CPES - Indexed Articles in Conferences

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    3D Virtual Labs for Internet Applications
    ( 2011) Fernando Maciel Barbosa ; M. M. Travassos Valdez ; Carlos Machado Ferreira
    This article covers a rather innovative and powerful technology that enables the creation of a 3D interactive laboratory for WEB applications based on open standard VRML format for 3D multimedia and the subsequent distribution of this virtual laboratory on the Internet. The project develops an environment, called 'interactive technology of a 3D Internet Laboratory' to create various types of 3D laboratory experiments as well as their application via the Internet. The application produced is the creation of a 3D virtual laboratory for measurements and instrumentation. The description of the laboratory, fonts and data are also provided. The various steps for creating a 3D virtual laboratory are presented. Lastly, the application of the 'interactive technology laboratory 3D' is displayed and can be considered as a step forward in the development of innovative technologies for distance learning.
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    3D Virtual Reality Experiments To Promote Electrical Engineering Education
    ( 2015) Travassos Valdez,MT ; Machado Ferreira,CM ; Martins,MJM ; Fernando Maciel Barbosa
    3D Virtual Labs are the support of learning, a tool of education in the future. Learning in a 3D environment allows greater interaction with contents in a unique way as students perceive it as being really there. Simulations are being designed, a combination of real-world environment with the information supplied by devices, where measurements can be replicated and data analyzed. This study presents a virtual scenario of a Measurements and Instrumentation laboratory. Electrical Engineering courses aim to train students to succeed in meeting the challenges within competitive and ever-changing professional contexts. In order to prepare undergraduate students for ongoing success, the courses must provide effective training in the application and development of practices, typically implemented in large projects and organizations. Developing high quality engineering course units is definitely a challenging task. Courses can be provided remotely, but careful planning is required to design quality course units because problems may occur in meeting quality targets. The developments in information and communication technologies (ICT), including multimedia and internet-based education platforms, facilitate the creation of reliable solutions to these challenges. Studies show that a smart application of multimedia technologies and web-based education platforms can provide great results towards better quality of engineering courses. Many challenges on how to suitably approach the educational process have already been put forward. Higher Education institutions use multiple approaches to teaching and learning, combining a range of methods, including e-learning, videoconferencing, face-to-face teaching and hard-copy resources in course delivery. The authors present a software model for engineering, which is based mainly on the Wirefusion (R) software, and a virtualreality platform called VEMA. The project intends to improve the quality of teaching and learning in higher education through effective application of information technologies and the sciences of learning. 3D virtual learning environments arise as solutions to the extent that, in addition to offering features associated with communication and information sharing, they promote flexible learning spaces and moments. At the level of higher education, and in accordance with the paradigm of Bologna, virtual environments acquire special importance to allow learning beyond the classroom time and space.
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    ACTIVE / REACTIVE DISPATCH IN MARKET ENVIRONMENT AND NODAL ACTIVE / REACTIVE PRICE DETERMINATION
    ( 2006) João Tomé Saraiva ; M. H. Gomes
    This paper describes a mathematical formulation for the active/reactive dispatch in electricity markets, addressing a number of technical and economic difficulties present in market models in force in several countries. Traditional market approaches are implemented considering a sequence of activities namely in terms of active power dispatch (via the pool centralized market and bilateral contracts) and ancillary services. However, these two problems are coupled in the sense that dispatching reactive power is not independent from active power scheduling of generators and so a particular reactive power output required by the ISO may be unfeasible in view of the active power dispatch. The proposed model admits that it is known the purely economic pool dispatch together with bilateral contracts and then it aims at dispatching reactive resources considering voltage and branch limit constraints and constraints reflecting the alternator capability curve. The search on the solution spa
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    An Active / Reactive Power Market Dispatch Model Including Soft Constraints
    ( 2006) João Tomé Saraiva ; M. H . Gomes
    This paper describes an active / reactive dispatch model based on bids transmitted by market agents to the Market Operator. The Market Operator economic schedule is then conveyed to the System Operator in order to evaluate its technical feasibility. If it is unfeasible, the System Operator runs a secondary market based on adjustment bids aiming at regaining feasibility while changing as little as possible the initial economic schedule. This secondary market is modeled as a non-linear optimization problem including the AC power flow equations, branch flow and nodal voltage limits as well as constraints related with the capability curve of synchronous generators. This problem is converted into a Symmetric Fuzzy Decision formulation admitting that branch flow and nodal voltage limit constraints have a soft nature. The resulting problem is solved using a Sequential Linear Programming, SLP, approach. The paper includes a case study based on the 24 bus IEEE Test System to illustrat
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    An Active / Reactive Power Market Dispatch Model Including Soft Constraints
    ( 2006) João Tomé Saraiva ; Mário Hélder Gomes
    This paper describes an active / reactive dispatch model based on bids transmitted by market agents to the Market Operator. The Market Operator economic schedule is then conveyed to the System Operator in order to evaluate its technical feasibility. If it is unfeasible, the System Operator runs a secondary market based on adjustment bids aiming at regaining feasibility while changing as little as possible the initial economic schedule. This secondary market is modeled as a non-linear optimization problem including the AC power flow equations, branch flow and nodal voltage limits as well as constraints related with the capability curve of synchronous generators. This problem is converted into a Symmetric Fuzzy Decision formulation admitting that branch flow and nodal voltage limit constraints have a soft nature. The resulting problem is solved using a Sequential Linear Programming, SLP, approach. The paper includes a case study based on the 24 bus IEEE Test System to illustrate its appl
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    Active/reactive Market Model Based on Adjustment Bids and Integrating Capacitor Banks and Transformer Taps
    ( 2008) Mário Hélder Gomes ; João Tomé Saraiva
    This paper describes a mathematical model and the developed solution algorithm to solve an integrated active / reactive dispatch while retaining competitive aspects. The main drive for this research was the recognition that the introduction of competitive mechanisms lead to a certain extent to a decoupling between active and reactive power scheduling. Aiming at remarrying them, the developed approach includes an initial bid based uniform price active power auction run by the Market Operator, followed by a technical validity analysis run by the System Operator. If necessary, the System Operator uses adjustment bids to recover the technical feasibility of the dispatch. These bids are presented both by the demand and by generators meaning that demand can play an important role in increasing the liquidity of this specific market. This approach also includes capacitor banks and transformer taps leading to a combinatorial problem solved using Simulated Annealing. Finally, the paper includes results from a case study based on the IEEE 24 Bus Test System to illustrate the interest of this type of approaches.
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    Addressing th Impact of Demand and Generation Cost Uncertainties in the Operation of Power Systems
    ( 2012) João Tomé Saraiva ; Bruno André Gomes
    This paper describes a set of mathematical formulations designed to include uncertainties modeled by fuzzy numbers in DC OPF studies. These approaches enhance and generalize an initial formulation and solution algorithm described in several papers co-authored by the second author. The approaches described in this paper adopt multiparametric optimization techniques in order to translate to the results the uncertainties affecting loads, for one side, the generation costs, for another, and also both of them in a simultaneous way. These approaches can be very useful nowadays given the uncertainties and volatility affecting data required to run several studies. They can also be the basis for the computation of nodal short time marginal prices reflecting these uncertainties. This paper also includes results obtained from a Case Study based on the IEEE 24 bus test system.
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    Addressing the Impact of Demand and Generation Cost Uncertainties in the Operation of Power Systems
    ( 2012) João Tomé Saraiva ; Bruno André Gomes
    This paper describes a set of mathematical formulations designed to include uncertainties modeled by fuzzy numbers in DC OPF studies. These approaches enhance and generalize an initial formulation and solution algorithm described in several papers co-authored by the second author. The approaches described in this paper adopt multiparametric optimization techniques in order to translate to the results the uncertainties affecting loads, for one side, the generation costs, for another, and also both of them in a simultaneous way. These approaches can be very useful nowadays given the uncertainties and volatility affecting data required to run several studies. They can also be the basis for the computation of nodal short time marginal prices reflecting these uncertainties. This paper also includes results obtained from a Case Study based on the IEEE 24 bus test system.
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    Adequacy of the long-term operational reserve of a system with wind power and electric vehicles under severe scenarios
    ( 2014) Bremermann,LE ; Da Rosa,MA ; Manuel Matos ; João Peças Lopes ; Leonel Magalhães Carvalho ; Costa,IC
    Combining conventional and unconventional generations with hard forecasting properties and consumption variability has made the task of fitting large amounts of wind generation into unit commitment procedures very challenging. In this context, massive integration of electric vehicles in the electric systems, is expected. This paper aims at evaluating the adequacy of a generating system taking into account the electric vehicles and high wind power integration level in its energy mix. This study was conducted on the European project MERGE framework, and the results have shown that the generating system evaluated is reliable. Nevertheless, the simulations carried out for scenarios with adverse weather conditions (dry years) have revealed specific circumstances that might jeopardize the system adequacy. © 2014 IEEE.
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    Adequacy of the long-term operational reserve of a system with wind power and electric vehicles under severe scenarios
    ( 2014) Bremermann,LE ; da Rosa,MA ; Manuel Matos ; João Peças Lopes ; Leonel Magalhães Carvalho ; Costa,IC
    Combining conventional and unconventional generations with hard forecasting properties and consumption variability has made the task of fitting large amounts of wind generation into unit commitment procedures very challenging. In this context, massive integration of electric vehicles in the electric systems, is expected. This paper aims at evaluating the adequacy of a generating system taking into account the electric vehicles and high wind power integration level in its energy mix. This study was conducted on the European project MERGE framework, and the results have shown that the generating system evaluated is reliable. Nevertheless, the simulations carried out for scenarios with adverse weather conditions (dry years) have revealed specific circumstances that might jeopardize the system adequacy.
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    Adjustable Pitch of Variable Speed Wind Turbine Generation Using a Neural Network Controller
    ( 2006) José Nuno Fidalgo ; António F. Silva F. Silva ; Fernando A. Aristides
    Pitch control has so far been the dominating method for power control in modern variable speed wind turbines. This paper proposes an improved control technique for pitching the blades of a variable speed wind turbine, by application of Artificial Neural Networks (ANN). The control objective is divided into below rated operation and above rated operation. Below rated power, the aim of control is to extract maximum energy from the wind. Above rated power, the control design problem is to limit and smooth the output electrical power. A model has been constructed and validated by experimental data obtained from Vestas V-47 660 kW wind turbine.
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    Advanced Metering Infrastructure Functionalities for Electric Mobility
    ( 2010) Ricardo Jorge Rei ; Filipe Joel Soares ; Pedro Rocha Almeida ; João Peças Lopes ; David Emanuel Rua ; Diego Issicaba
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    Advanced models and algorithms for demand participation in electricity markets
    ( 2014) José Pedro Iria ; Filipe Joel Soares ; André Guimarães Madureira
    This paper proposes a novel Energy Aggregator model responsible for managing the flexibility of low voltage customers in order to reduce electricity costs. The flexibility of the customers is represented by the availability of their controllable loads to reduce/increase power consumption. The flexible loads are managed according to the customers' preferences and the technical limitations of the flexible loads. The Energy Aggregator model developed includes an algorithm designed to manage customers' flexibility in quasi-real-time, with the objective of minimizing the deviations from the energy bought by the aggregator in the market. A scenario with 30 households located in a semi-urban area is used to illustrate the application of the algorithm and validate the proposed approach.
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    Aggregated models of wind-based generation and active distribution network cells for power system studies - literature overview
    ( 2011) S. Mat Zali ; J. Matevosyan ; S. Martinez Villanueva ; S. J. Djokic ; Jovica Milanovic ; Fernanda Resende ; J. L. Acosta
    The paper describes some of the initial results of the CIGRE Working Group C4.605 'Modeling and aggregation of loads in flexible power networks'. One of the tasks of the working group is to provide recommendations on developing equivalent static and dynamic models for clusters of diverse loads/generators, i.e., models of distribution network cells and microgrids and recommendations on procedures for data/response gathering and processing. This paper focuses on critical review of existing literature on aggregated models of wind-based generation, active distribution network cells and microgrids for power system studies.
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    Analysis of battery energy storage systems participation in multi-services electricity markets
    ( 2022) Agrela J.C. ; Rezende I. ; Tiago André Soares ; 6611
    This work performs a comparative analysis of battery energy storage system (BESS) participation in the multi-services electricity market, considering the optimal operating cost and better profitability for the BESS portfolios. A comparison of the application of these portfolios in different market conditions is proposed: (i) energy-only market, (ii) reserve-only market, (iii) sequential energy and reserve market, and (vi) joint energy and reserve market. For each BESS portfolio, hourly strategies for buying and selling offers are proposed, to maximize the revenue, accounting for the expected load and generation variations in the grid. The analysis of the BESS strategies is carried out through a case study based on actual generation data, where operating costs and BESS flexibility are assessed. One conclusion is that, even though, BESS makes a profit by participating in single markets, the best strategy is to participate in both energy and reserve markets, especially in the presence of a joint energy and reserve market model. © 2022 IEEE.
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    Analysis of consumer-centric market models in the Brazilian context
    ( 2020) Barbosa,PHP ; Dias,B ; Tiago André Soares ; 6611
    In recent years, the large deployment of distributed energy resources (DERs) in low voltage networks is changing the traditional approach to power systems. This massive change is pushing towards new solutions to improve energy trading in low voltage networks. Consumer-centric options, such as full peer-to-peer (P2P) and energy community markets (CM) are seen as viable options to increase the active participation of end-users in the electricity markets. This work studies the full P2P and CM market approaches applied to the actual regulatory framework in Brazil, evaluating and comparing both approaches to be potentially applied in Brazil. A case study based on a typical Brazilian neighborhood is designed, allowing to assess the behavior of consumers and prosumers in both markets. The results show the economic viability of both models, considering the social welfare and the penetration of distributed generation in the system. An important conclusion under the current regulatory framework is that the full P2P can have greater benefits over the CM, as long as the distributed generation is enough to confer near self-sufficiency to the peer's demand. © 2020 IEEE.
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    Analysis of Electricity Markets Using Multidimensional Scaling
    ( 2012) J. Tenreiro Machado ; Filipe Azevedo
    This paper studies the impact of the energy upon electricity markets using Multidimensional Scaling (MDS). MDS is a computational and statistical technique that produces a spatial representation of similarity between objects through factors of relatedness. MDS represents in a low dimensional map data points whose similarities are defined in a higher dimensional space. Data from major energy and electricity markets is considered. Several maps produced by MDS are presented and discussed revealing that this method is useful for understanding the correlation between them. Furthermore, the results help electricity markets agents hedging against Market Clearing Price (MCP) volatility.
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    Analysis of Phase Interrogated SPR Fiber Optic Sensors with Different Bimetallic Combinations
    ( 2014) Hamed Moayyed ; Leite,IT ; Luís Carlos Coelho ; José Luís Santos ; Ariel Guerreiro ; Diana Viegas
    Optical fiber sensors based on the phenomenon of plasmonic resonance can be interrogated applying different methods, the most common one being the spectral approach where the measurand information is derived from the reading of the wavelength resonance dip. In principle, a far better performance can be achieved considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This approach is investigated in this work for surface plasmon based fiber optic sensors with overlays which are combinations of bimetallic layers, permitting not only to tune the wavelength of the plasmon resonance but also the sensitivity associated with the phase interrogation of the sensors. The metals considered for the present analysis are silver, gold, copper, and aluminum.
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    Analysis of phase interrogation in SPR-based sensing supported by tapered optical fibres
    ( 2013) Hamed Moayyed ; Leite,IT ; Luís Carlos Coelho ; José Luís Santos ; Diana Viegas
    An analytical model based on geometrical optics and multilayer transfer matrix method is applied to the surface plasmonic resonance supported by fibre taper structures in the context of optical sensing applications. Phase interrogation is considered in particular as a methodology to attain enhanced sensitivities, and the performance of the sensing heads as function of the metal clad and taper parameters is analyzed. General topics concerning the actual relevance of plasmonics are also presented, first in a global perspective and then when applied to sensing.
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    Analysis of phase interrogation of SPR fiber optic sensors with characteristics tailored by the application of different metal-dielectric overlays
    ( 2014) Hamed Moayyed ; Leite,IT ; Luís Carlos Coelho ; José Luís Santos ; Ariel Guerreiro ; Diana Viegas
    Optical fiber sensors based on the phenomenon of plasmonic resonance can be interrogated applying different methods, the most common one being the spectral approach where the measurand information is derived from the reading of the wavelength resonance dip. In principle, a far better performance can be achieved considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This approach is investigated in this work for fiber optic SPR sensors with overlays which are combinations of metallic and dielectric thin films, permitting not only to tune the wavelength of the SPR resonance but also the sensitivity associated with the phase interrogation of the sensors.