Single-stage inverter-based grid-connected photovoltaic power plant with ride-through capability over different types of grid faults

In this paper the control of a single-stage grid-connected photovoltaic power plant (GCPPP) is developed to address the issue of inverter disconnection under various grid faults. There are three main reasons for inverter disconnection which are (i) excessive dc-link voltage, (ii) excessive ac currents and (iii) loss of grid-voltage synchronization. The control of the inverter incorporates reactive power support in the case of voltage sags based on grid code requirements to ride-through the faults and support the grid voltages. Accordingly, another requirement of the grid codes is to control the reactive current injection under unbalanced voltage sags so that the voltages in the non-faulty phases do not exceed the specified limitations. All these issues are discussed in this paper for a case study of 1-MVA GCPPP using MATLAB/Simulink. The results illustrate the capability of the developed GCPPP to ride-through different types of faults occurred on the grid side.