Assessing and Mitigating Impacts of Electric Vehicle Harmonic Currents on Distribution Systems

Abstract

Harmonic currents of electric vehicle (EV) chargers could jeopardize the power quality of distribution systems and add to the transformer’s losses, thus degrading its lifetime. This paper assesses and mitigates the impacts of different EV chargers on distribution transformers and the voltage quality of distribution systems. The effect of state-of-charge (SOC) of the EV battery is considered through applying weighted arithmetic mean to accurately assess the impacts of EV harmonic currents on aging and losses of the EV interfacing transformer. The voltage quality of the IEEE 33-bus distribution system, supplying several EV parking lots, is also assessed at different charging levels using a fast-decoupled harmonic power flow. A new optimal harmonic power flow algorithm—that incorporates photovoltaic-based distribution generation units (DGs)—is developed to enhance the voltage quality of distribution systems, and elongate the lifetime of the substation transformer. The effectiveness of the proposed mitigation method is confirmed using the IEEE 33-bus distribution system, hosting several EV charging stations and photovoltaic-based DGs.

Impact Assessment of Electric Vehicle Charging in an AC and DC Microgrid: A Comparative Study

“…While the scope of the presented work does not consider harmonic distortion, Marah et al [23] highlight the importance of mitigating the adverse impact on the overall network's power quality due to electric vehicle charging stations. Similarly, the impact of harmonic currents caused by electric vehicles is assessed in [24], demonstrating that the power quality could be jeopardized and thus influence the degradation of the low-voltage distribution transformers. Therefore, they proposed an optimal harmonic power flow in order to restrain the harmonic distortion within the standard limit.…”

A Linearized Approach for the Electric Light Commercial Vehicle Routing Problem Combined with Charging Station Siting and Power Distribution Network Assessment

“…The flow conservation constraint in (6) enforces that the number of ongoing arcs equals the number of incoming arcs at each vertex, which covers both customers and charging station candidate points. Constraint (7) prevents a customer to be visited by several vehicles. For a customer node, the change in the remaining freight load of an EV is tracked based on node sequence by constraint (8) [47].…”

“…As shown throughout the works mentioned in Section 2, the EVRP has been largely studied with different perspectives; nonetheless, the power distribution system is not introduced as part of the mathematical model that covers the operation of logistics company and the power utility, which properly fits into real-world scenarios. The charging process requires a huge quantity of energy that can affect the power network in terms of energy losses, voltage drop, and introduction of harmonics and components lifetime [7], it being necessary to look for suitable and proper siting of charging stations considering both transportation and power distribution networks. In this sense, this paper presents a novel mathematical model for the approach named the electric Light Commercial Vehicles Routing Problem with Charging Station Location and impact on Power Distribution System eLCVRP-CS-PDS.…”

Impact of Reactive Power from Public Electric Vehicle Stations on Transformer Aging and Active Energy Losses

“…One of the best ways to promote the use of electric vehicles (EVs) is to increase the number of available public electric vehicle charging stations (EVCSs). Connecting a large EV fleet in a small area faces a number of challenges such as: overheating distribution transformers, increasing power losses, voltage instability and harmonic distortion [2,3]. Therefore, there is a need for modeling and mitigating the impacts of EVCSs on the distribution grid.…”