基于双馈风电机组有效储能的变参数虚拟惯量控制

双馈风电机组采用电力电子变流器控制使得机械部分与电气部分解耦,大规模风电并网后电力系统总有效转动惯量下降,增加了系统的调频压力。文中通过对双馈风电机组运行及控制特性的分析,研究给出了反映机组有效储能的等效虚拟惯性时间常数的计算方法,提出了基于双馈风电机组有效储能的变参数虚拟惯量控制策略。该控制策略通过检测电网频率变化以及动态识别机组运行状态,修改控制参数控制机组有功输出,释放或吸收机组有效动能,对电网提供动态频率支撑。在理论分析基础上进行时域仿真验证,仿真结果表明,双馈风电机组变参数虚拟惯量控制在机组各种运行工况下实现了对系统频率的有效支撑,提高了电力系统频率稳定性,且保证了机组调频过程中自身运行的稳定性。

Variable Parameter Virtual Inertia Control Based on Effective Energy Storage of DFIG-based Wind Turbines

The total equivalent rotational inertia of power system decreases with increasing wind power penetration. It is because the mechanical parts of wind turbines based on doubly-fed induction generator (DFIG) are decoupled from their electrical parts, which will cause pressure to the main system frequency control. On the basis of operation and control characteristic of DFIG-based wind turbines, a calculation method of equivalent virtual inertia time constants is presented, and the variable parameter virtual inertia control strategy based on the DFIG-based wind turbines effective energy storage is proposed. By releasing or absorbing effective kinetic energy and providing dynamic frequency support to the grid, the proposed strategy can control wind turbine output power according to the frequency deviation and operating state. The time domain simulation is carried out on the basis of theoretical analysis, simulation results show that the proposed control strategy can provide effective frequency support to the grid under all kinds of operating conditions, and the frequency stability of power system with large wind power integration is improved. In the mean time the stability of DFIG-based wind turbines is also maintained in the process of frequency regulation. This work is supported by National Basic Research Program of China (973 Program) (No. 2012CB215105).