Performance and control of PhotoVoltaic systems supplying both primary and ancillary services

The paper presents a comprehensive study on grid-connected photovoltaic (PV) systems, dealing both with control strategy aspects and performance evaluation techniques. In particular, an advanced control scheme to suitably drive the injection of both active and reactive power into a MV radial distribution grid is here discussed, highlighting its main features by means of the numerical simulation of a real PV unit into the PSCAD-EMTDC electromagnetic environment. The developed circuit model is then used to derive the capability curve of the PV unit under study, thus enabling to characterize the whole system at its AC side.