Artigos - Engenharia Elétrica - FEIS

URI Permanente para esta coleção

https://hdl.handle.net/11449/9646

Navegar

Agora exibindo 1 - 20 de 1487

Otimização do planejamento da expansão de sistemas de transmissão usando redução do espaço de busca
(IEEE, 2024-01-31) Meneses Oriondo, Marco Alonso; Possagnolo, Leonardo Henrique Faria Macedo [UNESP]; Romero Lázaro, Rubén Augusto [UNESP]
O problema de planejamento da expansão de sistemas de transmissão é um tópico relevante e de elevada complexidade no campo da otimização da operação e do planejamento de sistemas de energia elétrica. O modelo matemático desse problema é um problema de programação não linear inteiro misto com característica combinatória. Nesse tipo de problemas foram usados diferentes modelos matemáticos, modelos cada vez mais complexos e mais próximos da operação real do sistema elétrico. Entretanto, o problema de planejamento da expansão de sistemas de transmissão é difícil de se resolver, mesmo para os modelos mais relaxados. Neste artigo, apresenta-se uma proposta de redução do espaço de busca para diminuir o gap entre o ótimo do modelo inteiro misto do problema e o ótimo do modelo relaxado, relaxando a integralidade das variáveis inteiras. Essa proposta permite diminuir o tempo de processamento quando é usado um solver de otimização. Com essa estratégia foi possível encontrar a solução ótima de um sistema teste cuja solução ótima ainda não era conhecida
Medição de misturas de glicerol e água usando espectroscopia ultrassônica
(Universidade Estadual Paulista (Unesp), 2024-01-05) Camargo, Gabrielle Ceola; Higuti, Ricardo Tokio [UNESP]
A medição de propriedades de líquidos por ultrassom é amplamente empregada no controle de processos industriais, permitindo-se a medição de parâmetros acústicos como a velocidade de propagação e o coeficiente de atenuação em função da frequência e temperatura, beneficiando-se do caráter não-invasivo e não-destrutivo das técnicas de ultrassom. No trabalho apresentado, aplica-se a técnica chamada relativa ou de substituição para a medição dos parâmetros acústicos das amostras, sendo caracterizado pela medição de uma amostra de referência com propriedades já conhecidas para a comparação com a amostra do líquido de interesse. Um dos escopos propostos na metodologia é solucionar as limitações de banda de frequência do líquido de interesse que possui maior coeficiente de atenuação, e consequentemente menor amplitude em relação ao sinal do líquido de referência, por meio da aplicação de ganho no sinal, e principalmente uso de outras amostras de referências com maior coeficiente de atenuação, como por exemplo, o glicerol, que é vastamente utilizado em vários campos da indústria, devido ao seu potencial como biomolécula e baixo custo. O sistema de medição utilizado no desenvolvimento do projeto destaca-se pela facilidade de troca de amostras, higienização do sistema, pouca complexidade de manuseio, além do controle de temperatura com variações menores que 0,01°C de erro de regime permanente. Por conseguinte, os resultados foram obtidos através do programa de controle e aquisição de dados, junto à interface gráfica intuitiva ao usuário desenvolvida no ambiente do Matlab, gerando-se curvas de velocidade de propagação do som e coeficiente de atenuação em função da frequência para amostras compostas por misturas de água destilada e glicerol, e verificando-se o resultado aplicável e semelhante à água destilada, quando utilizadas como referência para medição de líquidos mais atenuantes, como óleos, visto que, as curvas de atenuação mostram-se sobrepostas, com distanciamento inferior a 2% para uma frequência de 50 MHz.
Estimation of non-technical loss rates by regions
(Elsevier, 2023-07-18) Ventura, Lucas; Felix, Gustavo Estevo; Vargas, Renzo; Faria, Lucas Teles; Melo, Joel David; Federal University of ABC
Identifying vulnerable regions to non-technical losses allows more assertive combat against them. In this context, this paper presents a spatiotemporal methodology composed of two modules, spatial and temporal, to assist distribution companies in action planning to decrease the rates of non-technical losses by region. The spatial module contains a neighborhood structure based on the similarity among small regions named ‘‘neighborhood by the similarity of attributes’’, which improves the characterization of non-technical losses actions performed by end-consumers. That neighborhood structure is incorporated as an input parameter into a hierarchical spatial autoregressive regression model to represent the relationships between inhabitants. On the other hand, the temporal module uses a linear mixed-effects model to consider future values that are subject to the actions of consumers or distribution companies. The proposed methodology is applied to a medium-sized city with approximately 200,000 inhabitants, considering the inspections carried out by a Brazilian distribution utility. The proposal identified the future non-technical loss state in all the city’s regions with values greater than 69% of the success rate in identifying NTL to residential, commercial, and industrial consumer classes.
Integração de recursos energéticos distribuídos e postos de recarga de veículos elétricos no planejamento da expansão de sistemas de distribuição de energia elétrica
(Universidade Estadual Paulista (Unesp), 2023-09-08) Lima, Tayenne Dias de; Baquero, John Fredy Franco [UNESP]; João Soares
A integração dos conceitos de redes inteligentes (smart grids) nos sistemas de distribuição de distribuição energia elétrica (SDEE) convencionais é uma abordagem almejada e frequentemente discutida na literatura. A implementação massiva de automação e tecnologia da informação pode oferecer elevada eficiência na aplicação de estratégias de otimização e controle, proporcionando inúmeros benefícios, que se estendem desde a estrutura física da rede até o consumidor final. O SDEE passou por grandes transformações na última década, devido principalmente à crescente integração da geração distribuída (GD), em particular a GD renovável. Uma vez que os recursos de energia renováveis têm comportamento incerto, os sistemas de armazenamento de energia elétrica (SAEE) têm o potencial de reduzir o impacto dessas incertezas. Além disso, o incremento na integração de veículos elétricos (VEs), incentivado por preocupações ambientais, trouxe novos desafios para a operação e planejamento do SDEE. Neste contexto, as novas abordagens para o problema de planejamento de expansão do sistema de distribuição de energia elétrica (PESDEE) devem considerar os recursos de energia distribuídos (unidades de GD, SAEE e VEs) e incluir os impactos ambientais. Portanto, neste trabalho propõe-se um modelo de programação linear inteira mista para solucionar o problema de PESDEE, incluindo unidades de GD, SAEE e postos de recarga de veículos elétricos. Esta proposta considera as questões ambientais e as incertezas associadas à demanda (convencional e de VEs) e a geração renovável. O modelo proposto inclui o desenvolvimento de um método para a previsão de demanda de carregamento dos VEs. O método de otimização foi desenvolvido na linguagem de modelagem AMPL e resolvido via CPLEX. Os testes realizados com um sistema de 24 barras ilustram sua eficácia como uma ferramenta que pode auxiliar os planejadores de SDEE na integração de recursos energéticos distribuídos.
Development of a Short-Term Electrical Load Forecasting in Disaggregated Levels Using a Hybrid Modified Fuzzy-ARTMAP Strategy
(2023-05-01) Fernández, Leonardo Brain García [UNESP]; Lotufo, Anna Diva Plasencia [UNESP]; Minussi, Carlos Roberto [UNESP]; Universidade Estadual Paulista (UNESP)
In recent years, electrical systems have evolved, creating uncertainties in short-term economic dispatch programming due to demand fluctuations from self-generating companies. This paper proposes a flexible Machine Learning (ML) approach to address electrical load forecasting at various levels of disaggregation in the Peruvian Interconnected Electrical System (SEIN). The novelty of this approach includes utilizing meteorological data for training, employing an adaptable methodology with easily modifiable internal parameters, achieving low computational cost, and demonstrating high performance in terms of MAPE. The methodology combines modified Fuzzy ARTMAP Neural Network (FAMM) and hybrid Support Vector Machine FAMM (SVMFAMM) methods in a parallel process, using data decomposition through the Wavelet filter db20. Experimental results show that the proposed approach outperforms state-of-the-art models in predicting accuracy across different time intervals.
Design of a mixed ℋ2/ℋ∞ gain scheduling state derivative feedback controller for linear parameter-varying systems
(2023-01-01) Beteto, Marco Antonio Leite [UNESP]; Assunção, Edvaldo [UNESP]; Teixeira, Marcelo Carvalho Minhoto [UNESP]; Universidade Estadual Paulista (UNESP)
In this paper, the mixed (Formula presented.) guaranteed cost for continuous-time linear parameter-varying (LPV) systems is proposed. In addition, the gain scheduling (GS) strategy and the state derivative feedback (SDF) were considered. The time-varying parameter is assumed to be available for online measurement, and the conditions are based on linear matrix inequalities (LMIs). To improve the behaviour of the system, the (Formula presented.) -stability is used. Examples show that the proposed conditions achieved good results in reducing the disturbance effect in the system. Furthermore, with the proposed methods, it is possible to guarantee the asymptotic stability and a mixed (Formula presented.) guaranteed cost minimisation.
Novel Landslide Susceptibility Mapping Based on Multi-criteria Decision-Making in Ouro Preto, Brazil
(2023-06-01) Mantovani, José Roberto [UNESP]; Bueno, Guilherme Taitson; Alcântara, Enner [UNESP]; Park, Edward; Cunha, Ana Paula [UNESP]; Londe, Luciana [UNESP]; Massi, Klécia [UNESP]; Marengo, Jose A. [UNESP]; Universidade Estadual Paulista (UNESP); Universidade Federal de Goiás (UFG); Nanyang Technological University (NTU); National Center for Monitoring and Early Warning of Natural Disasters (CEMADEN)
Weather-related disasters have caused widespread deaths and economic losses in developing countries, including Brazil. Frequent floods and landslides in Brazil are mostly climatic driven, often aggravated by human activities and poor environmental planning. In this paper, we aimed to map and discuss the susceptibility to landslides in the urban area of Ouro Preto, Brazil, a municipality with colonial and world heritage houses. We used data on precipitation, soil types, geology, digital elevation model (DEM), and land use and land cover (LULC) of high spatial resolution (1 m). The location of landslides in the urban perimeter was provided by the Civil Defense of Ouro Preto, and these were validated by fieldwork. A novel mathematical model based on multi-criteria decision-making (MCDA) and the Analytic Hierarchy Process (AHP) was used to map the susceptible areas to landslides. Results show that areas most affected by strong landslides were low-density vegetation (high susceptibility) and rocky outcrops (very high susceptibility). The largest areas susceptible to landslides are urban land use areas. Particularly, landslides that occurred in February 2022 in the region were related to intense soil saturation. With an average monthly rainfall of 122.60 mm, the uneven relief and edaphoclimatic characteristics had caused percolation of the surface runoff, naturally triggering landslides. This study supports mitigation efforts by local governments and decision-makers.
Deadly disasters in southeastern South America: flash floods and landslides of February 2022 in Petrópolis, Rio de Janeiro
(2023-03-21) Alcantara, Enner [UNESP]; Marengo, José A. [UNESP]; Mantovani, José [UNESP]; Londe, Luciana R. [UNESP]; San, Rachel Lau Yu; Park, Edward; Lin, Yunung Nina; Wang, Jingyu; Mendes, Tatiana [UNESP]; Cunha, Ana Paula [UNESP]; Pampuch, Luana; Seluchi, Marcelo [UNESP]; Simões, Silvio [UNESP]; Cuartas, Luz Adriana [UNESP]; Goncalves, Demerval; Massi, Klécia [UNESP]; Alvalá, Regina [UNESP]; Moraes, Osvaldo [UNESP]; Filho, Carlos Souza; Mendes, Rodolfo [UNESP]; Nobre, Carlos [UNESP]; Universidade Estadual Paulista (UNESP); National Center for Monitoring and Early Warning of Natural Disasters (CEMADEN); Nanyang Technological University (NTU); Academia Sinica; Universidade Estadual de Campinas (UNICAMP); Universidade de São Paulo (USP)
On 15 February 2022, the city of Petrópolis in the highlands of the state of Rio de Janeiro, Brazil, received an unusually high volume of rain within 3 h (258 mm), generated by a strongly invigorated mesoscale convective system. It resulted in flash floods and subsequent landslides that caused the deadliest landslide disaster recorded in Petrópolis, with 231 fatalities. In this paper, we analyzed the root causes and the key triggering factors of this landslide disaster by assessing the spatial relationship of landslide occurrence with various environmental factors. Rainfall data were retrieved from 1977 to 2022 (a combination of ground weather stations and the Climate Hazards Group InfraRed Precipitation - CHIRPS). Remotely sensed data were used to map the landslide scars, soil moisture, terrain attributes, line-of-sight displacement (land surface deformation), and urban sprawling (1985-2020). The results showed that the average monthly rainfall for February 2022 was 200 mm, the heaviest recorded in Petrópolis since 1932. Heavy rainfall was also recorded mostly in regions where the landslide occurred, according to analyses of the rainfall spatial distribution. As for terrain, 23 % of slopes between 45-60 had landslide occurrences and east-facing slopes appeared to be the most conducive for landslides as they recorded landslide occurrences of about 9 % to 11 %. Regarding the soil moisture, higher variability was found in the lower altitude (842 m) where the residential area is concentrated. Based on our land deformation assessment, the area is geologically stable, and the landslide occurred only in the thin layer at the surface. Out of the 1700 buildings found in the region of interest, 1021 are on the slope between 20 to 45 and about 60 houses were directly affected by the landslides. As such, we conclude that the heavy rainfall was not the only cause responsible for the catastrophic event of 15 February 2022; a combination of unplanned urban growth on slopes between 45-60 , removal of vegetation, and the absence of inspection were also expressive driving forces of this disaster.
Alternative Current Injection Newton and Fast Decoupled Power Flow
(2023-03-01) Coutinho de Oliveira, Cristina; Bonini Neto, Alfredo [UNESP]; Alves, Dilson Amancio [UNESP]; Minussi, Carlos Roberto [UNESP]; Castro, Carlos Alberto; Pedra Branca do Amapari Center; Universidade Estadual Paulista (UNESP); Universidade Estadual de Campinas (UNICAMP)
This article presents an alternative Newton-Raphson power flow method version. This method has been developed based on current injection equations formulated in polar coordinates. Likewise, the fast decoupled power flow, elaborated using current injection (BX version), is presented. These methods are tested considering electrical power systems composed of 57-, 118-, and 300-bus, as well as a realistic system of 787-bus. For the robustness analysis, simulations were performed considering different loading conditions and R/X ratios of the transmission line. Based on the simulations that were realized, there is evidence that the performance of the proposed current injection methods is similar to the power injection methods.
An Output-Feedback Design Approach for Robust Stabilization of Linear Systems With Uncertain Time-Delayed Dynamics in Sensors and Actuators
(2023-01-01) Sereni, Bruno [UNESP]; Galvao, Roberto Kawakami Harrop; Assuncao, Edvaldo [UNESP]; Teixeira, Marcelo Carvalho Minhoto [UNESP]; Universidade Estadual Paulista (UNESP); Instituto Tecnológico de Aeronáutica (ITA)
In this paper, we propose a control approach for the robust stabilization of linear time-invariant (LTI) systems with non-negligible sensor and actuator dynamics subject to time-delayed signals. Our proposition is based on obtaining an augmented model that encompasses the plant, sensor, and actuator dynamics and also the time-delay dynamic effect. We make use of the Padé Approximation for modeling the time-delay impact on the feedback loop. Since the actual plant state variables are not available for feedback, the sensor outputs, which represent a subset of the augmented system state variables, are used for composing a static output-feedback control law. The robust controller gains are computed by means of a two-stage strategy based on linear matrix inequalities (LMI). For obtaining less conservative conditions we consider the use of homogeneous-polynomial Lyapunov functions (HPLF)- and other decision variables- of arbitrary degree. In our proposition, we also take into account the inclusion of a minimum decay rate criterion in order to improve closed-loop system transient response. Disturbance rejection is also addressed through extensions to H2 guaranteed cost minimization. The effectiveness of the proposed strategy is attested in the design of a controller for the lateral axis dynamics of an aircraft and other academic examples.
New Stabilization Conditions for Fuzzy-Based Sampled-Data Control Systems Using a Fuzzy Lyapunov Functional
(2023-01-01) Oncoy, Dante J. S. [UNESP]; Cardim, Rodrigo [UNESP]; Teixeira, Marcelo C. M. [UNESP]; Faria, Flavio A. [UNESP]; Assuncao, Edvaldo [UNESP]; Lazarini, Adalberto Z. N. [UNESP]; Universidade Estadual Paulista (UNESP); Computer Engineering Course Coordination (COENC)
This paper focuses on the stabilization problem of Takagi-Sugeno fuzzy systems via a sampled-data controller using a fuzzy dependent functional. By employing a property of convex combination, a new approach to deal with the time derivatives of the fuzzy membership functions (FMFs) in the stabilization conditions is proposed, and less conservative conditions are derived in the form of linear matrix inequalities (LMIs). Moreover, the proposed approach introduces a switching function which opens up possibilities to use a switched controller and take advantage of its benefits well known in the literature. Therefore, two sampled-data control strategies are proposed, where the first one is a fuzzy controller and the second is a robust switched controller, that does not require the expressions of the FMFs to implement the control law, which guarantees the robustness of the controlled system in cases where the FMFs depend on uncertain parameters. Finally, the effectiveness of the proposed strategies is verified by two examples.
The Impact of Transmission Line Modeling on Lightning Overvoltage
(2023-02-01) Leon Colqui, Jaimis Sajid; Ribeiro de Moura, Rodolfo Antônio; De Oliveira Schroeder, Marco Aurélio; Filho, José Pissolato; Kurokawa, Sérgio [UNESP]; Universidade Estadual de Campinas (UNICAMP); Universidade Federal de Sergipe (UFS); Universidade Estadual Paulista (UNESP)
In most of the work that investigates the backflashover phenomenon due to direct lightning strikes, using EMT-type simulators, transmission lines are represented by the J. Marti model and the ground effect is computed employing J. R. Carson’s formulations. Thus, the ground displacement current is neglected, the line voltage definition corresponds to the wire potential formulation, and soil resistivity is considered frequency-independent. These considerations can lead to erroneous measurements of the occurrences of the backflashover phenomenon in the insulator strings of transmission line. In this sense, this paper presents a systematic sensitivity analysis study of lightning overvoltage in insulator strings considering more physically consistent models of the transmission line, which consider the displacement current, ground admittance correction, rigorous voltage definition, and frequency-dependent soil parameters. According to the results, for the case study, transmission line parameters modeling can present a maximum percentual difference of around 71.54%, considering the frequency range of first strokes. This difference leads to a percent difference of around 5.25% in the maximum overvoltage across the insulator strings. These differences confirm that the occurrence or not of backflashover in the insulator strings, including the disruption time, are sensitive to the line model considered.
Harmonic grounding impedance of rods in horizontally stratified soils using ABCD-matrix approach
(2023-03-01) de Araújo, Anderson R.J.; de Azevedo, Walter L.M.; Colqui, Jaimis S.L.; Kurokawa, Sérgio [UNESP]; Filho, José Pissolato; Universidade Estadual de Campinas (UNICAMP); Universidade Estadual Paulista (UNESP)
Grounding electrodes play a fundamental role in the operation of power systems. In this context, precise computation of grounding impedance must consider the frequency-dependence of the soil parameters and the ground organized in stratified layers of soil. This paper proposes an ABCD matrix approach to compute the harmonic grounding impedance of rods buried in frequency-dependent stratified soils directly in the frequency domain. This technique is based on the traditional ABCD matrix used for overhead multi-phase transmission lines extended to grounding systems. In this approach, each rod segment is modeled as a short transmission line where the equivalent harmonic grounding impedance is calculated. Then, the Ground Potential Rise (GPR) waveforms are computed by lightning currents injected into the rods buried in different scenarios. Results indicated that the ABCD matrix approach has shown a good agreement with those obtained using a full-wave electromagnetic software FEKO. The frequency-dependence of the soil electrical parameters causes a significant modification in the harmonic impedance of grounding rods which reduces the GPR peaks considerably, being this reduction more pronounced in homogeneous and 2-layer soils. The proposed technique is an attractive tool since that considers the frequency dependence on each layer of soil, with a low computational cost and good accuracy from 100 Hz up to 1 MHz.
Impact of Volumetric Water Content and Porosity on Transmission Lines Submitted to Energization and Lightning Strikes
(2022-01-01) Pascoalato, Taina F. G. [UNESP]; De Araujo, Anderson R. J.; Kurokawa, Sérgio [UNESP]; Filho, Jose Pissolato; Universidade Estadual Paulista (UNESP); Universidade Estadual de Campinas (UNICAMP)
This paper investigates the impact of the improved Archie's model for soil resistivity considering the volumetric water content and porosity on the transient responses developed for energization and a lightning strike applied at only one phase of the line. In this study, an overhead transmission line located on saturated sandy soil modeled by different levels of volumetric water content and porosity was assumed. The transient responses were compared to those obtained adopting a high-resistivity dry sandy soil. Results have demonstrated that the transient voltages have a significant impact on the volumetric water content and porosity for this type of soil. The pronounced variation is seen in the induced voltages for both types of disturbances.
A strategy to enhance the distribution systems recoverability via the simultaneous coordination of planning actions and operational resources
(2023-05-01) Home-Ortiz, Juan M. [UNESP]; Melgar-Dominguez, Ozy D. [UNESP]; Javadi, Mohammad Sadegh; Gough, Matthew B.; Mantovani, José Roberto Sanches [UNESP]; Catalão, João P.S.; Universidade Estadual Paulista (UNESP); Faculty of Engineering of the University of Porto and INESC TEC; Technology and Science (INESC TEC)
This paper presents a planning and operational strategy to improve the recoverability of distribution systems (DSs) to deal with a set of possible line fault scenarios. The strategy simultaneously optimizes the allocation of dispatchable distributed generation (DG) units while coordinating a dynamic restoration process based on a radial topology reconfiguration, an islanding operation, a demand response program, and the pre-positioning and dispatch of mobile emergency storage units. The uncertainty and variability associated with solar irradiation and demand are captured via a multi-period formulation based on a stochastic mixed-integer linear programming model. The objective function of this model minimizes the investment cost of new dispatchable DG units and the amount of energy shedding within the system. Simulations are performed on adapted 33-node and 53-node test systems to validate the proposed strategy under four different test conditions, numerical results reveal the advantages of simultaneously solving the planning and operational stages to improve the recoverability of the system.
Implementation of an Alternative Frequency-Dependent Three-Phase Transmission Line Model Based on the Folded Line Equivalent Model in MatLab-Simulink
(2022-12-01) Leon Colqui, Jaimis Sajid; Timaná, Luis; Caballero, Pablo Torrez; Pissolato Filho, José; Kurokawa, Sérgio [UNESP]; Universidade Estadual de Campinas (UNICAMP); Catholic University of Colombia; Research and Development Center in Telecommunications (CPQD); Universidade Estadual Paulista (UNESP)
This paper proposes an alternative multiconductor transmission line model that combines the folded line equivalent with the modal transformation. The folded line equivalent decomposes the nodal admittance matrix of a transmission line into its open-circuit and short-circuit contributions. These contributions are fitted to rational functions, which are associated with Norton equivalent circuits based on their state space models. The proposed model uses an orthogonal matrix to transform voltages and currents from the phase domain to the folded line equivalent domain and vice versa. Because the transformation matrix is orthogonal, we represent it using ideal transformers in simulation software. First, we use a circuit representation of Clarke’s matrix to decompose a transmission line into its modes. Then, each mode is decomposed into its open-circuit and short-circuit contributions using a circuit implementation of the proposed matrix. The proposed approach can accurately represent short lines in simulations with time steps equal to or greater than the propagation time of the transmission line. We compare the results obtained with the proposed approach to those obtained with power systems computer-aided design/electromagnetic transients including the DC universal line model.
AC Multi-Stage Transmission Network Expansion Planning considering a Multi-Voltage Approach
(2022-01-01) Cajas, Patricio; Torres, Santiago P.; Chillogalli, Jose E.; Chamorro, Harold R.; Sood, Vijay K.; Romero, Ruben R. [UNESP]; and Telecommunications Engineering (DEET); CNPq Scholarship Student; Kth; Ontario Tech University; Universidade Estadual Paulista (UNESP)
Long-term transmission network expansion planning aims to determine where, when and which types of equipment should be installed over a period of time, in order to meet the electric market needs with certain specifications of quality in services at the lowest possible cost. Until now, several methods have been proposed to solve the Static Transmission Network Expansion Planning (STNEP) problem, considering a multi-voltage approach using the DC load flow, however, these solutions may not be feasible when the AC model is used for the operational problem. In this paper a multi-stage model based on the mathematical formulation of the AC load flow is solved, considering a multi-voltage approach, power losses and reactive power compensation. The AC multi-stage transmission network expansion planing problem with multi-voltage approach (MTNEP-MV) was solved by the hybrid meta-heuristic, Differential Evolution (DE) and Continuous Population-Based Incremental Learning (PBILc) algorithm. To evaluate the proposed mathematical formulation Garver 6-bus system was used. The results show that raising the transmission system voltage and considering the MTNEP-MV problem, less transmission lines are required, and also power losses and reactive power compensation needs, are reduced.
Optimal Planning of Electric Vehicles Energy Exchange in Parking Lots Considering Uncertainties
(2022-01-01) Sanchez, David A.; Torres, Santiago P.; Chillogalli, Jose E.; Chamorro, Harold R.; Gonzalez, Luis G.; Sood, Vijay K.; Romero, Ruben R. [UNESP]; and Telecommunications Engineering (DEET); CNPq Scholarship Student; Kth; Ontario Tech University; Universidade Estadual Paulista (UNESP)
With the growing concern for energy conservation and environmental protection around the world, the use of Electric Vehicles (EVs) is being encouraged. In this way, the optimum allocation of EVs' parked in a distribution network is a challenging issue. In this paper, the optimal energy exchange between EVs and the distribution network is analyzed in two types of parking lots, which will be controlled by a charging provider or aggregator, and where the randomness related to vehicles and vehicle-to-grid (V2G) capability at the charging stations will be considered. In this way the stochastic behavior of an EV during the day was formulated as a mixed integer linear programming (MILP) problem, and Monte Carlo simulations were used to estimate the optimal loading and unloading patterns of EVs inside the parking lots based on the time-of-use (ToU) tariffs.
IMPROVED BIASED RANDOM KEY GENETIC ALGORITHM FOR THE TWO-DIMENSIONAL NON-GUILLOTINE CUTTING PROBLEM
(2022-01-01) de Oliveira, Eliane Vendramini [UNESP]; Romero, Rubén [UNESP]; Sao Paulo State Technological College; Universidade Estadual Paulista (UNESP)
The two-dimensional cutting problem has a direct relationship with industry problems. There are several proposals to solve these problems. In particular, solution proposals using metaheuristics are the focus of this research. Thus, in this paper, we present a specialized biased random key genetic algorithm. Several tests were performed using known instances in the specific literature, and the results found by the metaheuristics proposed were, in many cases, equal or superior to the results already published in the literature. Another comparison of results presented in this paper is related to the results obtained by specialized metaheuristics and the results found by a mathematical model using commercial software. Once again, in this case, the genetic algorithm presented results equal to or very close to the optimum found by the mathematical model. In addition, the optimization proposal was extended to two-dimensional non-guillotine cutting without parts orientation.
Artificial Neural Networks: Multilayer Perceptron and Radial Basis to Obtain Post-Contingency Loading Margin in Electrical Power Systems
(2022-11-01) Bonini Neto, Alfredo [UNESP]; Alves, Dilson Amancio [UNESP]; Minussi, Carlos Roberto [UNESP]; Universidade Estadual Paulista (UNESP)
This paper presents the ANN (Artificial Neural Networks) approach to obtaining complete P-V curves of electrical power systems subjected to contingency. Two networks were presented: the MLP (multilayer perceptron) and the RBF (radial basis function) networks. The differential of our methodology consisted in the speed of obtaining all the P-V curves of the system. The great advantage of using ANN models is that they can capture the nonlinear characteristics of the studied system to avoid iterative procedures. The applicability and effectiveness of the proposed methodology have been investigated on IEEE test systems (14 buses) and compared with the continuation power flow, which obtains the post-contingency loading margin starting from the base case solution. From the results, the ANN performed well, with a mean squared error (MSE) in training below the specified value. The network was able to estimate 98.4% of the voltage magnitude values within the established range, with residues around 10−4 and a percentage of success between the desired and obtained output of approximately 98%, with better result for the RBF (radial basis function) network compared to MLP (multilayer perceptron).

Navegar

Submissões Recentes