Experimental methods to evaluate the impact of a photovoltaic system at the point of common coupling low voltage networks

After the presentation of the limits within which it is possible to define the equivalent impedance of the network, the focus of the paper, at this aim, is on two measuring methods. The first one is based on grid perturbation, due to current injection of photovoltaic (PV) inverters, whereas the second one is based on grid perturbation, due to current injection of load standards (resistive or capacitive). The experimental results, related to some PV systems, show relatively high values of impedances (ap 1Omega) with respect to the values calculated under simplified assumptions. For all the PV systems analysed, the results show that it is possible to upgrade further the PV systems without particular problems of voltage rise on the grid