Impact of EV Integration and Fast Chargers in a Norwegian LV Grid - An analysis based on data from a residential grid in Steinkjer

Abstract

Given a renewable power supply, the replacement of conventional vehicles with electric alternatives has the potential to significantly reduce climate gas emissions from the transport sector. Norway has implemented economic incentives over several years to encourage a transition from conventional vehicles to electric cars (EVs), and has now the largest share of EVs per capita in the world. The power levels required to charge this fleet may constitute a significant strain on the existing power grid, especially at a low voltage level. The deployment of fast chargers may further aggravate this. More knowledge about the challenges ahead will be advantageous.

This thesis explores the effects of increasing EV penetration levels in a Norwegian distribution grid, by analyzing real power measurements obtained from household smart meters. The implications of installing a fast charger in the grid has been assessed, an optimal location for it has been proposed, and the potential for reactive power injection to reduce the voltage deviations caused by it has been investigated.

After presenting the theoretical groundwork, data set and methodology, the model is presented in detail and the following results are described. Results show that the EV hosting capacity of the grid is good for a majority of the end-users, but that the weakest power cable would be overloaded at a 20 % EV penetration level. The network tolerated an EV penetration of 50 % with regards to the voltage levels at all end-users. Injecting reactive power at the location of an installed fast charger proved to significantly reduce the voltage deviation otherwise imposed by the charger.