Bruno W. França

• D.Sc.
• Professor at Fluminense Federal University

Integrating distributed energy sources has introduced significant challenges to power quality. One notable issue is the generation of harmonic distortions by power electronics converters, which significantly affect the performance and efficiency of power transformers, leading to overheating and related adverse effects. Traditional metrics for non-s...

Sistemas de monitoramento e diagnóstico de transformadores a seco são particularmente importantes na indústria de óleo e gás, onde o fornecimento de energia é mais suscetível a interrupções pelas falhas nestes equipamentos. Durante sua operação, os transformadores enfrentam estresses elétricos, térmicos, mecânicos e ambientais, que aceleram a degra...

O envelhecimento dos Transformadores de Potência (transformadores) é um efeito natural de sua operação, principalmente pela degradação do isolamento causada por aquecimento e esforços mecânicos. Além disso, os transformadores estão sujeitos a curtos-circuitos e sobretensões, que aumentam a solicitação dielétrica dos materiais isolantes. Descargas P...

The aerial distribution systems are vulnerable to extreme weather events induced by global warming and climate change. This vulnerability is evident in the growing frequency of faults caused by lightning strikes, direct contact with trees, and equipment failures. Also, wind and PV solar inject power variability into the system. Consequently, reclos...

Power transformers are recognized as high-value assets in substation design, but their susceptibility to various failure modes poses a significant risk of damage and power supply disruptions. Consequently, extensive research has been conducted to develop diagnostic techniques and monitoring methodologies for these devices. This project aims to deve...

RESUMO ESTRUTURADO Nos últimos anos o mercado de lâmpadas LED vem melhorando e amadurecendo nos quesitos de certificação, disponibilizando no mercado produtos em conformidade com padrões específicos de segurança, desempenho e qualidade previstos em normas e portarias. Porém, como todo produto tecnológico, deve haver esforços dos órgãos competentes...

The increase in distribution power demand and distributed generation may lead to a rise in power substation fault current levels. One possible solution to this problem is the use of a solid-state fault current limiter (SS-FCL). In this context, this paper proposes the concept of a bridge-type solid-state device switching an air-core reactor as an S...

Neste trabalho foi realizada a modelagem de um sistema estilizado, com características similares ao SIN, para a realização de estudos de elos HVDC-VSC com transmissão aérea. A modelagem foi realizada nos programas Anarede, Anafas, Anatem e PSCAD. O estudo tem ênfase no desempenho dinâmico do elo, incluindo as suas interações com uma rede elétrica q...

RESUMO ESTRUTURADO Diante da necessidade de soluções de planejamento do setor elétrico cada vez mais direcionadas ao aproveitamento racional de recursos, alinhado ainda ao crescimento por demanda de energia elétrica que se evidencia nos sistemas de distribuição, este artigo propõe a aplicação de compensação série em um sistema distribuição de energ...

The increase in distribution power demand and distributed generation may lead to a rise in power substation fault current levels. One possible solution to this problem is the use of a Solid-State Fault Current Limiter (SS-FCL). In this context, this paper proposes the concept of a bridge-type solid-state device switching an air-core reactor as an S...

Real-time simulation programs and hardware-in-the-loop (HIL) systems have been increasingly used in electrical engineering, each one with its own peculiarities. The company Typhoon HIL Inc. has software and hardware for HIL simulations. The complexity of the network, for example when there are multiple power converters, influences the modelling. Ha...

With the advent of smart grid theory, distribution networks can include different microgrids (MGs). Therefore, to achieve the desired technical and economic objectives in these networks, there is a need for bilateral coordination between their operators. In the following, by defining an energy management problem for them, it is predicted that the m...

Several substations in operation were commissioned decades ago. These substations are overstressed, then their protection equipment cannot provide an e_ective safety condition to the system. In the worst cases, short-circuits can cause permanent damages to the system if the overcurrent is higher than the capacity of the installed equipment. There a...

The presence of telecommunications and intelligent devices is increasing in electrical systems. With the IEC 61850 standard, the topology of electrical substations is being modified to the known digital substations. These substations are divided into process, bay, and station levels. With this new topology, there is a need for detailed studies abou...

Grid-forming (GFM) converter aims to enforce the voltage and frequency at its terminals in grid-connected and islanded microgrid scenarios. The generalized closed control (GCC) scheme is a well-known solution to achieve this objective, composed of a single-loop voltage control with embedded virtual impedance. Although originally proposed to operate...

This paper introduces a methodology for modelling a digital admittance-type distance relay using PSCAD/EMTDC. The proposed distance relay was tested in a simulation of the Brazilian power grid with predetermined fault scenarios. The goal of this paper is to make a detailed evaluation of the mho distance relay. The main aspects include the correct o...

This paper proposes a Shunt Active Filter (SAF) operating as a Synchronverter to enhance its performance, including the virtual inertia functionality. The SAF behaves as a voltage source with a low-impedance path for harmonic contents. Synchronverter behavior is used together with selective filtering through Proportional-Resonant controllers to pro...

Abstract Fault current limiters are essential devices used to protect the power system and its equipment against high levels of fault current, which are growing up due to the increase of new power sources. This paper proposes a novel design of a Hybrid Superconducting Fault Current Limiter (Hybrid SFCL), which is composed basically by thyristors in...

The fault current level in distribution systems has increased in the last years mainly due to the energy consumption is in the limit of the production capacity and also the insertion of distributed generation, since the short circuits happen very closer to the generators now. In addition to this, most of the power substations were designed decades...

The electrical transformer is one of the most used equipment in electrical power systems. The non-linear electrical loads are increasing, mainly in the electrical distribution system, and the electrical power transformer is inserted in this scenario, supplying these loads. Consequently, the increasing non-linear loads affect the electrical transfor...

Ferroresonance has been a widely studied area in the last few decades due to the nonlinear behavior and power quality problems it presents. Some power quality problems related to the ferroresonance phenomenon are sustained overvoltage and overcurrent and maintained levels of waveform distortions. The phenomenon can lead to the dielectric breakdown...

This paper proposes an application in VBA (Visual Basic for Applications) for automatic modelling of a distribution network in ANAFAS software, in which short-circuit simulations are available. The simulation response may subsidize actions to locate permanent faults, reducing total reestablishment times, as well as leading directed maintenance acti...

In Brazil, technical energy losses in power distribution systems are determined by power flow studies considering medium and low voltage systems, according to ANEEL recommendations, presented in PRODIST Module 7. These technical losses occur due to physical phenomena and are intrinsically associated with the energy distribution process. However, st...

The increase in demand for electric power and the insertion of a distributed generation led to the rise of the short-circuit current in substations. Most of these Brazilian substations were designed decades ago, because of that their equipment may not support the new short-circuit current levels. To protect the installed equipment and avoid excessi...

Este artigo propõe um aplicativo emVBA (Visual Basic for Applications) para modelagem automática de uma rede de distribuição no software ANAFAS, na qual simulações de curto-circuito estão disponíveis. A resposta à simulação pode subsidiar ações para localizar falhas permanentes, reduzindo os tempos totais de restabelecimento, bem como as principais...

Diferenças entre o código computacional utilizado para o controle de equipamentos eletrônicos de Redes de Distribuição Ativas (RDA) simulados e o código embarcado para o controle dos equipamentos reais podem criar discrepâncias entre os resultados obtidos nas duas etapas. Foi desenvolvido um conjunto de bibliotecas na linguagem C de programação par...

Electrical faults on medium voltage electric power distribution systems can damage transformers. This fact motivated an R&D project in Brazil to study Fault Current Limiters for a utility. In this context, innovative design with a bifilar winding was developed for the present work, aiming to reduce self-inductance and to improve cooling rate. Long...

The increase in demand for electric power and the growing of distributed generation led to the increase of the short-circuit current in the substations. Most of these Brazilian substations, for example, were designed decades ago, so their equipment may not support the new short-circuit current levels. To protect the installed equipment or to avoid...

This paper presents the modeling and experimental validation of a recently presented DFIG wind power system driven by a two-level three-phase converter in which the grid-side converter is connected in series with the grid. The series-grid-side converter is able to compensate for stator-voltage sags, unbalance and harmonic distortion resulting in a...

The DFIG has been widely used in the wind power industry due to its technical advantages. However, current researches are being developed aiming at overcoming some of its drawbacks concerning reliability, efficiency and power quality. Since the wind farms are usually located at remote places, connected to weak grids, high reliability is required an...

Resumo - A elevação do nível de curto-circuito devido à expansão do sistema de distribuição de energia transformou os limitadores de corrente de curto-circuito (LCCs) em uma solução adequada para adiar a necessidade de reforço do equipamento de proteção e evitar danos graves no sistema de energia. Embora existam muitos tipos de limitadores, este ar...

This paper proposes a fully autonomous controller that slides the droop curves of a Static Synchronous Generator, avoiding the need of hierarchical controllers to perform power sharing and frequency and voltage regulation. The aim of this controller is to enhance the primary controller in order to perform additional functionalities in a similar way...

Among the variable-speed wind power systems the DFIG configuration is one of the most interesting ones since it can achieve optimal power extraction of the wind energy using a low-cost, low-rated-power converter. However, there are some drawbacks in this wind system configuration considering that its stator is directly connected to the grid. Distor...

The number of worldwide installed wind power plants has been growing rapidly. With the development of power electronics technology, the new wind power systems are able to optimize the extraction of the wind energy. Among the systems configurations, the doubly-fed induction generator (DFIG) is the most used, since it can make the system operate with...

The environmental effects of the massive usage of carbon-based fuels are leading the trends of change in the energy production and consumption profile, which is characterized by seeking clean alternatives of energy generation and by optimizing the energy consumption efficiency. Among these clean alternatives, the wind power system applications are...

This paper presents the behavior of a modified synchronverter topology under non-ideal loads. It also proposes a harmonic compensation scheme to overcome voltage harmonic pollution. First, this work presents an integration of two renewable sources to the electrical network, then it studies the effects of non-ideal loads, and proposes and evaluates...

The large increase in renewable generation insertion in the electrical grid has been the subject of many studies. This is due to the fact that renewable energy replaces fossil fuel based generation, which is finite and harmful to the environment. From a technical perspective, renewable generation drives research to guarantee its large scale inserti...

This paper presents a deep investigation on the synchronverter performance as a Power Oscillation Damping (POD) device. It is applied to damp multiple electromechanical oscillations in the Brazilian Transmission Grid. The electromechanical oscillations are identified through a filter that receives the measured active power and provides the referenc...

This paper evaluates a system with variable-speed wind power and photovoltaic generation connected to the power grid through a full-scale Synchronverter. It analyses the effects of dynamically controlled virtual inertia as a means of increasing performance. The full-scale power converter is composed of a back-to-back three-phase power converter. Th...

Nowadays a SVC at the Bom Jesus da Lapa (BJL) substation (250 MVAr) is utilized to control voltage at the Southeast/Northeast interconnection. This paper has two purposes. One is to show the technical possibility to substitute the Static VAR Compensator (SVC) by a synchronverter. Secondly, that the synchronverter mitigates electromechanical oscilla...

This paper presents an improved controller for the dual topology of the unified power quality conditioner (iUPQC) extending its applicability in power-quality compensation, as well as in microgrid applications. By using this controller, beyond the conventional UPQC power quality features, including voltage sag/swell compensation, the iUPQC will als...

The iUPQC is a Unified Power Quality Conditioner in which the series converter emulates a sinusoidal current source and the shunt converter emulates a sinusoidal voltage source. This approach provides indirect power quality compensation of the load voltage and the source current. Recent studies have suggested that the iUPQC has technical advantages...

In this work a Maximum Power Point Tracker (MPPT) for photovoltaic modules is developed using fuzzy logic. As it is well known, the output of the photovoltaic module is a non-linear curve which has a unique point of maximum power (MPP) for a given condition of radiation and temperature. When a load is connected to the module, only in very specifics...

In this paper the Unified Power Quality conditioner is studied with conventional operation mode (UPQC) and with its dual topology (iUPQC). The iUPQC is presented as solution to improve the dynamic response in power quality disturbance mitigation. Comparisons in steady-state and dynamic response are provided. Simulations and experimental results are...

This paper proposes a generalized model of Proton exchange membrane fuel cell (PEMFC) with Z-source converter design in PSCAD/EMTDC simulator. The fuel cell model considers the chemical and electrical parameters, and it is composed by five inputs and one electrical output. In the other words, the user needs to filled up five parameters of fuel cell...

The iUPQC is a dual approach of the well-known UPQC, which uses the series compensator as sinusoidal current source and the shunt compensator as sinusoidal voltage source. In this way, the control references outputs are sinusoidal signals at the fundamental frequency. This paper compares two different controllers for the PWM reference signal genera...

In this paper is proposed a novel predictive controller to improve the Power Electronic Load (PEL) dynamic. Moreover, details of the developed three-phase PEL prototype (25 kVA) are provided with capability of burn-in-test series, shunt and series-shunt power conditioners. In order to validate the load emulation effectiveness and dynamic improvemen...

This paper studies a hybrid filter formed by a single tuned LC filter per phase and a small-rated three-phase active filter, which are directly connected in series without any matching transformer. The required rating of the active filter is much smaller than that of a conventional standalone active filter would be and it comprises a four-switch H-...

Nowadays fuel cell stack and other alternative energy sources use batteries to store energy. However, the battery cannot be quickly charged or discharged because of low rate chemical reaction. In this way, a flywheel energy storage system (FESS) has been widely employed to provide dynamic storage and supply energy. Here, the FESS feeds mechanically...

This paper presents a frequency switching analysis of an interchanging topology of the Unified Power Quality Conditioner (iUPQC). It includes simulations with hardware-in-the-loop development tool, which allows the control code development (embedded in an actual fixed-point DSP) directly working in a simulated iUPQC (PSCAD/EMTDC simulator). The aim...

Translation of power electronic circuit designs from simulations into actual hardware can give rise to difficulties, regarding the implementation of control functions with embedded controllers. This task is even more difficult when the power converter must operate connected to the grid. A design framework is described in this paper, which is suitab...

This paper discusses a new PLL (Phase-Locked-Loop) approach for detection of the fundamental positive-sequence component of three-phase systems. Details about this three-phase PLL structure are provided. The positive sequence detector presented computes inner-products between the input and a locally generated version of the fundamental frequency. T...

In this paper, is proposed a new three-phase synchronization algorithm having a fast dynamic response and robust performance under distortion and/or fault conditions. Details on the structure and the digital implementation are provided. In order to validate the effectiveness of the three-phase phase-locked loop (PLL) algorithm, simulations using PS...

In this paper is proposed a Power Electronic Load (PEL), which simulates four load configurations: balanced, unbalanced, harmonic and unbalanced harmonic. Thus, this PEL is able to burn-in-test not only series equipment as AC power sources, but also shunt equipment as shunt Power Conditioning. In this way, the control strategy is presented based on...