The impact of electric vehicle charging on a residential low voltage distribution network in Malaysia

The increasing number of Electric Vehicles (EV) charging at an electricity distribution network could have a significant impact on the planning and operation of a power system. This paper presents a case study investigating the impact of EV charging at households on a typical Malaysia Low Voltage (LV) network. The residential LV network sample is provided by the local power utility (namely TNB) and some rearrangement of house load´s connection to feeders was made to comply with the utility´s requirement. In addition, the LV network has been modelled in detail to take into account the neutral wire and the self and mutual impedance of the cable. The impact of the EV charging on both newly developed residential areas and mature residential areas were evaluated in terms of voltage profile, voltage unbalance as well as feeders and transformer thermal limit. Results from the presented studies indicate that the LV network can safely accommodate 10% safe EV penetration level for a mature residential area without any controlled charging method being applied. However, with controlled charging strategy, the EV penetration level can be increased up to 60% without adverse effect to the system parameters such as voltage. For the case of a new residential LV network, the increase was from 20% to 100% EV penetration level. Furthermore, it is important to mention that the impact of EV is very locational and network dependent.