1,721,240 research outputs found
An Innovative Conversion Device to the Grid Interface of Combined RES-Based Generators and Electric Storage Systems
No full textThis paper is focused on the development of an innovative device, which is based on a bidirectional converter, for the interface to the supply utility grid of combined renewable-energy-source-based generators and electric storage systems. The device can be controlled so as to ease the interface between the low-voltage grid and photovoltaic or wind generators combined with lithium-ion LiFePO4 batteries, taking into account the requirements of the reference technical standards for users connection and offering different ancillary services. The operational functioning of the device, the architecture, and its electronic components, as well as laboratory and field test activities and results are described. The conversion device has been developed, and the main results that have been achieved are detailed. © 1982-2012 IEEE
Optimal Design of der for Economic/Environmental Sustainability of Local Energy Communities
No full textIn this paper, a multi-objective optimization model is proposed to obtain the optimized configuration of interconnected distributed energy resource (DER) systems in a local energy community (LEC), while considering economic and environmental aspects. The objective is the optimal selection and sizing of DER with corresponding operation strategies, and the optimal configuration of the heating pipeline network, which allows the heat exchange among the DER systems. The economic objective is to minimize the total annual cost, whereas the environmental objective is to minimize the total annual CO2emissions. The Pareto frontier is found through the weighted-sum method, by using branch-and-cut. Numerical results show that the design method allows identifying different configurations of the interconnected DER systems and heating pipeline network on the Pareto frontier, thereby providing trade-off options to planners for economic/environmental sustainability of the LEC. Moreover, the total annual cost and emissions of the LEC with the optimized configurations are significantly reduced as compared with the conventional energy supply scenario. İ 2018 IEEE
Electric Vehicles integration in demand response programs
No full textAn important support in Demand Response (DR) programs can be provided by the Electric Vehicles (EVs). EVs may behave as a load to the grid, a supplier of electricity to the grid or an energy storage device. Thanks to the smart grid enabling technologies, Utilities can manage EVs charging time and rates, gather EVs-detailed meter data and, therefore, implement DR programs. In the present paper an overview on DR definitions and a classification of the types of customers involved and implementable programs is reported. Then a special focus on EVs integration in DR programs is given, stressing the valuable services that EVs in smart grid asset can provide. © 2014 IEEE
Operation Optimization of Multiple Distributed Energy Systems in an Energy Community
No full textIn recent years, energy communities have attracted growing interest as an efficient paradigm to exploit local energy sources to satisfy local multi-energy demand. Within an energy community, multiple distributed energy systems (DESs) connected through local grid and heating network need to be coordinated in a cost-effective way, while accounting for environmental impacts. However, most of work in the literature and our previous work focused on optimal operation of individual DESs. This paper focuses on operation optimization of multiple DESs in an energy community. The problem is to commit and dispatch energy devices in DESs to minimize the net daily energy and CO2emission cost, while satisfying the user demand. It is challenging since the energy devices and energy processes are coupled within and among DESs through local grid and heating network with thermal losses. A mixed-integer linear programming problem is formulated, and it is solved by using branch-and-cut. In numerical testing, an energy community with different types of utility customers is considered. Results show that integrated management of the DESs is efficient for reduction of the total net daily energy and CO2emission cost of the community as compared to other operation modes without interconnections among DESs. İ 2018 IEEE
Market Transparency for the Architecture of Frequency and Voltage Control under the Web-of-Cells Power Grid Structure
No full textMarket transparency is a key aspect for a well-functioning and efficient electricity market. In this paper, the concept of market transparency is addressed for the architecture of frequency and voltage control under the Web-of-Cells power grid structure developed within the European ELECTRA Integrated Research Programme. A critical review of the European Regulations on wholesale electricity market transparency issues is carried out and the related findings are tailored to the proposed architecture. The results of the analysis show that the problem of market transparency for the proposed architecture should be tackled by: Setting the qualitative requirements for data; determining the minimum data set required for the Merit Order Collection and the Merit Order Decision making; establishment of clear and specific roles for the actors regarding data and information; establishment of data placement; and setting the data set for publication. İ 2018 IEEE
Stochastic optimal scheduling of distributed energy resources with renewables considering economic and environmental aspects
No full textA distributed energy resource (DER) system is a multi-input and multi-output energy system consisting of small-scale technologies, which provide electricity and thermal energy close to end-users. In recent years, DER systems have attracted much interest as a promising opportunity with substantial economic and environmental benefits. To reduce energy costs and environmental impact of DER systems, daily operation scheduling is crucial, and presents significant challenges even more under energy demand and supply uncertainty in presence of renewables. The contribution of this paper is to provide a stochastic programming model for the optimal operation scheduling of a DER system with multiple energy devices including renewables, considering economic and environmental aspects. To model uncertain parameters of supply and demand side, 24-h scenarios are generated by using roulette wheel mechanism and Monte Carlo simulation method. A stochastic multi-objective linear programming problem is formulated to find the optimized operation strategies of the DER system to reduce the expected energy costs and CO2 emissions, while satisfying the time-varying user demand. By minimizing a weighted sum of the total energy cost and CO2 emissions, the problem is solved by using branch-and-cut. Numerical results show that the Pareto frontier provides good trade-off solutions for DER system operators based on economic and environmental priorities. The total daily energy cost and CO2 emissions under a stochastic approach result to be lower than those under a deterministic one. Moreover, the operation method provided is found to be efficient in reducing significantly energy costs and CO2 emissions of the DER system, as compared with conventional energy supply systems and combined heat and power systems. In addition, a sensitivity analysis is also carried out to investigate the impact of renewables penetration on the economic and environmental performances of the DER system. © 2017 Elsevier Lt
Power data fusion for train and railway electrification system
No full textThe reduction of energy consumption in electric trains is a big challenge of the next years. Lower consumptions means a more convenient design of the electric power supply network of the trains; in particular increasing the margin between peak demand and maximum power limit of the network improves the overall reliability. To this aim, the energy recovered from braking of one train may be used to aid the acceleration of the same or another train. Recovering energy from braking is a well-known idea, and the possibility to exchange energy between breaking trains and departing trains is very attractive. With this goal in mind the train vectors need to exchange information about their instantaneous power consumption and the data should be available for comparisons in a common time scale. In this paper will be presented an Android based measurement system for electric trains able to make synchronous measurements. The measurement system presented is composed of wireless sensors making it easy to install on modern train vectors. © 2013 IEEE
An optimization approach for efficient management of EV parking lots with batteries recharging facilities
No full textIn this paper an optimization approach to devise efficient management strategies for Electric Vehicles parking lots is proposed. A Monte Carlo approach is used to evaluate the load consumption profile for groups of Electric Vehicles showing different features. The Monte Carlo approach allows to combine the different social and economical features affecting the commercial penetration of Electric Vehicles with the technical aspects. The basic feature to be assessed is the initial State Of Charge, which in turn depends on the distance travelled by the vehicle since the last recharge and thus by the usage of the vehicle (private, professional). The model is then used to optimize some objective function such as the losses minimization or the cost of purchased energy minimization. Finally, a Simulated Annealing algorithm is used to identify the time intervals, along the day, in which the Electric Vehicles should be put in charge to minimize technical or economical objectives. The objective function is evaluated using a probabilistic model based on Monte Carlo simulations. © 2013 Springer-Verlag Berlin Heidelberg
Multi-objective optimized management of electrical energy storage systems in an islanded network with renewable energy sources under different design scenarios
No full textThe subject addressed in this paper is the definition of some strategies for the design and the optimaized management of EES (Electrical Energy Storage) systems, for an existing islanded distribution network supplying the Island of Pantelleria (Italy) in the Mediterranean Sea. In the paper the authors have drawn interesting conclusions through the application of an efficient MO (multi-objective) optimization algorithm, the NSGA-II, minimizing the energy losses in the grid, the total electricity generation cost and the greenhouse gas emissions. The results obtained for different installation scenarios of the EES are presented and discussed, putting into evidence the technical, environmental and economical benefi{ligature}ts of using EES as well as the technical issues connected to their installation into an existing distribution network. The paper describes in details the second part of a feasibility study about the transition from a "fuel-based" traditional centralized electrical system to an active and smart "renewables-based" electrical distribution system. © 2013 Elsevier Ltd
Power conditioning units in grid-connected photovoltaic systems: A comparison with different technologies and wide range of power ratings
No full textNowadays, the electronic converter which connects the photovoltaic array (PV) with the utility grid is subject to multiple requirements in terms of energy efficiency, power quality and grid stability. The paper focuses on a comparison among grid-connected Power Conditioning Units (PCUs) with different sizes, technologies and PV system architectures. In particular, the comparison includes the following items: single-phase and three-phase systems; with low-frequency or high-frequency transformers and transformerless version; with MOSFETs and IGBTs transistors. The comparison, based on experimental tests in which the signals of voltage, current and power are sampled at fast rate and with low uncertainty, is performed thanks to the normalisation of the input/output powers with respect to the power ratings. A set of meaningful parameters permits to characterise the behaviour of the PCUs which are studied both in field operation and in laboratory with known and constant test conditions. Regarding the PV systems in field operation, five plants have been analysed with PCUs from 230. kW down to 3. kW. The PCUs under study in laboratory include 1-kW inverter, one string-inverter with multi-MPPT, one per string, and two module integrated inverters. The experimental results demonstrate that the different PCUs mostly have similar performance, although the single-phase PCUs exhibit lower DC-AC efficiency at partial load, whereas a three-phase PCU shows lower MPPT efficiency, when defects in the solar cells generate multiple maximum power points in the current-voltage curve of the PV array. © 2014 Elsevier Ltd
- …
