GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULT

Line-to-line-to-line unsymmetrical faults either involving or not involving ground are in the classical fault analysis approach difficult to analyse. This is because the classical solution requires use of the knowledge of connection of symmetrical component sequence networks for various common fault...

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Main Authors: J. D. SAKALA, J. S. J. DAKA
Format: Article
Language:English
Published: Taylor's University 2015-09-01
Series:Journal of Engineering Science and Technology
Subjects:
Online Access:http://jestec.taylors.edu.my/Vol%2010%20Issue%209%20September%202015/Volume%20(10)%20Issue%20(9)%201131-1143.pdf
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author J. D. SAKALA
J. S. J. DAKA
author_facet J. D. SAKALA
J. S. J. DAKA
author_sort J. D. SAKALA
collection DOAJ
description Line-to-line-to-line unsymmetrical faults either involving or not involving ground are in the classical fault analysis approach difficult to analyse. This is because the classical solution requires use of the knowledge of connection of symmetrical component sequence networks for various common faults. In this approach, the phase fault constraints are converted into symmetrical sequence constraints and the sequence networks connected in a way that satisfies the constraints. The symmetrical component constraints for an unsymmetrical three-phase fault not involving ground do not lend themselves easy to the connection of the sequence networks. The exception is that, because the phase currents at the fault summate to zero, the zero sequence current is zero and therefore the zero sequence network is not connected. The connection of the positive and negative sequence networks is difficult to deduce when the fault is unsymmetrical. A classical solution is therefore difficult to find. In contrast, a solution by the general method of fault admittance matrix does not require prior knowledge of how the sequence networks are connected. It is therefore more versatile than the classical methods. The paper presents a procedure for solving a three-phase unsymmetrical fault, with different fault impedances, hence fault admittances in each phase. A computer program based on the general fault admittance method is developed and used to analyse an unsymmetrical three-phase fault on a simple power system with a delta-earthed-star connected transformer.
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spelling doaj.art-82fd9aaba7c84ed68074d2ab720f3a8d2022-12-22T01:44:54ZengTaylor's UniversityJournal of Engineering Science and Technology1823-46902015-09-0110911311143GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULTJ. D. SAKALA0J. S. J. DAKA 1Faculty of Engineering and Technology, University of Botswana, Private Bag UB0061, Gaborone, BotswanaFaculty of Engineering and Technology, University of Botswana, Private Bag UB0061, Gaborone, BotswanaLine-to-line-to-line unsymmetrical faults either involving or not involving ground are in the classical fault analysis approach difficult to analyse. This is because the classical solution requires use of the knowledge of connection of symmetrical component sequence networks for various common faults. In this approach, the phase fault constraints are converted into symmetrical sequence constraints and the sequence networks connected in a way that satisfies the constraints. The symmetrical component constraints for an unsymmetrical three-phase fault not involving ground do not lend themselves easy to the connection of the sequence networks. The exception is that, because the phase currents at the fault summate to zero, the zero sequence current is zero and therefore the zero sequence network is not connected. The connection of the positive and negative sequence networks is difficult to deduce when the fault is unsymmetrical. A classical solution is therefore difficult to find. In contrast, a solution by the general method of fault admittance matrix does not require prior knowledge of how the sequence networks are connected. It is therefore more versatile than the classical methods. The paper presents a procedure for solving a three-phase unsymmetrical fault, with different fault impedances, hence fault admittances in each phase. A computer program based on the general fault admittance method is developed and used to analyse an unsymmetrical three-phase fault on a simple power system with a delta-earthed-star connected transformer.http://jestec.taylors.edu.my/Vol%2010%20Issue%209%20September%202015/Volume%20(10)%20Issue%20(9)%201131-1143.pdfUnbalanced faults analysisLine-to-line-to-line unsymmetrical faultFault admittance matrixDelta-earthed-star transformer
spellingShingle J. D. SAKALA
J. S. J. DAKA
GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULT
Journal of Engineering Science and Technology
Unbalanced faults analysis
Line-to-line-to-line unsymmetrical fault
Fault admittance matrix
Delta-earthed-star transformer
title GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULT
title_full GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULT
title_fullStr GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULT
title_full_unstemmed GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULT
title_short GENERAL FAULT ADMITTANCE METHOD LINETO- LINE-TO-LINE UNSYMMETRICAL FAULT
title_sort general fault admittance method lineto line to line unsymmetrical fault
topic Unbalanced faults analysis
Line-to-line-to-line unsymmetrical fault
Fault admittance matrix
Delta-earthed-star transformer
url http://jestec.taylors.edu.my/Vol%2010%20Issue%209%20September%202015/Volume%20(10)%20Issue%20(9)%201131-1143.pdf
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