Development of Photovoltaic Inverter Model with Islanding Detection Using the Sandia Frequency Shift Method

With increasing interest in renewable energy, more distributed energy resources (DERs) are being connected into the grid. Islanding conditions occur when a DER disconnects from the grid but remains energized. The Sandia Frequency Shift (SFS) is an islanding detection technique that introduces a small perturbation into the current phase angle of the photovoltaic (PV) inverter, with the use of positive feedback, triggering under frequency or over frequency protection when islanding occurs. Herein, this work presents PV inverter model that utilizes the SFS method for islanding detection. MATLAB/Simulink is used to test the performance of the developed PV inverter model with the SFS islanding detection capabilities. A comparison is made between PV inverters with different SFS control parameters. Simulation results are obtained for the dynamic response of each PV inverter when subjected to different islanding conditions.