Asymmetrical fault ride-through of three-phase PV systems using four-wire Dc-ac converters

This paper examines the fault ride-through strategy of a three-phase PV system with respect to compliance to the German Transmission Code. Specifically, the paper examines the case of a single line-ground fault which occurs predominantly in the distribution system. The paper proposes the injection of reactive power on a per-phase basis to the faulty phases while maintaining active power injection to the healthy phases thereby avoiding power generation deficit. Simulation results from a study performed in MATLAB/Simulink with the SimPowerSystem toolbox present the unbalanced nature of currents during an unbalanced fault. An experimental setup has been shown and described that has been used to implement the strategy. Experimental results have been provided to validate the simulation results.