中文摘要：

对双馈风电机组采用传统的固定下垂系数控制策略时,不能根据风速的变化自适应调整风电机组的实时可用容量。若下垂系数设定偏小,将导致风电机组过度响应,造成系统频率二次跌落,同时发电机转速不能恢复;若下垂系数设定偏大,将无法充分发挥风电机组的频率响应能力。针对此问题,提出了变下垂系数控制策略,即在低、中风速区,将纯机械减载容量和可利用转子动能的总和作为机组可用容量整定下垂系数;而在高风速区内,则以纯机械减载容量整定下垂系数的策略。仿真结果表明,所提策略可有效提升双馈风电机组的频率响应能力,防止双馈风电机组发生过度响应,有利于双馈风电机组的稳定运行。

英文摘要：

Traditional fixed frequency-droop control strategy cannot be adapted to available reserve capacity of doubly-fed induction generators with the change of wind speed.If the droop coefficient is too small,the generators will respond excessively,a double fall will occur to the system frequency and the rotor speed cannot be restored.On the contrary,if the droop coefficient is set too large,it will not make full use of the frequency response capability of wind turbines.In order to solve this problem,a variable droop control strategy is proposed.At low or middle wind speeds,the sum of available mechanical load shedding capacity and kinetic energy is taken as the available reserve capacity of wind turbines to adjust the droop coefficients,while at high wind speeds,the actual available mechanical capacity is taken to adjust the droop coefficients. The effectiveness of the proposed variable droop control strategy in avoiding the over responding of wind turbine and enhancing the frequency response ability is verified by simulation results. This work is supported by National Natural Science Foundation of China (No.5 1377047) and Fundamental Research Funds for the Central Universities (No.2013B27614).