基于PSCAD的双馈机组低电压穿越特性分析

Analysis of Low Voltage Ride Through Characteristics of Doubly-Fed Units Based on PSCAD

针对以双馈感应异步发电机的(double-fed induction generator,DFIG)为主体的风电场研究了低电压穿越(low voltage ride through,LVRT)技术。在PSCAD仿真软件上搭建双馈风电场模型,从系统运行角度分析了电网电压不同跌落深度下,撬棒保护与直流侧过电压保护电路的有效性,分析比较了不同阻值的撬棒电路在发生电压跌落时对转子过电流的限制能力强弱,仿真结果显示直流侧过电压保护电路和拥有合适阻值的撬棒电路可以明显改善低电压穿越能力,研究结论能够为风电接入电网后的保护特性分析及应用提供良好的理论支撑。

This paper investigates the low voltage ride through(LVRT)techniques for wind farms with double fed induction generators(DFIG).The model is built in PSCAD simulation platform.The effectiveness of the crowbar protection and DC side over-protection circuit is analyzed under different drop depths of the grid voltage from the perspective of system operation.Analyze and compare the ability of the crowbar circuit with different resistance values to limit the overcurrent of the rotor when a voltage drop occurs.The results show that reasonable crowbar resistance value and the DC side overvoltage protection circuit can improve low voltage ride through(LVRT)ability of wind turbines,the research conclusions can provide good theoretical support for the analysis and application of protection characteristics after wind power is connected to the grid.