Understanding ethanol versus methanol formation from insulating paper in power transformers

Celis, E. M. Rodriguez; Duchesne, Steve; Jalbert, Jocelyn; Ryadi, Mohamed

doi:10.1007/s10570-015-0693-0

Cited by 49 publications

(20 citation statements)

References 37 publications

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“…The lead is crepe paper that has been mechanically treated and is of a different type than the winding (Kraft) paper. In unit C, ethanol concentration is higher than methanol concentration, which has been reported to be caused by higher temperatures in the transformer [83]. A visual inspection of the paper in this unit showed blackened areas, confirming the presence of hot spots in the transformer.…”

Section: Distribution Transformersmentioning

confidence: 54%

Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

et al. 2019

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This manuscript presents a comprehensive literature review with the aim to provide readers a reference document with up-to-date information on the field of methanol use as a chemical marker. It has been a little more than a decade since methanol was first introduced as a marker for assessing solid insulation condition in power transformers. It all started when methanol was identified in the laboratory during thermal ageing tests carried out with oil-immersed insulating papers and was subsequently also identified in transformer field samples. The first publication on the subject was released in 2007 by our research group. This review covers the methanol fundamentals such as the analytical methods for its determination in transformer oil, which is generally performed by headspace gas chromatography with mass spectrometry or flame ionization as a detector. Current standardization efforts for its determination include ASTM working group 30948 and IEC TC10. Kinetic studies have confirmed the relationship between methanol generation, the number of broken 1,4-β-glycosidic bonds of cellulose and changes in mechanical properties. Laboratory tests have confirmed its stability at different accelerated ageing temperatures. Several utilities have identified methanol during field measurements, case studies on power and some distribution transformers are presented, as well as transformer postmortem investigations. These field-testing results demonstrate its utility in monitoring cellulosic insulation degradation. Recently, a model of methanol interpretation has become available that allows for evaluation of the average degree of polymerization of core type transformer cellulose winding. Methanol has a role as an indicator of cellulosic solid insulation ageing in transformer mineral oil, and it is expected that in the future it will be in routine use by utilities.

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Section: Distribution Transformersmentioning

confidence: 54%

Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

et al. 2019

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“…In the last decades, the state assessment methods of transformer polymer insulation materials based on the traditional chemical and electrical technique have been widely reported [5][6][7]. However, traditional methods require further research in the field test due to various limitations.…”

Section: Introductionmentioning

confidence: 99%

Correction for Polarization Current Curve of Polymer Insulation Materials in Transformers Considering the Temperature and Moisture Effects

et al. 2020

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Depending on the study of the master curve technique, a temperature correction model for the polarization current of transformer polymer (cellulose) insulation, considering the effects of both moisture content (mc%) and temperature is proposed. In the current work, the shift factors of polarization current curves of samples with various moisture contents are extracted at different temperatures. Then, the variation law among the shift factor, test temperature, and moisture content are studied so as to establish the corresponding functional relationship. The findings reveal that the modified model derived from the above functional relationship could be employed to perform the temperature correction of oil-immersed polymer samples with various insulation states. Therefore, the proposed temperature correction model in this paper will promote the state assessment of the field transformer polymer insulation.

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“…This can lead to a gradual decline in the insulation performance of the oil–paper insulation system, or even complete loss, resulting in a dangerous electrical accident. Since insulating paper, unlike transformer oil, cannot be changed regularly, it is generally considered that the aging of insulating paper is more important than the aging of oil .…”

Section: Introductionmentioning

confidence: 99%

Concentration of 5‐hydroxymethylfurfural produced by insulating paper in an oil–paper insulation system

Chen

et al. 2020

IEEJ Transactions Elec Engng

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The transformer is a core device of the power system, and it is generally considered that the aging of insulating paper is important to the transformer. The aging process of insulating paper is the degradation process of cellulose. If it can be detected regularly, the aging of oil-paper insulating systems can be monitored conveniently. 5-hydroxymethylfurfural is an important chemical substance produced by cellulose decomposition. It has broad prospects because of its many advantages. The oil-paper insulation system was thermally aged at 80, 90, 100, and 110 • C to measure the concentration of 5-hydroxymethylfurfural on insulating paper and in transformer oil. In this paper, the concentration of 5-hydroxymethylfurfural is detected by high-performance liquid chromatography. The linear correlation coefficient of this method can reach 0.99, and the minimum detected concentration can be reduced to 10 μg/l. Experiments show that the concentration of 5-hydroxymethylfurfural increases with the aging time, and when degree of polymerization (DP) decreased, the concentration of 5-hydroxymethylfurfural increased. The correlation coefficient is greater than 0.92, which shows that there is an experimental relationship between the concentration of 5-hydroxymethylfurfural and DP. The parameters of regression curves are different at different temperatures, but in actual operation, the temperature is low and remains stable. Therefore, 5-hydroxymethylfurfural is expected to be a new indicator of the aging degree of oil-paper insulation system.

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Understanding ethanol versus methanol formation from insulating paper in power transformers

Cited by 49 publications

References 37 publications

Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

Correction for Polarization Current Curve of Polymer Insulation Materials in Transformers Considering the Temperature and Moisture Effects

Concentration of 5‐hydroxymethylfurfural produced by insulating paper in an oil–paper insulation system

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