Experimental studies of influence of DC and AC electric fields on bridging in contaminated transformer oil

Mahmud, Shekhar; Chen, G.; Golosnoy, Igor O.; Wilson, Gordon; Jarman, Paul

doi:10.1109/tdei.2014.004573

Cited by 82 publications

(44 citation statements)

References 22 publications

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“…The twoparameter Weibull distribution is shown in Eq. (1), where F(u) is the probability of breakdown, α is the scale parameter and β is the shape parameter and u is breakdown [4][5][6][7] show that the breakdown voltage data of contaminated oil are distributed in both sides of the Weibull probability straight line, which indicates that the breakdown voltage data of contaminated oil almost satisfy the Weibull distribution.…”

Section: Weibull Distribution Analysismentioning

confidence: 99%

“…The particles in transformer insulating oil will move to the high electric field region and form impurity bridges due to the electric field force, which will reduce the breakdown strength of the insulating oil [3]. The motion of particles at combined AC and DC voltage is different from that at AC voltage, which will lead to different breakdown characteristics of contaminated insulating oil [4]. Investigation into the breakdown characteristics of transformer insulating oil contaminated with solid particles at combined AC and DC voltage is conductive to the understanding of breakdown mechanism of insulating oil used in converter transformer in presence of particle contamination.…”

Section: Introductionmentioning

confidence: 99%

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Copper Particle Effect on the Breakdown Strength of Insulating Oil at Combined AC and DC Voltage

Wang¹,

Li²,

Wei³

et al. 2017

Journal of Electrical Engineering and Technology

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-Converter transformer is the key equipment of high voltage direct current transmission system. The solid suspending particles originating from the process of installation and operation of converter transformer have significant influence on the insulation performance of transformer oil, especially in presence of DC component in applied voltage. Under high electric field, the particles easily lead to partial discharge and breakdown of insulating oil. This paper investigated copper particle effect on the breakdown voltage of transformer oil at combined AC and DC voltage. A simulation model with single copper particle was established to interpret the particle effect on the breakdown strength of insulating oil. The experimental and simulation results showed that the particles distort the electric field. The breakdown voltage of insulating oil contaminated with copper particle decreases with the increase of particle number, and the breakdown voltage and the logarithm of particle number approximately satisfy the linear relationship. With the increase of the DC component in applied voltage, the breakdown voltage of contaminated insulating oil decreases. The simulation results show that the particle collides with the electrode more frequently with more DC component contained in the applied voltage, which will trigger more discharge and decrease the breakdown voltage of insulating oil.

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Section: Weibull Distribution Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Copper Particle Effect on the Breakdown Strength of Insulating Oil at Combined AC and DC Voltage

Wang¹,

Li²,

Wei³

et al. 2017

Journal of Electrical Engineering and Technology

View full text Add to dashboard Cite

show abstract

“…Thus, when the HVDC reaches its saturated level, the current will flow through the cellulose particles between the electrodes, leading to breakdown. Several researchers have also observed this phenomenon [12], [22], [23].…”

Section: Stage Fivementioning

confidence: 71%

“…It is believed that this phenomenon occurs due to the distribution of the electric field generated between the electrodes and cellulose particles attached on the electrode surface. In addition, it has been reported that the cellulose bridge ) to flow between the electrodes [12].…”

Section: Stage Threementioning

confidence: 99%

Dielectrophoresis Effect of Dielectric Liquids with Suspended Cellulose Impurities under DC Electric Field

Zainoddin¹,

Zainuddin²,

Aman³

2017

IJECE

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For decades, petroleum-based mineral oils are the insulating media conventionally used in the industry, particularly for high voltage (HV) applications. However, due to the disadvantages of mineral oils, there is growing interest in replacing these oils with environmentally friendly alternatives in order to fulfill the demanding requirements of dielectric liquids. One of the promising substitutes for mineral oils is ester oils. Nevertheless, the implementation of ester oils is not widespread compared with mineral oils due to the lack of understanding on the performance of ester oils in HV applications. Hence, the objective of this study is to investigate the bridging phenomenon of two dielectric liquids with different viscosities: palm fatty acid ester and mineral oil under the influence of direct current electric field. The results show that oil viscosity plays an important role in the formation of cellulose bridge and breakdown behavior. Keyword:Mineral oil Ester oil Bridging Cellulose pressboard Dielectrophoresis

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“…Dodecylbenzene was chosen as as a model oil system whose viscosity does not change after aging [10]. Furthermore, the effect of precipitate formation on the high field performance of such oils was studied in view of particulate "bridging", which can prove troublesome in paper/oil insulation systems [7,14].…”

Section: Introductionmentioning

confidence: 99%

Effect of aging on the physical, chemical and dielectric properties of dodecylbenzene cable oil

Hosier

Koilraj

Vaughan

2016

2016 IEEE International Conference on Dielectrics (ICD)

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Abstract-In high voltage transformers a liquid dielectric, such as mineral oil, serves both as an electrical insulator (in conjunction with paper) and as a coolant. Similarly, in paper/oil cables mineral oil or dodecylbenzene in conjunction with paper serves as the electrical insulator. In such systems, the oil serves as a convenient medium for sampling to indicate plant health. In the current study dodecylbenzene was aged at elevated temperatures in the presence of air and copper. A battery of tests was then performed to assess the changes in physical, chemical and electrical properties. After aging the oils were yellowed and oils aged with copper showed oxidation, increased water content and the formation of a precipitate, whilst those aged in the absence of copper showed much less aging. Changes in electrical properties were noted such as increased dielectric loss, increased electrical conductivity and decreased dielectric breakdown strength. It was found that the presence of the precipitate did not affect the electrical properties of the oil.

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Experimental studies of influence of DC and AC electric fields on bridging in contaminated transformer oil

Cited by 82 publications

References 22 publications

Copper Particle Effect on the Breakdown Strength of Insulating Oil at Combined AC and DC Voltage

Copper Particle Effect on the Breakdown Strength of Insulating Oil at Combined AC and DC Voltage

Dielectrophoresis Effect of Dielectric Liquids with Suspended Cellulose Impurities under DC Electric Field

Effect of aging on the physical, chemical and dielectric properties of dodecylbenzene cable oil

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