一种用于并网光伏逆变器的孤岛检测新方法

NEW ISLANDING DETECTION METHOD FOR GRID-CONNECTED PV INVERTER

分析光伏并网发电系统中孤岛效应产生的原因和危害以及传统孤岛检测方法的优缺点,在传统被动式孤岛检测方法的基础上,提出一种利用电压谐波故障分量检测孤岛效应的新方法。根据光伏逆变器侧以及主电网侧谐波故障分量不相等的原理,通过对逆变器端电压进行快速傅里叶变换提取出孤岛故障发生时的特定次谐波故障分量信号,理论上可彻底消除检测盲区。分析结果及现场实验数据表明,该方法具有不影响电能质量以及响应速度快的特点,并用PSCAD/EMTDC对其进行建模仿真研究。仿真结果可验证该检测方法的正确性。

The islanding problem in grid-connected PV generation system and traditional islanding detecting methods were studied. Based on the technology of passive islanding detection, an islanding detection method using voltage harmonic fault component was proposed. According to the unequal principle of harmonic fault components between PV inverter-side power quality and grid-side power quality, the characteristic harmonic frequency fault components of islanding could be extracted by the fast Fourier transform of voltages at the inverter-side. Theoretically, the non-detection zone could be thoroughly eliminated. The analyses results and experiment data show that the method has high response speed and no influence on the power quality of the system. The simulation results by PSCAD/EMTDC verify the method is effective.