直驱式变速恒频风力发电系统低电压穿越研究

Study on Low Voltage Ride Through for Direct-drive VSCF Wind Power System

新的电网规则要求风力发电机组须具有低电压穿越能力,并在电压跌落时向系统提供一定的无功补偿。直驱式风电系统通过增加Crowbar保护电路,可以极大地提高其低电压穿越能力。文章分析了直驱式风电系统常用的Crowbar保护电路模式,讨论了其工作原理和实现方法,重点论述了直流侧卸荷电阻式Crowbar电路的低电压穿越策略,并对其进行了仿真分析。仿真结果表明,直流侧卸荷电阻式低电压穿越方案成本较低、可靠性较高。

New grid regulation brings forward the requirements on wind turbines for having Low Voltage Ride Through（LVRT） capability and supplying reactive power compensation to the grid during voltage sag process.By adding Crowbar protective circuits,the LVRT capability of direct-drive wind turbines can be greatly improved.In this paper,Crowbar protective circuits for direct-drive wind turbines are analyzed;the working principles and implementation approaches are also discussed.Especially,LVRT strategy of Crowbar protective circuit with DC-link unloading resistance has been studied and simulated.The simulated result shows that this scheme has the advantages of low cost and high reliability.