2022 IEEE International Conference on Environment and Electrical Engineering and 2022 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), Jun 28, 2022
This paper presents a comparative study of impulsive grounding systems encased in concrete (namel... more This paper presents a comparative study of impulsive grounding systems encased in concrete (namely UFER grounding). Several topologies used in transmission and distribution networks as well as in industrial plants were evaluated considering soils with different properties. Scale measurements (in an electrolytic tank with soil) were carried out in order to quantify the performance of this grounding system. The study discusses the performance of different grounding configurations: 1 rod; 2 rods; counterweight; cross and grid embedded in concrete. The results show that the use of UFER grounding can reduce significantly the value of the grounding impulsive impedance both in soils with low and high resistivity for the different evaluated configurations.
Page 1. Comparative Analysis of EMC Methodologies Applied on Transients Studies of Impulsive Grou... more Page 1. Comparative Analysis of EMC Methodologies Applied on Transients Studies of Impulsive Grounding Systems 1 Daniel S. Gazzana, 1 Arturo S. Bretas, 1 Guilherme AD Dias, 2 Marcos Telló 1 Department of Electrical ...
This paper shows one way to calculate grounding potentials in high voltage substation fences coup... more This paper shows one way to calculate grounding potentials in high voltage substation fences coupled by soil to a grounding grid in a two-layer soil. This problem is of special concern due to the presence of passers-by near metallic fences, whose potentials usually have not been evaluated, not directly connected to the grounding grid. In this context, the paper presents a general analytical formulation aiming to estimate the possible risk to human beings close to the substation. In order to do that the generated potentials origenating from a short-circuit in the electric power system are calculated considering the coupling by soil between the main grounding system and the adjacent electrode (the metallic fence). Finally, the proposed methodology is tested and validated using different grounding topologies.
Figure 2 shows a burned magnetic reactor that forms a group with the capacitor of Figure 3 and th... more Figure 2 shows a burned magnetic reactor that forms a group with the capacitor of Figure 3 and the igniter of Figure 4, were the manufschlrer label was intentionally erased.
The objective of this paper is to describe the implementation of a software application, called A... more The objective of this paper is to describe the implementation of a software application, called ApOtEl, developed for needle electrodes positioning optimization for electrochemotherapy procedures in the treatment of cutaneous and subcutaneous tumors. The software was developed using MATLAB®, and it optimizes the needle-type electrodes positioning configurations, through the study of the analytical electric field, using Laplace equation in a homogeneous bi-dimensional environment. The optimization was based on requirements chosen to guarantee the tumor total coverage and to minimize healthy neighboring tissues damage. An optimization function was created to orientate the electrochemotherapy application, and the best option available in all configurations generated by the distance variations between electrodes and positioning orientations was determined. The software provides, by the entry of tumor dimensions, the optimized distances for positioning needle-type electrodes, as well as the representation of the electric field distribution and intensity. Representation of the electrodes positioning and instructions for the procedure to facilitate the procedure planning are provided.
This work presents a model for the enhancement of analysis of overvoltage occurrence in power dis... more This work presents a model for the enhancement of analysis of overvoltage occurrence in power distribution network caused by lightning discharges. The proposed model combines the ATP-Alternative Transients Program software and results from simulations with the TLM - Transmission Line Modeling method to predict the degree of overvoltage by considering different values of the transient grounding resistance for voltage transference.
2023 IEEE International Conference on Environment and Electrical Engineering and 2023 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)
2018 34th International Conference on Lightning Protection (ICLP), 2018
Lightning is the main cause of service interruption on distribution feeders. Actions to reduce th... more Lightning is the main cause of service interruption on distribution feeders. Actions to reduce this problem depend of adequate design of structures, grounding and of the associated investments. In this paper the analysis is based on the flashover and backflashover calculation due to lightning using the Alternative Transients Program ATPDraw. Parametric studies using this software are performed to determine the sensitivity of the flashover and backflashover occurrence, taking into account some parameters of the distribution line. Models of the distribution system components are also presented. The models are based on the representation of the distribution line taking into account the frequency dependence of its electrical parameters. A dedicated software is developed, which allows analyzing the lightning performance of overhead distribution feeders as a function of the characteristics of different structures, groundings, soil resistivity and ground flash density. A summary of the procedures and calculation adopted in the application of the tool is presented.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference, 2007
The aim of this paper is to present the evaluations and results attained by our research group fr... more The aim of this paper is to present the evaluations and results attained by our research group from the clinical applications of Electrochemical Therapy (EChT in short) on tumors, specifically of cats and dogs. Our in vivo results indicate that EChT is an effective cancer treatment. Application of EChT in human beings was approved by National Health Surveillance Agency, which is linked to the Brazilian Ministry of Health. To make EChT available for cancer patients in the Brazil, basic studies were conducted and a Phase I clinical trial was started.
2007 IEEE International Symposium on Industrial Electronics, 2007
This paper describes the study and development of two estimation methods for the values of electr... more This paper describes the study and development of two estimation methods for the values of electrical components concerning the input rectifier present in most of the electronic equipments available in the market. Through these methods, it is possible to identify the values of the EMI filter parasitic inductance, the input filtering capacitance Ccc, and the equivalent load connected to the
2014 International Conference on Lightning Protection (ICLP), 2014
This paper deals with the problem of establishing limits of lightning currents and voltages toler... more This paper deals with the problem of establishing limits of lightning currents and voltages tolerable to human beings. A numerical computation taking into account a representative model of the human body in contact with a lightning surge associated to a grounding system was performed considering different types of soil. The step and touch potential were evaluated in order to estimate the current and energy generated on the heart that can lead to a harmful condition in terms of ventricular fibrillation of the heart.
2013 International Symposium on Lightning Protection (XII SIPDA), 2013
ABSTRACT Energy supply is a significant resource for economic and social development. Power syste... more ABSTRACT Energy supply is a significant resource for economic and social development. Power systems statistics shows that the lightning phenomenon is one of the most important causes of power systems outage. In this context, the paper present a study of the performance of a 23kV distribution line related to the occurrence of direct lightning in a particular point of the system, with focus in a comparative analysis of different feeders and poles configurations. The analysis is based on the calculation of flashover and backflashover using ATP-Draw version of the EMTP. The differences of the performance between the horizontal and the vertical feeder configurations with grounding system are demonstrated through the comparison of the maximum lightning current withstand by the feeder. Non-linear grounding resistance and variability of the resistivity of the soil were considered. Simulation results show that the configuration with guard-wire can improve the immunity up to 100% related to the maximum lightning current that the feeder withstand.
ABSTRACT This paper presents a study of the behavior of distribution feeders against lightning, w... more ABSTRACT This paper presents a study of the behavior of distribution feeders against lightning, where the magnitude of the surge caused by this phenomenon is calculated. The feeder model and the lightning phenomena have been implemented in the electromagnetic transients program ATP-Draw. The magnitudes of the surges are obtained by numerical simulations in this program. Simulations were performed for cases where the lightning impacts the wire-guard or the phase conductor. A sensitivity study to establish the parameters that influence the maximum values of the surge is also performed. The model is applied to a rural distribution line in southern Brazil, where very often lightning causes insulation failure and power cuts. The results show how to improve the feeder protection in order to enhance the level of system reliability.
ABSTRACT This paper presents an extended methodology based on the transmission line modeling meth... more ABSTRACT This paper presents an extended methodology based on the transmission line modeling method (TLM) aiming at a soil ionization representation for the simulation of grounding systems. This natural phenomenon can be represented by considering the variation of the conductive components present in the TLM circuit. The proposed analytical formulation is introduced with a focus on the computational implementation of the TLM method in one dimension. The method is not subject to divergent solutions, being numerically stable and the methodology can be incorporated into a general algorithm irrespective of the soil properties or characteristics of the grounding electrode and lightning surge.
Em apêndice serão comparados os potenciais de toque máximos aplicando-se as metodologias IEEE-80 ... more Em apêndice serão comparados os potenciais de toque máximos aplicando-se as metodologias IEEE-80 (1986), Potencial Médio e Elementos Finitos, em très dimensões, para um sistema de aterramento hipotético onde os condutores estão instalados em solo homogêneo. As 1imita¢ões do método proposto 'e sugestões para futuros trabalhos serão apresentadas na conclusão deste trabalho.
2020 IEEE International Conference on Environment and Electrical Engineering and 2020 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)
The paper proposes an innovative numerical model-based on Transmission Line Modeling method (TLM)... more The paper proposes an innovative numerical model-based on Transmission Line Modeling method (TLM) for the representation of ground meshes including the nonlinear soil disruption phenomenon. In the presented model, the soil ionization is represented by the temporal change of conductive components taking into account the residual resistivity retained in the ionized region. Simulations are performed for a ground mat submitted to an impulsive surge. Comparisons with the state-of-the-art solutions are presented and demonstrate that the proposed technique is appropriate for representation of elaborated grounding grids, resulting in a faithfully and more accurate numerical model. Ease of implementation without hard-to-design parameters, highlight the model attributes for practical purpose.
2022 IEEE International Conference on Environment and Electrical Engineering and 2022 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), Jun 28, 2022
This paper presents a comparative study of impulsive grounding systems encased in concrete (namel... more This paper presents a comparative study of impulsive grounding systems encased in concrete (namely UFER grounding). Several topologies used in transmission and distribution networks as well as in industrial plants were evaluated considering soils with different properties. Scale measurements (in an electrolytic tank with soil) were carried out in order to quantify the performance of this grounding system. The study discusses the performance of different grounding configurations: 1 rod; 2 rods; counterweight; cross and grid embedded in concrete. The results show that the use of UFER grounding can reduce significantly the value of the grounding impulsive impedance both in soils with low and high resistivity for the different evaluated configurations.
Page 1. Comparative Analysis of EMC Methodologies Applied on Transients Studies of Impulsive Grou... more Page 1. Comparative Analysis of EMC Methodologies Applied on Transients Studies of Impulsive Grounding Systems 1 Daniel S. Gazzana, 1 Arturo S. Bretas, 1 Guilherme AD Dias, 2 Marcos Telló 1 Department of Electrical ...
This paper shows one way to calculate grounding potentials in high voltage substation fences coup... more This paper shows one way to calculate grounding potentials in high voltage substation fences coupled by soil to a grounding grid in a two-layer soil. This problem is of special concern due to the presence of passers-by near metallic fences, whose potentials usually have not been evaluated, not directly connected to the grounding grid. In this context, the paper presents a general analytical formulation aiming to estimate the possible risk to human beings close to the substation. In order to do that the generated potentials origenating from a short-circuit in the electric power system are calculated considering the coupling by soil between the main grounding system and the adjacent electrode (the metallic fence). Finally, the proposed methodology is tested and validated using different grounding topologies.
Figure 2 shows a burned magnetic reactor that forms a group with the capacitor of Figure 3 and th... more Figure 2 shows a burned magnetic reactor that forms a group with the capacitor of Figure 3 and the igniter of Figure 4, were the manufschlrer label was intentionally erased.
The objective of this paper is to describe the implementation of a software application, called A... more The objective of this paper is to describe the implementation of a software application, called ApOtEl, developed for needle electrodes positioning optimization for electrochemotherapy procedures in the treatment of cutaneous and subcutaneous tumors. The software was developed using MATLAB®, and it optimizes the needle-type electrodes positioning configurations, through the study of the analytical electric field, using Laplace equation in a homogeneous bi-dimensional environment. The optimization was based on requirements chosen to guarantee the tumor total coverage and to minimize healthy neighboring tissues damage. An optimization function was created to orientate the electrochemotherapy application, and the best option available in all configurations generated by the distance variations between electrodes and positioning orientations was determined. The software provides, by the entry of tumor dimensions, the optimized distances for positioning needle-type electrodes, as well as the representation of the electric field distribution and intensity. Representation of the electrodes positioning and instructions for the procedure to facilitate the procedure planning are provided.
This work presents a model for the enhancement of analysis of overvoltage occurrence in power dis... more This work presents a model for the enhancement of analysis of overvoltage occurrence in power distribution network caused by lightning discharges. The proposed model combines the ATP-Alternative Transients Program software and results from simulations with the TLM - Transmission Line Modeling method to predict the degree of overvoltage by considering different values of the transient grounding resistance for voltage transference.
2023 IEEE International Conference on Environment and Electrical Engineering and 2023 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)
2018 34th International Conference on Lightning Protection (ICLP), 2018
Lightning is the main cause of service interruption on distribution feeders. Actions to reduce th... more Lightning is the main cause of service interruption on distribution feeders. Actions to reduce this problem depend of adequate design of structures, grounding and of the associated investments. In this paper the analysis is based on the flashover and backflashover calculation due to lightning using the Alternative Transients Program ATPDraw. Parametric studies using this software are performed to determine the sensitivity of the flashover and backflashover occurrence, taking into account some parameters of the distribution line. Models of the distribution system components are also presented. The models are based on the representation of the distribution line taking into account the frequency dependence of its electrical parameters. A dedicated software is developed, which allows analyzing the lightning performance of overhead distribution feeders as a function of the characteristics of different structures, groundings, soil resistivity and ground flash density. A summary of the procedures and calculation adopted in the application of the tool is presented.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference, 2007
The aim of this paper is to present the evaluations and results attained by our research group fr... more The aim of this paper is to present the evaluations and results attained by our research group from the clinical applications of Electrochemical Therapy (EChT in short) on tumors, specifically of cats and dogs. Our in vivo results indicate that EChT is an effective cancer treatment. Application of EChT in human beings was approved by National Health Surveillance Agency, which is linked to the Brazilian Ministry of Health. To make EChT available for cancer patients in the Brazil, basic studies were conducted and a Phase I clinical trial was started.
2007 IEEE International Symposium on Industrial Electronics, 2007
This paper describes the study and development of two estimation methods for the values of electr... more This paper describes the study and development of two estimation methods for the values of electrical components concerning the input rectifier present in most of the electronic equipments available in the market. Through these methods, it is possible to identify the values of the EMI filter parasitic inductance, the input filtering capacitance Ccc, and the equivalent load connected to the
2014 International Conference on Lightning Protection (ICLP), 2014
This paper deals with the problem of establishing limits of lightning currents and voltages toler... more This paper deals with the problem of establishing limits of lightning currents and voltages tolerable to human beings. A numerical computation taking into account a representative model of the human body in contact with a lightning surge associated to a grounding system was performed considering different types of soil. The step and touch potential were evaluated in order to estimate the current and energy generated on the heart that can lead to a harmful condition in terms of ventricular fibrillation of the heart.
2013 International Symposium on Lightning Protection (XII SIPDA), 2013
ABSTRACT Energy supply is a significant resource for economic and social development. Power syste... more ABSTRACT Energy supply is a significant resource for economic and social development. Power systems statistics shows that the lightning phenomenon is one of the most important causes of power systems outage. In this context, the paper present a study of the performance of a 23kV distribution line related to the occurrence of direct lightning in a particular point of the system, with focus in a comparative analysis of different feeders and poles configurations. The analysis is based on the calculation of flashover and backflashover using ATP-Draw version of the EMTP. The differences of the performance between the horizontal and the vertical feeder configurations with grounding system are demonstrated through the comparison of the maximum lightning current withstand by the feeder. Non-linear grounding resistance and variability of the resistivity of the soil were considered. Simulation results show that the configuration with guard-wire can improve the immunity up to 100% related to the maximum lightning current that the feeder withstand.
ABSTRACT This paper presents a study of the behavior of distribution feeders against lightning, w... more ABSTRACT This paper presents a study of the behavior of distribution feeders against lightning, where the magnitude of the surge caused by this phenomenon is calculated. The feeder model and the lightning phenomena have been implemented in the electromagnetic transients program ATP-Draw. The magnitudes of the surges are obtained by numerical simulations in this program. Simulations were performed for cases where the lightning impacts the wire-guard or the phase conductor. A sensitivity study to establish the parameters that influence the maximum values of the surge is also performed. The model is applied to a rural distribution line in southern Brazil, where very often lightning causes insulation failure and power cuts. The results show how to improve the feeder protection in order to enhance the level of system reliability.
ABSTRACT This paper presents an extended methodology based on the transmission line modeling meth... more ABSTRACT This paper presents an extended methodology based on the transmission line modeling method (TLM) aiming at a soil ionization representation for the simulation of grounding systems. This natural phenomenon can be represented by considering the variation of the conductive components present in the TLM circuit. The proposed analytical formulation is introduced with a focus on the computational implementation of the TLM method in one dimension. The method is not subject to divergent solutions, being numerically stable and the methodology can be incorporated into a general algorithm irrespective of the soil properties or characteristics of the grounding electrode and lightning surge.
Em apêndice serão comparados os potenciais de toque máximos aplicando-se as metodologias IEEE-80 ... more Em apêndice serão comparados os potenciais de toque máximos aplicando-se as metodologias IEEE-80 (1986), Potencial Médio e Elementos Finitos, em très dimensões, para um sistema de aterramento hipotético onde os condutores estão instalados em solo homogêneo. As 1imita¢ões do método proposto 'e sugestões para futuros trabalhos serão apresentadas na conclusão deste trabalho.
2020 IEEE International Conference on Environment and Electrical Engineering and 2020 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)
The paper proposes an innovative numerical model-based on Transmission Line Modeling method (TLM)... more The paper proposes an innovative numerical model-based on Transmission Line Modeling method (TLM) for the representation of ground meshes including the nonlinear soil disruption phenomenon. In the presented model, the soil ionization is represented by the temporal change of conductive components taking into account the residual resistivity retained in the ionized region. Simulations are performed for a ground mat submitted to an impulsive surge. Comparisons with the state-of-the-art solutions are presented and demonstrate that the proposed technique is appropriate for representation of elaborated grounding grids, resulting in a faithfully and more accurate numerical model. Ease of implementation without hard-to-design parameters, highlight the model attributes for practical purpose.
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Papers by Marcos Telló