云南电网低频问题下风机转子动能控制研究

风电机组提供频率响应后,转子转速恢复过程可能导致的频率二次跌落是制约风机提供向上调节能力的关键问题。文章对云南电网风机转子动能控制展开研究,提出风机转子动能控制参数整定方法,在扰动初期利用综合惯量控制快速抑制频率变化率,减小最大频率偏差;在扰动中后期与水火等常规同步机组和直流频率限制器(frequency limit controller,FLC)协调配合,避免频率二次跌落问题,实现频率整体动态过程的优化。仿真研究表明,增加虚拟惯性控制系数K_df,不利于改善频率最大偏差,会让频率在进入直流FLC死区后出现严重超调和反调现象;下垂控制系数K_pf是改善频率最大偏差和直流FLC动作量的关键,K_df和K_pf取值相同时,运行在最大功率追踪区的风电机组改善频率最大偏差的能力几乎相同。

Research on Rotor Kinetic Energy Control of Wind Turbines Under Low-Frequency Condition in Yunnan Power Grid

Secondary frequency drop that may be caused by rotor speed recovery process is a key issue that restricts the ability of wind turbines to provide upward adjustment after wind turbines provide frequency response. In this paper, a study on kinetic energy control of wind turbines in Yunnan Power Grid is carried out, and a method for setting kinetic energy control parameters of wind turbines is proposed. In the early stage of disturbance, integrated inertia control is used to quickly suppress the rate of frequency change and reduce frequency deviation; in the middle and later stages of disturbance, it is coordinated with conventional synchronous units such as thermal and hydropower or frequency limit controller to avoid the problem of secondary frequency drop and realize the optimization of the overall frequency dynamic process. Simulation research shows that increasing the virtual inertia control coefficient K_df is not conducive to improving the maximum frequency deviation, and will cause serious overshoot and reverse modulation after the frequency enters the dead zone of FLC; the droop conrol coeffircent K_pf is the key to improve the maximum frequency deviation and reduce the amount of action about FLC; the wind turbines operating under the maximum power point tracking almost have the same ability to improve the maximum deviation of the frequency when their K_df and K_pf are same.