连接VSC-HVDC的弱电网低频振荡研究  

Study on low frequency oscillation of weak grid connected to VSC-HVDC

作　　者：刘正茂[1] 唐欣[1] 肖茂[1] 

机构地区：[1]长沙理工大学电气与信息工程学院,湖南长沙410004

出　　处：《电力科学与技术学报》2016年第1期34-40,共7页Journal of Electric Power Science And Technology

基　　金：国家自然科学基金(51277013)

摘　　要：电压源换流器型的高压直流输电连接弱电网时,逆变站采用虚拟转动惯性控制方式,将VSC-HVDC的逆变站模拟为同步发电机以增加受端交流系统的转动惯量,为受端电网提供动态频率支持。受端电网可能会因为电力系统的负阻尼作用产生低频振荡现象而造成系统不能正常稳定运行。理论分析了VSC-HVDC连接弱电网的低频振荡问题,提出采用增大逆变站阻尼系数的方法抑制弱电网的低频振荡。利用PSCAD/EMTDC软件进行仿真,结果表明所采用的方法能够较好抑制此情况下弱电网的低频振荡。The inverter station of VSC-HVDC is modelled as a synchronous generator when connected to a weak grid.In order to increase the moment of inertia,the virtual inertia control mode is used.The moment of inertia for the weak grid can be increased and the dynamic frequency for receiving end grid can be provided.In this case,aproblem of low frequency oscillation phenomenon may occur due to the negative damping effect of the power system,which causes the system un-stable operation.In this paper,the theory on low frequency oscillation of the weak grid connected to VSC-HVDC was analyzed.A method of increasing the damping coefficient at inverter was adopted to avoid low frequency oscillation.PSCAD/EMTDC based simulation was carried out.Results showed that the proposed method can effectively inhibit the low frequency oscillation when VSC-HVDC is connected with a weak grid.

关 键 词：电压源换流器型的高压直流输电 虚拟转动惯性 低频振荡 阻尼系数 

分 类 号：TM721[电气工程—电力系统及自动化]