Comparative evaluation of parameters of the dielectric breakdown test on transformer oil

Vincent, Claire; Benoît, Clémentine; Olivier, R.

doi:10.1109/icdl.1996.565505

Cited by 12 publications

(4 citation statements)

References 3 publications

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“…Thus, the influence of the particles is considered as being negligible with respect to the class of particulate pollution we obtained for each sample [6]. Also, the IEC 60156 method is not sufficiently sensitive to oil particle contamination [7] to be influenced by particles of this size present in the samples. The BDV results are characterized by means of the cumulative Gaussian probabilities approach, which seems to be the most appropriate method.…”

Section: Breakdown Voltagementioning

confidence: 99%

Improvement of power transformers by using mixtures of mineral oil with synthetic esters

Perrier

Béroual

Bessede

2006

IEEE Trans. Dielect. Electr. Insul.

111

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This paper is aimed at the optimization of power transformer insulation via the improvement of the characteristics of the most commonly used insulating liquid, i.e., mineral oil. For that purpose, mixtures consisting of mineral oil and other insulating liquids (namely silicon and synthetic ester oils) are investigated. The main properties such as the heat transfer, breakdown voltage (BDV), aging stability and electrostatic charging tendency (ECT) of different mixtures as well as the liquids alone are compared. The heat transfer is studied by means of kinematic viscosity. The measurements of breakdown voltage are analyzed by means of Gaussian probabilities. The results of aging tests at controlled temperature and in contact with atmosphere are presented, as well as the ECT effect versus the oil humidity and resistivity. It is shown that the best mixture enabling optimization of the power transformer insulation, (i. e. improving the dielectric properties and the aging stability of mineral oil without degrading its viscosity and ECT), is that of mineral oil with 20% by volume of synthetic ester oil.

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Section: Breakdown Voltagementioning

confidence: 99%

Improvement of power transformers by using mixtures of mineral oil with synthetic esters

Perrier

Béroual

Bessede

2006

IEEE Trans. Dielect. Electr. Insul.

111

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“…VDE electrode with a diameter of 36 mm facing at each other at a gap distance of 1 mm was used in the test. This configuration represents the quasi-uniform field which is mainly relevant to insulation structure in transformers where in such configurations, the dielectric strengths of the insulating liquid mainly depend on the liquid qualities [14]. The test container was filled with 400ml fluid and the voltage ramping rate was set to 0.5 kV/s.…”

Section: Ac Breakdown Testmentioning

confidence: 99%

Effect of Particles on the AC Breakdown Voltage of Palm Oil and Coconut Oil

Sinan

Jasni

Azis

et al. 2015

AMM

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Under current scenario of regulation on the safety and environment, biodegradable oils are gaining interest as dielectric insulating fluid in transformers. There are different types of biodegradable oils that are currently examined and among them are Palm Oil (PO) and Coconut Oil (CO). It is important to carry out extensive examination on these oils at laboratory level since the failure in-service could be costly. Among the important studies are the AC breakdown strength properties under the influence of particles. In this paper, a study is carried out to examine the influence of particles on the AC breakdown voltage of POand CO. The PO used in this study is Refined Bleached and Deodorized (RBDPO) Olein type. Two types of particles are used for the investigations which are cellulose and copper particles.Four different weights of particles are added on each of the samples and tested with the AC breakdown tester at a gap distance of 1 mm using VDE electrodes. It was found that copper particles have more significant effect on the AC breakdown strength of RBDPO and CO than cellulose particles.

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“…An idea therefore is to use a coaxial electrode arrangement. There are also considerations to replace the ramp voltage by a step-by-step test voltage [2,4]. An result of such tests is presented in the following Fig.…”

Section: Measurementsmentioning

confidence: 99%

“…Breakdown field (vertical scale) versus particles contamination of the oil (horizontal scale) for different breakdown test methods, according[4] …”

mentioning

confidence: 99%

Improvement of the Test Method for Insulating Oils

Lick

Pukel

Muhr

Conference Record of the 2006 IEEE International Symposium on Electrical Insulation

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Standard dielectric breakdown tests for insulating oils consist of five or six single breakdowns in a glass or a plastic vessel with about 0.5 litter test oil content. For each breakdown the voltage is raised up linear from zero to the breakdown value usually by 0,5 … 3 kV/s. After filling the test cell with the test oil there is a pause between 3 to 10 minutes until the start of the first breakdown test. Between each breakdown there are breaks about 1 … 2 minutes. Optional, a stirrer produces an oil circulation in the test oil. The form of electrodes are different, according VDE (sphere formed) or ASTM (flat formed). With these single breakdown values the mean value, a parameter for the oil quality, and the coefficient of variation were calculated. A weak point of the standard dielectric breakdown tests is that it is possible to reach values for the coefficient of variation up to 30 % and higher. Further repeated tests lead frequently to contradictory results. So the standard oil test is very common but the results are sometimes not satisfied. Therefore we have performed breakdown tests with changing test parameters like pause times, different voltage raising up velocities and with and without stirring. Further we have tried to use additional methods for filling the test cell with test oil or better cleaning of the electrodes after each breakdown. And last but not least we have also created a new test cell. This paper will show the results of our efforts.

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Comparative evaluation of parameters of the dielectric breakdown test on transformer oil

Cited by 12 publications

References 3 publications

Improvement of power transformers by using mixtures of mineral oil with synthetic esters

Improvement of power transformers by using mixtures of mineral oil with synthetic esters

Effect of Particles on the AC Breakdown Voltage of Palm Oil and Coconut Oil

Improvement of the Test Method for Insulating Oils

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