Abstract：Full-scale wind turbines (FSWT) are susceptible to lose synchronization due to the continuous control interaction between FSWT and faulty grid. To reveal the mechanisms, a nonlinear reduced order model of FSWT was deducted based on its multi-time scale properties. Because the derived model has similar structural characteristics to the transient stability model of synchronous generator, the concepts of emulated mechanical torque and emulated synchronizing torque were introduced for better understanding. The mechanism of frequency instability of FSWT during grid faults was revealed by applying the principal of equal area. It is concluded that, the smaller the phase-locked loop (PLL) bandwidth is, the closer the distance from faulty point to FSWT terminal is, the larger the frequency stability margin is. Based on the mechanism, a time-sequence control of active and reactive current was proposed for frequency stabilization as well as grid reactive power support. Finally, time domain simulations in PSCAD/EMTDC prove the correctness of mechanism analysis and effectiveness of the proposed control strategy.
韩刚, 张琛, 蔡旭. 电网短路故障引发的全功率风电机组频率失稳机理与控制方法[J]. 电工技术学报, 2018, 33(10): 2167-2175.
Han Gang, Zhang Chen, Cai Xu. Mechanism of Frequency Instability of Full-Scale Wind Turbines Caused by Grid Short Circuit Fault and Its Control Method. Transactions of China Electrotechnical Society, 2018, 33(10): 2167-2175.
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