Performance Analysis of Active Islanding Detection Method for Grid Connected Inverter

Islanding detection is an important component in an inverters-based distributed generation to provide the necessary protection function and manpower safety. Various anti-islanding detection techniques are presented in the literature. Passive techniques mainly have a large non-detection zone (NDZ). Active techniques have lower NDZ compared with passive methods, but it affects the power quality such as total harmonic distortion (THD). This paper presents a performance analysis of the active frequency drift technique (AFD). Additionally, this paper proposed a modified active frequency drift (AFD) to improve the THD and increase its sensitivity. The proposed method is analyzed mathematically and verified by simulation results. A single-phase grid connected photovoltaic system is modeled in MATLAB/Simulink program to analyze the proposed technique. the simulation result demonstrates that the proposed method improves the NDZ and reduces THD injected into the system.