兆瓦级风电机组叶片延长载荷分析及平稳运行控制方法

Analysis of blade extension load and smooth operation control method for megawatt wind turbines

为提高已建成风场中风电机组的发电效益,风电机组叶片延长是其有效途径之一。然而,叶片延长后风电机组易受到不同湍流强度扰动而导致机组极限载荷大幅变化,甚至损伤。首先从叶根、轮毂与塔基三个部位分别分析了湍流对风电机组的极限载荷变化。针对中低风速区间高湍流风况导致机组变桨频繁与功率输出不稳定的问题,采用桨距角控制与转速优化相结合的主动减载控制策略,通过预留出一部分转子转速以应对减载后的湍流现象,减轻变桨系统的负担。实验结果表明,在减载25%的情况下,所采用控制策略能够使桨距角基本稳定在2.5°左右,有效地减缓了湍流波动对桨距角,为使用叶尖延长等技术的风电机组稳定运行提供了一定的理论基础。

To improve the power generation efficiency of wind turbines in existing wind farms,extending the blades of wind turbines is one of the effective ways.However,after the blade is extended,the wind turbine unit is susceptible to disturbances of different turbulence intensities,resulting in significant changes in the unit's ultimate load,and even damage.This article first analyzes the impact of turbulence on the ultimate load variation of wind turbines from three parts:blade root,hub,and tower base.In response to the problem of frequent pitch control and unstable power output caused by high turbulence wind conditions in the middle and low wind speed range,an active load shedding control strategy combining pitch angle control and speed optimization is adopted.By reserving a portion of rotor speed to cope with the turbulence phenomenon after load shedding,the burden on the pitch system is reduced.The experimental results show that,under a 25%load reduction,the control strategy adopted can basically stabilize the pitch angle at around 2.5°,effectively reducing the impact of turbulent fluctuations on the pitch angle,and providing a certain theoretical basis for the stable operation of wind turbines using technologies such as blade tip extension.