2011
Autores
Almeida, PMR; Lopes, JAP; Soares, FJ; Seca, L;
Publicação
2011 IEEE PES Trondheim PowerTech: The Power of Technology for a Sustainable Society, POWERTECH 2011
Abstract
This paper addresses the problematic of operating isolated networks with large penetration of intermittent renewable power sources, as well as the benefits that electric vehicles might bring to these systems. A small island's network was used as case study and a 100% renewable dispatch for a valley period, only with hydro and wind generation, was tested in a dynamic simulation platform developed in Eurostag. Two distinct wind speed disturbances were simulated and, for both, the impact in the network's frequency was evaluated considering two different situations: electric vehicles only in charging mode and electric vehicles participating in primary frequency control. It was assumed the existence of 575 electric vehicles in the island. The impact of having electric vehicles performing primary frequency control in the expected batteries state of charge was also evaluated. © 2011 IEEE.
2009
Autores
Pecas Lopes, JAP; Soares, FJ; Rocha Almeida, PMR;
Publicação
2009 IEEE BUCHAREST POWERTECH, VOLS 1-5
Abstract
This paper describes a research developed to identify management procedures to deal with the charging of Electric Vehicles (EVs) batteries in scenarios characterized by a large scale deployment of this new kind of load. Three approaches were studied: dumb charging, dual tariff policy and smart charging. To assess the efficacy of such procedures, the grid integration of EVs was pushed to its limit for each of the adopted charging management approaches. A Medium Voltage (MV) grid, representative of a residential area distribution grid in Portugal, was used as testing environment. Several shares of EVs technologies were considered for different integration scenarios. Voltage profiles and branch congestion levels were evaluated, for the peak load hour, for grid technical limits checking. Losses were also evaluated for a typical daily load profile.
2010
Autores
Rei, RJ; Soares, FJ; Rocha Almeida, PM; Pecas Lopes, JA;
Publicação
IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC
Abstract
This paper describes technical solutions to be adopted by Electric Vehicles (EV) battery grid interfaces, in order to get the provision of ancillary services to the grid. The developed solution exploits an EV battery charge control approach based in a grid cooperative response to frequency and/or voltage deviations. To be effective, those cooperative actions must result from both centralized/coordinated commands and local/individual EV charger response to the grid behaviour. In a scenario characterized by a massive deployment of EV, the adoption of such a solution allows an improvement on the power system dynamic behaviour, namely in small island grids. ©2010 IEEE.
2009
Autores
Pecas Lopes, JAP; Rocha Almeida, PMR; Soares, FJ;
Publicação
2009 INTERNATIONAL CONFERENCE ON CLEAN ELECTRICAL POWER (ICCEP 2009), VOLS 1 AND 2
Abstract
This paper presents the results of a dynamic behaviour analysis study developed with the objective of quantifying the amount of wind power that can he safely, integrated in an isolated electricity grid where Electric Vehicles (EVs) are present. The assessment was performed considering two distinct situations: a) when EVs are only, in charging mode and b) when EVs participate in primary frequency, control. The test system, a small island, contains, in addition to wind generation, a small amount of solar PV plants and four conventional diesel generators. Only wind power influence in system's frequency, was assessed since, from a dynamic perspective, this is the renewable resource whose high intermittency level might be more harmful for the electric system operation. Sudden wind variations were simulated and, for both situations, a) and b), the amount of Intermittent Renewable Energy Sources was maximized, keeping always the grid frequency, within the limits defined by: the power quality standards.
2009
Autores
Pecas Lopes, JAP; Soares, FJ; Rocha Almeida, PMR; Baptista, PC; Silva, CM; Farias, TL;
Publicação
2009 8TH INTERNATIONAL SYMPOSIUM ON ADVANCED ELECTROMECHANICAL MOTION SYSTEMS (ELECTROMOTION 2009)
Abstract
In this paper a typical electricity distribution network for a residential area in Portugal is used in order to assess the impact of integrating different levels of pure electric vehicles and plug-in hybrid vehicles in the grid and in pollutants emissions. First, the amount of vehicles that can be safely accommodated in the grid will be determined. Second, changes in pollutants emissions will be evaluated, by applying a vehicle full life cycle analysis.
2010
Autores
Soares, FJ; Pecas Lopes, JA; Rocha Almeida, PM;
Publicação
2010 IEEE Conference on Innovative Technologies for an Efficient and Reliable Electricity Supply, CITRES 2010
Abstract
This paper describes a statistical approach developed for assessing the impacts resulting from EV presence in a given electricity network was developed. The algorithm, developed for this purpose, is based on a Monte Carlo method and can be seen as a planning tool that allows obtaining average values for several system indexes, like buses voltages, branches loading and energy losses. Additionally, it also allows identifying the most critical operation scenarios and the network components that are subjected to more demanding conditions and that might need to be upgraded. The example of a small grid from one of the Azores islands, Flores Island, was used for illustration purposes and two scenarios of EV integration were considered: 25% and 50% of the current light vehicles fleet replaced by EV. ©2010 IEEE.
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