Σκοπός της παρούσας διπλωματικής εργασίας είναι σε πρώτη φάση η βιβλιογραφική ανασκόπηση των μοντέλων πυλώνων, των συστημάτων γείωσης τους και των αλυσοειδών μονωτήρων ανάρτησής τους. Εν συνεχεία γίνεται προσομοίωση πραγματικών πυλώνων του ελληνικού συστήματος μεταφοράς και μελέτη των υπερτάσεων που εμφανίζονται σε αυτούς λόγω κεραυνικών πληγμάτων είτε απευθείας στον πυλώνα είτε σε έναν από τους αγωγούς προστασίας. Στο πρώτο κεφάλαιο παρατίθενται κάποια στοιχεία θεωρίας σχετικά με τις ατμοσφαιρικές εκκενώσεις. Περιγράφονται τα διάφορα είδη κεραυνού, οι βασικές παράμετροι και τα χαρακτηριστικά τους και δίνονται κάποια βασικά χαρακτηριστικά για την κυματομορφή του κεραυνικού ρεύματος. Στο δεύτερο κεφάλαιο παρουσιάζονται οι τρόποι μελέτης της συμπεριφοράς του πυλώνα σε πλήγμα κεραυνού και γίνεται μια ανασκόπηση των μοντέλων πυλώνων που υπάρχουν στη βιβλιογραφία. Στο τρίτο κεφάλαιο περιγράφεται το σύστημα γείωσης του πυλώνα και γίνεται αναφορά στο φαινόμενο του ιονισμού του εδάφους και περιγράφεται το μοντέλο προσομοίωσης που λαμβάνει υπόψη το φαινόμενο αυτό. Στο τέταρτο κεφάλαιο παρουσιάζονται κάποια γενικά στοιχεία για τους μονωτήρες ανάρτησης και τα μοντέλα που υπολογίζουν το χρόνο διάσπασής τους υπό κρουστική τάση. Στο πέμπτο κεφάλαιο δίδονται τα επιμέρους στοιχεία του υπολογιστικού προγράμματος που θα αποτελέσει το μέσο της εξομοίωσης, του ΕΜΤΡ. Αναφέρονται τα σημεία υπεροχής και η ευελιξία του για τέτοιου είδους αναλύσεις, ενώ παρουσιάζονται και τα επιμέρους υποπρογράμματα από τα οποία αποτελείται. Έμφαση δίνεται στο ΑΤΡ – DRAW που είναι το κυρίως όργανο της εξομοίωσης και στα προγράμματα επεξεργασίας δεδομένων για τη παρουσίαση γραφικών αποτελεσμάτων, όπως το Pcplot. Στο έκτο και τελευταίο κεφάλαιο παρουσιάζονται τα αποτελέσματα των προσομοιώσεων στο λογισμικό ΕΜΤΡ. Περιγράφονται αναλυτικά τα κυκλώματα που χρησιμοποιήθηκαν για την προσομοίωση πυλώνων μονού και διπλού κυκλώματος καθώς και τα επιμέρους στοιχεία τους και αναλύεται ο τρόπος εξομοίωσης των γραμμών μεταφοράς υψηλής τάσης. Σε πρώτη φάση εξετάζεται αν θα συμβεί επιφανειακή διάσπαση στο μονωτήρα ανάρτησης για πλήγματα κεραυνού διαφορετικού χρόνου μετώπου και ουράς και καταγράφονται οι χρόνοι και οι τάσεις διάσπασης. Από τα διαγράμματα που προέκυψαν φαίνεται καθαρά ότι οι μονωτήρες στους πυλώνες διπλού κυκλώματος διασπόνται πιο γρήγορα σε σχέση με τους μονού κυκλώματος. Το γεγονός αυτό οφείλεται στο ότι οι πυλώνες διπλού κυκλώματος εμφανίζουν γενικά μεγαλύτερη κυματική αντίσταση και συνεπώς η υπέρταση που αναπτύσσεται κατά μήκος του μονωτήρα να είναι μεγαλύτερη και έτσι να διασπόνται νωρίτερα. Στη συνέχεια εξετάζεται η επίδραση της ειδικής αντίστασης του εδάφους στο χρόνο και στην τάση διάσπασης του μονωτήρα με μοντέλα συστημάτων γείωσης που λαμβάνουν υπόψη το φαινόμενο του ιονισμού του εδάφους αλλά και με μοντέλα με σταθερή αντίσταση γείωσης. Από τα αποτελέσματα της προσομοίωσης προκύπτει ότι αύξηση της αντίστασης γείωσης του πυλώνα οδηγεί σε μικρότερους χρόνους διάσπασης του μονωτήρα και αύξηση της τάσης διάσπασης του. Τέλος, η διπλωματική εργασία ολοκληρώνεται με τα Παραρτήματα Α,Β στα οποία δίνονται τα σχέδια των πραγματικών πυλώνων του συστήματος μεταφοράς που προσομοιώθηκαν και ο κώδικας σε γλώσσα MODELS (MODELS language) που χρησιμοποιήθηκε για την προσομοίωση της διάσπασης των αλυσοειδών μονωτήρων ανάρτησης. / The purpose of this thesis is initially a review of the models for steel towers, their grounding system and suspension string insulators and then the simulation analysis of towers of the Greek transmission system and the study of overvoltages arising across them due to lightning strikes. Chapter one gives the basic theory concerning atmospheric discharges. It describes the different types of lightning strikes, its parameters and characteristics and provides the basic characteristics of the lightning current waveform. The following chapters give a review of the different models of towers, grounding system and insulators we can find in literature. In the third chapter there is a description of the soil ionization effect and a description of the grounding model that takes into consideration that effect. Chapter five describes the ATP-EMTP simulation tool which is a specific software to simulate power system transient problems. Special emphasis is given to the ATP - DRAW which is the main body of the simulation and to the data processing programs for the graphical presentation of the results, such as Pcplot. The final chapter presents the simulation results in ATP-EMTP. The simulation circuit is fully described that includes the basic components of overhead transmission lines, that is, the towers and their grounding system and flashover of the string insulators for both single and double circuit lines. The overvoltages arising across string insulators and whether there will be a flashover or not were investigated for various current waveshapes with different front and tail times. The time and voltage for flashover is recorded. From the simulation results we can see that flashover in double circuit line happens faster than flashover in single circuit lines. This is due to the fact that double circuit towers have bigger surge impedance and thus the overvoltage arising across their string insulators is bigger. Furthermore the effect of soil resistivity in time and voltage for flashover is studied for constant and current dependant tower grounding resistance. The current dependant resistance that takes into consideration the soil ionization effect was modeled using the MODELS language. From the simulation results we can see that rise in the tower resistance results in smaller flashover computed times.

Estudos sobre proteção contra os surtos chamados de transitórios rápidos, principalmente os que afetam os sistemas elétricos de potência, exigem que o comportamento dos sistemas de aterramento quando submetidos a esses eventos seja meticulosamente estimado. Isto se deve ao fato de o chamado comportamento dinâmico associado aos sistemas de aterramento, muitas vezes, produzir resultados diferentes do chamado comportamento estático. Em face disso é consenso que, para a realização de tais estudos, é necessário obter um modelo acurado seja do sistema de aterramento como um todo ou dos elementos que o compõe para conseguir uma boa representação nas simulações digitais. Durante as últimas duas décadas muitas tentativas vêem sendo feitas nessa direção. Essas tentativas são baseadas ora em modelos computacionais, os quais são resolvidos numericamente, ora sobre expressões analíticas para as distribuições de tensão e corrente sob simplificações ou condições iniciais especiais. Diversas soluções lidam com as equações de propagação, considerando os parâmetros dos componentes do sistema de aterramento dependentes da freqüência. Outro grupo de métodos baseia-se nos princípios do eletromagnetismo. Neste contexto, este trabalho propõe uma modelagem, usando um bipolo elétrico equivalente, para representar um sistema de aterramento em simulações digitais, por meio de programas baseados no SPICE - simulation program with integrated circuits emphasis. Diferente de modelos anteriores, que usaram o bipolo elétrico para simular apenas o comportamento dinâmico de determinadas partes de um sistema de aterramento, nesta modelagem utiliza-se apenas um bipolo elétrico para simular tanto o comportamento dinâmico quanto o estático. Essa modelagem foi desenvolvida ao longo de um estudo teórico-experimental realizado sobre o tema. / Fast transients protection studies, mainly with regard to electric power systems, require accurate estimation of grounding systems behavior under such phenomena. Therefore, the called dynamic behavior of grounding systems leads those studies, most of cases, to different results from the other called static behavior. For this reason, either the whole grounding system or each one of its components need to be accurately modeled to offer a good representation in digital simulations. Researchers have been made many attempts to this direction, during the last two decades. These attempts are based sometimes on computer models, which are solved numerically, sometimes on analytical expressions for voltage and current distributions under simplifications or special initial conditions. Several solutions deal with the propagation equations, considering the parameters frequency dependence of the grounding system elements. Another class of solution methods is based on the electromagnetism principles. Inserted in this context, the present work proposes a model to represent grounding systems as a whole in digital simulations carried out by computer programs based on SPICE - simulation program with integrated circuits emphasis. This task was performed by using only one experiment-based two-port electric circuit model. Unlike previous works, that explored the two-port electric circuit model to simulate only the dynamic behavior of grounding systems, this work shows the possibility to incorporate both dynamic and static behavior to the two-port electric circuit model. This procedure relies on a methodology developed from a theoretic-experimental study.

Τα κεραυνικά πλήγματα αποτελούν σημαντικό κίνδυνο ζημιάς στις ανεμογεννήτριες. Το πρόβλημα γίνεται μεγαλύτερο καθώς ο αριθμός και το ύψος τους συνεχώς αυξάνεται. Έτσι τα κεραυνικά πλήγματα στις ανεμογεννήτριες είναι μια από τις κυριότερες αιτίες βλαβών που προκαλούν απώλειες της προβλεπόμενης παραγωγής ισχύος με σοβαρές οικονομικές συνέπειες. Τα συστήματα γείωσης σχεδιάζονται με σκοπό να παρέχουν την απαραίτητη ασφάλεια τόσο σε συνθήκες κανονικής λειτουργίας όσο και σφάλματος. Όσον αφορά κεραυνικά ρεύματα ή ρεύματα βραχυκύκλωσης το σύστημα γείωσης θα πρέπει να επιτυγχάνει την απαγωγή και διάχυση των ρευμάτων αυτών μέσα στη γη, με ταχύτητα και ασφάλεια, χωρίς να δημιουργούν επικίνδυνες υπερτάσεις στον περιβάλλοντα χώρο. Η εμφάνιση των υπερτάσεων αυτών είναι ικανή να πλήξει των άνθρωπο αλλά και να προκαλέσει ανεπανόρθωτες βλάβες στον εξοπλισμό. Προκειμένου να ελεγθεί η αξιοπιστία ενός συστήματος γείωσης σε σχέση με την ασφάλεια που παρέχει σε συνθήκες σφάλματος είναι απαραίτητη η μελέτη της μεταβατικής συμπεριφοράς του. Έτσι μπορούμε να προβλέψουμε την απόδοση τους σε περιπτώσεις κρουστικών ρευμάτων κεραυνού. Η παρούσα εργασία αναφέρεται στη μελέτη της μεταβατικής συμπεριφοράς συστημάτων γείωσης ανεμογεννήτριας μέσω της εξομοίωσης τους με το λογισμικό EMTP-ATP. Οι εξομοιώσεις γίνονται βάσει του μοντέλου κυκλωματικής προσέγγισης για διάφορες τιμές ειδικών αντιστάσεων εδάφους. Σκοπός είναι η σύγκριση των αποτελεσμάτων και η επιλογή του κατάλληλου συστήματος γείωσης. Παρακάτω γίνεται σύντομη περιγραφή των κεφαλαίων Στο Πρώτο Κεφάλαιο γίνεται αναφορά στο φαινόμενο του κεραυνού, στις παραμέτρους των ανερχόμενων και κατερχόμενων κεραυνών και τέλος στις επιπτώσεις των κεραυνικών πληγμάτων. Στο Δεύτερο Κεφάλαιο γίνεται αναφορά στο ρόλο της γείωσης, στα διάφορα είδη γειωτών καθώς και στις μεθόδους υπολογισμού των παραμέτρων τους. Στο Τρίτο Κεφάλαιο παρουσιάζονται χαρακτηριστικά μεγέθη που αφορούν την απόκριση των συστημάτων γείωσης όπως είναι η αντίσταση γείωσης, η ειδική αντίσταση εδάφους και η κρουστική σύνθετη αντίσταση. Στο Τέταρτο Κεφάλαιο γίνεται αναφορά στα διάφορα μοντέλα συστημάτων γείωσης. Παρουσιάζονται τόσο αυτά που χρησιμοποιούνταν κατά το παρελθόν όσο και τα επικρατέστερα σύγχρονα. Στο Πέμπτο Κεφάλαιο γίνεται αρχικά επιλογή του μοντέλου προσομοίωσης. Στη συνέχεια παρατίθενται τα στοιχεία των συστημάτων γείωσης που εξετάζουμε. Κατόπιν παρουσιάζονται τα αποτελέσματα των εξομοιώσεων. Τέλος γίνεται σύγκριση των αποτελεσμάτων. Από τις συγκρίσεις προκύπτουν οι παράγοντες από τους οποίους εξαρτάται η μεταβατική συμπεριφορά των εξεταζόμενων συστημάτων γείωσης. Βάσει των αποτελεσμάτων παρατηρούμε αρχικά ότι η ειδική αντίσταση εδάφους έχει μεγάλη επίδραση στην μεταβατική απόκριση των συστημάτων γείωσης έχει. Συγκεκριμένα για μικρότερες τιμές ειδικής αντίστασης εδάφους έχουμε παράλληλη μείωση των τιμών των μέγιστων μεταβατικών υπερτάσεων στους κόμβους τους συστήματος. Επιπλέον παρατηρούμε σημαντική εξάρτηση των τιμών των τάσεων στους κόμβους των συστημάτων από την απόστασή τους από το σημείο εγχύσεως του ρεύματος. Έτσι όσο απομακρυνόμαστε από το σημείο εγχύσεως του κρουστικού ρεύματος μειώνεται το δυναμικό των κόμβων. Τέλος δεδομένων ίδιων τιμών ειδικής αντίστασης εδάφους, οι δύο διατάξεις παρουσίαζουν διαφορετικές μεταβατικές αποκρίσεις, / Lightning strokes consist one of the most important damage risks in wind turbines. The problem grows bigger as the number and height of modern wind turbines continuously increases. So lightning strikes on wind turbines are one of the most important malfunction causes which have serious inflictions on the predicted power production with severe economic consequences . Grounding systems are designed to provide the necessary safety on normal operation conditions as well as on fault conditions. The grounding system must be able to divert fault currents as well as lightning currents to the ground with speed and safety without the development of over voltages on the surrounding space. The appearance of over voltages is extremely dangerous both for people and equipment. To test the reliability of a grounding system on fault conditions, a study of its transient behavior is necessary in order to predict the performance of the grounding system in the case of an impulse lightning current. The purpose of this diploma thesis is to study the transient response of two grounding systems for wind turbines by means of simulation with the EMTP-ATP software. The equivalent circuits used for the simulation are based on the circuit theory approach for various values of soil resistivity. Finally the two grounding systems are compared regarding their transient response behavior. Bellow follows a brief description of the chapters. In Chapter One the phenomenon of lightning is presented including the parameters that define lightning as well as the effects of lightning strokes on people and equipment. Chapter Two focuses on the role of grounding in electrical installations, the various types of grounding electrodes and the calculation methods of their parameters. Chapter Three presents the effect of figures such as the grounding resistance, soil resistivity and impulse resistance on the response of grounding systems. Chapter Four refers to the various modeling approaches for grounding systems. Modeling approaches such as the circuit theory approach, the electromagnetic field approach etc are presented an analyzed. In Chapter Five the model for the simulation is selected and the values for the grounding system parameters are presented, followed by the results of the simulations. In conclusion the results of the simulations are compared. From comparing the results of the simulations we observe that the soil resistivity has a great effect on the transient response of the simulated grounding systems. Moreover for low values of soil resistivity there is a parallel decrease of the peak voltage values on the system nodes. Furthermore we observe a considerate dependence of the voltage values to the distance to the injection point of the lightning current. So as we move away from the injection point of the impulse current the node potential decreases. Finally, given the same values of soil resistivity, the two grounding systems have different transient responses.

Estudos sobre proteção contra os surtos chamados de transitórios rápidos, principalmente os que afetam os sistemas elétricos de potência, exigem que o comportamento dos sistemas de aterramento quando submetidos a esses eventos seja meticulosamente estimado. Isto se deve ao fato de o chamado comportamento dinâmico associado aos sistemas de aterramento, muitas vezes, produzir resultados diferentes do chamado comportamento estático. Em face disso é consenso que, para a realização de tais estudos, é necessário obter um modelo acurado seja do sistema de aterramento como um todo ou dos elementos que o compõe para conseguir uma boa representação nas simulações digitais. Durante as últimas duas décadas muitas tentativas vêem sendo feitas nessa direção. Essas tentativas são baseadas ora em modelos computacionais, os quais são resolvidos numericamente, ora sobre expressões analíticas para as distribuições de tensão e corrente sob simplificações ou condições iniciais especiais. Diversas soluções lidam com as equações de propagação, considerando os parâmetros dos componentes do sistema de aterramento dependentes da freqüência. Outro grupo de métodos baseia-se nos princípios do eletromagnetismo. Neste contexto, este trabalho propõe uma modelagem, usando um bipolo elétrico equivalente, para representar um sistema de aterramento em simulações digitais, por meio de programas baseados no SPICE - simulation program with integrated circuits emphasis. Diferente de modelos anteriores, que usaram o bipolo elétrico para simular apenas o comportamento dinâmico de determinadas partes de um sistema de aterramento, nesta modelagem utiliza-se apenas um bipolo elétrico para simular tanto o comportamento dinâmico quanto o estático. Essa modelagem foi desenvolvida ao longo de um estudo teórico-experimental realizado sobre o tema. / Fast transients protection studies, mainly with regard to electric power systems, require accurate estimation of grounding systems behavior under such phenomena. Therefore, the called dynamic behavior of grounding systems leads those studies, most of cases, to different results from the other called static behavior. For this reason, either the whole grounding system or each one of its components need to be accurately modeled to offer a good representation in digital simulations. Researchers have been made many attempts to this direction, during the last two decades. These attempts are based sometimes on computer models, which are solved numerically, sometimes on analytical expressions for voltage and current distributions under simplifications or special initial conditions. Several solutions deal with the propagation equations, considering the parameters frequency dependence of the grounding system elements. Another class of solution methods is based on the electromagnetism principles. Inserted in this context, the present work proposes a model to represent grounding systems as a whole in digital simulations carried out by computer programs based on SPICE - simulation program with integrated circuits emphasis. This task was performed by using only one experiment-based two-port electric circuit model. Unlike previous works, that explored the two-port electric circuit model to simulate only the dynamic behavior of grounding systems, this work shows the possibility to incorporate both dynamic and static behavior to the two-port electric circuit model. This procedure relies on a methodology developed from a theoretic-experimental study.

Este trabalho tem como objetivo fornecer contribuições ao estudo de sistemas de aterramento submetidos a correntes elétricas no regime permanente senoidal pelo Método dos Elementos Finitos. Nele se discutem as motivações para a utilização deste procedimento numérico em problemas desta categoria, e mais especificamente para o uso da variante deste método com elementos finitos de aresta. O tratamento completo necessário à construção das funções de forma para a aproximação local de grandezas vetoriais com elementos hexaédricos é nele desenvolvido e detalhado. Com estes resultados, uma aplicação computacional capaz de modelar o comportamento de uma haste de aterramento verticalmente enterrada no solo foi desenvolvida, utilizando-se para a discretização do domínio elementos finitos hexaédricos tri-lineares e quadráticos incompletos. Esta aplicação computacional foi utilizada para o estudo da resposta em freqüência da impedância equivalente a aterramentos desta categoria em diferentes condições de solo e com as duas variedades de elemento hexaédrico anteriormente mencionados. Os resultados obtidos são então discutidos, bem como a validade da modelagem adotada para o problema físico aqui considerado. / This work aims to provide contributions to the study of grounding systems subjected to electric currents at the sinusoidal steady state by the Finite Element Method. Motivations for the use of this numerical procedure in problems of this category, and more specifically for the usage of the Edge Finite Element Method variant, are discussed in it. The complete treatment required for building the shape functions for the local approximation of vector physical quantities with hexahedral finite elements is here developed and detailed. With these results a computer application capable of modeling the behavior of vertically buried grounding rods was developed, in which domain discretization is accomplished by the usage of both tri-linear and incomplete quadratic hexahedral finite elements. This computer application was employed in the study of the frequency response of the impedance equivalent to grounding systems of this class at different soil conditions and with both hexahedral element varieties previously mentioned. The results obtained are then discussed, as well as the validity of the modeling adopted for this physical problem.

Este trabalho tem como objetivo fornecer contribuições ao estudo de sistemas de aterramento submetidos a correntes elétricas no regime permanente senoidal pelo Método dos Elementos Finitos. Nele se discutem as motivações para a utilização deste procedimento numérico em problemas desta categoria, e mais especificamente para o uso da variante deste método com elementos finitos de aresta. O tratamento completo necessário à construção das funções de forma para a aproximação local de grandezas vetoriais com elementos hexaédricos é nele desenvolvido e detalhado. Com estes resultados, uma aplicação computacional capaz de modelar o comportamento de uma haste de aterramento verticalmente enterrada no solo foi desenvolvida, utilizando-se para a discretização do domínio elementos finitos hexaédricos tri-lineares e quadráticos incompletos. Esta aplicação computacional foi utilizada para o estudo da resposta em freqüência da impedância equivalente a aterramentos desta categoria em diferentes condições de solo e com as duas variedades de elemento hexaédrico anteriormente mencionados. Os resultados obtidos são então discutidos, bem como a validade da modelagem adotada para o problema físico aqui considerado. / This work aims to provide contributions to the study of grounding systems subjected to electric currents at the sinusoidal steady state by the Finite Element Method. Motivations for the use of this numerical procedure in problems of this category, and more specifically for the usage of the Edge Finite Element Method variant, are discussed in it. The complete treatment required for building the shape functions for the local approximation of vector physical quantities with hexahedral finite elements is here developed and detailed. With these results a computer application capable of modeling the behavior of vertically buried grounding rods was developed, in which domain discretization is accomplished by the usage of both tri-linear and incomplete quadratic hexahedral finite elements. This computer application was employed in the study of the frequency response of the impedance equivalent to grounding systems of this class at different soil conditions and with both hexahedral element varieties previously mentioned. The results obtained are then discussed, as well as the validity of the modeling adopted for this physical problem.

Orientador: Jose Pissolato Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-06T10:45:47Z (GMT). No. of bitstreams: 1 MarinMesa_HenryRamon_M.pdf: 775188 bytes, checksum: d44b6096c03070dff5fb491bb2b0d7dd (MD5) Previous issue date: 2005 / Resumo: Este trabalho apresenta uma análise computacional usando a técnica numérica TLM (Transmission Line Method) do comportamento das tensões transitórias em sistemas de aterramento, quando submetidas a fenômenos impulsivos do tipo descargas atmosféricas. É apresentada uma revisão bibliográfica sobre o tema e os diferentes métodos numéricos usados para modelar sistemas de aterramento. A técnica numérica TLM é apresentada, assim como, as equações para a determinação dos parâmetros usados nas simulações e o fluxograma do programa computacional desenvolvido. O programa foi escrito em Fortran e validado comparando os resultados obtidos com simulações e testes experimentais publicados por outros autores. Com o objetivo de obter o comportamento das tensões transitórias sobre diferentes situações, foi estudada a influência de alguns parâmetros no comportamento transitório das malhas de aterramento / Abstract: This work, by using the TLM (Transmission Line Method) numeric technique, presents a computational analysis of the transitory tensions behavior in grounding systems, when submitted to impulsive phenomena of the atmospheric discharge type. A bibliographical revision on the theme and the different numeric methods used for modelling grounding systems, including the TLM numeric technique, are explained, as well as the equations for the determination of the parameters used in the simulations and the flowchart of the software developed. The program written in Fortran was validated comparing simulations and experimental tests published by other authors. For the purpose of obtaining the transitory tensions behavior in different situations, we studied the influence of some parameters in the transitory behavior of grounding meshes / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

Este trabalho fundamenta-se no desenvolvimento e aprimoramento de metodologias para a melhor representação do aterramento elétrico sob uma análise transiente. O estudo concentrase no estabelecimento de contribuições ao estado da arte associadas à análise e modelagem de aterramento impulsivo e em altas frequências. O estudo vincula-se também à avaliação da suportabilidade de seres humanos submetidos a potenciais produzidos na superfície do solo, provenientes da corrente elétrica gerada por um surto atmosférico. A concepção das metodologias propostas baseou-se no uso do Método da Modelagem por Linhas de Transmissão em uma dimensão (TLM-1D). Destacam-se três grandes tópicos da pesquisa. O primeiro concentra-se no desenvolvimento de formulação para a inclusão do fenômeno de ionização do solo ao Método TLM-1D clássico. A formulação desenvolvida tem como característica ser uma técnica generalista, independente das propriedades do meio, dimensões do eletrodo e do surto atmosférico. O segundo foco concentra-se no aprimoramento e desenvolvimento de equacionamento analítico para a estimação de potenciais gerados na superfície do solo, originados pela corrente elétrica estabelecida sobre eletrodo de aterramento. Tal equacionamento tem grande aplicabilidade em conjunto com metodologias numéricas unidimensionais, as quais não são capazes de determinar diretamente os referidos potenciais. Por fim, a realização de estudo de suportabilidade e segurança de seres humanos em contato com eletrodos de aterramento submetidos a surto atmosférico, considerando modelo representativo baseado em circuitos elétricos, consolida o trabalho desenvolvido. / This work is based on the development and improvement of methodologies for the best representation of the electrical grounding under a transient analysis. The study concentrated on establishing contributions to the state of the art related to the analysis and modeling of impulsive and high frequencies grounding systems. The study is also associated to the evaluation of the supportability of human beings submitted to the potentials produced on the soil surface from the electric current generated by a lightning. The conception of the proposed methodology was based on the Transmission Line Modeling Method in one dimension (TLM- 1D). Three major research topics can be highlighted. The first involves the development of a formulation to include the soil ionization phenomenon in the classic TLM-1D algorithm. The developed formulation is a generalist technique, independent of the medium properties, characteristic of the electrode and lightning surge. The second aims at the improvement and development of analytical equations for estimating the generated potential on the soil surface, originated by the electric current calculated in the grounding electrode. Such equationing has great applicability in conjunction with one-dimensional numerical methods which are not able to determine such potential directly. Finally, the achievement of a supportability study and personal safety of humans in contact with the grounding electrodes subjected to a lightning, considering a representative model based on electrical circuits, consolidates the developed work.

Este trabalho fundamenta-se no desenvolvimento e aprimoramento de metodologias para a melhor representação do aterramento elétrico sob uma análise transiente. O estudo concentrase no estabelecimento de contribuições ao estado da arte associadas à análise e modelagem de aterramento impulsivo e em altas frequências. O estudo vincula-se também à avaliação da suportabilidade de seres humanos submetidos a potenciais produzidos na superfície do solo, provenientes da corrente elétrica gerada por um surto atmosférico. A concepção das metodologias propostas baseou-se no uso do Método da Modelagem por Linhas de Transmissão em uma dimensão (TLM-1D). Destacam-se três grandes tópicos da pesquisa. O primeiro concentra-se no desenvolvimento de formulação para a inclusão do fenômeno de ionização do solo ao Método TLM-1D clássico. A formulação desenvolvida tem como característica ser uma técnica generalista, independente das propriedades do meio, dimensões do eletrodo e do surto atmosférico. O segundo foco concentra-se no aprimoramento e desenvolvimento de equacionamento analítico para a estimação de potenciais gerados na superfície do solo, originados pela corrente elétrica estabelecida sobre eletrodo de aterramento. Tal equacionamento tem grande aplicabilidade em conjunto com metodologias numéricas unidimensionais, as quais não são capazes de determinar diretamente os referidos potenciais. Por fim, a realização de estudo de suportabilidade e segurança de seres humanos em contato com eletrodos de aterramento submetidos a surto atmosférico, considerando modelo representativo baseado em circuitos elétricos, consolida o trabalho desenvolvido. / This work is based on the development and improvement of methodologies for the best representation of the electrical grounding under a transient analysis. The study concentrated on establishing contributions to the state of the art related to the analysis and modeling of impulsive and high frequencies grounding systems. The study is also associated to the evaluation of the supportability of human beings submitted to the potentials produced on the soil surface from the electric current generated by a lightning. The conception of the proposed methodology was based on the Transmission Line Modeling Method in one dimension (TLM- 1D). Three major research topics can be highlighted. The first involves the development of a formulation to include the soil ionization phenomenon in the classic TLM-1D algorithm. The developed formulation is a generalist technique, independent of the medium properties, characteristic of the electrode and lightning surge. The second aims at the improvement and development of analytical equations for estimating the generated potential on the soil surface, originated by the electric current calculated in the grounding electrode. Such equationing has great applicability in conjunction with one-dimensional numerical methods which are not able to determine such potential directly. Finally, the achievement of a supportability study and personal safety of humans in contact with the grounding electrodes subjected to a lightning, considering a representative model based on electrical circuits, consolidates the developed work.

Este trabalho fundamenta-se no desenvolvimento e aprimoramento de metodologias para a melhor representação do aterramento elétrico sob uma análise transiente. O estudo concentrase no estabelecimento de contribuições ao estado da arte associadas à análise e modelagem de aterramento impulsivo e em altas frequências. O estudo vincula-se também à avaliação da suportabilidade de seres humanos submetidos a potenciais produzidos na superfície do solo, provenientes da corrente elétrica gerada por um surto atmosférico. A concepção das metodologias propostas baseou-se no uso do Método da Modelagem por Linhas de Transmissão em uma dimensão (TLM-1D). Destacam-se três grandes tópicos da pesquisa. O primeiro concentra-se no desenvolvimento de formulação para a inclusão do fenômeno de ionização do solo ao Método TLM-1D clássico. A formulação desenvolvida tem como característica ser uma técnica generalista, independente das propriedades do meio, dimensões do eletrodo e do surto atmosférico. O segundo foco concentra-se no aprimoramento e desenvolvimento de equacionamento analítico para a estimação de potenciais gerados na superfície do solo, originados pela corrente elétrica estabelecida sobre eletrodo de aterramento. Tal equacionamento tem grande aplicabilidade em conjunto com metodologias numéricas unidimensionais, as quais não são capazes de determinar diretamente os referidos potenciais. Por fim, a realização de estudo de suportabilidade e segurança de seres humanos em contato com eletrodos de aterramento submetidos a surto atmosférico, considerando modelo representativo baseado em circuitos elétricos, consolida o trabalho desenvolvido. / This work is based on the development and improvement of methodologies for the best representation of the electrical grounding under a transient analysis. The study concentrated on establishing contributions to the state of the art related to the analysis and modeling of impulsive and high frequencies grounding systems. The study is also associated to the evaluation of the supportability of human beings submitted to the potentials produced on the soil surface from the electric current generated by a lightning. The conception of the proposed methodology was based on the Transmission Line Modeling Method in one dimension (TLM- 1D). Three major research topics can be highlighted. The first involves the development of a formulation to include the soil ionization phenomenon in the classic TLM-1D algorithm. The developed formulation is a generalist technique, independent of the medium properties, characteristic of the electrode and lightning surge. The second aims at the improvement and development of analytical equations for estimating the generated potential on the soil surface, originated by the electric current calculated in the grounding electrode. Such equationing has great applicability in conjunction with one-dimensional numerical methods which are not able to determine such potential directly. Finally, the achievement of a supportability study and personal safety of humans in contact with the grounding electrodes subjected to a lightning, considering a representative model based on electrical circuits, consolidates the developed work.