Stable Operation of PV Plants to Achieve Fault Ride Through Capability - Evaluation in Field and Laboratory Tests

This paper first explains the required feed-in of voltage supporting currents during grid faults in a simplified case. Secondly, resonance points of the grid connection point are calculated analytically. The influence of weak grid conditions and large numbers of inverters is analysed. To underline the theoretical discussion on test conditions, measurements concerning Low Voltage Ride Through (LVRT) and stable operation of PV plants are presented. They comprise measurements from single inverters, as well as from large PV plants in the megawatt range.