风电不同外送输电系统低电压穿越特性研究

Different Transmission System to be Delivered to the Outside Through Low Voltage Characteristics of Wind Power Research

随着风电机组安装容量不断增加,风电场在电网故障情况下的暂态运行特性变得尤为重要。本文应用PSCAD软件建立了分别含有直驱永磁风电机组、双馈感应式风电机组的风电场动态模型,并研究了2种模型对电网暂态稳定性的影响。仿真分析了风电场-电网系统的传输线路上分别发生对称故障和不对称故障2种工况时,风电场中2种机组的低电压穿越能力以及在加装无功补偿装置后风电场低电压穿越能力。比较不同风电机组有功功率、无功功率和直流电压的特性,得出以下结论:双馈感应式风电机组虽然可以通过串联制动电阻提高低电压穿越能力,但在故障消除后电网电压的突变对双馈机有一定的影响,其对电网具有很强的依赖性;直驱永磁风电机组由于自身结构的特点,在电网故障时具有较好的运行特性,有利于优化电能质量。针对风电场不同机组采用无功补偿装置来提高故障时电网电压恢复能力,维持系统稳定运行。

With the increasingly installed capacity of wind power,it is important to take focus of the faults in the grid side of wind power which will cases transient state characteristic. A direct-drive permanent magnet wind turbine with doubly-fed induction wind dynamic model of wind turbines is built by using PSCAD software, and the influence of the two models on transient stability of power grid is discussed.Two kinds of LVRT results are discussed which including symmetrical faults and asymmetric faults occurring in the wind under,as well as the installation of reactive power compensation device in low voltage after the wind farm through the ability. The wind generator simulation analysis to compare active power、reactive power and dc voltage came to the following conclusions： although double-fed induction wind power generator can improve low voltage by series of braking resistor across ability,after the failure of eliminating the grid voltage mutation has certain influence to the doubly-fed machine,the strong dependence of power grids. In order to optimize the power quality,a direct-drive permanent magnet wind turbine in the power grid failure due to its structure having good running characteristics.Wind farms in different wind turbines should adopt different strategies to improve the stability of power grid.