送端多直流落点谐波耦合引发铁心饱和不稳定的研究  

Research on core saturation instability caused by harmonic coupling in multi-infeed HVDC on the sending end

作　　者：晏小彬[1] 刘天琪[1] 李兴源[1] 汤凡[2] 尹专[1] 程道卫[1] 

机构地区：[1]四川大学电气信息学院,四川成都610065 [2]四川省电力试验研究院,四川成者610072

出　　处：《电力系统保护与控制》2012年第16期1-7,14,共8页Power System Protection and Control

基　　金：国家自然科学基金项目(51037003)

摘　　要：换流站的谐波通过交流网络相互作用使得送端多落点直流输电系统的谐波不稳定问题很复杂。在PSCAD/EMTDC中建立只含整流器的送端多直流系统模型的基础上,采用频率扫描和时域仿真相结合的方法,研究了送端多直流落点换流站谐波通过二次耦合阻抗相互作用引起换流变压器铁心饱和直流侧基频阻抗角差对系统的影响;并提出了二次耦合阻抗的阈值来评估送端多落点直流。结果表明:当耦合阻抗阻抗角一定时,阈值的幅值随交流侧二次频率阻抗幅值增大而增大,随直流侧基频阻抗幅值减小而增大,随变压器拐点降低而增大,随变压器磁化电流的降低而增大。The harmonic of converter interacts through AC network, which makes the issue of harmonic instability of multi-infeed DC system on sending end more complex. Based on the model of multi-infeed DC system on sending end containing only rectifier in PSCAD/EMTDC, this paper studies the converter transformer core saturation instability caused by the interaction of harmonic between converter stations in multi-infeed DC on sending end and the influence of the fundamental frequency impedance angle difference on system by using frequency scanning and time domain simulation method. It puts forward threshold of secondary coupling impedance to evaluate the core saturation stability of multi-infeed DC system on sending end. The result shows that when angle of coupling impedance is constant, the amplitude of threshold increases with the increase of the AC amplitude of secondary frequency impedance, while with the decrease of the DC amplitude of fundamental frequency impedance, and it increases with the reduction of the inflection point of transformer as well as the decrease of the magnetizing current of transformer.

关 键 词：高压直流 送端多落点 谐波耦合 铁心饱和不稳定 频率扫描 

分 类 号：TM711[电气工程—电力系统及自动化]