Review of Research Progress on the Electrical Properties and Modification of Mineral Insulating Oils Used in Power Transformers

Wang, Xiaobo; Tang, Chao; Huang, Bo; Hao, Jian; Chen, Guanghui

doi:10.3390/en11030487

Cited by 89 publications

(41 citation statements)

References 73 publications

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“…The TAN of oil with formic and levulinic acids remained lower for 1500 and 2000 h aging, while the TAN of oil with mixed acid suddenly increased up close to 2000 h of aging. The increase in the TAN of oil with mixed acids during aging can certainly be traced to the generation of high molecular weight acids resulting from oil and paper degradation [6,8,16,18]. These findings are confirmed by partitioning studies reported by Lungaard et al [8,18].…”

Section: Degree Of Polymerisation (Dpv) Before Thermal Agingsupporting

confidence: 63%

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Impact of Low Molecular Weight Acids on Oil Impregnated Paper Insulation Degradation

et al. 2018

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Aging of a power transformer's insulation system produces carboxylic acids. These acids-acetic, formic and levulinic-are absorbed by the paper insulating material, thus accelerating the degradation of the whole insulation system. In this contribution, the effect of these acids on the aging of oil-impregnated paper insulation used in power transformer is reported. A laboratory aging experiment considering different concentrations of these three acids was performed to assess their effect on the insulation system's degradation. Each acid was individually mixed with virgin oil, and a mixture of acids was also blended with oil. The paper's degradation was assessed by the degree of polymerization (DPv). It was found that the DPv of paper aged with formic acid decreased much faster in comparison to the other acids.

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Section: Degree Of Polymerisation (Dpv) Before Thermal Agingsupporting

confidence: 63%

“…Increasing requirements for appropriate tools allowing diagnosing of power transformers non-destructively and reliably has promoted the development of modern complementary diagnostic techniques [1,2]. Research activities are still in progress worldwide to improve these techniques [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Impact of Low Molecular Weight Acids on Oil Impregnated Paper Insulation Degradation

et al. 2018

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“…Dielectric properties, mechanical properties, and thermal behavior are the crucial properties of insulating paper. [ 29–31 ] According to literature, cellulosic paper treated with BTCA crosslinking presented enhanced mechanical properties. [ 32,33 ] BTCA crosslinking could consume hydroxyl groups and change the molecular structure and composition of cellulose, thereby reducing its polarizability.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Cellulose Insulating Paper with Low Dielectric Constant by BTCA Esterification Crosslinking

Yang

Hou

et al. 2020

Macro Materials & Eng

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This study aims to decrease the dielectric constant of kraft paper by 1,2,3,4‐butanetetracarboxylic acid (BTCA) esterification crosslinking. Kraft paper samples are treated with various concentrations of BTCA to prepare modified paper with different reaction degrees. Morphology and surface chemical composition are characterized. The dielectric constant and loss of the plain and modified paper are also investigated. Results show that esterification occurs successfully between cellulose molecular chain and BTCA. The intrinsic dielectric constant and loss of 6 g L−1 BTCA‐treated paper decrease by 23.5% and 36.3%, respectively, at 50 Hz. The esterification can reduce the hydroxyl amounts on cellulose. The formed crosslinking network between the cellulose chains restricts the cellulose orientation polarization, thereby reducing cellulose polarizability. The electrical strength, mechanical properties, and thermal behavior of the samples are explored to evaluate comprehensively the modifying effect. BTCA esterification crosslinking proves to be a promising method for decreasing the dielectric constant of kraft paper.

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“…For these purposes, maintenance policies and procedures are planned and applied to ensure the least interruption of such equipment [1][2][3]. In fact, any failure in this equipment can affect the whole network, compromise other elements in the grid and generate significant economic impacts [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…Due to its complexity and importance, the problems of aging degree of paper insulation has been object of study in many recent works [2][3][4]. Several other tests of insulation items have been an important part of transformers fault diagnosis systems, with emphasis on chromatographic oil-dissolved gas analysis, namely dissolved gas analysis (DGA) [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Autoregressive Neural Network Models for Prediction of Transformer Oil-Dissolved Gas Concentrations

et al. 2018

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Transformers are one of the most important part in a power system and, especially in key-facilities, they should be closely and continuously monitored. In this context, methods based on the dissolved gas ratios allow to associate values of gas concentrations with the occurrence of some faults, such as partial discharges and thermal faults. So, an accurate prediction of oil-dissolved gas concentrations is a valuable tool to monitor the transformer condition and to develop a fault diagnosis system. This study proposes a nonlinear autoregressive neural network model coupled with the discrete wavelet transform for predicting transformer oil-dissolved gas concentrations. The data fitting and accurate prediction ability of the proposed model is evaluated in a real world example, showing better results in relation to current prediction models and common time series techniques.

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Review of Research Progress on the Electrical Properties and Modification of Mineral Insulating Oils Used in Power Transformers

Cited by 89 publications

References 73 publications

Impact of Low Molecular Weight Acids on Oil Impregnated Paper Insulation Degradation

Impact of Low Molecular Weight Acids on Oil Impregnated Paper Insulation Degradation

Preparation of Cellulose Insulating Paper with Low Dielectric Constant by BTCA Esterification Crosslinking

Nonlinear Autoregressive Neural Network Models for Prediction of Transformer Oil-Dissolved Gas Concentrations

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