双馈风电系统参与频率调节的小扰动稳定性分析

Small signal stability analysis of doubly-fed wind power system participated in frequency regulation

为了分析风电系统并网后对电网频率的影响,建立考虑调频的双馈风电系统小扰动稳定性分析的数学模型。根据风速的变化,研究功率控制策略,额定风速以下采用最大功率追踪控制,实现输出功率最大;额定风速以上采用恒功率控制,保证整个系统安全稳定地运行;考虑负荷动态模型时,分析风速变化对系统特征值的影响;利用Matlab建模进行时域仿真。理论研究和仿真结果表明,在全风速变化区间,能实现输出功率调节,系统能保持较好的小扰动稳定;增加频率调节环节后,风电系统在一定程度上能参与电网频率调节,有效地改善电网的频率特性,仿真结果验证了该方法的可行性和有效性。

Aiming at wind power system effects on power system,a small signal stability analysis mathematical model of doubly-fed wind power system considering adjust frequency is established.Power control scheme was researched according to wind speed variation： under rated wind speed,wind power system was controlled by maximum power point tracking scheme,and maximum output power was realized;above rated wind speed,constant power control method was applied,which ensures safe and stable system operation.Eigenvalues variation with wind speed change was analyzed considering load dynamic model;time domain simulation was performed after model was built by Matlab.Theory analysis and simulation show output power can be controlled and system keeps good small signal stability in full wind speed condition;wind power system participates in grid frequency regulation in a certain extent after frequency regulation link is added,which effectively improves grid frequency characteristics.Simulation results verify scheme feasibility and availability.