couple_tr_FE_BEM_nonlinear - Coupled Transient Finite...

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Coupled Transient Finite Element and Boundary Element Method odeling of Nonlinear, Nonhomogeneous, Electric Field Devices with Mesh Refinement M. D. Driga Dept. of Electrical and Computer Engineering The University of Texas at Austin Austin, Texas 78712 Abstract This paper introduces the structures of 2-D and 3- D finite and boundary element methods codes for calculating electric field strength distribution in high voltage insulation systems in arrangements wtfA complex boundaries. A very accurate representation of the space distribution of electrical fields, varying in time as the combined effect of the circuit parameters, modulated by di'fusion and time changing properties of the dielectric materials can be the basis for a global performance criterion for the system, large enough to represent the complexity of the phenomena, but still simple to be meaningful. Also, the paper describes a promising technique for rezoning the mesh in order to achieve a high resolution in critical areas of high field strength. I. Introduction Powerful modeling tools are indispensable for advanced insulation systems design and evaluation, since such modern insulation systems require an accurate representation of the time marching electromagnetic stresses, especially if the components and materials are nonhomogeneous and their characteristics are nonlinear [ 11. A global performance criterion for such systems encompassing enough but still simple to express - at least methodologically - is needed. This paper is the first in a series, trying to prove that the basis for a global performance criterion is the transient three-dimensional (3-D) space distribution for the electric field quantities, and their varia?ion in time after the high electric fields have been applied. Albert Wu ATC Ltd. Hong Kong Since the known mechanisms responsible for dielectric failure such as intrinsic-electro- mechanical, avalanche and thermal breakdown are field and time-dependent, it is believed that such 3-D transient field representations will provide a valuable tool in design and performance evaluation of electrical systems ranging from both performance capacitors used for electric guns to complex, industrial applications of high electric field technologies systems. In the last few years, several authors, notably Sarjeant [Z] and others [3, 41 stressed the fact that modern, very advanced pulsed capacitors and other electrical devices designed for fast discharge and heavy-duty operation have a surprisingly predictable mechanism of aging and failure after a small number of early random failures are eliminated 141. 11. Finite Element Method (EM) Combined with the Boundary Element Method (BEM) for Numerical Characterization of Transient, 3-D Electric Fields If a global (general) performance criterion for the capacitor system, based on a transient 3-D system of electric fields is chosen, the numerical characterization should be achieved by using concomitantly the finite and the boundary element methods, 3-D in space and transient in time, thus
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This note was uploaded on 06/08/2011 for the course ELECTRICAL 124 taught by Professor Ghjk during the Spring '11 term at Institute of Technology.

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couple_tr_FE_BEM_nonlinear - Coupled Transient Finite...

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