The analysis of paper degradation by-products as a tool for monitoring fault conditions in oil-filled electric apparatus

Griffin, P.J.; Lewand, Lance; Pahlavanpour, B.

doi:10.1049/cp:19950222

Cited by 10 publications

(5 citation statements)

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“…J. Unsworth and F. Mitchell tested the stability of furfural in oil at 20 • C, 80 • C, and 110 • C, and they corroborated that furfural is only stable at low temperatures (less than 80 • C), and the furfural content in oil may drop drastically at 110 • C [15]. P. Griffin affirmed that furfural degrades significantly with copper at 140 • C and proposed furfural was not stable at high temperature [16]. On the contrary, H. Kan kept insulation oil containing furfural at 100 • C for 2 months and verified that the furfural content was invariant, thereby concluding that furfural is stable [17].…”

Section: Introductionmentioning

confidence: 91%

Influential Factors and Correction Method of Furfural Content in Transformer Oil

et al. 2019

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Furfural content in transformer oil is considered a credible method to evaluate the aging extent of insulation paper and is extensively applied to the aging assessment of insulation system in transformers. Clearly, the accuracy of furfural analysis is directly related to the stability of furfural in oil, which, nevertheless, may be affected by various factors. In this research, furfural was added to insulation oil directly to analyze its stability in oil firstly. Furfural contents in different conditions, such as different temperatures, copper, and oxygen atmosphere, are measured regularly. The results corroborate that the furfural content in the oil keeps constant when the oil temperature is less than 130 • C without copper or oxygen; copper cannot make furfural in oil degrade without oxygen when the temperature is below 90 • C. These results indicate that the furfural is stable at the common operating temperature of transformer oil (40 • C ∼ 70 • C) as long as no oxygen is in oil. Oxygen is the main degradation cause of furfural in oil, and high temperature and copper accelerate this progress. The oxidation product of furfural in oil has been explored, which shows that the furoic acid is the main degradation product of furfural when the temperature is less than 90 • C. Thus, the furoic acid content in oil can be measured as a reference to increase the accuracy of the furfural analysis.

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Section: Introductionmentioning

confidence: 91%

Influential Factors and Correction Method of Furfural Content in Transformer Oil

et al. 2019

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“…Experience in the U.K. [10], Australia [11], and the U.S. [12] indicates that even after 40 years of service the aging of transmission units is generally consistent with midlife. The excep- tions arise where there have been hot spots at design specific areas.…”

Section: B Aging In the Transformer Insulation System 1) Winding Insmentioning

confidence: 99%

“…Early deterioration of the general winding insulation was found where moisture ingress had occurred. Reference [12] relates the relatively slight aging in 40 year old U.S. transformers but contrasts with 10 to 13 year old units where the oil had been allowed to sludge. Here, paper had reached DP values of 150 and the end of life.…”

Section: B Aging In the Transformer Insulation System 1) Winding Insmentioning

confidence: 99%

Monitoring and diagnostic of transformer solid insulation

Bolhuis

Gulski

Smit

2002

IEEE Trans. Power Delivery

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Abstract-Liberalization of the energy market has put increasing pressure on both electricity producers and distributors for lower costs. Since maintenance is a major expense account, such companies will be inclined to reduce maintenance budgets. At the same time, increased liability for non-delivered-energy increases the costs of sudden failure of a component. Transformers are such a component; they are often an essential link in the distribution network.In order to reconcile both decreasing maintenance spending and reliable service, condition-based maintenance (CBM) is often proposed. The basis of a successful application of CBM lies in obtaining information on transformers, so that, on the one hand, a critical condition will be noted early enough to take measures and, on the other hand, so that only minimal maintenance is being applied to transformers still in good condition. This paper will review a series of often mentioned techniques in order to assess what the value of this technique will be for CBM and whether it can be used for condition monitoring.

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“…Experiments have shown that under non-oxidative conditions 2-FAL is stable at transformer operating temperatures up to about 110 °C [9]. Furthermore, some studies have shown that factors such as oxygen [10], copper and di-cy compounds found in thermally upgraded paper [11] could also reduce the stability of 2-FAL in transformer oil. In addition to the loss of 2-FAL through chemical reactions, 2-FAL content in oil could change considerably during oil reclamation [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of Paper Type and Water Content in Paper on the Partitioning of 2-FAL between Liquid and Paper Insulations

Matharage

Liu

Wang

et al. 2020

2020 IEEE International Conference on High Voltage Engineering and Application (ICHVE)

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For nearly four decades 2-furfural (2-FAL) in transformer oil has been used as a chemical marker to indicate the ageing state of transformer paper insulation. Nevertheless, it has always been a challenge to define an acceptable limit for 2-FAL due to issues related to non-uniform temperature distribution in transformers, stability of 2-FAL in oil and its partitioning between liquid and solid insulation. Therefore, transformer users try to combine the laboratory findings, the operational experience and post-mortem analyses together for predicting ageing state of paper insulation through 2-FAL content in oil. Due to increase in the use of ester liquids in transformers, there is a need to investigate the ability to use 2-FAL as a paper ageing indicator for ester based insulation systems. Laboratory ageing studies have shown that 2-FAL is indeed generated in ester based insulation systems. However, there is a lack of understanding related to the partitioning of 2-FAL in ester based insulation systems. This paper studies the partitioning of 2-FAL in synthetic ester based insulation systems and compares to that in mineral oil based insulation systems with the focus on the effect of paper type and water content in paper. Under the investigated conditions the synthetic ester had higher partitioning coefficients (ratio between the 2-FAL content in oil and paper) than the mineral oil. Partitioning coefficients in both oil types decreased with the increase of the water content in paper. However, change in paper type did not significantly affect the partitioning coefficients in this study.

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The analysis of paper degradation by-products as a tool for monitoring fault conditions in oil-filled electric apparatus

Cited by 10 publications

References 0 publications

Influential Factors and Correction Method of Furfural Content in Transformer Oil

Influential Factors and Correction Method of Furfural Content in Transformer Oil

Monitoring and diagnostic of transformer solid insulation

Effect of Paper Type and Water Content in Paper on the Partitioning of 2-FAL between Liquid and Paper Insulations

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