双馈风电场经混合串补外送系统次同步振荡特性

运行经验表明,双馈风机(doubly fed induction generator,DFIG)经串联补偿线路外送系统存在发生次同步振荡(subsynchronous oscillation,SSO)的风险。文中给出了由静止同步串联补偿器(static synchronous series compensator,SSSC)和固定电容器组成的混合串补装置结构及控制策略,设计了串联型柔性交流输电装置次同步频段阻抗特性仿真测试方法,并分析了SSSC的次同步频段阻抗特性及DFIG经混合串补外送系统的SSO特性。分析结果表明,SSSC的次同步频段等效电抗和等效电阻均为正,且系统的SSO阻尼随混合串联补偿中SSSC占比、补偿阻抗及补偿电压的增大而增大。文中研究成果可为大规模风电外送系统的规划设计和运行提供指导和参考。

SSO Characteristics of Doubly Fed Wind Farm Integrated by Hybrid Series Compensator

According to the practical operating experience, wind farms with DFIG(doubly fed induction generator) integrated by series compensated AC transmission lines are confronting with the problem of SSO(subsynchronous oscillation). In this paper, the configuration and control strategy of hybrid series compensator composed by SSSC(static synchronous series compensator) and fixed capacitor are proposed, and testing method for subsynchronous frequency equivalent impedance of series FACTS is presented as well. Consequently, subsynchronous frequency impedance characteristics of SSSC are analyzed, and SSO characteristics of DFIG integrated by hybrid series compensator are studied. The results reveal that the subsynchronous frequency equivalent impedance of SSSC is positive,and the SSO damping is larger with higher proportion of SSSC in hybrid series compensator;in addition, the SSO damping is larger with larger compensation impedance or voltage of SSSC. The research is helpful for the planning and operating of the power system with large scale wind farm integrated.