A Review on Impact Analysis of Electric Vehicle Charging on Power Distribution Systems

Abstract

With superior performance, zero-emission, and less maintenance cost, EVs are forecasted to replace the conventional internal combustion engines entirely. The charging time of EVs is seen as a significant hindrance to EV adaptation. There are two different charging methods: (a) Slow charging – via the domestic power supply and (b) Fast charging – via commercial charging stations. With high penetration levels of EV forecasted in the future, EV load would become a significant part of any utility load curve. Compared to other stationary loads connected to the grid, EV battery loads, on the other hand, are highly mobile in nature, i.e., the location of EV load is not specified in the distribution line throughout the day. Additionally, distribution systems are not rated for high overload capacities and are usually characterized by congestion zones in heavily populated areas (which would become worse with the addition of EV loads). Thus, the impact of EVs load o the utility grid must be analyzed both on the circuit level and system level. This paper discusses the power topologies used for EV charger realization, followed by the grid performance issues introduced by different EV charger topologies. The impact of EV load on grid power quality, power system equipment, and grid performance indicator are also explained in detail. Then the paper presents a brief review of different analyses and studies performed to assess the impact of higher EV penetration levels on the distribution side of the utility grid. Finally, strategies proposed to improve the grid performance by reinforcing the existing structure are discussed.