Aging of transformer insulating materials under selective conditions

Fofana, I.; Borsi, H.; Gockenbach, E.; Farzaneh, M.

doi:10.1002/etep.134

Cited by 51 publications

(21 citation statements)

References 22 publications

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“…During operation, a deterioration in the chemical, physical and electrical properties of an insulation material is termed as ageing, which reduces the operation life of the insulation material. For years, the single thermal stress ageing (accelerated ageing) test procedures have proved to have been useful and can be performed in the laboratory to deduce the lifespan of liquid and solid insulation systems [17,18]. Thus, based on the ageing experiment, the effects of material ageing on space charge behaviors were investigated.…”

Section: Ageingmentioning

confidence: 99%

Progress of Space Charge Research on Oil-Paper Insulation Using Pulsed Electroacoustic Techniques

et al. 2016

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This paper focuses on the space charge behavior in oil-paper insulation systems used in power transformers. It begins with the importance of understanding the space charge behavior in oil-paper insulation systems, followed by the introduction of the pulsed electrostatic technique (PEA). After that, the research progress on the space charge behavior of oil-paper insulation during the recent twenty years is critically reviewed. Some important aspects such as the environmental conditions and the acoustic wave recovery need to be addressed to acquire more accurate space charge measurement results. Some breakthroughs on the space charge behavior of oil-paper insulation materials by the research team at the University of Southampton are presented. Finally, future work on space charge measurement of oil-paper insulation materials is proposed.

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Section: Ageingmentioning

confidence: 99%

Progress of Space Charge Research on Oil-Paper Insulation Using Pulsed Electroacoustic Techniques

et al. 2016

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“…Assuming normal loading, the lifetime can be much longer, especially if they are not moved. There are aging procedure is more rapid, less expensive and provides samples with a controlled thermal history [8,21].…”

Section: Introductionmentioning

confidence: 99%

Characterization of aging transformer oil-pressboard insulation using some modern diagnostic techniques

Fofana

Bouaicha

Farzaneh

2010

Euro. Trans. Electr. Power

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SUMMARYThis paper presents a study on the characterization of aging of transformer oil-pressboard insulation. Traditional and modern diagnostic tools and techniques were used to investigate aging of oil-paper insulation under controlled laboratory conditions. Insulation condition testing includes common chemical diagnostics such as acidity tests and new chemical techniques: determination of relative content of dissolved decay products by spectrophotometry, solid suspension by turbidimetry, Fourier Transform Infrared (FTIR) spectroscopy and electrical diagnostic techniques that have gained exceptional importance for utility professionals: polarisation/depolarisation current, recovery voltage measurement and frequency domain dielectric spectroscopy measurements. From the obtained results it is found that chemical tests depicted more sensitivity to insulation degradation. Also, different oil-pressboard insulation ratios were investigated to assess the influence of the relative amount of cellulosic materials on aged mineral oil decay products and vice versa. Emphasize is laid on the potentialities/avenues offered by FTIR to assess oil insulation condition. Notable experimental results have been reported, which could be valuable to researchers and practicing engineers in this field.

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“…The sources of energy capable of splitting of a molecular covalent bond made up of a pair of electrons are three fold [1,9,16,17]:…”

Section: Background On Transformer Insulation's Agingmentioning

confidence: 99%

Measurement of the Relative Free Radical Content of Insulating Oils of Petroleum Origin

Fofana

Sabau²,

Bétié

2015

Energies

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Oil/paper insulation degradation in transformers involves chemical and physical changes in the materials. Some of the chemical reactions involve very reactive intermediates called free radicals. Free radicals play a major role in a wide variety of ageing processes. The detection of these reactive species in oil may, in principle, provide useful information for monitoring oil degradation. This manuscript details a laboratory technique, which determines the relative content of free radicals in insulating oils of petroleum origin by a spectrophotometric method. Free radicals may be formed in oils under operating or test conditions. The procedure enables the determination of the relative concentration of free radicals, which can act as the precursors of decay products such as charge carriers, oxidized molecules, as well as polymerization products. The technique involves using a reactive free radical reagent, 2,2-diphenyl-1-picrylhydrazyl (DPPH), added to oil to assess free radical concentration. This method is applicable to new, reclaimed, or used oils as well as naturally or artificially oxidized oil (the cause of aging can be chemical, physical, or electrical). In this contribution, free radicals were assessed following electrical discharge application in oil.

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Aging of transformer insulating materials under selective conditions

Cited by 51 publications

References 22 publications

Progress of Space Charge Research on Oil-Paper Insulation Using Pulsed Electroacoustic Techniques

Progress of Space Charge Research on Oil-Paper Insulation Using Pulsed Electroacoustic Techniques

Characterization of aging transformer oil-pressboard insulation using some modern diagnostic techniques

Measurement of the Relative Free Radical Content of Insulating Oils of Petroleum Origin

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