Performance analysis of distribution networks under high penetration of solar PV

Integration of solar photovoltaic (PV) resources into distribution networks changes the normally expected network behaviour by injecting real power into the point of connection. Depending on the characteristics and setup of the PV inverter, reactive power could also be injected into the network. The impact will depend on the control strategy adopted for reactive power injection. Typically, solar PV units are installed at low voltage (LV) level in distribution networks. Cluster based installation of numerous PV inverters in the LV level will impact the operation of both the host LV network and the upstream medium voltage network. With random variations in load and PV output throughout the day, the behaviour of distribution network needs to be studied so that any unexpected operational behaviour of the network arising from PV integration can be avoided. In this paper, the distribution network performance under high penetration of solar PV resources is studied. Novel indices are developed to analyse network performance in terms of voltage deviation from nominal value, average feeder loading, substation capacity and feeder power losses. Variations of the indices for increasing level of PV penetration are investigated under different types of power control strategies. Day long behaviour analysis is performed in terms of the performance indices by adopting the most suitable control strategy for the PV inverters. A practical distribution feeder from Australia is used to examine the applicability of the developed indices and control strategies.