Solubility of carboxylic acids in paper (Kraft)-oil insulation systems

Ingebrigtsen, S.; Dahlund, Mats; Hansen, W. C.; Linhjell, D.; Lundgaard, L.E.

doi:10.1109/ceidp.2004.1364236

Cited by 40 publications

(26 citation statements)

References 3 publications

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“…It is known that the ageing of pressboard will produce moist soluble carboxylic acids. The severer the deterioration of the pressboard, the larger the quantity of acids it generates [15,35,37]. The natural ester can restrain the ageing rate of pressboard effectively [2,6,9,22,23,34].…”

Section: Acids Content Of Oil Impregnatedmentioning

confidence: 99%

A comparative study of physicochemical, dielectric and thermal properties of pressboard insulation impregnated with natural ester and mineral oil

Liao

Hao

Chen

et al. 2011

IEEE Trans. Dielect. Electr. Insul.

190

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Natural ester is considered to be a substitute of mineral oil in the future. To apply natural ester in large transformers safely, natural ester impregnated solid insulation should be proved to have comparable dielectric strength and thermal stability to mineral oil impregnated solid insulation. This paper mainly focuses on a comparative study of physicochemical, ac breakdown strength and thermal stability behavior of BIOTEMP natural ester/pressboard insulation and Karamay 25# naphthenic mineral oil/pressboard insulation after long term thermal ageing. The physicochemical and dielectric parameters including moisture, acids and the ac breakdown strength of these two oil/pressboard insulation systems at different ageing status were compared. The permittivity and ac breakdown strength of these two oil/pressboard insulation systems at different temperatures were also investigated. And a comparative result of the thermal stability behavior of these two oil/pressboard insulation systems with different ageing status was provided at last. Results show that though natural ester has higher absolute humidity and acidity during the long ageing period, the lower relative humidity of natural ester helps to keep its ac breakdown strength higher than mineral oil. The pressboard aged in natural ester also has higher ac breakdown strength than that aged in mineral oil. The lower relative permittivity ratio of natural ester impregnated paper to natural ester is beneficial to its dielectric strength. Using natural ester in transformer, the resistance to thermal decomposition of the oil/pressboard insulation system could be also effectively improved.Index Terms -Natural ester, mineral oil, pressboard, physicochemical, dielectric strength, thermal stability.

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Section: Acids Content Of Oil Impregnatedmentioning

confidence: 99%

A comparative study of physicochemical, dielectric and thermal properties of pressboard insulation impregnated with natural ester and mineral oil

Liao

Hao

Chen

et al. 2011

IEEE Trans. Dielect. Electr. Insul.

190

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“…The failure rate of the other parts of bushings is far less than that of the capacitor core [6]. Thus, the crucial insulation part of capacitive bushing is the internal capacitive core [7].…”

Section: Introductionmentioning

confidence: 94%

“…The construction of capacitor core is shown in Figure 1. It is mentioned in [7] that the main manufacturing steps for a bushing consist of rolling the capacitor core, vacuum drying, assembly and vacuum oil immersion, as shown in Figure 2. The manufacturing steps of a condenser core [7].…”

Section: Test Samplementioning

confidence: 99%

“…(2) Identify the layer number of aluminum foil and the thickness of insulation In accordance with the insulation requirement of a 10 kV bushing, according to reference [7], the number of layers should be three. The common insulation layer thickness is approximately 1.0-1.2 mm, so a nine-layer cable paper (approximately 1.08 mm) is selected as an insulating layer.…”

Section: Test Samplementioning

confidence: 99%

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Study of the Impact of Initial Moisture Content in Oil Impregnated Insulation Paper on Thermal Aging Rate of Condenser Bushing

et al. 2015

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This paper studied the impact of moisture on the correlated characteristics of the condenser bushings oil-paper insulation system. The oil-impregnated paper samples underwent accelerated thermal aging at 130˝C after preparation at different initial moisture contents (1%, 3%, 5% and 7%). All the samples were extracted periodically for the measurement of the moisture content, the degree of polymerization (DP) and frequency domain dielectric spectroscopy (FDS). Next, the measurement results of samples were compared to the related research results of transformer oil-paper insulation, offering a theoretical basis of the parameter analysis. The obtained results show that the moisture fluctuation amplitude can reflect the different initial moisture contents of insulating paper and the mass ratio of oil and paper has little impact on the moisture content fluctuation pattern in oil-paper but has a great impact on moisture fluctuation amplitude; reduction of DP presents an accelerating trend with the increase of initial moisture content, and the aging rate of test samples is higher under low moisture content but lower under high moisture content compared to the insulation paper in transformers. Two obvious "deceleration zones" appeared in the dielectric spectrum with the decrease of frequency, and not only does the integral value of dielectric dissipation factor (tan δ) reflect the aging degree, but it reflects the moisture content in solid insulation. These types of research in this paper can be applied to evaluate the condition of humidified insulation and the aging state of solid insulation for condenser bushings.

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“…Besides, power transformer life governance is an important topic in the modern power operation system. Oil filled power transformer technology has been used for more than 50 years [1]. Impurity is the principal factor that diminishes the insulating efficiency [2].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the usage of palm oils with the aim of insulation in high voltage power system equipments

2015

Teh. vjesn.

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Original scientific paper Power system equipment have conventionally used mineral oil for insulation and cooling. The preferable alloy material has to be generated with good chemical and electrical features. However, recent case has indicated the shortcomings of these fluids where they have poor characteristics particularly at fire and flash point and most significantly poor dielectric malfunction voltage. The most critical of these deficiencies is the disability to meet up with the environmental and health laws. Further, they are not organic and hence not biodegradable. In this study, natural palm oil and its derivatives have been studied in attempt to discover an environmental friendly insulating fluid. Patterns such as crude and refined palm oils were chemically and electrically tested and comparisons were made with the mineral oil. Electrical tests such as the malfunction voltage, power factor and resistivity were pursued. Besides that, chemical characteristics such as water content, kinematic viscosity, moisture content of the alloy, flash point, density, pour point, corrosion, neutralization value and dissolution of gases were also being investigated. Results from the test laboratory studies have indicated that the natural palm oil has preferable chemical and electrical features as compared to the existing mineral oil for power system equipment insulation.Keywords: electrical breakdown stress; interfacial tension; mineral oil; palm oil; power factor Istraživanje o uporabi palminih ulja za izolaciju opreme energetskog sustava velike snageIzvorni znanstveni članak U opremi energetskog sustava uobičajeno se koristi mineralno ulje za izolaciju i hlađenje. Preferirani legirni materijal mora imati dobre kemijske i električne karakteristike. Međutim, nedavni je slučaj ukazao na nedostatke tih fluida i loše karakteristike naročito kod točke paljenja i plamišta, i najvažnije, na slabi dijalektrički napon. Njihov najbitniji nedostatak je nepoštivanje zakona o zaštiti zdravlja i okoliša. Nadalje, oni nisu organski i stoga nisu biološki razgradivi. U ovom radu, prirodno palmino ulje i njegovi derivati proučavani su kako bi se pronašao izolirajući fluid bez loših posljedica za okoliš. Uzorci nerafiniranog i rafiniranog palminog ulja kemijski su i električki ispitani te uspoređeni s mineralnim uljem. Provedena su električna ispitivanja kao na pr. neodgovarajući napon, faktor snage i otpornost. Osim toga također su ispitivane kemijske karakteristike kao što su sadržaj vode, kinematički viskozitet, sadržaj vlage legure, plamište, gustoća, temperatura tečenja metala prilikom lijevanja, korozija, vrijednost neutralizacije i rastvaranje plinova. Rezultati laboratorijskih ispitivanja pokazali su da prirodno palmino ulje ima poželjnija kemijska i električna svojstva u usporedbi s postojećim mineralnim uljem za izolaciju opreme energetskog sustava.Ključne riječi: električni probojni napon; faktor snage; mineralno ulje; naprezanje u dodirnoj površini; palmino ulje

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Solubility of carboxylic acids in paper (Kraft)-oil insulation systems

Cited by 40 publications

References 3 publications

A comparative study of physicochemical, dielectric and thermal properties of pressboard insulation impregnated with natural ester and mineral oil

A comparative study of physicochemical, dielectric and thermal properties of pressboard insulation impregnated with natural ester and mineral oil

Study of the Impact of Initial Moisture Content in Oil Impregnated Insulation Paper on Thermal Aging Rate of Condenser Bushing

Investigation of the usage of palm oils with the aim of insulation in high voltage power system equipments

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