Islanding Prevention Scheme for Grid-Connected Photovoltaic Systems in Matlab/Simulink

This work presents a novel Anti-Islanding (AI) protection of Photovoltaic (PV) Systems based on monitoring the dc-link voltage of the PV inverter. A PV System equipped with AI protection like frequency relays, a rate of change of frequency (ROCOF) relay, and respectively the proposed dc-link voltage relay is simulated under the conditions of islanding and the detection time for all these AI techniques are compared. The study shows under which conditions our proposed dc-link voltage AI relay is the most efficient. The presented AI detection technique consists in monitoring the dc-link voltage, which raises significantly during transient grid faults. The raise detection can be carried out in the Voltage Source Converter (VSC) control of the PV inverter that monitors the dc-link voltage. The time for AI detection of the dc-link voltage relay is compared with the detection time offered by the ROCOF and frequency relays. Compared to the ROCOF and frequency relays, the AI technique using dc-link voltage relay has the fastest detection time. Also, the dc-link voltage, the ROCOF, and the frequency relays are triggered in the same order in all studied scenarios. During islanding condition, the dc-link voltage decrease with the increase of the connected load. A small variation of inductive power does not influence much the detection time of the AI relays.Please cite my paper in your work: I. V. Banu and M. Istrate, Islanding prevention scheme for Grid-Connected Photovoltaic systems in Matlab/Simulink, 2014 49th International Universities Power Engineering Conference (UPEC), Cluj-Napoca, 2014, pp. 1-6. doi: 10.1109/UPEC.2014.6934698 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6934698&isnumber=6934581