Impact of electric vehicles on power quality in a smart grid context

The large dependency of the imported fossil fuels and the soaring oil prices, makes essential the look for alternatives to the traditional people transportation system. The natural bet is the electric mobility, namely Electric Vehicles (EV), and Plug-in Hybrid Electric Vehicles (PHEV). This way, in this paper is analyzed the potential impacts of the battery charging systems on the grid power quality, in a Smart Grid context. It is considered the current consumed, according to a typical electric consumption profile, and the voltage degradation for a large number of houses. Two different types of EV batteries chargers were considered: a traditional charger; and a smart charger with sinusoidal current consumption and unitary power factor. It presents simulation results of the integration of EVs and PHEVs in terms of power quality, and experimental results of a smart charger which was specially developed for EV charging and that allows mitigation of the power quality degradation.Fundação para a Ciência e a Tecnologia (FCT

Batteries charging systems for electric and plug-in hybrid electric vehicles

Many countries have a large dependence on imported fossil fuels whose prices increase almost every day. Knowing that much of this consumption is for transportation systems, it becomes essential to seek for alternatives. The natural bet is the electric mobility, namely through Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs). However, the wide spread utilization of these vehicles has consequences on the electrical power grid, mainly in terms of load management and electric power quality, which are associated to the batteries charging systems. In this scenario, this chapter assesses the electric mobility integration in Smart Grid context, focusing different approaches to the operation of EVs and PHEVs charging processes and the specifications of the chargers, as well as different topologies of charging systems and their features, modes of operation, typical waveforms, and impact in the electrical power grid in terms of power quality. It is also presented a laboratory prototype of a bidirectional EV charger and shown some experimental results. This prototype was developed to charge the batteries aiming to preserve their lifespan, and to contribute to mitigate the degradation of the power quality. The experimental results show the operation of this prototype during the batteries charging process (G2V – Grid-to-Vehicle operation), and during the delivering of stored energy back to the electrical power grid (V2G – Vehicle-to-Grid operation).FEDER Funds - Operational Program for Competitiveness Factors – COMPETEFundação para a Ciência e a Tecnologia (FCT) - FCOMP-01-0124-FEDER-022674, MITPT/ EDAM-SMS/0030/200

Well-to-wheels energy efficiency analysis of plug-in electric vehicles including varying charging regimes

ABSTRACT Well-to-Wheels Energy Efficiency Analysis and Optimal Energy Management Strategy for Varying Electric Vehicle Operational Characteristics Ebrahim Saeidi Dehaghani Transition to electric vehicles (EVs) is already under way. EVs were demonstrated to be the most fuel economic and emission free among other propulsion technologies. Electric and plug-in hybrid electric vehicles (EVs/PHEVs) can have a large impact on greenhouse gases (GHGs) reduction, increase in fuel economy and higher fuel efficiency. This thesis seeks to investigate the Well-to-Wheels (WTW) energy efficiency analysis of Electric Vehicles (EVs) in Canada. The main idea behind this research work is to analyze step by step energy efficiency, which is one of the key factors for EVs technology acceptance. Penetration of battery electric and more electric vehicles (BEVs/MEVs) into vehicle fleet, affects load demand as well as electricity market. Smart charging of EVs can remove a lot of stress from electricity grid. Effect of home charging of EVs/PHEVs on electricity demand in the province of Quebec was analyzed. More recently, EVs have been looked at as distributed sources of energy, whereby they could back up the power grid during critical high demand periods. With the help of an on-board battery pack, EVs can act as distributed generators and feedback energy to the AC grid. However, efficiency of energy conversion could become an issue in this power flow. Hence, in this thesis stage-by-stage efficiency of vehicle-to-grid (V2G) power flow was evaluated. In addition, feasibility of using EVs in international islanding to sustain the local grid in the event of an emergency was analyzed

Power Management and Protection in MT-HVDC Systems with the Integration of High-Voltage Charging Stations

Due to the significant increase of the long-distance electricity demand, effective use of Distributed Generations (DGs) in power system, and the challenges in the expansion of new transmission lines to improve the reliability of power system reliability, utilizing Multi-Terminal HVDC (MT-HVDC) technology is an applicable, reliable, and cost-effective solution in hybrid AC/DC grids. MT-HVDC systems have flexibility in terms of independent active and reactive power flow (reversible control) and voltage control. Interconnecting two AC grids with different frequencies and transmitting electricity for the long-distance with low power-losses, which leads to less operation and maintenance costs, can be done through the MT-HVDC systems. The integration of large-scale remote DGs, e.g., wind farms, solar power plants, etc., and high-voltage charging stations for Electric Vehicles (EVs) into the power grid have different issues, such as economic, technical, and environmental challenges of transmission and network expansion/operation of both AC and DC grids. In details, damping oscillation, voltage support at different buses, operation of grid-connected inverters to the off-shore and on-shore AC systems, integrating of existing converter stations in MT-HVDC systems without major changes in control system, evaluation of communication infrastructure and also reactive power and filtering units’ requirements in MT-HVDC systems are the technical challenges in this technology. Therefore, a reliable MT-HVDC system can be a possible mean of resolving all the above-mentioned issues. MT-HVDC systems need a control system that can bring stability to the power system during a certain period of the operation/planning time while providing effective and robust electricity. This thesis presents an improved droop-based control strategy for the active and reactive power-sharing on the large-scale MT-HVDC systems integrating different types of AC grids considering the operation of the hybrid AC/DC grids under normal/contingency conditions. The main objective of the proposed strategy is to select the best parameters of the local terminal controllers at the site of each converter station (as the primary controller) and a central master controller (supervisory controller) to control the Power Flow (PF) and balance the instantaneous power in MT-HVDC systems. In this work, (1) various control strategies of MT-HVDC systems are investigated to propose (2) an improved droop-based power-sharing strategy of MT-HVDC systems while the loads (e.g., high-voltage charging stations) in power systems have significant changes, to improve the frequency response and accuracy of the PF control, (3) a new topology of a fast proactive Hybrid DC Circuit Breaker (HDCCB) to isolate the DC faults in MT-HVDC grids in case of fault current interruption. The results from this research work would include supporting energy adequacy, increasing renewable energy penetration, and minimizing losses when maintaining system integrity and reliability. The proposed strategies are evaluated on different systems, and various case scenarios are applied to demonstrate their feasibility and robustness. The validation processes are performed using MATLAB software for programming, and PSCAD/EMTDC and MATLAB/Simulink for simulation

Objetivos y Metodología para establecer una Smart Grid

Una Smart Grid es aquella red eléctrica que, gracias a la implantación de tecnologías de información y comunicación, es capaz de integrar de manera eficiente, sostenible, segura y rentable a todos sus usuarios, sean estos generadores, consumidores, prosumers, sistemas de almacenamiento, microgrids o vehículos eléctricos, entre otros. La red eléctrica debe adaptarse actualmente a todos los cambios que el usuario, la sociedad y el contexto retributivo y legal cambiante le exigen. Se pretende con la presente tesis mostrar los beneficios y funcionalidades potenciales que tienen las distintas tecnologías de Smart Grids para la empresa eléctrica y la sociedad, y definir una metodología para transformar la red actual en una red inteligente. Esta metodología propuesta no existe en la literatura técnica actual y es la aportación principal que se ofrece. El principio básico es el flujo bidireccional de información y de electricidad entre el consumidor final y la compañía eléctrica y la integración y gestión de todos los usuarios en la red con una operación descentralizada. Síntesis de la metodología propuesta. 1. Inventariado de la red y estudio de históricos de consumo y comportamiento. Análisis de la capacidad excedente. En el caso práctico estudiado de las subestaciones de Málaga capital existiría una capacidad del 35% en líneas de media tensión. 2. Implantación de tecnologías de telegestión a gran escala, para obtener la medida y gestión a distancia de los consumos en tiempo real. 3. Despliegue de Comunicaciones, unida a sensores y dispositivos inteligentes, instalados en los puntos que se quieran gestionar. 4. Automatización avanzada de la red, es fundamental una operación automática frente a incidencias en la red. 5. Integración de la generación distribuida y almacenamiento en zonas cercanas a los lugares de consumo, así se evitan las pérdidas asociadas al transporte y se hace un uso más eficiente tanto de la energía distribuida como de los activos instalados en las redes. 6. Gestión activa de la demanda, SGAD, para ejercer actuaciones en los consumos, en la generación y en el almacenamiento de energía, a nivel de consumidor y de alumbrado público. 7. Implantación de tecnologías de control de las infraestructuras de recarga del vehículo eléctrico . 8. Desarrollo de nuevos Sistemas de gestión de la red e integración con los sistemas ya existentes en el operador de la red. La implantación de esta metodología proporcionará la transformación de la red eléctrica actual en la red del futuro, Smart Grid

Demand Response for Residential Appliances in a Smart Electricity Distribution Network: Utility and Customer Perspectives

This thesis introduces advanced Demand Response algorithms for residential appliances to provide benefits for both utility and customers. The algorithms are engaged in scheduling appliances appropriately in a critical peak day to alleviate network peak, adverse voltage conditions and wholesale price spikes also reducing the cost of residential energy consumption. Initially, a demand response technique via customer reward is proposed, where the utility controls appliances to achieve network improvement. Then, an improved real-time pricing scheme is introduced and customers are supported by energy management schedulers to actively participate in it. Finally, the demand response algorithm is improved to provide frequency regulation services