Mitigating the Impact of an Official PEV Charger Deployment Plan on an Urban Grid

Abstract

Plug-in electric vehicles (PEVs) are rapidly increasing all over the world as electromobility is being promoted to reduce the greenhouse gas (GHG) emissions. PEVs locally produce zero emissions and they are more efficient in contrast to internal combustion engine vehicles. On the other hand, the impact of the uncoordinated charging of PEVs is expected to create new challenges for the established distribution grid. This article initially evaluates the impact of uncoordinated charging on the voltage regulation and transformer loading in the city of Heraklion, Greece. Then, a coordinated charging strategy is proposed to deal with the issue of transformer capacity violation by PEVs. Two cases were considered when the transformer overloading from PEV charging was taken into consideration: (a) keeping the transformer below its nominal capacity limit and (b) keeping the transformer below 90% of its nominal capacity limit. This was achieved by distributing the available capacity (nominal capacity minus the residential loads) of the transformer to the PEV chargers in a way that the aforementioned limits were satisfied. Real-world data of the distribution grid and the hourly power consumption of the city were used to validate the proposed method. Results show that possible transformer capacity violation can be tackled by the proposed coordinated charging, without exceeding the voltage regulation limits.

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

“…It has been concluded that with a high penetration of EVs, and no support from photovoltaic (PV) and ES, the transformers will dramatically age. Furthermore, researchers have dealt with the influence of the charging method on transformers' aging [8][9][10][11][12][13]. The main idea is to find an optimal charging scheme to minimize the impact of EVs' charging demand on distribution transformers.…”

“…Based on the obtained results, it has been concluded that hierarchical charging strategies are the most desirable in terms of LOL, while the centralized charging strategy (valley filling) has shown the greatest LOL of transformers. In one paper [10], a simple method is used to coordinate the charging process of PEVs to avoid the overloading of transformers by using the fact that idle time represents a significant percentage of EV parking time. In the paper, [11] reducing the impact on transformer aging by implementing the capability of delivering a variable charging rate has been proposed.…”

Solving PEV Charging Strategies with an Asynchronous Distributed Generalized Nash Game Algorithm in Energy Management System

“…Recently, the charging problem of PEVs has been extensively studied [5][6][7][8][9][10]. In these studies, the electrical-energy-related aspects of the PEV charging problem are managed through different aspects.…”

“…Smith et al [5] investigated the effect of variable-rate charging on reducing overload in charging PEVs. In [6], the problem of transformer overload due to PEV charging was investigated by considering different cases of assigning different available transformer capacities to PEV chargers. In [7], the charging demand of PEVs was assessed by considering the category of PEVs, charging strategy, battery capacity, and other factors, and then a corresponding power supply scheme was developed based on the obtained demand.…”