DocumentCode :
1525057
Title :
Finite element based Kerr electro-optic reconstruction of space charge
Author :
Üstündag, A. ; Zahn, M.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., MIT, Cambridge, MA, USA
Volume :
8
Issue :
4
fYear :
2001
fDate :
8/1/2001 12:00:00 AM
Firstpage :
612
Lastpage :
628
Abstract :
Recently we used the onion peeling method to reconstruct the axisymmetric electric field distribution of point/plane electrodes from Kerr electro-optic measurements. The method accurately reconstructed the electric field from numerically generated data. However in the presence of experimental noise the performance was less satisfactory. The measurements were especially noisy and unstable near the needle tip which is also the interesting region since most charge injection initiates here. We develop a new algorithm for Kerr electro-optic reconstruction of space charge in axisymmetric point/plane electrode geometries. The algorithm is built on the finite element method (FEM) for Poisson´s equation and will be called finite element based Kerr electro-optic reconstruction (FEBKER) hereafter. FEBKER calculates the space charge density directly to avoid the numerical problems associated with taking the divergence of the electric field, uses single parameter light intensity measurements to enable transient analysis, which otherwise is difficult since multiple parameter intensity measurements are slow due to the rotation of polarizers, and is capable of reconstruction even when the number and/or position of measurements are limited by the electrodes and/or the experimental setup. The performance of the algorithm is tested on synthetic Kerr electro-optic data obtained for an axisymmetric point/plane electrode geometry in transformer oil with specified space charge density distributions. The impact of experimental error is analyzed by incorporating random error to the synthetic data. Regularization techniques that decrease the impact of experimental error are applied. In principle FEBKER is applicable to arbitrary three-dimensional geometries as well
Keywords :
Kerr electro-optical effect; Poisson equation; charge injection; finite element analysis; space charge; transformer oil; transient analysis; FEBKER; Kerr electro-optic reconstruction; Poisson´s equation; axisymmetric electric field distribution; charge injection; finite element method; needle tip; onion peeling method; point/plane electrodes; random error; single parameter light intensity measurements; space charge; transformer oil; transient analysis; Charge measurement; Current measurement; Density measurement; Electric variables measurement; Electrodes; Finite element methods; Geometry; Position measurement; Rotation measurement; Space charge;
fLanguage :
English
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
Publisher :
ieee
ISSN :
1070-9878
Type :
jour
DOI :
10.1109/94.946714
Filename :
946714
Link To Document :
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