The importance of spatial distribution when analysing the impact of electric vehicles on voltage stability in distribution networks

The recent emergence of distributed generation, smart meters, and electric vehicles means that much attention is now being given to network modelling and analysis at the distribution, rather than transmission, level. Many optimisation studies, both regarding technical and economic questions, aim to satisfy the constraints posed by grid infrastructure. We explore in detail one of these network constraints, minimum required voltage, at the distribution level and demonstrate that the physical locations of individual loads in the network play a significant role in determining whether voltages throughout the network remain within required limits or not. Our simulations use real distribution network data and are run on models of two real neighbourhoods. We show that the addition of a single load at a weak point of the network can have the same impact as considerably greater numbers of loads at stronger locations of the network. This has important implications for applications such as electric vehicle charging, and suggests that spatial distribution of loads should be taken into account when analysing network stability.