流对系统直流电压稳定性造成的不利影响,指出级联型H桥拓扑结构可能增加机间谐波环流发生的风险,而谐波环流是导致直流电压失稳的主要原因。通过仿真验证了所提谐波环流及其负面影响理论分析方法的正确性。In the wind farm conflux stations,the issue of inter-machine harmonic circular current sometime is unavoidable with the parallel-SVG(Static Var Generator). The cascaded H-bridge parallel-SVG system is employed as the research object,the mechanism of inter-machine harmonic circular current is analyzed,and the analytical formula of harmonic circulating current is deduced. Firstly,the relationship between the harmonic current and low-frequency disturbance is revealed using the unipolar double frequency CPS-PWM(Carrier Phase Shift-PWM)theory. Then,an iterative mapping equation is established to describe the causality between the harmonic circular current and DC voltage bifurcation for H-bridge SVG. Considering the harmonic interaction,the transfer function model of control system is built to investigate the negative impacts caused by the harmonic circular current on DC voltage stability. It is pointed out that the cascaded H-bridge topology may raise the risk of inter-machine harmonic circulation,which is the main reason of DC voltage instability. Finally,simulative results verify the correctness of the theoretical analysis method of the proposed harmonic circular current and its negative impacts.

关 键 词：风电场汇流站 静止无功发生器 谐波环流 非线性 低频扰动 电压分岔 

分 类 号：TM614[电气工程—电力系统及自动化]