A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application

Surface discharge at the oil-pressboard interface is known as the development of a conducting path which is characterized by white and carbonized marks. This phenomenon tends to cause damage on the cellulose pressboard insulation which is subsequently promotes catastrophic failure in transformer’s i...

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Main Author:	Othman, Nur Amirah
Format:	Thesis
Language:	English English
Published:	2017
Subjects:	T Technology (General)
Online Access:	http://eprints.utem.edu.my/id/eprint/22406/1/A%20Fundamental%20Study%20Of%20Surface%20Discharge%20Characteristics%20On%20Pressboard%20Immersed%20In%20Ester%20Oil%20For%20Power%20Transformer%20Application%20-%20Nur%20Amirah%20Othman%20-%2024%20Pages.pdf http://eprints.utem.edu.my/id/eprint/22406/2/A%20Fundamental%20Study%20Of%20Surface%20Discharge%20Characteristics%20On%20Pressboard%20Immersed%20In%20Ester%20Oil%20For%20Power%20Transformer%20Application%20-%20Nur%20Amirah%20Othman.pdf
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topic	T Technology (General) T Technology (General)
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description	Surface discharge at the oil-pressboard interface is known as the development of a conducting path which is characterized by white and carbonized marks. This phenomenon tends to cause damage on the cellulose pressboard insulation which is subsequently promotes catastrophic failure in transformer’s insulation. One of the major defects that may cause surface discharge to occur along the pressboard surface is an excessive moisture content in pressboard insulation. In order to increase the understanding on this failure, this thesis presents the investigation on the degradation behaviour of surface discharge along dry and wet pressboard samples (3 % and 6 %) immersed with different viscosity of natural ester insulation (NEI) oils, i.e. palm fatty acid ester (PFAE) and MIDEL eN oil. There are three types of experiments that were discussed in this thesis, i.e. surface breakdown, partial discharge inception voltage (PDIV) and surface discharge experiments. These experiments were conducted in oil bath by using a needle-bar electrode configuration under AC voltage stress. Three differences gap distances between the needle tip and earth electrode, i.e. 20 mm, 30 mm and 40 mm were used in surface breakdown and PDIV experiments. On the other hand, surface discharge experiment was conducted under a long duration of constant AC voltage (30 kV) with a fixed 30 mm gap distance. The development of surface discharge have been analysed by correlating the visual records of surface discharge and phase-resolved partial discharge (PRPD) pattern. The results show that the moisture contents in the pressboard and viscosity of insulation oils play important roles in all experiments. In general, as moisture increases, the PDIV and surface breakdown voltage decreases, whilst the PD number from the surface discharge experiment increases. However, unexpected results are observed when pressboard of 6 % moisture content are used in MIDEL eN oil, whereby the surface breakdown voltage was unexpectedly increased and no PD data was recorded in the surface discharge experiment. This might be due to the trapped vaporised moisture and dissolved gases in the pressboard structure as a result of higher viscosity of MIDEL eN oil compared to PFAE oil. Another effect of high viscosity of MIDEL eN oil is also observed when the MIDEL eN oil-impregnated pressboard has a higher surface breakdown voltage by approximately 27.82 % on average and lower PDIV approximately by 8.98 % on average compared to PFAE oil-impregnated pressboard, regardless the moisture contents in pressboard. In addition, the maximum PD magnitude for the MIDEL eN oil-impregnated pressboard is in the order of 1×10−12C which is lower than PFAE oil-impregnated pressboard that is in order of 1×10−9C. On the other hand, the number of PD is observed higher for MIDEL oil-impregnated pressboard compared to PFAE oil-impregnated pressboard.
format	Thesis
qualification_name	Master of Philosophy (M.Phil.)
qualification_level	Master's degree
author	Othman, Nur Amirah
author_facet	Othman, Nur Amirah
author_sort	Othman, Nur Amirah
title	A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application
title_short	A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application
title_full	A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application
title_fullStr	A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application
title_full_unstemmed	A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application
title_sort	fundamental study of surface discharge characteristics on pressboard immersed in ester oil for power transformer application
granting_institution	Universiti Teknikal Malaysia Melaka
granting_department	Faculty of Electrical Engineering
publishDate	2017
url	http://eprints.utem.edu.my/id/eprint/22406/1/A%20Fundamental%20Study%20Of%20Surface%20Discharge%20Characteristics%20On%20Pressboard%20Immersed%20In%20Ester%20Oil%20For%20Power%20Transformer%20Application%20-%20Nur%20Amirah%20Othman%20-%2024%20Pages.pdf http://eprints.utem.edu.my/id/eprint/22406/2/A%20Fundamental%20Study%20Of%20Surface%20Discharge%20Characteristics%20On%20Pressboard%20Immersed%20In%20Ester%20Oil%20For%20Power%20Transformer%20Application%20-%20Nur%20Amirah%20Othman.pdf
_version_	1747834018505687040
spelling	my-utem-ep.224062022-02-03T10:57:46Z A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application 2017 Othman, Nur Amirah T Technology (General) TK Electrical engineering. Electronics Nuclear engineering Surface discharge at the oil-pressboard interface is known as the development of a conducting path which is characterized by white and carbonized marks. This phenomenon tends to cause damage on the cellulose pressboard insulation which is subsequently promotes catastrophic failure in transformer’s insulation. One of the major defects that may cause surface discharge to occur along the pressboard surface is an excessive moisture content in pressboard insulation. In order to increase the understanding on this failure, this thesis presents the investigation on the degradation behaviour of surface discharge along dry and wet pressboard samples (3 % and 6 %) immersed with different viscosity of natural ester insulation (NEI) oils, i.e. palm fatty acid ester (PFAE) and MIDEL eN oil. There are three types of experiments that were discussed in this thesis, i.e. surface breakdown, partial discharge inception voltage (PDIV) and surface discharge experiments. These experiments were conducted in oil bath by using a needle-bar electrode configuration under AC voltage stress. Three differences gap distances between the needle tip and earth electrode, i.e. 20 mm, 30 mm and 40 mm were used in surface breakdown and PDIV experiments. On the other hand, surface discharge experiment was conducted under a long duration of constant AC voltage (30 kV) with a fixed 30 mm gap distance. The development of surface discharge have been analysed by correlating the visual records of surface discharge and phase-resolved partial discharge (PRPD) pattern. The results show that the moisture contents in the pressboard and viscosity of insulation oils play important roles in all experiments. In general, as moisture increases, the PDIV and surface breakdown voltage decreases, whilst the PD number from the surface discharge experiment increases. However, unexpected results are observed when pressboard of 6 % moisture content are used in MIDEL eN oil, whereby the surface breakdown voltage was unexpectedly increased and no PD data was recorded in the surface discharge experiment. This might be due to the trapped vaporised moisture and dissolved gases in the pressboard structure as a result of higher viscosity of MIDEL eN oil compared to PFAE oil. Another effect of high viscosity of MIDEL eN oil is also observed when the MIDEL eN oil-impregnated pressboard has a higher surface breakdown voltage by approximately 27.82 % on average and lower PDIV approximately by 8.98 % on average compared to PFAE oil-impregnated pressboard, regardless the moisture contents in pressboard. In addition, the maximum PD magnitude for the MIDEL eN oil-impregnated pressboard is in the order of 1×10−12C which is lower than PFAE oil-impregnated pressboard that is in order of 1×10−9C. On the other hand, the number of PD is observed higher for MIDEL oil-impregnated pressboard compared to PFAE oil-impregnated pressboard. 2017 Thesis http://eprints.utem.edu.my/id/eprint/22406/ http://eprints.utem.edu.my/id/eprint/22406/1/A%20Fundamental%20Study%20Of%20Surface%20Discharge%20Characteristics%20On%20Pressboard%20Immersed%20In%20Ester%20Oil%20For%20Power%20Transformer%20Application%20-%20Nur%20Amirah%20Othman%20-%2024%20Pages.pdf text en public http://eprints.utem.edu.my/id/eprint/22406/2/A%20Fundamental%20Study%20Of%20Surface%20Discharge%20Characteristics%20On%20Pressboard%20Immersed%20In%20Ester%20Oil%20For%20Power%20Transformer%20Application%20-%20Nur%20Amirah%20Othman.pdf text en validuser https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=107367 mphil masters Universiti Teknikal Malaysia Melaka Faculty of Electrical Engineering 1. ABB, 2004. Transformer Handbook. Zurich: ABB Business Transformer. 2. Akiyama, H., 2000. 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A Fundamental Study Of Surface Discharge Characteristics On Pressboard Immersed In Ester Oil For Power Transformer Application

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