Electric conduction phenomena and carrier mobility behavior in dielectric fluid with dissolved impurities

Yasufuku, S.; Umemura, Tokihiro; Tanii, T.; Yoshimitsu, Tetsuo

doi:10.1109/eic.1978.7463638

Cited by 1 publication

(2 citation statements)

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“…It can be helpful in understanding the physical and thermal properties, which are relevant when oil is used as a coolant as well as the dielectric. Dynamic viscosity and Ionic mobility are related by Stokes's law and Walden's rule, with the approximation that monovalent ions are present, which are given by the following expressions (7 ) and (8 ) [41–44 ]

μ = \frac{e}{6 π η a}

μ η = constant

where a is the ionic radius, µ is the ionic mobility and η (Pa.s) is the dynamic viscosity. The analysis was carried out with the assumption that monovalent ions are present and its influence gets altered depending on the level of ageing of the insulant.…”

Section: Resultsmentioning

confidence: 99%

“…Ionic radius is a parameter that takes into account the viscosity and mobility, to study the quality of the oil. Studies performed on various dielectric fluids suggested that with the addition of impurities, there was an increase in mobility and also conductivity [44 ]. Previous studies on Ionic mobility were performed on a different type of oils at different temperatures suggested that all the ionic properties tend to follow the Arrhenius laws which can be used for estimating the dielectric properties with less experimental data [43, 44 ].…”

Section: Resultsmentioning

confidence: 99%

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Dielectric properties of mixed mineral and synthetic ester oil

Mahidhar

Karthikeyan

Sarathi

et al. 2020

IET Science, Measurement &Amp; Technology

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The dielectric properties of 20% synthetic ester oil mixed with mineral oil were studied for its potential applications as an insulator in transformers. The corona inception voltage of mixed oil under AC and DC voltages was measured by the ultra‐high frequency (UHF) technique. A statistical study of the breakdown voltage of mixed oil under AC, DC and standard lightning impulse voltages was carried out to obtain a database which would be useful for designing transformer insulation. Further, the mixture was subjected to continuous breakdown studies under AC voltage with lightning impulse voltages, at regular intervals and characterised through measurement of interfacial tension, flash point, ionic mobility as well as UV–vis spectroscopy and frequency‐domain spectroscopy studies to understand the liquid's chemical stability. The results of the study have shown that the mixture was stable even after several breakdowns. The ionic mobility and polarisation current have increased, indicating higher losses in the oil. UHF signal energy analysis and phase‐resolved partial discharge analysis have revealed a reduction in discharge activity with mixed oils.

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