A Novel Smart Charging Method to Mitigate Voltage Fluctuation at Fast Charging Stations

Sami Alshareef

doi:10.3390/en15051746

Abstract

The research presented in this paper focuses on the impact of fast charging stations (FCSs) on voltage quality. When the operation of FCSs causes a voltage fluctuation and light flicker, the FCSs may be disconnected, as per the utility general standard practice, which results in financial loss represented by FCS downtime. FCS downtime can be avoided by mitigating voltage fluctuation and light flicker. Flicker mitigation devices that are available in the market are characterized by their high total annual equivalent costs. As an alternative, a novel smart charging method is proposed in this study in order to mitigate both voltage fluctuation and light flicker, whereby customers can select one of three charging services available in fast chargers: premium, regular, or economic charging power. The charging power is selected according to customer priority in relation to time and cost, which offers more flexibility than those currently available in the literature. For instance, the premium power can be selected if the time is more valuable to the customer at the time of arrival at the FCS; in contrast, the regular or economic power are utilized if the cost is more valuable than the time. The results reveal that when an FCS charges a vehicle by an uncontrolled charging method, the FCS violates the flicker tolerance especially when demand for its service is increased by 20% and beyond. In contrast, the flicker limit is not violated when vehicles are charged from an FCS as per the proposed smart charging approach, even when the penetration on the FCS is increased by 50%. The proposed smart charging method offers a compromise solution to satisfy several stakeholders with different interests. Thus, the system operator equipment, FCS investors, nearby customers, and owners of electric vehicles will not be impacted by integrating the FCSs into the distribution networks.

Highlights

The results reveal that when an Fast charging stations (FCSs) charges a vehicle by an uncontrolled charging method, the FCS
Five case studies are considered whereby, in each case, a subset of all Battery poweredTypes electric vehicles (BPEVs) in the system needs to charge from the FCS which is connected to the primary main feeder using a three-phase distribution transformer rated
The proposed charging method assumes that the same port of a fast charger can provide three different levels of charging powers, namely, economic, regular, and premium

Summary

Introduction

As the number of electric vehicles (EVs) increases, fast charging becomes a necessity in electric service stations, to reduce charging and waiting times for EVs, whether in service or in a queue, and to increase their commercial benefits by increasing their utilization rates. If flicker emission levels are violated by the operation of customer equipment, the network operator may require [3,4]: mitigative action taken by the Energies 2022, 15, 1746 lead to light flicker for nearby customers. If flicker emission levels are violated by the operation of customer equipment, the network operator may require [3,4]: mitigative action takenaby the customer; disconnection of the customer’s equipment until customer; disconnection of athe customer’s equipment until mitigative action canmitigative be taken; action can be taken; and/or a possible service of theItfluctuating facility. Itof is and/or a possible service disconnection of the disconnection fluctuating facility

Methods

Results

Conclusion