A novel approach for inspecting the condition of porcelain insulators based on statistical analysis of electromagnetic radiations of live insulators is demonstrated in this thesis. Physical defects such as puncture and contamination can degrade the insulators performance and result in power outages, potentiating costs to utilities. Therefore, condition assessment of line insulators has always been one of the most important aspects of maintenance programs in power networks. Realistic replicas of punctured and contaminated insulators were created in the High Voltage Lab at University of Manitoba, following the IEC standards. These defective insulators were tested under high voltage stress while the electromagnetic radiations originated from the partial discharge activities on the insulators were captured using electromagnetic sensors. During the experimental part of this thesis, a multitude of tests were conducted and resulted in measuring and recording a total of 410,000 cycles of discharge activities. The feature extraction algorithm, developed as part of this thesis, calculates the statistical features of the phase resolved interpretation of partial discharge (PD) pulses. The results of analyzing the extracted features from the radiated signature of defective insulators indicate that the scale and shape parameters of a two sided Weibull distribution function fit to the recorded measurement entail distinct information about the source of discharges that can be used to identify the source of defects. Based on the library of features extracted from the recorded electromagnetic radiations, a support vector machine (SVM) classier, developed as part of this thesis, can successfully classify the radiation signature of punctured and contaminated insulators. Therefore, the main outcome of this research was introducing a novel porcelain insulator inspection technique that can remotely differentiate the defective punctured and contaminated insulators using their electromagnetic radiation signature in a laboratory environment. By utilizing the signature of common discharge activities present in the recorded signature of all tested insulators, a gating algorithm was developed which improved the successful classification rate from 51 % to 75%. The inspection technique proposed in this research can eliminate the safety hazards involved in the live maintenance of line insulators, lower the maintenance costs, and improve the inspection efficiency considering the conventional labour intensive live maintenance assessments. / February 2016

Made available in DSpace on 2014-06-11T19:30:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-20Bitstream added on 2014-06-13T19:40:18Z : No. of bitstreams: 1 silva_rm_dr_ilha.pdf: 2780916 bytes, checksum: 6decfae89e48d3addc3e2f3c8889ff34 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho é apresentada a modelagem analítica baseada nas equações de Maxwell e a modelagem numérica baseada no Método da Simulação de Cargas (MSC) e no Método dos Elementos Finitos (MEF) empregados no cálculo do campo eletromagnético quase-estático em linhas de transmissão. O método dos elementos finitos consiste numa adaptação do método residual de Galerkin. Ele é atualmente considerado um método matemático para a solução de equações diferenciais parciais, entre as quais se inclui a Equação de Poisson, Equação de Laplace, Equação de Helmholtz, Navier-Stokes, etc. Esse é um método de aproximação de problemas contínuos em domínios fechados onde o contínuo se divide em um número finito de partes, ou elementos, cujo comportamento se especifica mediante um número finito de parâmetros associados a certos pontos característicos denominados nós. Os nós são os pontos de união de cada elemento com seus adjacentes. A solução do sistema completo segue as regras dos problemas discretos. O sistema completo se forma pela associação dos N elementos. As incógnitas do problema deixam de ser funções matemáticas e passam a ser o valor dessas funções nos n nós. O comportamento no interior de cada um dos N elementos passa a ser definido a partir do comportamento dos n nós, mediante adequadas funções de interpolação ou funções de forma. A precisão do método depende da forma do elemento da malha bidimensional, ou seja, se ele é triangular ou quadrilateral, por exemplo. Além disso, a quantidade de pontos de integração e conseqüentemente a base polinomial do elemento finito, podem ser explorados para aumentar a precisão dos resultados. A base do método dos elementos finitos são as funções de mapeamento, e suas derivadas. No método de Galerkin as funções de mapeamento são igualadas às funções de forma originando os elementos... / In this research is presented a mathematical modeling based on Maxwell's equations and numerical modeling based on Charge Simulation Method (CSM) and the Finite Element Method (FEM) for calculating the quasi-static electromagnetic field in transmission lines. The finite element method is an adaptation of Galerkin residual method. It’s currently considered a mathematical method for solving partial differential equations, among which includes the Poisson equation, Laplace equation, Helmholtz equation, Navier-Stokes, etc. This is an approximation method of continuing problems in closed domains where the continuous is divided into a finite number of parts or elements whose behavior is specified by a finite number of parameters associated with certain characteristic points called nodes. The nodes are union points of each element with its adjacent. The solution of the entire system follows the rules of the discrete problems. The complete system is formed by the association of N elements. The unknowns of the problem, mathematical functions, become the value of these functions on n nodes. The behavior within each of elements N is now defined from the behavior of n nodes, using appropriate interpolation functions or shape functions. The method precision depends on the shape of two-dimensional mesh element, i.e., if it is triangular or quadrilateral. Moreover, the number of integration points and therefore the polynomial finite element basis, can be exploited to increase the accuracy of the results. The basis of the finite element method are the mapping functions and their derivatives. In the Galerkin method the mapping functions are matched to the shape functions form the isoparametric. Finally, from above definitions, simply refer to the tables of numerical integration, showing how the elements are integrated, and use them in the rest of the numerical modeling

Diagnostiquer et identifier des défauts dans des machines électriques (moteur asynchrone monophasé à condensateur en priorité) à l'aide de mesures sur le champs électromagnétiques et acoustiques. / Diagnostic and identification of defaults providing in electrical machines (mainly single phased asynchrone motors) by stray flux measurement.

Le réseau électrique s'utilise aujourd'hui comme support de transmission des signaux Ethernet. C’est le concept des courants porteurs en ligne. Cette technique de transmission permet d’obtenir des débits supérieurs au Wifi. Cependant, la complexité des réseaux électriques et l'environnement électromagnétique domestique peuvent dégrader les performances de cette technologie. L’environnement électrique de l'habitat avec ses appareils électroménagers divers en font un milieu difficilement maitrisable. L’objectif est d’appréhender et de modéliser cet environnement et le comportement des équipements qui y sont déployés. Pour cela, ce mémoire présente plusieurs méthodes pour modéliser les lignes électriques dans l'habitat. Les modélisations existantes sont difficilement généralisables à un réseau électrique quelconque. Nous proposons une modélisation de type circuit électrique.Son intérêt réside dans la simplicité de l'outil de simulation d'un réseau électrique, réalisé parla mise en cascade de plusieurs blocs intégrés à la librairie SPICE. Les blocs SPICE proposés prennent en compte la dépendance fréquentielle des paramètres des quadripôles. Une étape de caractérisation expérimentale est développée pour implémenter ces blocs. Un réseau expérimental de test, constitué de différentes technologies de câble, a été caractérisé en termes de bruit, d'impédance et de pertes d'insertion. Le rayonnement émis lors d'une transmission CPL a également été mesuré. / The power line grid is used for data transmission by means of the broad band powerline communication systems (BPLC) The main advantage of this technology consists in providing an existing infrastructure of wires and wall sockets that are easy to access throughout a building and offering physical data rates comparable with other existing communication technologies such as Wi-Fi. Nevertheless, the power line grid complexity, the various connected household appliances and the housing electromagnetic environment,impact the PLC transmission performances. As results the housing environment is not a controllable medium. The objective of the current thesis is to study the electromagnetic environment of the Indoor power line network, and to model the potential impacts of both the power line grid topology and the household devices on the PLC physical layer. The existing modeling approaches require a deduction of theirs parameters from the measurements and cannot be generally applied. We propose a new model based on circuitry approach. Its main interest consists in the simplicity of the simulation tool of power line grid which is based on series symmetric SPICE circuit integrated to SPICE library. To this aim, the characterization of the power cable, of the electrical accessories and household devices is necessary. The impedance of powered household devices is measured according to simple measurement protocol. The proposed model takes into account the variation of the whole primary parameters of the electrical cable as function of frequency. An experimental characterizationof the so called PLC READY test bench was carried out in terms of noise, impedance and insertion loss. The radiated electromagnetic field during a PLC communication is measured.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-05-20T12:31:27Z No. of bitstreams: 1 Marcio Botelho Pedrosa.pdf: 1800527 bytes, checksum: 11a367f2109b6bdb35c4c412d6888313 (MD5) / Made available in DSpace on 2016-05-20T12:31:27Z (GMT). No. of bitstreams: 1 Marcio Botelho Pedrosa.pdf: 1800527 bytes, checksum: 11a367f2109b6bdb35c4c412d6888313 (MD5) Previous issue date: 2015-08-06 / The advancement of technology and the significant increase in radio networks and telecommunications, causes, increasingly, people are exposed and immersed in electromagnetic fields, the effects appear to be controversial and parameter-dependent, and short-term can not represent an imminent risk when applied in a controlled manner, however, as these will behave with the immersion chronic forms in our daily lives is inconclusive and without sufficient studies. On the other hand, the short-wave electromagnetic fields (27.12 MHz) represent an alternative in treatment with electrotherapies for pains and inflammatory processes that affect millions of people worldwide. This work conducted application of short wave field into three groups of Wistar rats divided by daily exposure times of 15, 30 and 60 consecutive days and controls was studied the effects of electromagnetic fields may generate the testes and on spermatogenesis. With such irradiation observed changes primarily on Leydig cells and a variation in testosterone dose between groups, as well as a reduction in long-term prostate weight. Although no alterations in testicular weights and no indication of lesions histopathology with optical microscopy. / O avanço da tecnologia e o aumento significativo das redes de radiofrequências e telecomunicações, faz com que, cada vez mais, as pessoas fiquem expostas e imersas em campos eletromagnéticos, cujos efeitos aparentam ser controversos e parâmetro-dependentes, e a curto prazo podem não representar um risco iminente quando aplicados de forma controlada, no entanto, como estes comportar-se-ão com a imersão de formas crônicas em nosso cotidiano é inconclusivo e sem estudos suficientes. Por outro lado, os campos eletromagnéticos de ondas curtas (27,12 MHz) representam uma alternativa nos tratamentos com eletroterapias para algias e processos inflamatórios, que atingem milhares de pessoas pelo mundo. Este trabalho realizou aplicação do campo de ondas curtas em três grupos de ratos wistar divididos pelos tempos de exposição diário em 15, 30 e 60 dias consecutivos e seus controles, foi estudado os efeitos que os campos eletromagnéticos podem gerar nos testículos e sobre a espermatogênese. Com esta irradiação observou-se mudanças principalmente sobre as células de Leydig e uma variação na dosagem de testosterona entre os grupos, bem como uma diminuição do peso da próstata a longo prazo. Embora não tenham ocorridas alterações nos pesos testiculares e nenhum indicativo de lesões na análise histopatológica com a microscopia óptica.

This Master’s project deals with general aspects and possible solution of effective shielded cover and cell/chamber shielding measurement for needs of electromagnetic compatibility EMC on the basis of available norms and standards. Electromagnetic shielding is one of the most anticlutter means of EMC. Its main task is reduction of disturbing emission at the side of sources of disturbing signals as well as electromagnetic resistance increase at the side of disturbing signal receivers. Shielding is considered to be an important structural means to reduce electromagnetic field referring to a defined space part. Technical means for achieving the given goals are called shielded covers or shielded cells/chambers. Shielding is one of highly effective methods related to electromagnetic protection, for instance against power/output disturbance. To express the shielding quality so called shielding effectiveness SE is used. It represents logarithmic rate of shielding coefficient that is defined by the intensity ratios of electric and magnetic fields in a certain point of the shielded space to electric or magnetic field intensity incident/impinging on the shielded screen or wall.

The aim of the work is to study the electromagnetic field theory, finite element method and the interaction of electromagnetic field with tissues. Gained knowledge is then used to calculate spreading of the electromagnetic field in the microwave field and to create a temperature profile of spreading the electromagnetic fields in human tissue. The finite element method was implemented in the Matlab programming environment, where the 1D model was created in the frequency and time domain and a simple 2D model created in time domain. The program was developed to analyze spreading electromagnetic wave. Another part of work was done in the programming environment of COMSOL Multiphysics. In this case was the human leg exposed to electromagnetic fields. The analysis determined the changes of temperature in these biological tissues for six minutes.

This thesis deals with the basic theory of the electromagnetic field in the first part and the field interactions with biological tissues. Than describes shortwave diathermy as a technique used for purposes of medical treatment. The aim is to built a model of tissue heating in shortwave diathermy in COMSOL Multiphysics environment, so there is included a description of the programming environment, including the mathematical method that COMSOL uses for calculations. The output of the whole work is a model of the lower limb in the knee part and display the results after his diathermy heating.

The aims of this study were to evaluate the influence of an extremely low-frequency electromagnetic field (ELF-EMF) on [3H]glucose uptake in the peripheral tissues and organs of rats. Rats were exposed to ELF-EMF (frequency-10 Hz, induction -1.8-3.8 mT) one hour daily for 14 consecutive days. Control animals were sham exposed. On the 15th day (24 hours after last exposure) rats were injected with D-[3H]-6-glucose 500μCi/kg IP. Fifteen minutes later animals were sacrificed by decapitation and peripheral tissues were excised and examined for radioactivity (desintegrations per minute, DPM/ 100 mg wet tissue weight), which expressed [3H]glucose uptake. In most of the examined tissues and organs, such as liver, kidney, heart muscle, cartilage, connective tissue, tendon and skin, [3H]glucose uptake in ELF-EMF-exposed animals was significantly higher as compared to that in the sham control. Exposure to ELF-EMF did not influence [3H]glucose uptake in the thoracic aorta and the skeletal muscle. It is concluded that ELF-EMF impacts tissue glucose uptake by facilitating glucose transport via cell membranes, dependent and probably also independent of its role in increasing insulin action in insulin-dependent tissues.

We discuss the physical problem of a molecule interacting with an electromagnetic field pulse and model the problem using a time-dependent perturbation of the Born-Oppenheimer approximation to the Schrodinger equation. Using previous results that develop asymptotic series solutions in the Born-Oppenheimer parameter ε, we derive a formal Dyson series expansion in the perturbation parameter μ, which is proportional to the electromagnetic field strength. We then prove that this series is asymptotically accurate in both parameters, provided that the Hamiltonian for the electrons has purely discrete spectrum. Under more general hypotheses, we show that the series is accurate to first order in μ, and that it is accurate to one higher order if we place conditions on the abruptness of the EM pulse. We also show how this series development provides a justification for the Franck-Condon factors in the case of a diatomic molecule. / Ph. D.