A Correlation-Based Islanding-Detection Method Using Current-Magnitude Disturbance for PV System

Since islanding of photovoltaic (PV) generation can cause safety problems, it should be prevented. This paper proposes a correlation-based islanding-detection method (IDM) using current-magnitude disturbance for a PV system. As an islanding-detection index, this paper uses the correlation factor between current-magnitude disturbance and the corresponding inverter output voltage. The proposed IDM uses the characteristics in which the up/down current disturbance has a strong correlation with the PV output voltage when islanding occurs. The proposed method has fast islanding capability and high power quality. For verification of the proposed method, the simulated and experimental results of a 3-kW PV inverter by IEEE Std. 929-2000 and IEEE Std. 1547.1-2005 are provided. The proposed correlation technique can be used in other active antiislanding methods based on the correlation between the current and voltage after islanding occurs.