Electrifying transportation is a promising approach to alleviate the climate change issue. The adoption of electric vehicle into market has introduced significant impacts on various fields, especially the power grid. Various policies have been implemented to foster the electric vehicle deployment and the increasing trend of electric vehicle adoption in the recent years has been satisfying. The continual development of electric vehicle power train, battery and charger technologies have further improved the electric vehicle technologies for wider uptake. Despite the environmental and economical benefits, electric vehicles charging introduce negative impacts on the existing network operation. Appropriate charging management strategies can be implemented to cater for this issue. Furthermore, electric vehicle integration in the smart grid can bring many potential opportunities, especially from the perspective of vehicle-to-grid technology and as the solution for the renewable energy intermittency issue. This paper reviews the latest development in electric vehicle technologies, impacts of electric vehicle roll out and opportunities brought by electric vehicle deployment.

A review on the state-of-the-art technologies of electric vehicle, its impacts and prospects

Assessment of the theoretical demand response potential in Europe

Electric vehicles (EV), including Battery Electric Vehicle (BEV), Hybrid Electric Vehicle (HEV), Plug-in Hybrid Electric Vehicle (PHEV), Fuel Cell Electric Vehicle (FCEV), are becoming more commonplace in the transportation sector in recent times. As the present trend suggests, this mode of transport is likely to replace internal combustion engine (ICE) vehicles in the near future. Each of the main EV components has a number of technologies that are currently in use or can become prominent in the future. EVs can cause significant impacts on the environment, power system, and other related sectors. The present power system could face huge instabilities with enough EV penetration, but with proper management and coordination, EVs can be turned into a major contributor to the successful implementation of the smart grid concept. There are possibilities of immense environmental benefits as well, as the EVs can extensively reduce the greenhouse gas emissions produced by the transportation sector. However, there are some major obstacles for EVs to overcome before totally replacing ICE vehicles. This paper is focused on reviewing all the useful data available on EV configurations, battery energy sources, electrical machines, charging techniques, optimization techniques, impacts, trends, and possible directions of future developments. Its objective is to provide an overall picture of the current EV technology and ways of future development to assist in future researches in this sector.

https://www.preprints.org/manuscript/201705.0090/v1/download

A Comprehensive Study of Key Electric Vehicle (EV) Components, Technologies, Challenges, Impacts, and Future Direction of Development

The world population depends highly on fossil fuels, particularly for transportation and power generation. This dependency leads to oil price increases because of the depletion of fossil fuels. Burning of fossil fuels also increases greenhouse gas emissions that are greatly responsible for global warming. Thus, electric vehicles (EVs) are considered one of the premium solutions in the land transportation system because they can significantly reduce the dependency on crude oil and minimize transportation-related carbon dioxide emissions along with other pollutants. This study presents an extensive review of the three key areas of EV research, namely, EV charging technologies, the various impacts of EVs, and optimal EV charging station (CS) placement and sizing. Several technical publications related to EV charging technologies are highlighted, and the performance comparison of different EV technologies is discussed. A review of literature on these key areas reveals an increasing interest in these topics in the last decade, with the impacts of EV on the electric power system and the optimal placement and sizing of CS issues widely investigated. By providing an overview of these areas, this study demonstrates the current issues and challenges of widespread deployment of EVs in the market as well as the future research direction in this field. A total of 185 publications are arranged and appended for quick referencing.

A review of the stage-of-the-art charging technologies, placement methodologies, and impacts of electric vehicles

Recent concerns about environmental pollution and escalating energy consumption accompanied by the advancements in battery technology have initiated the electrification of the transportation sector. With the universal resurgence of Electric Vehicles (EVs) the adverse impact of the EV charging loads on the operating parameters of the power system has been noticed. The detrimental impact of EV charging station loads on the electricity distribution network cannot be neglected. The high charging loads of the fast charging stations results in increased peak load demand, reduced reserve margins, voltage instability, and reliability problems. Further, the penalty paid by the utility for the degrading performance of the power system cannot be neglected. This work aims to investigate the impact of the EV charging station loads on the voltage stability, power losses, reliability indices, as well as economic losses of the distribution network. The entire analysis is performed on the IEEE 33 bus test system representing a standard radial distribution network for six different cases of EV charging station placement. It is observed that the system can withstand placement of fast charging stations at the strong buses up to a certain level, but the placement of fast charging stations at the weak buses of the system hampers the smooth operation of the power system. Further, a strategy for the placement of the EV charging stations on the distribution network is proposed based on a novel Voltage stability, Reliability, and Power loss (VRP) index. The results obtained indicate the efficacy of the VRP index.

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Impact of Electric Vehicle Charging Station Load on Distribution Network

Rooftop photovoltaic (PV) hosting capacity has become a concern for utilities in scenarios of high penetration due to impacts on voltage quality, such as over/undervoltage and voltage unbalance, and on equipment loading (conductors and transformers). This paper uses a simplified Monte Carlo-based method to analyze this issue, which is applied to 50 000 real low-voltage (LV) systems. Results show that it is possible to perform a risk-based analysis of hosting capacity by means of a lognormal distribution. Furthermore, overvoltage is found to be the most restrictive impact of PV integration; such information can help to guide utility actions to avoid technical violations. Extensive sensitivity studies are also presented to quantify the effects of several factors on the PV hosting capacity. The effects of number of customers with PV generators, PV power factor, voltage magnitude on the medium-voltage system, load level, and conductor impedances are investigated. It is also shown that the hosting capacity for the entire utility can be estimated by performing simulations only on 1% of the circuits randomly selected. In addition to providing a comprehensive overview of PV hosting capacity in real systems, the method can be used by utilities to improve the management of LV systems with high PV penetration.

A Comprehensive Assessment of PV Hosting Capacity on Low-Voltage Distribution Systems

This paper presents a probabilistic harmonic simulation method to study the power-quality impact of electric vehicles (EVs). The proposed method takes into account the random operating characteristics of the vehicles, such as random charging time, charging duration, and vehicle locations. A multiphase model of the primary and secondary systems is used to represent the study system. Extensive case studies have been conducted using the method and the measured EV data. The results reveal that the current versions of plug-in hybrid EVs have no significant harmonic impact on power systems. However, the Level 1 charger can increase the neutral-to-earth voltage at homes which could lead to increased stray voltage incidents.

Method to Assess the Power-Quality Impact of Plug-in Electric Vehicles

The proliferation of power-electronic-based residential loads has resulted in significant harmonic distortion in the voltages and currents of residential distribution systems. There is an urgent need for techniques that can determine the collective harmonic impact of these modern residential loads. These techniques can be used, for example, to predict the harmonic effects of mass adoption of compact fluorescent lights. In response to the need, this paper proposes a bottom-up, probabilistic harmonic assessment technique for residential feeders. The method models the random harmonic injections of residential loads by simulating their random operating states. This is performed by determining the switching-on probability of a residential load based on the load research results. The result is a randomly varying harmonic equivalent circuit representing a residential house. By combining multiple residential houses supplied with a service transformer, a probabilistic model for service transformers is also derived. Measurement results have confirmed the validity of the proposed technique. The proposed model is ideally suited for studying the consequences of consumer behavior or regulatory policy changes.

Assessing the Collective Harmonic Impact of Modern Residential Loads—Part I: Methodology

This paper studies the harmonic impact of modern residential loads on the secondary power distribution systems. Several issues of concern to utilities, such as the neutral-to-earth voltage rise, the overloading of service transformers, the impact of compact fluorescent lights (CFL), and the benefits of adopting IEC 61000-3-2 limits, have been investigated. A bottom-up probabilistic harmonic assessment method proposed in the companion paper was applied to conduct the study. Several interesting results have been obtained. For example, the adoption of CFLs based on market trend could result in an increase of voltage total harmonic distortion by about 10% per year over the next couple of years. Adopting the IEC limits on CFLs will drop the growth rate to 2% per year. In addition to the results of interest to utility companies, this paper demonstrates the usefulness and necessity of a bottom-up-based approach to conduct harmonic assessment for residential loads.

Assessing the Collective Harmonic Impact of Modern Residential Loads—Part II: Applications

Unintentional islanding detection is a primary requirement for the interconnection of synchronous distributed generators (DGs). For this purpose, voltage and frequency-based relays are largely employed due to their low cost and simplicity However, these devices are not totally reliable due to their associated nondetection zone (NDZ). The NDZ is an effective tool to evaluate the performance of these relays against islanding occurrence. In this context, this paper presents a simple and practical analytical method to estimate the NDZ of frequency and voltage-based relays without relying on numerous, time-consuming electromagnetic transient (EMT) simulations. The main contribution is that one can easily estimate the NDZ of these protection systems based on a few analytical expressions. The effectiveness and generality of the analytical method are verified by comparing its results with those obtained by repeated, intensive EMT simulations for different power distribution networks and different relay types.

Diogo Salles

Papers

A Comprehensive Assessment of PV Hosting Capacity on Low-Voltage Distribution Systems

Method to Assess the Power-Quality Impact of Plug-in Electric Vehicles

Assessing the Collective Harmonic Impact of Modern Residential Loads—Part I: Methodology

Assessing the Collective Harmonic Impact of Modern Residential Loads—Part II: Applications

A Practical Method for Nondetection Zone Estimation of Passive Anti-Islanding Schemes Applied to Synchronous Distributed Generators