改进的主动频率偏移孤岛检测算法

针对被动孤岛检测存在检测盲区以及传统主动频率偏移(AFD)孤岛检测算法会带来有功电流波动的不足,提出一种改进的AFD孤岛检测算法。该算法通过控制无功电流的大小来实现电流频率偏移,从而实现孤岛状态下接入点电压频率的正反馈,进而检测出孤岛。为了减小无功电流对电力系统的污染,需将该AFD算法与传统的被动孤岛检测算法结合使用。仿真和实验结果表明,该孤岛检测算法不仅消除了被动孤岛检测算法在负载功率和逆变器功率匹配时存在的检测盲区,而且克服了传统AFD算法有功电流波动的缺点,提高了直流母线电压的稳定性。

Improved Active Frequency Drift Anti-islanding Algorithm

Since passive islanding detection methods have non-detection zone and traditional active frequency drift(AFD) methods may cause active current fluctuation,an improved AFD islanding detection algorithm is proposed.The algorithm realizes current frequency drift by controlling reactive current,so as to achieve positive feedback of voltage frequency at the point of common coupling(PCC) in islanding state and realize anti-islanding function.To reduce reactive current injection to the power system,the improved AFD algorithm should be combined with traditional passive islanding detection algorithm.Simulation and experiment results show that the improved algorithm can not only eliminate the non-detection zone of passive islanding detection algorithms when the loads power and the inverter power match,but also overcome the active current fluctuation of traditional AFD algorithms and improve the stability of DC bus voltage.