Active islanding detection for three-phase grid-connected inverters

Islanding protection is an indispensable function of the grid-connected inverters, where the fast islanding detection is a key issue. Based on features of negative sequence components in the three-phase system, an islanding detection method based on the active negative sequence component disturbance (ANSCD) is proposed. It can lead to the significant variations of the voltage negative sequence component after islanding. Therefore, islanding is confirmed judging by the negative sequence component amplitude. Simulations are performed according to IEEE Std.929-2000, and results verify the effectives of the ANSCD. This project is supported by National Natural Science Foundation of China(No.50837003) and National Natural Science Foundation of Hebei Province(No.E2008000801).