变速恒频双馈风电机组分段分层控制策略的研究

针对并网后变速恒频双馈风电机组的优化运行及其与电网的协调问题,依据分段分层控制思想,提出了变速恒频风电机组的并网控制策略:按照风速将风电机组的控制分为两个阶段,即低风速的最大风能追踪控制阶段和高风速的恒功率控制阶段,同时依据分层思想将风电机组电气部分的控制分为参考值的整定和对参考值的跟踪两层控制.利用该分段分层控制策略,对北方某风电场及其接入系统中风电机组的运行特性和接入系统中关键性节点的电压特性进行了仿真分析,结果表明该控制策略不但可以实现风电机组的优化运行,而且能较充分地发挥风电机组中双馈发电机的无功调节能力,提高风电机组并网后的电压稳定性,保证全网无功优化运行.

RESEARCH ON SUBSECTION AND LAYER CONTROL STRATEGY OF DOUBLY-FED VARIABLE SPEED WIND TURBINE

To optimize and coordinate the operation of doubly-fed Variable Speed Wind Turbines (VSWT) connected to power grid, based on the idea of sectional and hierarchical control idea a control strategy for VSWT connected to power grid is proposed. According to wind speed the control of VSWT is divided into two stages, namely maximal wind energy tracing control at low wind speed and constant power control at high wind speed, at the same time according to the hierarchical idea the electrical control of VSWT is divided into two hierarchical controls, i.e., the setting of reference value and the tracing of reference value. Through the sectional and hierarchical control strategy the operating characteristics of a certain wind farm in North China and its VSWT connected to power grid as well as the voltage characteristic of key node in the power grid, where the VSWT is connected, are simulated. The simulation results show that using the proposed control strategy not only the optimal operation of VSWT can be realized, but also the reactive power adjusting capability of the doubly-fed VSWT in the wind turbines can be fully brought into play, so the voltage stability of wind turbines connected to power grid can be improved and ensure the purpose of reactive power optimized operation of the whole power grid.