Harmonic profile injection based active islanding detection for PV-VSC based grid

A new harmonics profile injection based active islanding detection technique is proposed for Photovoltaic (PV) based voltage source inverter (VSI) system. Positive sequence active (Ps) and reactive power (Qs) at PCC is obtaining the multivariable control structure dynamics of the VSI, where a local perturbation of % harmonic amplification factor (%HAF) is simultaneously implemented with proper threshold. Dynamic variables, Ps and Qs is obtained from three phase voltage at PCC and VSI current to avoid unnecessary PLL angel calculation of the unmodelled VSI framework. The % HAF of PCC voltage is determined as disturbance injection parameter to the VSI P-Q control loop. Threshold before injection is determined by observation of negative sequence reactive power (Qneg) at PCC to avoid false detection. To accommodate the system with worst case handling capability, IEEE UL 1741 standard is being followed for proposed PV-VSI modeling. Performance of the proposed islanding detection technique is determined based on run on time for over/ under voltage protection (OVP/UVP). The performance study is obtained by modeling a 100 kW, 115 volt PV-VSI system integrated with utility grid in MATLAB/Simulink environment.