Ageing assessment of transformer paper insulation through post mortem analysis

A post mortem analysis of scrapped transformers provides an opportunity to directly measure the properties of in-service aged paper insulation. Investigations on 10 scrapped 275 kV and 400 kV power transformers were carried out, where Tensile Index (TI) and Low Molecular Weight Acid (LMA) of the pap...

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Main Authors: Azis, Norhafiz, Liu, Qiang, Wang, Zhongdong
Format: Article
Language:English
Published: Institute of Electrical and Electronics Engineers 2014
Online Access:http://psasir.upm.edu.my/id/eprint/36344/
http://psasir.upm.edu.my/id/eprint/36344/1/Ageing%20assessment%20of%20transformer%20paper%20insulation%20through%20post%20mortem%20analysis.pdf
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author Azis, Norhafiz
Liu, Qiang
Wang, Zhongdong
author_facet Azis, Norhafiz
Liu, Qiang
Wang, Zhongdong
author_sort Azis, Norhafiz
building UPM Institutional Repository
collection Online Access
description A post mortem analysis of scrapped transformers provides an opportunity to directly measure the properties of in-service aged paper insulation. Investigations on 10 scrapped 275 kV and 400 kV power transformers were carried out, where Tensile Index (TI) and Low Molecular Weight Acid (LMA) of the paper insulation sampled from various locations were measured. Multiple-layer TI profile demonstrated the effect of oxidized oil on paper ageing which was confirmed by laboratory ageing experiments. It is LMA rather than High Molecular Weight Acid (HMA) that accelerates the paper degradation. LMA acts as the paper ageing accelerator and also as the paper degradation by-product, supporting the view that self-accelerated hydrolysis process is the main paper ageing mechanism. Finally, a generic relationship between LMA in paper and TI of paper was revealed based on both in-service and laboratory ageing data, i.e. the lower the TI of paper, the higher value of LMA in paper is measured. It implies that LMA in oil can be a potential paper ageing indicator pro viding a link between LMA in oil and paper is found.
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spelling upm-363442015-08-25T07:53:00Z http://psasir.upm.edu.my/id/eprint/36344/ Ageing assessment of transformer paper insulation through post mortem analysis Azis, Norhafiz Liu, Qiang Wang, Zhongdong A post mortem analysis of scrapped transformers provides an opportunity to directly measure the properties of in-service aged paper insulation. Investigations on 10 scrapped 275 kV and 400 kV power transformers were carried out, where Tensile Index (TI) and Low Molecular Weight Acid (LMA) of the paper insulation sampled from various locations were measured. Multiple-layer TI profile demonstrated the effect of oxidized oil on paper ageing which was confirmed by laboratory ageing experiments. It is LMA rather than High Molecular Weight Acid (HMA) that accelerates the paper degradation. LMA acts as the paper ageing accelerator and also as the paper degradation by-product, supporting the view that self-accelerated hydrolysis process is the main paper ageing mechanism. Finally, a generic relationship between LMA in paper and TI of paper was revealed based on both in-service and laboratory ageing data, i.e. the lower the TI of paper, the higher value of LMA in paper is measured. It implies that LMA in oil can be a potential paper ageing indicator pro viding a link between LMA in oil and paper is found. Institute of Electrical and Electronics Engineers 2014 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/36344/1/Ageing%20assessment%20of%20transformer%20paper%20insulation%20through%20post%20mortem%20analysis.pdf Azis, Norhafiz and Liu, Qiang and Wang, Zhongdong (2014) Ageing assessment of transformer paper insulation through post mortem analysis. IEEE Transactions on Dielectrics and Electrical Insulation, 21 (2). pp. 845-853. ISSN 1070-9878; ESSN: 1558-4135 10.1109/TDEI.2013.004118
spellingShingle Azis, Norhafiz
Liu, Qiang
Wang, Zhongdong
Ageing assessment of transformer paper insulation through post mortem analysis
title Ageing assessment of transformer paper insulation through post mortem analysis
title_full Ageing assessment of transformer paper insulation through post mortem analysis
title_fullStr Ageing assessment of transformer paper insulation through post mortem analysis
title_full_unstemmed Ageing assessment of transformer paper insulation through post mortem analysis
title_short Ageing assessment of transformer paper insulation through post mortem analysis
title_sort ageing assessment of transformer paper insulation through post mortem analysis
url http://psasir.upm.edu.my/id/eprint/36344/
http://psasir.upm.edu.my/id/eprint/36344/
http://psasir.upm.edu.my/id/eprint/36344/1/Ageing%20assessment%20of%20transformer%20paper%20insulation%20through%20post%20mortem%20analysis.pdf