Mestrado em Engenharia Elétrica
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- ItemA Control Structure for a Bidirectional DC-AC Converter with Power Quality Support Functions(Universidade Federal do Espírito Santo, 2022-12-02) Ribeiro, Laila Sindra; Simonetti, Domingos Savio Lyrio; https://orcid.org/0000000159202932; http://lattes.cnpq.br/1107005171102255; https://orcid.org/; http://lattes.cnpq.br/; Encarnacao, Lucas Frizera; https://orcid.org/0000000261627697; http://lattes.cnpq.br/5578918284508758; Reis, Fernando Soares dos; https://orcid.org/; http://lattes.cnpq.br/abstract
- ItemA rede de média tensão como meio de transporte de dados em redes smart grid(Universidade Federal do Espírito Santo, 2015-12-11) Castor, Leonardo Ribas Martins; Silva, Jair Adriano Lima; Segatto, Marcelo Eduardo Vieira; Garcia, Anilton Salles; Souza, Flávio Rabello deThe main purpose of any company is to increase its production with reduced operating costs and in the Oil & Gas industry is not different. In this scenario industrial automation plays a key role, maximizing operational safety and production efficiency. The use of human resources in order to operating, monitoring and controlling productionś processes is intense on this field, which is, yet, a serious drawback for this kind of company. Systems communications as part of the productionś automation contribute for reducing the operative expenditure and at same time provide efficient and reliable data traffic. The Oil & Gas industry has used fibre optics and wireless communications systems as last mile network solutions. However, these networks are implemented with high costs and at long time. More recently, the technology of data transmission over power line grid, called PLC, has becomes economically and technically a more interesting solution related to others technologies. As the onshore oil wells are already covered by the medium voltage power line grid, the reduced installationś costs for a PLC data network makes the project mre attractive. Additionally, the new PLC system use modern techniques, such as, adaptative coding and modulation, multiple access protocols, QoS, etc, for ensuring robustness, better use of signal power and greater privacy of data transmitted. In contrast, its performance depends on the communication channel condition based on transmission multipath, frequency selectivity, impulsive noise, RF interference, and others. This work was developed under a real scenario of Smart Grid conception. Through a three-phase medium voltage grid, supervisory, control and video surveillance information in oil production process have been transported to the remote operation center located at SM-8, São Mateus. It was obtained upstream and downstream speeds of 60 Mbps approximately in the physical layer through a multipath PLC channel with 322 m long without repeater. In a multipath stretch of 2 km long, a 3 Mbps ethernet traffic composed by automation data and high-definition images, was transported in a real-time frame to their servers without errors.
- ItemAdaptação dos modelos de Markov para um sistema de segmentação e classificação de sinais de eletrocardiograma(Universidade Federal do Espírito Santo, 2006-04-03) Müller, Sandra Mara Torres; Andreão, Rodrigo Varejão; Bastos Filho, Teodiano Freire; Sarcinelli Filho, Mário; Resende Junior, Fernando Gil Vianna; Salles, Evandro Ottoni TeatiniIn this work three incremental adaptation methods for the hidden Markov models (HMM) are studied and implemented, which are based on the Expectation-Maximization (EM), Segmental k-Means and Maximum a Posteriori (MAP) algorithms. These methods, already used in the speech recognition field, are applied here in the electrocardiogram (ECG) segmentation problem. For that, it was used an ECG analysis system able to segment and classify cardiac diseases, like premature ventricular contraction (PVC) and ischemia. The use of these methods allow us to adjust the models to the signal fluctuations commonly met during ambulatory recording. The methods can also be implemented for other kinds of biomedical signals, like electroencephalogram (EEG).
- ItemAdequação ao requisito cintilação em sistemas de comunicação via luz visível mediante uso de sinais OFDM com envoltória constante(Universidade Federal do Espírito Santo, 2018-09-21) Neves, José Luís Costa; Segatto, Marcelo Eduardo Vieira; Silva, Jair Adriano Lima; Nunes, Reginaldo Barbosa; Pereira, Esequiel da Veiga; Pontes, Maria JoséThe scarcity of electromagnetic spectrum has been a problem in the development of new wireless applications. To solve this problem, visible light communication has emerged as a promising and complementary technology to radiofrequency due to its advantages such as green technology, unlicensed spectrum, low power consumption, high privacy protection and resistance to electromagnetic interference . Allied to this, because it is a technology that uses light emitting diodes for data transmission, also guaranteeing the lighting function, it allows its use in di erent types of environments. Orthogonal frequency division multiplexing (OFDM) in visible light communication systems has been attractive because of its ability to combat intersymbol interference and ensuring high data rates. However, OFDM signals have large amplitude uctuations, resulting in high peak-to-average power ratio (PAPR) and therefore can degrade the quality of the illumination due to Flicker light. Flickering light is harmful to vision and causes eye fatigue, seizures, headache, malaise, and other problems. The present work presents a simulation and experimental study that evaluates the performance of the OFDM transmission technique that transmits signals with constant envelope (CE-OFDM) in a communication system via visible light, by means of the adequacy of the Flickering requirements. The CE-OFDM system is based on the phase modulation of an electric carrier and reduces the PAPR parameter to 3 dB. The results obtained in the line-of-sight channel using a bandwidth of 5 MHz showed that, by adapting the icker requirements and considering the mapping levels 4, 16 and 64-QAM, the CE-OFDM system presents a upper performance than those presented by the conventional OFDM and ACO-OFDM systems. The results also showed that, in the presence of non-linearities introduced by the LED, the CE-OFDM system presents greater robustness.
- ItemAlgoritmo de calibração de magnetômetros triaxiais utilizando ajuste de quádrica por distância algébrica(Universidade Federal do Espírito Santo, 2017-08-22) Mucciaccia, Sérgio Silva; Salles, Evandro Ottoni Teatini; Frizera Neto, Anselmo; Ciarelli, Patrick Marques; Nogueira, Samuel LourençoThe measurements obtained from magnetometers are sensitive to disturbances and errors, requiring a calibration method that can considerably improve accuracy. The ellipsoid fitting is one of the most widely used methods for magnetometer calibration, but most algorithms use iterative methods, causing runtime and convergence problems. As an alternative, a direct algorithm based on the method of least squares using the algebraic distance metric is proposed. This present work presents an algorithm of calibration of magnetometers and its use in a system of calibration and fusion of data of magnetometers, accelerometers and gyroscopes based on a Kalman filter forming an inertial sensor able to obtain its orientation in the space. Computational simulations and tests with real data show that the calibration algorithm eliminates almost all the linear errors while performing much faster than traditional algorithms. Measurements of a magnetometer calibrated with the proposed algorithm are used in conjunction with measurements from accelerometers and gyroscopes to form an inertial measurement unit (IMU) using a simple Kalman filter. The complete system worked as expected and the test results indicate that the magnetometer calibration algorithm is suitable for use in an IMU being more than ten times faster than traditional algorithms and presenting similar accuracy
- ItemAlgoritmos Evolutivos Aplicados em Projetos de Redes Ópticas Passivas(Universidade Federal do Espírito Santo, 2019-08-23) Silva, David Moscon Inacio; Rocha, Helder Roberto de Oliveira; https://orcid.org/000000016215664X; http://lattes.cnpq.br/8801325729735529; https://orcid.org/; http://lattes.cnpq.br/; Moraes, Renato Elias Nunes de; https://orcid.org/; http://lattes.cnpq.br/; Nunes, Reginaldo Barbosa; https://orcid.org/; http://lattes.cnpq.br/tba
- ItemAlocação de Recursos de uma Rede Óptica Passiva BS-OFDMA-PON usando Otimização Multiobjetivo(Universidade Federal do Espírito Santo, 2020-12-18) Flores, Jardel Terci; Rocha, Helder Roberto de Oliveira; https://orcid.org/000000016215664X; http://lattes.cnpq.br/8801325729735529; https://orcid.org/; http://lattes.cnpq.br/; Coura, Daniel Jose Custodio; https://orcid.org/0000000221347981; http://lattes.cnpq.br/5570995348839001; Nunes, Reginaldo Barbosa; https://orcid.org/; http://lattes.cnpq.br/With the growing demand for Internet traffic by users and the increased need for transmission rate by applications, it is necessary to use bandwidth efficiently and economically in optical networks, which plays an important role in improving service deliv
- ItemAlocação de Recursos em Redes de Sensores IoT Híbrida ZigBee e LoRa(Universidade Federal do Espírito Santo, 2020-12-21) Santos, Willian Garcia Viega dos; Segatto, Marcelo Eduardo Vieira; https://orcid.org/000000034083992X; http://lattes.cnpq.br/2379169013108798; https://orcid.org/; http://lattes.cnpq.br/; Munaro, Celso Jose; https://orcid.org/0000000222977395; http://lattes.cnpq.br/5929530967371970; Lima, Fabio de Oliveira; https://orcid.org/; http://lattes.cnpq.br/With the growth in the number of devices on IoT networks, the requirements for communication reliability and efficient use of energy are increasing. In this work, a hybrid network topology for IoT sensors is proposed, using the mesh and star topologies. T
- ItemAlocação de Recursos em um fronthaul Óptico com functional split Recomendado para o 5G(Universidade Federal do Espírito Santo, 2020-06-30) Amaral, Murilo Porto; Silva, Jair Adriano Lima; https://orcid.org/000000032567184X; http://lattes.cnpq.br/3099010533644898; https://orcid.org/; http://lattes.cnpq.br/; Garcia, Anilton Salles; https://orcid.org/; http://lattes.cnpq.br/1029501009628001; Dalarmelina, Carlos Alberto; https://orcid.org/; http://lattes.cnpq.br/It is presented in this dissertation the application of functional split technic applied in an access network section model, tested on a dynamic optical fronthaul simulator developed fot the 5G technology. The adjustment made by selecting a level of the f
- ItemAlocação e Dimensionamento de Geração Distribuída e Coordenação Otimizada de Religador-Fusível baseados em Algoritmos Genéticos(Universidade Federal do Espírito Santo, 2020-09-18) Ferraz, Renato Santos Freire; Medina, Augusto Cesar Rueda; https://orcid.org/0000000242913153; http://lattes.cnpq.br/7397584412509839; https://orcid.org/; http://lattes.cnpq.br/; Trujillo, Joel David Melo; https://orcid.org/; http://lattes.cnpq.br/; Fardin, Jussara Farias; https://orcid.org/000000034785556X; http://lattes.cnpq.br/1912113095988528Nowadays, it is possible to notice a growth in the integration of Distributed Energy Resource (DER) in the distribution systems. Despite the many benefits caused by this integration, there are some changes in the load and short-circuit current, which may
- ItemAlocação Ótima de Geração Distribuída e de Sistemas de Baterias em um Sistema de Distribuição para Redução das Perdas e Controle de Tensão nas Barras(Universidade Federal do Espírito Santo, 2021-04-16) Menezes, Luiza Saleme de; Encarnacao, Lucas Frizera; https://orcid.org/0000000261627697; http://lattes.cnpq.br/5578918284508758; https://orcid.org/; http://lattes.cnpq.br/; Rocha, Helder Roberto de Oliveira; https://orcid.org/000000016215664X; http://lattes.cnpq.br/8801325729735529; Donadel, Clainer Bravin; https://orcid.org/; http://lattes.cnpq.br/; Medina, Augusto Cesar Rueda; https://orcid.org/0000000242913153; http://lattes.cnpq.br/7397584412509839A proposal of a method to determine the optimal allocation of Battery Banks and photovolvaic painels in a Distribution System. The methodology makes use of the photovoltaic generation profile in the summer season and is based on the load curve of low volt
- ItemAlocação ótima de geração distribuída em sistemas de distribuição considerando incertezas no modelo probabilístico de geração(Universidade Federal do Espírito Santo, 2018-06-08) Pereira, Luan Diego de Lima; Rocha, Helder Roberto de Oliveira; Fardin, Jussara Farias; Donadel, Clainer Bravin; Medina, Augusto César RuedaThis dissertation proposes a methodology to determine a probabilistic model of distributed generation of electrical energy from wind generators and photovoltaic panels and to determine the optimal location of these generators in a distribution network of electric energy, based on technical and economic parameters. The methodology correlates the historical wind speed and solar irradiance data of a particular study region and applies the Monte Carlo simulation to model the power of wind and solar generation, preserving its stochastic nature. The optimization of the location of the distributed generation units aims to minimize the annual losses of active power and the installation costs of the generators connected to the network. The optimization problem also provides for the allocation of capacitor banks in conjunction with the distributed generators, in order to manage the reactive power of the network and, consequently, to improve the voltage profile and minimize the electrical losses. The optimization algorithm used was the Genetic Algorithm, which receives as input the annual data of active power of the wind generators, solar and the demand of the load and search for better solutions to the problem. In order to validate the effectiveness of the proposed model, tests were performed on two real radial feeders, resulting in annual losses of active power, voltage profiles and total investment cost.
- ItemAlocação resiliente de Equipamentos BPL para comunicação em redes elétricas de média tensão(Universidade Federal do Espírito Santo, 2017-04-20) Oliveira, Alinne Pereira de; Silva, Jair Adriano Lima; Rocha, Helder Roberto de Oliveira; Salles, Jose Leandro Félix; Nunes, Reginaldo BarbosaPower line communications (PLC) appears as a good alternative for data communication due to the already installed and pervasive power distribution infrastructure. It is based on this features that, a methodology for resilient allocation of PLC equipments for data communication in medium voltage (MV) networks is proposed in this work. However, because electrical networks were not customized for data transmission purposes, destructive interference exists in the medium to degrades high data rate communications. In the frequencies above 1 MHz, the PLC medium is characterized as a multipath channel caused by the derivations and impedance mismatches that exists along the main transmission segment. Normally called interfering branches, the ramification lengths around 10 % of the main segment have a destructive influence on the PLC signal. Therefore, a methodology to strategically allocate the lowest quantity of PLC equipments in the MV considering the presence or absence of interfering branches is proposed. Moreover, due to changes in the topology of the electrical MV access network during its operation and/or mantainence, the proposed method should allocate repeaters to fit all the topological scenarios in order to prevent interruptions in the data communications. Another problem contemplated is the loss of any repeater without the powerline communications being impaired or even interrupted. The methodology proposed in this work uses metaheuristics based on a Genetic Algorithm and on a new Binary Particle Swarm optimization (NBPSO) to generate good solutions to the particular allocation problem addressed in this work. The same amount of PLC equipments installed in a real network was achieved after the application of the proposed methodology. Using the proposed Genetic Algorithm, the method also successfully designated 14 PLC repeaters for the MV located in Rio Preto do Oeste in S˜ao Mateus-ES, which should be addressed with technology in the near future.
- ItemAmplificadores Raman em fibras microestruturadas(Universidade Federal do Espírito Santo, 2009-09-11) Castellani, Carlos Eduardo Schmidt; Cani, Shirley Peroni Neves; Pontes, Maria José; Romero, Murilo Araújo; Segatto, Marcelo Eduardo VieiraThe development of microstructured fibers, also known as photonic crystal fibers (PCF), which has happened principally during the last decade, has raised new possibilities on the field of optics and telecommunications due to its capability of presenting some constructive parameters with non conventional values. In the context of optical communications, more precisely on the construction of optical amplifiers, these photonic crystal fibers also have brought some new interesting possibilities. Due to its capability of at the same time presents very high negative dispersion and high non linearity, it allows for example, the construction of Raman amplifiers with high gains that also compensate dispersion with reduced fiber lengths. The conventional silica-based fibers need tens of kilometers of fiber length to accomplish the same task. Taking advantage of that situation, the main purpose of this dissertation is exactly the project and the study of multi-pump Raman amplifiers operating as discrete devices providing gain and compensating dispersion over the entire C band, using a PCF. In order to project such amplifiers, an optimization technique made through an exhaustive search based on an analytical solution method for the signal propagation is proposed. The analysis of these amplifiers is made via computational simulations that are done with numerical and also analytical models, by means of the verification of the gain, ripple, optical signal to noise ratio (OSNR), and eye penalty parameters. Their performance is also evaluated by comparing the performance of a Raman amplifier operating with a conventional dispersion compensating fiber (DCF).
- ItemAnálise arquitetural, ontológica e proposta de modelo de referência para a recomendação ITU-T G.805(Universidade Federal do Espírito Santo, 2011-04-07) Barcelos, Pedro Paulo Favato; Monteiro, Maxwell Eduardo; Garcia, Anilton Salles; Rezende, Luiziana Silveira de; Soares, Rosane BodartThe ITU-T Recommendation G.805 (ITU-T, 2000) is an important recommendation for transport networks. It describes a generic functional architecture that is independent of technology for this domain and it is used as the basis for recommendations that describe the functional architecture of networks, management, performance analysis and functional specification of equipment. Despite providing a flexible tool for the architecture description, the recommendation presents its concepts textually, leading to confusion because of recursive definitions and unclear examples that are often contradictory. These aspects of the recommendation make it difficult to understand and may confuse the reader. It is important that, due to its fundamental importance, this recommendation is free from these problems. For this purpose, this work proposes the use of ontology-based conceptual modeling techniques for the generation of a reference model for the transport network domain, based on the ITU-T Recommendation G.805. In addition to the recommendation main concepts, the advantages of creating an ontology-based reference model and the main technologies used for this purpose are also presented. An architectural analysis and a restructuring of the components defined by the recommendation are performed together with an ontological evaluation of it. Cases of incompleteness, ambiguities and other deficiencies are checked and solutions are pointed. Finally, the ontology-based reference model developed for the ITU-T Recommendation G.805 is presented, including the conceptual model and its derivation and restrictions rules.
- ItemAnalise comparativa de algumas estruturas de filtros digitais de segunda ordem imunes a ciclos limite(Universidade Federal do Espírito Santo, 1994-08-19) Simmer, Ana Cristina Staut; Orientador1; Sarcinelli Filho, MárioThis work is a comparative study of the relative output roundoff noise variance performance for some second-order state-space structures, as a function of the filter bandwidth. The addressed second-order structures are used as building blocks for realizing lowpass, highpass, bandpass and bandreject digital filters. In this sense, this study complements a recent one, which just investigated the lowpass filter case. In both studies only narrow-band digital filters are discussed, regarding the well known good performance of the state-space structures in those cases. In order to compare the output roundoff noise performance for all spectra, new firstorder spectral transformations, derived from the well known transformations due to Constantinides, are developed, for varying the filter bandwidth of a parallel-form prototype filter. All this effort is justified by the importance of knowing the performance of the structures which are suitable for a desired application, what represents a significative contribution to the problem of designing digital filters.
- ItemAnálise comparativa entre filtros híbridos aplicados a cicloconversores em uma siderúrgica(Universidade Federal do Espírito Santo, 2009-07-20) Antunes, Hélio Marcos André; Sousa, Gilberto Costa Drumond; Simonetti, Domingos Sávio Lyrio; Aragão Filho, Wilson; Canesin, Carlos AlbertoIn steel industry that uses the process of hot strip mill, cycloconverter-fed synchronous motors of megawatts nominal power are usually employed. The cycloconverters absorb a distorted current from the electric main, causing voltage distortion in its point of common coupling (PCC) and many problems with respects the electric power quality. A standard solution used for the harmonic mitigation in this application is obtained through the use of composite passive filter. However this is a solution that can cause harmonic resonance, increasing the harmonic distortion in the electrical system and causing overload in the filtering system. In this work a case in a huge steel industry, located at Grande Vitória is presented. Through measurements in the substation of the hot strip mill, the main currents and voltages waveforms are presented, along with the harmonic spectrum, that confirm the existence of harmonic resonance phenomenon. As an expansion of 30% is foreseen in the load of the rolling mill, it becomes necessary a study of the influence in the associated electrical system. This is due to the harmonic amplification phenomenon, that can increase the distortion levels affecting the passive filtering system behavior. A previously developed model of the system under study was used, which allows the representation of the real system with great correlation degree. Using the model, a comparative simulation analysis is done, by simulation, between two topologies of hybrid filters, the series and parallel, with the objective of harmonic filtering and resonance damping. The obtained results show that the series hybrid filter is the topology that allows better damping of harmonic resonance, and improving the characteristics of harmonic compensation in the passive filtering system, with an active filter of low nominal power, when compared to a parallel hybrid filter. However, this structure doesn't have good filtering characteristics in high frequency, function that the parallel hybrid filter can perform, however with an active filter of higher nominal power. Finally, it is shown that a series hybrid filter, consisting in an active filter and a capacitor bank applied in the electrical system of the rolling mill, can provide the same results of harmonic compensation and resonance damping, with an active filter of smaller nominal power, when compared to the traditional hybrid structure, formed by the series association of active and passive filters.
- ItemAnálise comparativa teórica e experimental das estratégias de controle preditivo baseado em modelo do tipo FCS aplicadas a conversores estáticos(Universidade Federal do Espírito Santo, 2023-07-21) Comarella, Breno Ventorim; Encarnação, Lucas Frizera; https://orcid.org/0000000261627697; http://lattes.cnpq.br/5578918284508758; https://orcid.org/; http://lattes.cnpq.br/4805036353940163; Santos, Walbermark Marques dos; https://orcid.org/0000000298716028; http://lattes.cnpq.br/5558697161842579; Camargo, Renner Sartório; https://orcid.org/0000-0002-6604-7544; http://lattes.cnpq.br/3539297708118726; Carletti, Daniel; https://orcid.org/0000-0002-7903-200X; http://lattes.cnpq.br/5761813816367972; Amorim, Thiago SilvaWith the increasing use of power converters for various modern purposes, for example distributed generation and electrification of vehicles, the importance of studying power converters becomes increasingly relevant. One of the topics of great importance, and which has been the subject of a great deal of research, is the control of such converters, which has evolved over the years from the traditional Proportional Integral (PI) analogue control to modern strategies such as Model Predictive Control (MPC). This work proposes a theoretical and experimental (from the point of view of deployment the control in a physical controller) comparative study of some of the main MPC strategies. Within the MPC control, the subdivision that operates with a Finite Control Set (FCS) is considered a better option for the control of power converters and is the target of this study that will compare three of the main FCS control strategies. The first, called Optimal Switching Vector (OSV-MPC), is the simplest and most intuitive to implement, but it produces a variable switching frequency at the output. The second, Modulated Model Predictive Control (M2PC), and the third, Optimal Switching Sequence (OSS-MPC), are more modern strategies that produce a fixed switching frequency while maintaining most of the advantages of OSV-MPC. The three studied strategies will be described in detail and steady-state and transient comparisons will be made to produce a benchmark of the strategies. The experimental tests will be carried out on a hardware-in-the-loop (HIL) platform through the implementation of the control strategies in the Digital Signal Processor (DSP) F28379D from Texas Instruments with the real time simulator Typhoon HIL402 emulating a three-phase two-level voltage source inverter (VSI) connected to the grid through an inductive filter.
- ItemAnálise da aplicação de conexão em paralelo de capacitores em circuitos secundários de baixa tensão(Universidade Federal do Espírito Santo, 2005-05-13) Sarcinelli, Carlos Alberto; Sousa, Gilberto Costa Drumond; Simonetti, Domingos Sávio Lyrio; Aragão Filho, Wilson Correia Pinto de; Pomílio, José AntenorThe objective of this work is to analyze the behavior of a radial low voltage secondary distribution network subject to linear and non-linear loads, with and without magnitude voltage control by the automatic insertion of capacitor banks. The analysis is performed by considering the variations in the secondary distribution network elements. These elements are the loads connected to each pole of the network (power varying from no-load to full load, and displacement factor varying from 0.7 to 1.0), the changes in the ratings of the supply transformers (apparent power in kVA, primary and secondary impedances, and primary and secondary voltages), the number of poles and the distance among them. The harmonic behavior of the rms voltage of the distribution network is also analyzed, with and without the insertion of a capacitor bank at the last pole, since the distribution network might amplify harmonics as a result of resonances in the system, which have influence on the control of the voltage magnitude. Finally, a steady-state frequency domain analysis is performed by using a computer program (MATLAB), whose results are confirmed through time domain simulations performed using SIMULINK. The results concerning the time and frequency analyses are presented as a set of plots, from which some conclusions are highlighted, for a case study consisting in a network having five poles and a 13,800/220 V, 75kVA transformer.
- ItemAnálise da Contribuição do Uso do Gerador Síncrono virtual Como Técnica de Controle em Sistemas elétricos de Potência(Universidade Federal do Espírito Santo, 2017-12-20) Broedel, Dayane Corneau; Encarnação, Lucas Frizera; Medina, Augusto César Rueda; Donadel, Clainer BravinElectric power systems have to convey electricity at synchronized frequency and voltagein order to be reliable. Voltage control systems can use different strategies to achievevoltage regulation - reactive power compensation being one of them. On the other hand,frequency control is traditionally obtained by regulation of large scale synchronous machinesoperations. However, the increasing use of alternative energy sources and the operation ofthese generators in parallel with the traditional power systems emphasize the importanceof studying the integration of these generation units. An aspect to be analyzed is theimpact in the reduction of the system total inertia, that might increase frequency andvoltage variations, affecting the power system stability when facing different types ofdisturbance. In this context, this work is dedicated to discuss the use of the concept ofadditional virtual inertia, where each generation unit behaves as a virtual synchronousgenerator, in comparison with the traditional PQ technique for power control of interfaceinverters. Simulation results show the virtual generator contribution to the stability of aknown system, the IEEE-14 Bus.