Photovoltaic (PV) generation systems are increasingly being integrated into distribution networks, presenting new challenges for network operators and planners. To fully quantify the impact of this distributed generation, power systems and control engineers are often required to model a large number of networks across multiple scenarios of PIT uptake and allocation. However, due to the complexity of these network models and simulation methods, and the associated computational constraints, very simplified models are often adopted for solar irradiance, and PV module and inverter output power. These ad hoc models often utilise simple linear relationships, and are not validated against real data or more detailed models. The proposed model (SoL) is composed of pre-existing equations selected from the current state of the art models, as well as newly formulated equations. Each submodel is validated against pre-existing models using data from a number of meteorological sites around the world, showing good performance with reduced computational complexity. The resulting model is subsequently shown to be suitable for running large scale quasi-steady state power flow simulations and Monte Carlo analyses as required for grid integration studies. (C) 2015 Elsevier Ltd. All rights reserved.