Artigos em Revistas

Electricity systems are rapidly evolving toward decentralized architectures with high shares of variable renewable energy sources and distributed energy resources (DERs), increasing congestion in medium- and low-voltage networks. This paper presents a structured mixed-source review combining bibliometric mapping and targeted analytical synthesis on flexibility services for congestion management in electric distribution systems. Analysis of the quality-controlled Q3 corpus (n = 1827) identifies China as the leading national contributor and substantial collective European participation, with 79.6% of records published from 2018 onward. Author-keyword mapping reveals five streams: distribution-network optimization, market-based congestion management, uncertainty-aware active-network operation, flexibility-service coordination, and demand-response smart-grid control. Novelty lies in keeping the validated bibliometric corpus separate from an independently assembled, question-driven evidence base until interpretation. The analytical synthesis shows that distributed locational marginal pricing (DLMP), particularly in iterative formulations, can internalize network constraints and provide locational signals for DER coordination, although its effectiveness depends on adequate network modeling, uncertainty treatment, and flexible-demand participation. The review also identifies converging trends toward multilayer coordination between transmission system operators (TSOs) and distribution system operators (DSOs), local flexibility procurement, and digital platforms for ancillary-service provision. Across jurisdictions, explicit remuneration, interoperable data, and coordinated governance recur, but uneven implementation precludes causal comparisons or effectiveness rankings. The paper concludes by identifying research gaps related to cost–benefit validation, regulatory standardization, data interoperability, and large-scale implementation in distribution systems.

JONATHAN MUNOZ ˜ TABORA, KRZYSZTOF TOMALCZYK, DARIUSZ WITKOWSKI, RAFAEL MAXIMINO BASTOS, JOAO ˜ V. DOS REIS ALVES, CARLOS E. MOREIRA, THIAGO M. SOARES, MARIA EMÍLIA DE LIMA TOSTES, UBIRATAN H. BEZERRA, OZY D. MELGAR-DOMINGUEZ

Active distribution networks are increasingly exposed to feeder overloads, voltage deviations, and loss increases as distributed energy resources reshape operating conditions. This paper proposes a bi-objective optimization framework for the coordinated dispatch of distributed Battery Energy Storage Systems in active distribution networks. The method couples OpenDSS quasi-static time-series simulation over 96 fifteen-minute intervals with NSGA-II. The framework first identifies the critical congestion window from the uncontrolled feeder response, then constructs physically feasible dispatch schedules for nine BESS units distributed across three network zones of the IEEE 123-bus test feeder. The optimization minimizes a composite network-performance index of eight weighted terms and the total dispatched energy. The compromise and maximum-relief solutions bring the entry line below its thermal rating throughout the critical window, cutting the peak from 129.8% to 99.9% and 97.1%; the minimum-energy solution reaches 102.3% and does not eliminate the violation. Total active losses fall from 923.0 kWh to 745.6–779.3 kWh, or 15.6%–19.2%. The front is stable across ten seeds and insensitive to the weighting; rule-based baselines and an ablation separate the effects of temporal shaping and of allocation among units, and six alternative algorithms are compared under an identical budget. Applied unchanged to a 17,384-bus utility network under load growth, it reduces the overload area by up to 68% while exposing the limitation of the step-wise required injection. The loss reduction is a network benefit measured during the operating day and is not annualized, since recharging the fleet incurs a round-trip loss larger than the losses avoided.

JOÃO VICTOR DOS REIS ALVES, JONATHAN MUÑOZ TABORA, RAFAEL MAXIMINO BASTOS, CARLOS EDUARDO MOREIRA RODRIGUES, MARIA EMÍLIA DE LIMA TOSTES, UBIRATAN HOLANDA BEZERRA

Photovoltaic (PV) deployment is expanding rapidly, but the climate and economic value of identical generation varies with electricity-system and market conditions. This study exam- ines whether avoided-emission rankings align with project-level financial valuation when physical project characteristics are held constant. A documented 1.101 MWp PV project, with expected annual generation of 1592.6 MWh/year, was assessed counterfactually across seven regional electricity groupings, with Brazil as the reference case. The framework integrates generation-weighted emission factors, avoided-emission accounting, discounted cash flow, carbon-abatement costs, deterministic sensitivity analysis, Monte Carlo simulation, and ex- ploratory Pearson and Spearman correlations with exact permutation inference. To address the physical variability of the reference asset, an auxiliary hourly PV simulation covering ten complete years (2016–2025) was additionally performed using solar irradiance, ambient temper- ature, and wind-speed data. The modeled annual generation averaged 1472.4 MWh/year, with a coefficient of variation of 1.44%, indicating limited interannual variability over the evaluated decade. Financial indicators were evaluated over a 20-year horizon, whereas lifetime avoided emissions and carbon-abatement costs were assessed over a 25-year technical lifetime. The Arab League presented the highest avoided emissions (1005 tCO2/year; 6.1 times Brazil) but the weakest base-case financial result: a net abatement cost of approximately USD 7/tCO2 and a 70.1% probability of positive NPV. The European Union achieved the highest NPV, a net abatement cost of approximately −USD 255/tCO2, and a 100% probability of positive NPV despite lower mitigation. An inverse association between emission factor and electricity tariff further characterized this mismatch (Spearman’s ρ = −0.786; exact permutation p = 0.048). The results show that physical PV production, mitigation potential, and project-level financial valuation represent distinct but complementary dimensions that should be assessed jointly when comparing PV deployment contexts.

AYRTON LUCAS LISBOA DO NASCIMENTO, DEBORA HELENA DE SOUZA CAVALCANTE, JONATHAN MUÑOZ TABORA, ANA ROSA CARRIÇO DE LIMA MONTENEGRO DUARTE, CARMINDA CÉLIA MOURA DE MOURA CARVALHO, VITOR ALMEIDA BERNARDES, BRUNO SANTANA DE ALBUQUERQUE, MARIA EMÍLIA DE LIMA TOSTES

The increasing penetration of distributed photovoltaic generation is changing voltage behavior in distribution feeders and creating operational challenges related to voltage violations, losses, curtailment, and hosting capacity. This paper proposes a topology-aware analytical and computational framework for assessing voltage regulation and continuous photovoltaic hosting capacity in distribution feeders with smart-inverter controls. The framework combines topology-dependent voltage sensitivities, balanced steady-state power-flow simulations, explicit inverter apparent-power constraints, and gain indices that quantify the contributions of feeder topology, inverter controls, and their interaction. The IEEE 33-bus and IEEE 69-bus feeders are evaluated under radial and meshed configurations, heavy- and light-load conditions, and four photovoltaic operation modes: no control, Volt–Var, Volt–Watt, and combined Volt–Var/Volt–Watt control. A discrete sweep from 20% to 150% PV penetration is used to characterize voltage, active and reactive losses, and curtailment trends. Hosting-capacity boundaries are subsequently determined through an interval-aware procedure consisting of a one-percentage-point scan followed by bisection refinement to 0.1 percentage point, without assuming a globally monotonic feasibility transition. The results show that the feeder topology strongly affects voltage sensitivity and photovoltaic hosting capacity. The meshed operation generally increases voltage margins, while the interval-aware assessment identifies nonzero feasible penetration ranges, even when the zero-PV operating point is constrained by undervoltage. Volt–Watt achieves the largest hosting-capacity gains at the expense of curtailment, whereas Volt–Var preserves photovoltaic injection but may increase feeder losses. Therefore, hosting capacity should be interpreted jointly with topology, inverter controls, injected power, curtailment, and losses.

AYRTON LUCAS L. DO NASCIMENTO, BRUNO SANTANA DE ALBUQUERQUE, HERTZ FREITAS DA S. JUNIOR, CARLOS EDUARDO M. RODRIGUES, CARMINDA CÉLIA MOURA DE MOURA CARVALHO, UBIRATAN H. BEZERRA, JONATHAN MUÑOZ TABORA, MARIA EMÍLIA DE LIMA TOSTES

Large electricity consumers under Brazilian Group A tariffs face a cost–risk trade-off when defining contracted demand, since inadequate sizing leads either to payments for unused capacity or to penalties for exceeding regulatory limits. Despite this relevance, practical decision-support tools that convert tariff rules into reproducible contract optimization remain limited. This paper presents DSManager (version 0.0), a tool based on Python (version 3.14.4) developed to optimize tariff modality and contracted demand for Group A consumer units. The framework incorporates the mathematical formulation of Brazilian tariff structures, including green and blue time-of-use modalities, taxes, and excess-demand penalties, and evaluates two optimization strategies: the Maximum Recorded Demand method and a Grid Search procedure for direct minimization of the billing cost function. The tool was implemented with Pandas (version 3.0.2) and Streamlit (version 1.57.0) and validated using real billing data from two consumer units in the Equatorial Pará concession area. In the retrospective case, the green tariff combined with Grid Search produced projected savings of US$9554.20 relative to the unchanged contract. In the real implementation case, reducing contracted demand from 450 kW to 240 kW yielded an observed average saving of US$1944.31 per month. The results demonstrate the practical value of the proposed tool for tariff management and electricity cost reduction in large consumers.

CLEYDSON MATOS LIMA, JONATHAN MUÑOZ TABORA, CEZAR AUGUSTO ROCHA 1, CARMINDA CÉLIA MOURA DE MOURA CARVALHO, UBIRATAN H. BEZERRA, MARIAEMÍLIA DE LIMA TOSTES

This paper presents an integrated validation framework for EV taxi charging-hub plans that combines spatial accessibility, grid deployability, and operational performance. Candidate hub configurations are first generated through a demand-weighted p-median model based on 175 taxi stands and 2825 cooperative members in Belém, Brazil. The assigned demand is then translated into charger requirements through stochastic sizing, and the resulting infrastructure is screened against the available headroom of 12,905 medium-voltage transformers. Finally, the selected solution is evaluated through an Erlang-C queueing model under peak-demand concentration. The final plan, obtained with 14 hubs, achieved a weighted mean distance of 0.724 km and a weighted P95 distance of 1.488 km, while requiring 46 chargers and 2610 kW of installed capacity. Of these, 45 chargers were successfully allocated in the grid-screening stage, corresponding to a placement rate of 97.83%.

JOSIVAN RODRIGUES DOS REIS, RAFAEL MAXIMINO BASTOS, BRUNO SANTANA DE ALBUQUERQUE, CARMINDA CÉLIA MOURA DE MOURA CARVALHO, UBIRATAN HOLANDA BEZERRA, JONATHAN MUÑOZ TABORA, MARIA EMÍLIA DE LIMA TOSTES, AYRTON LUCAS LISBOA DO NASCIMENTO

Este estudo investiga o impacto de técnicas de feature engineering na previsão de preços de energia elétrica no curto prazo. Utilizando dados históricos semanais do mercado brasileiro, diferentes grupos de atributos, incluindo variáveis defasadas, estatísticas móveis e representações sazonais, são avaliados por meio de uma abordagem incremental. O objetivo é analisar a contribuição de cada grupo de atributos no desempenho do modelo. Os resultados demonstram que a inclusão de estatísticas móveis e variáveis sazonais categóricas melhora significativamente a precisão das previsões em comparação com modelos baseados apenas em variáveis defasadas. Os achados evidenciam a importância da construção de atributos em problemas de previsão de séries temporais, especialmente em mercados altamente voláteis como o de energia elétrica.

CARLOS SÁVIO SARUBI DE SOUZA, FLÁVIA PESSOA MONTEIRO, JOSIVAN RODRIGUES DOS REIS, UBIRATAN HOLANDA BEZERRA, MARIA EMÍLIA DE LIMA TOSTES

This study explores the application of Failure Modes and Effects Analysis (FMEA) to ground-mounted and Floating Photovoltaic (FPV) systems, with and without tracking systems, considering the particularities of each configuration. The FMEA methodology was applied to identify and prioritize failure modes, analyzing severity, occurrence and detection, as well as calculating the Risk Priority Number (RPN) and the Action Priority (AP). The FMEA methodology was adopted due to its preventive capability in identifying early-stage component failures and prioritizing actions. To this end, detailed analyses of the main failure modes and effects were carried out, covering critical components such as photovoltaic modules, inverters and support systems. In addition, preventive and corrective actions will be proposed. The study includes the case study of the Research Network for Technological Development and Innovative Extension of Advanced Materials in Energy and Mobility applied to the Amazon context (EMOBAMAZON). This study represents a novel application of FMEA to Floating Photovoltaic (FPV) systems in tropical environments, demonstrating its potential to improve predictive maintenance and operational reliability in renewable energy facilities. The integration of risk classification approaches has enabled a comprehensive and well-founded view of failures, contributing to the reliability, safety and operational efficiency of photovoltaic systems in the Amazon context.

ELEN PRISCILA LOBATO, EDUARDO MONTEIRO, YASMIM LISBOA, JOÃO ARAÚJO, WELLINGTON FONSECA

The global transition toward sustainable mobility and renewable energy integration demands intelligent energy management frameworks capable of coupling electric mobility, distributed generation, and energy storage. This study presents a comprehensive evaluation of the SIMA Project (Sistema Inteligente Multimodal da Amazônia), an innovative mobility pilot implemented at the Federal University of Pará, Brazil. The SIMA consists of the monitoring building, photovoltaic systems, lithium-based energy storage systems, and electric transportation modes (including urban and intercity buses, as well as a solar-powered catamaran), all interconnected within a microgrid. Field monitoring, data processing, and simulation analyses were conducted to assess energy performance, consumption patterns, and the operational feasibility of these electric systems under Amazonian conditions. The results indicate that the PV systems supply most of the SIMA’s demand, with the laboratory building accounting for 70% of total consumption and electric vehicles for 30%. Simulated full operation scenarios reveal the potential for near net-zero energy balance when energy management strategies are applied to generation, storage and charging. The findings demonstrate the technical viability of integrated mobility–energy systems in tropical contexts and provide practical insights for future low-carbon transport infrastructures in isolated or city-scale networks.

BRUNO SANTANA DE ALBUQUERQUE, AYRTON LUCAS LISBOA DO NASCIMENTO, MARIA EMÍLIA DE LIMA TOSTES, UBIRATAN HOLANDA BEZERRA, CARMINDA CÉLIA MOURA DE MOURA CARVALHO, JONATHAN MUÑOZ TABORA

This study focuses on the mathematical modeling, control design, and analysis of an interleaved bidirectional high-voltage-gain DC-DC converter for energy management in supercapacitors. The state of the art is reviewed, with an emphasis on research related to DC-DC converters and energy storage systems. The characteristics and modeling of the supercapacitors are thoroughly analyzed. The converter’s operation in both buck and boost modes is described, detailing its operating stages, design parameters, and component sizing. The modeling accounts for the dynamics of the converter in both operational modes. PI controllers and compensation techniques were implemented to ensure the desired performance and meet the design criteria. Simulations were conducted using PSIM software, version 2023.1, with a power flow of 1 kW, a 48 V DC bus (buck mode), and a 162 V supercapacitor module (boost mode), operating at 500 kHz. The performance of the controllers was evaluated during both the charging and discharging processes of the supercapacitor, analyzing the dynamic response and behavior in the continuous mode, even in the presence of system disturbances.

JESSICA C. A. SOUSA, THIAGO M. SOARES, JONATHAN M. TABORA, HUGO G. LOTT