SVG与直驱风机间的次同步相互作用特性分析

近年来,新能源并网系统的次同步振荡问题日益凸显,我国许多地区的直驱风电并网系统出现了次同步频率下的功率振荡。目前风电场基本均装设了SVG等无功补偿装置来改善风电场的电压稳定问题,而SVG装置与直驱风电在次同步频段下的相互作用尚未明确。该文采用模态分析法,研究考虑SVG与直驱风机间相互作用的并网系统次同步振荡问题。首先,根据直驱风机和SVG装置的数学模型推导了其小信号分析模型。基于该模型,计算系统根轨迹,研究了控制参数和运行参数对次同步振荡模态特性的影响。同时利用模态的参与因子观察并网系统中装置间的耦合作用特性,最后利用电磁暂态仿真验证了模态分析结果的正确性。结果表明SVG的并入会影响风机并网系统稳定性,装置间存在次同步相互作用。

Study on Subsynchronous Interaction Between D-PMSG-based Wind Turbines and SVG

With development of WECS (wind energy conversion system), subsynchronous oscillations (SSO) phenomena occur in the wind farms based on direct-drive permanent magnetic synchronous generators (D-PMSGs). Several studies tried to analyze these oscillation problems, all associating with single wind turbine situation. In practice, most wind farms have static var generator (SVG) installed to improve voltage stability. To consider interaction between direct-drive wind turbine and SVG, especially in weak grid condition, this paper conducted some researches. The model of the system was shown firstly. Then eigenvalue analysis was performed to explain the mechanism and characteristics of the interactions between wind farm and SVG. Control parameters of each equipment and wind turbine in operating conditions were taken into consideration. At last, electromagnetic simulations were carried out to verify the proposed study.