基于无功扰动的三相光伏逆变器孤岛检测

Islanding Detection Method for PV Three-phase Grid-connected Inverter Based on Dynamic Reactive Power Disturbance

大型光伏并网逆变器以单级式三相电压型逆变器作为变流设备,针对分布式发电系统固有的孤岛现象,提出一种动态无功扰动方法。根据无功功率与电网频率的关系,采用扰动无功功率的方法来检测孤岛现象,在发生孤岛现象后,该方法能迅速检测出频率异常并加速无功扰动,从而迅速分离逆变器与电网的联系。仿真和实验结果表明,该控制方法可有效地检测三相并网型光伏逆变器的孤岛现象。

Three-phase voltage source rectifier is always be used as converter equipment in large PV power plant, the islanding phenomenon of distributed power generation systems is inherent existed, a dynamic reactive power disturbance method is presented.According to the relationship of reactive power and frequency, reactive power disturbance method is adopted to detect islanding phenomenon,this method can quickly detect islanding phenomenon and fre- quency abnormal, and then accelerate reactive power disturbance, thus the connection between inverter and grid can be rapidly separated, the simulation and experimental results show that this control method can effectively detect islanding phenomenon of three-phase PV inverter.