Applying fault ride through capability to single phase grid connected PV systems

Abstract

The grid-tied low voltage photovoltaics are expanded day by day. Aiming for a high penetration level, the Fault Ride Through Capability (FRTC) standard should be extended to these units as well. In this paper, the behavior of Single Phase Grid Connected PV Systems under faulty conditions is investigated. For this purpose, a SPWM controlled full bridge voltage source inverter is used. The proposed control concept emerges from the conventional synchronous generator behavior during faults. In this way, the low voltage distributed PV Systems can contribute during faults with currents quite higher than their nominal ones, serving the FRTC demands by injecting reactive power amounts. However, in case of excessive inverter faulty currents, current limiters are enabled. The introduced control is validated by simulation results, emphasizing at the transient interval between the fault occurrence and the steady-state faulty situation. Furthermore, the impact of the inverter's equivalent impedance is investigated, regarding the inverter's current and the resulting active and reactive power injection.