Electric Power Systems Research 161 (2018) 139–151 Contents lists available at ScienceDirect Electric Power Systems Research j o ur na l ho mepage: www.elsevier.com/locate/epsr Decentralized electric vehicles charging coordination using only local voltage magnitude measurements John Edisson Cardona, Juan Camilo López, Marcos J. Rider ∗ University of Campinas — UNICAMP, School of Electrical and Computer Engineering, Department of Systems and Energy, Campinas, São Paulo, Brazil a r t i c l e i n f o Article history: Received 27 October 2017 Received in revised form 3 March 2018 Accepted 3 April 2018 Keywords: Decentralized EV charging coordination Internet of Things Monte Carlo simulations Unbalanced three-phase electrical distribution systems User priorities a b s t r a c t A new decentralized approach for the electric vehicles (EVs) charging coordination in electrical distri- bution systems (EDS) is presented. The proposed EV charging method uses historical information of the voltage magnitudes at each node in which an EV is plugged in and ready to be charged, in order to coor- dinate the charging of the vehicles and avoid exceeding the operational limits of the EDS, as dictated by the moment of maximum consumption. Furthermore, information gathered via the Internet of Things (IoT), such as user preferences, the cost of energy and EVs’ historical routes, can be used to deploy an economic EV charging method. The method was tested using an unbalanced three-phase EDS with 178 nodes, different EV penetration levels, and a fixed voltage regulator. Monte Carlo simulations have been implemented to analyze the performance of the proposed approach in different stochastic scenarios, with and without charging control, and with or without user priorities. Finally, the results are compared to the solution found by a centralized EV charging coordination method, based on a mixed-integer linear programming model. © 2018 Elsevier B.V. All rights reserved. 1. Introduction Climate change is causing severe impacts on society and nat- ural resources worldwide. As a result, people are becoming more aware of the irreversible effects of greenhouse emissions and global warming. Thus, the utilization of environment-friendly technolo- gies, such as electric vehicles (EVs) for urban transportation, is a prominent effort to reduce the consumption and dependency on fossil fuels [1]. In terms of efficiency, autonomy, comfort and cost/benefit, EVs are becoming more attractive than conventional internal combustion vehicles. Moreover, EV markets are expanding rapidly, especially in urban industrialized areas [2], and web-based technologies, integrated within the EVs, make it possible to inter- act with and supervise many features of the vehicles from a remote PC or from devices with Internet connection. This new paradigm is being coined as Internet of Things (IoT), in which a dynamic inter- action between users, web-based applications, and EVs, is possible via IoT [3]. EVs, however, have a significant power consumption compared to conventional household appliances. Thus, the massive EV pen- ∗ Corresponding author. E-mail addresses: jcardona@dsee.fee.unicamp.br (J.E. Cardona), jclopeza@dsee.fee.unicamp.br (J.C. López), mjrider@dsee.fee.unicamp.br (M.J. Rider). etration into electrical distribution systems (EDS) represents a greater network usage of both, the primary and the secondary sys- tems. The negative effects caused by high penetration of EVs are: elevation of peak load periods, low voltage profile, circuit over- loads, increased power losses, and imbalance among phases [4,5]. These issues, though, can be reduced by using suitable charging coordination strategies. Since EVs are interruptible, and there- fore controllable, electrical loads; the EV charging process can be rescheduled during low demand periods wherein the cost of energy is low, or in periods when the network has spare capacity to sup- ply the EVs without overloading the EDS. Note that a proper EV charging coordination method should prevent distribution system operators (DSOs) from making expensive investments in the net- work to support the increasing EV penetration levels [5]. Typically, most EV charging coordination techniques use a con- trol strategy that requires a centralized system that makes use of sophisticated measurement and communication infrastructures [4]. Centralized and distributed systems can be complex and incon- venient since they require intricate and expensive communication infrastructure and computational resources. Thus, there is a neces- sity for EV charging coordination solutions that are straightforward, adaptable, economic, easy to implement, maintain, and that effi- ciently coordinate the EV charging process; taking into account the EDS operational constraints. In this context, decentralized EV https://doi.org/10.1016/j.epsr.2018.04.003 0378-7796/© 2018 Elsevier B.V. All rights reserved.