Couette charger for measurement of equilibrium and energization flow electrification parameters: application to transformer insulation

Lyon, Dave; Melcher, James R.; Zahn, M.

doi:10.1109/14.2350

Cited by 54 publications

(13 citation statements)

References 14 publications

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“…Many papers on flow electrification in transformers have been published to identify the various factors that influence this phenomenon. The most important ones are temperature, moisture, the oil flow rate, aging of oil, oil electrical charging tendency, and surface condition [10,[15][16][17][18]. Some experimental measurements have reported that the overall flow electrification increases with temperature to a certain limit situated between 40 • C and 60 • C before decreasing [19].…”

Section: Static Electrification and Flow Electrificationmentioning

confidence: 99%

“…Other devices have been developed using a Couette charging apparatus where the fluid fills the Couette device consisting of rotating coaxial cylinders. The metal cylinder walls can be covered with insulating paper [16,31]. Kedzia [32] introduced an alternative method for testing the electrification of transformer oil based on a spinning disk in the liquid.…”

Section: Static Electrification and Flow Electrificationmentioning

confidence: 99%

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Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

Fofana

Hadjadj

2016

Energies

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Abstract:The condition of the internal cellulosic paper and oil insulation are of concern for the performance of power transformers. Over the years, a number of methods have been developed to diagnose and monitor the degradation/aging of the transformer internal insulation system. Some of this degradation/aging can be assessed from electrical responses. Currently there are a variety of electrical-based diagnostic techniques available for insulation condition monitoring of power transformers. In most cases, the electrical signals being monitored are due to mechanical or electric changes caused by physical changes in resistivity, inductance or capacitance, moisture, contamination or aging by-products in the insulation. This paper presents a description of commonly used and modern electrical-based diagnostic techniques along with their interpretation schemes.

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Section: Static Electrification and Flow Electrificationmentioning

confidence: 99%

Section: Static Electrification and Flow Electrificationmentioning

confidence: 99%

Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

Fofana

Hadjadj

2016

Energies

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“…The concept of rotating coaxial cylindrical electrodes brought about the development of a variety of Couette Chargers, first reported by Lyon et al [113]. They were used in the EPRI-sponsored MIT project on flow-induced electrification of liquid-insulated equipment.…”

Section: Couette Chargersmentioning

confidence: 98%

Electrostatic charging in transformer oils. Testing and assessment

Sierota

Rungis

1994

IEEE Trans. Dielect. Electr. Insul.

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“…4, where the inner cylinder can rotate at speeds giving laminar and turbulent flows as well as the transition cellular convection regime Lyon, 1987). The cylinder walls on either side of the oil gap can be bare metal or can be covered with oil-impregnated paper used in transformers.…”

Section: Electric Power Apparatusmentioning

confidence: 99%

Space Charge Effects in Dielectric Liquids

Zahn

1988

The Liquid State and Its Electrical Properties

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Insulating liquid dielectrics used in power apparatus, such as transformers and cables, and in pulse power technology, such as Marx generators and pulse forming lines, have their performance affected by injected space charge. The space charge distorts the electric field distribution and introduces the charge migration time between electrodes as an additional time constant over the usual dielectric relaxation and fluid transport times. Pipe flows and a Couette flow system of coaxial cylinders where the inner cylinder can rotate are described which measure the streaming current for flow electrification where the mobile part of the electrical double layer is entrained in the flow. Charge injection from high voltage stressed electrodes is measured by this Couette apparatus as well as by Kerr electrooptic field and charge mapping measurements. Such optical measurements are described between parallel plate and coaxial cylindrical electrodes for nitrobenzene, ethylene carbonate, highly purified water, water/ethylene glycol mixtures, transformer oil, liquid and gaseous SF 6 , and high voltage stressed and electron beam irradiated polymethylmethacrylate. Specific attention is directed to highly purified water because Kerr electrooptic measurements, voltage-current terminal measurements, and electrical breakdown tests have shown that the magnitude and polarity of injected charge and the electrical breakdown strength depend strongly on electrode material combinations and voltage polarity. APPLICATIONS OF LIQUID INSULATIONFor greater efficiencies in ac and dc power generation and transmission, and for larger energies in such pulsed power applications as

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Couette charger for measurement of equilibrium and energization flow electrification parameters: application to transformer insulation

Cited by 54 publications

References 14 publications

Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

Electrostatic charging in transformer oils. Testing and assessment

Space Charge Effects in Dielectric Liquids

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