Investigation of SSR in Practical DFIG-Based Wind Farms Connected to a Series-Compensated Power System
Investigation of SSR in Practical DFIG-Based Wind Farms Connected to a Series-Compensated Power System
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DOI：
10.1109/tpwrs.2014.2365197
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发表时间：
2015-09-01
影响因子：
6.6
通讯作者：
Liu, Huakun
中科院分区：
文献类型：
--
作者：
Wang, Liang;Xie, Xiaorong;Liu, Huakun
在华北地区的风电场中观测到了次同步谐振现象。这些风电场通常由双馈感应发电机（DFIG）组成，并连接到串联补偿传输线。观测到的共振频率约为6，近似于8 Hz，远低于报道的发生在德克萨斯州的SSR。频率在发生过程中变化，这是首次观察到的现象。当发生SSR时，输出功率通常在一定范围内。在实际系统的基础上，建立了一个等效的仿真系统，在该系统中，风电场被建模为多个相同的低额定DFIG。然后，通过模拟再现SSR事件。分析结果表明，即使风电场的等效输电系统补偿水平仅为6.67%，也会发生次同步谐振。特征值分析表明，这种现象是一种电谐振现象，并会受到风速，数量和DFIG控制的影响。在役DFIG的数量对SSR的阻尼有非线性影响。通过推导一个等效电路，直观地解释了SSR发生的原因以及上述因素对SSR的影响，结合SSR的特点，将其认定为双馈发电机控制参与感应发电机效应。
Subsynchronous resonance (SSR) was observed in wind farms located in North China. These wind farms prevailingly consist of doubly-fed induction generators (DFIGs) and are connected to series-compensated transmission lines. The observed resonant frequency is about 6 similar to 8 Hz, which is much lower than that of the reported SSR occurred in Texas. The frequency varies during the occurrence and this phenomenon is observed for the first time. The output power is usually within a certain range, when SSR occurs. Based on the practical system, an equivalent simulation system has been established, in which wind farms are modeled as many identical low rating DFIGs. Then, the SSR event is reproduced by simulations. Analysis results indicate that SSR happens even when the equivalent transmission system compensation level seen from wind farms is only 6.67%. Eigenvalue analysis shows that this phenomenon is an electrical resonance, and could be affected considerably by wind speed, number and control of DFIGs. The number of in-service DFIGs has a nonlinear impact on the damping of SSR. An equivalent electric circuit is deduced to intuitively explain why SSR happens and how the above factors affect it. Considering its features, this phenomenon is recognized as DFIG control participated induction generator effect.