Electrical field distribution in transformer oil

Gäfvert, U.; Jaksts, A.; Törnkvist, C.; Walfridsson, Lars

doi:10.1109/14.142730

Cited by 134 publications

(49 citation statements)

References 17 publications

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“…(26,29) At about the same period of time, measurement techniques were developed for the measurement of two-dimensional electric fields on the surface of dielectric solids in air using the Pockels effect.…”

Section: ∆V(t) =mentioning

confidence: 99%

“…(13,14) 3.3 Applications of optic methods to insulation system for power equipment A combination of optic methods and the PWP/PEA methods make it possible to measure the distribution of space charge in liquid/solid and gas/solid insulation systems that are often used in power equipment, such as in cables, transformers, bushings, reactors, capacitors, circuit breakers, motors, and generators. The Kerr effect method has been used to measure the electric field distribution in liquids, such as in transformer mineral oils (26)(27)(28)(29)(30) (Fig. 6).…”

Section: Applications To Power Transformersmentioning

confidence: 99%

“…The pressure pulse techniques have also been used for the measurement of space charge in composite oil/cellulose insulating systems. (21)(22)(23)(24)(25) For the measurement of electric fields and space charge in liquid dielectrics and surface charge on solids in air, the electrooptic Kerr effect technique (26)(27)(28)(29)(30) and Pockels effect technique (31)(32)(33) have been developed. In comparison with the earliest slice method, (34) these latest techniques can be used to measure quantitatively the distribution of space charge in an insulating material nondestructively, and thus are valuable tools in helping to understand the electrical behaviors of an insulation system in the development of power equipment, such as high-voltage direct-current (HVDC) cables ( Fig.…”

Section: Introductionmentioning

confidence: 99%

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Space Charge Measurement Technologies and Their Potential Applications

2017

Sensors and Materials

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The development history of major space-charge measurement technologies is reviewed. Advantages and disadvantages are analyzed regarding the electron beam, thermal pulse, pressure wave, pulsed electroacoustic wave, electrooptic Kerr effect, and Pockels effect methods. Measurement technologies are discussed further with regard to principles, knowhow, and milestones of development. With the pulsed electroacoustic method as an example, a deconvolution technique is introduced, as it is needed to quantify the density of space charge in a material. Potential applications of these technologies to measure the distribution of space charge in dielectrics and electrical insulation materials and systems are addressed. By the electrooptic Pockels effect method, two-dimensional discharge patterns on the surfaces of cellulose Kraft paper and Nomex T410 paper were measured and reported for the first time. With the progress of the technologies, it appears that today, sensors can be made to measure quantitatively the distribution of space charge in dielectrics and electrical insulation systems.

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Section: ∆V(t) =mentioning

confidence: 99%

Section: Applications To Power Transformersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Space Charge Measurement Technologies and Their Potential Applications

2017

Sensors and Materials

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“…From the literature it is clear that the ionic transports in the insulation liquids have to be taken into account in order make good predictions of the electrical field distribution under voltage stress. The so called ion-drift models have been discussed by several authors during the past decades [1][2][3]. Such models include dissociation of ions from pre-existing ion pairs as well as transport of ions in electrical field.…”

mentioning

confidence: 99%

“…[2] Kerr measurements of the electrical field over a 19 mm mineral oil gap are presented. At 2 kV a symmetric parabolic distribution of the electrical field along the oil gap is observed.…”

mentioning

confidence: 99%

Comparison of simulated and measured field dependent charge injection in mineral oil under dc bias

Hjortstam¹,

Sonehag²,

Schiessling³

2018

NORD-IS

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The present study aims at the understanding of charge injection from metal electrodes into mineral oil under DC stress. The work focuses on the field dependence of the charge injection. In a previous article the electrical field in a blank oil gap with parallel electrodes is measured with a so called Kerr electro-optic technique. The data show that the electrical field is close to symmetric for low fields (~ 0.1 kV/mm) but strongly asymmetric at higher fields (~ 1 kV/mm). In the present study an ion drift model is used to analyze the data. We show that an ion drift model including a field dependent injection term can reproduce the measured results fairly well. Furthermore, the comparison of measured and simulated results shows that the charge injection is stronger from an electrode with positive polarity compared to one of negative polarity.During the last years it has been a push for Ultra High Voltage Direct Current (UHVDC) transmission systems, due to the rising demands on transmitting electrical power over long distances. A key component in such systems is the mineral oil insulated HVDC converter transformer. The increased voltage levels are calling for a deeper understanding of high field phenomena under dc stress in mineral oil based insulation systems.

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Conduction and Breakdown in Dielectric Liquids

Zahn

1999

Wiley Encyclopedia of Electrical and Electronics Engineering

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The sections in this article are Overview of Liquid Dielectrics Liquid Insulation Systems Charge Injection and Conduction Streamers Space‐Charge Effects Zero Recombination Limit (α = 0) Langevin Recombination Limit Kerr Electrooptic Field Mapping Measurements Sensitive Kerr Electro‐Optic Measurements with Weakly Birefringent Materials Kerr Electro‐Optic Measurements with Electric Field Magnitude and Direction Varying Along the Light Path Acknowledgments

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Electrical field distribution in transformer oil

Cited by 134 publications

References 17 publications

Space Charge Measurement Technologies and Their Potential Applications

Space Charge Measurement Technologies and Their Potential Applications

Comparison of simulated and measured field dependent charge injection in mineral oil under dc bias

Conduction and Breakdown in Dielectric Liquids

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