高压直流输电系统直流偏磁下的谐波不稳定判据研究  

Study of harmonic instability criterion under DC magnetic bias in HVDC system

作　　者：魏玥[1] 刘天琪[1] 晏小彬 李兴源[1] 张洁[1] 

机构地区：[1]四川大学电气信息学院,四川成都610065 [2]西南电力设计院,四川成都610000

出　　处：《电力系统保护与控制》2014年第17期139-144,共6页Power System Protection and Control

基　　金：国家自然科学基金项目(51037003)~~

摘　　要：针对交直流互联输电系统的谐波不稳定问题,推导出判断直流系统是否发生铁芯饱和谐波不稳定的工程判据。该判据从直流输电谐波不稳定机理出发,计及直流偏磁铁芯饱和的影响,利用换流变直流偏磁产生的正序二次谐波幅度高于其他各次谐波的特点,整体考虑二次谐波通过换流器在交流系统和直流系统之间来回传递的全过程。算例分析建立了电磁暂态模型,通过PSCAD/EMTDC进行仿真,所得电磁暂态故障仿真的结果与基于新判据的频率扫描结果一致,验证了工程判据的正确性与适用性。For the harmonic instability problem in AC-DC interconnected transmission system, this paper deduces the criterion to determine whether the DC system occurs core saturation harmonic instability. From HVDC harmonic instability mechanism and considering the DC bias magnetic core saturation effects, the criterion makes use of the characteristic that positive sequence second harmonic amplitude is higher than the other harmonic generated in DC magnetic bias of converter transformer, takes into account the whole process that the second harmonic transfers between AC and DC systems back and forth through inverter overall. In the case analysis, electromagnetic transient model is established and simulated by PSCAD/EMTDC, the result of electromagnetic transient fault simulation is consistent with the result of frequency scanning method based on the new criterion, so the correctness and applicability of engineering criteria is verified.

关 键 词：高压直流系统 谐波不稳定 二次谐波 直流偏磁 开关函数 

分 类 号：TM721.1[电气工程—电力系统及自动化]