A modified X-model of the oil-impregnated bushing including non-uniform thermal aging of cellulose insulation

Liu, Jiefeng; Yang, Shichang; Zhang, Yiyi; Zheng, Hanbo; Shi, Zhen; Zhang, Chaohai

doi:10.1007/s10570-020-03086-w

Cited by 17 publications

(12 citation statements)

References 31 publications

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“…The research of oil-paper insulation of the transformer has received extensive attention [7]- [9], and the aging mechanism of oil-paper insulation have been fully studied. Insulation aging is closely related to the internal temperature field of the transformer.…”

Section: Introductionmentioning

confidence: 99%

A Prediction Model of Hot Spot Temperature for Split-Windings Traction Transformer Considering the Load Characteristics

et al. 2021

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Hot spot temperature (HST) is an important parameter reflecting the working state of the traction transformer, and the load characteristics have a great influence on the HST. The current researches rarely consider the load characteristics of transformers in-depth, and most of the research on the temperature field focuses on steady load. Therefore, a prediction model of HST for the traction transformer considering the load characteristics is established by the finite element simulation in this paper. Considering the impact and nonlinearity of traction load, the influence of the load characteristics on the HST is studied. Analysis of the load curve revealed that the steady and step load combination could well simulate the traction load. Based on the analysis of traction transformer load characteristics, the temperature field coupling calculation of traction transformer is carried out according to the VI normative duty class. On this basis, the influence of load rate and time on HST is studied. The present findings show that the method can predict the HST of traction transformer under different working conditions and provide a reference for load dispatching of traction transformer. The simulation data are in good agreement with the test results, and the average relative error is 3.4%. The results verify the effectiveness of the proposed method.INDEX TERMS Traction transformers, hot spot temperature, load characteristics, temperature field analysis, finite element simulation.

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Section: Introductionmentioning

confidence: 99%

A Prediction Model of Hot Spot Temperature for Split-Windings Traction Transformer Considering the Load Characteristics

et al. 2021

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“…Generally, the main insulation of a power transformer is composed of mineral-insulating oil and insulating cellulose. However, the main insulation of the transformer is irreversibly deteriorated due to the combined effects of electrical, thermal, vibration, and other aging factors during long-term operation [ 5 , 6 , 7 , 8 , 9 ]. Based on the current studies, the aging of cellulose insulation will result in serious failure problems for transformers [ 10 ], which may bring security risks to the power system and cause huge socioeconomic losses.…”

Section: Introductionmentioning

confidence: 99%

Influence of Oil–Pressboard Mass Ratio on the Equilibrium Characteristics of Furfural under Oil Replacement Conditions

et al. 2020

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The distribution behavior of furfural in insulation systems is influenced by the oil–pressboard mass ratio. In addition, the equilibrium distribution of furfural between oil and pressboard will be disturbed after oil replacement. Therefore, it is of great significance to study the distribution ratio of furfural in oil with various oil–pressboard mass ratios after oil replacement. In this research, an accelerated thermal aging experiment and oil replacement experiment were conducted in the lab. Furthermore, the equilibrium characteristics of furfural dissolved in oil with various oil–pressboard mass ratios were studied. Multiple regression analysis was used to analyze the relationship between the oil–pressboard mass ratios and the distribution ratio of furfural in oil. The equilibrium distribution model of furfural was thus obtained. Afterwards, the modified furfural distribution model under oil replacement conditions was established. A novel scheme is provided for analyzing the equilibrium characteristics of furfural under various oil–pressboard mass ratios after oil replacement. The work of this paper is expected to improve the accuracy of furfural analysis.

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“…Reviewing the existing researches, the approaches for state evaluation and condition monitor of transformer cellulose insulation have been widely reported. The typical analysis method is constituted of direct measurement (including the degree of polymerization [7], tensile strength [8], and Karl Fischer titration [9]), dissolved chemical indicators in the oil (dissolved gas [10], acid, aldehyde [11], furfural [12]), electrical indicators (insulation resistance, absorption ratio [13]), the theory of chemical reaction kinetics (aging kinetics model [14]- [16]), and especially dielectric response technique (time-domain response [17][18] and frequency-domain spectroscopy, FDS [19]- [20]). Relying on the strong anti-interference and the rich insulation information, the FDS is thus of great interest to the scholars in lab or field conditions [4].…”

Section: Introductionmentioning

confidence: 99%

Normalization for FDS of Transformer Insulation Considering the Synergistic Effect Generated by Temperature and Moisture

et al. 2020

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Frequency domain spectroscopy (FDS) technique is widely applied in the condition assessment of the oil-paper system in power transformers. However, the synergistic effect generated by moisture and temperature on the FDS data cannot be analyzed by the existing model since the single independent variable (moisture or temperature) is considered in the construction of the model. To quantify such the synergistic effect, a novel method that utilized for normalizing (or standardizing) the FDS curve is reported based on the theory of the power series and fitting analysis. The present findings reveal that the reported method is capable of predicting the dielectric loss (tanδ) curve under diverse test conditions, in which the average error is less than 7%. The synergistic effect can be also explored by using the extracted feature parameters. The potential application is then proved to make up for the measurement errors during the FDS test, the findings are expected to promote the moisture analysis of the transformer insulation.

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A modified X-model of the oil-impregnated bushing including non-uniform thermal aging of cellulose insulation

Cited by 17 publications

References 31 publications

A Prediction Model of Hot Spot Temperature for Split-Windings Traction Transformer Considering the Load Characteristics

A Prediction Model of Hot Spot Temperature for Split-Windings Traction Transformer Considering the Load Characteristics

Influence of Oil–Pressboard Mass Ratio on the Equilibrium Characteristics of Furfural under Oil Replacement Conditions

Normalization for FDS of Transformer Insulation Considering the Synergistic Effect Generated by Temperature and Moisture

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