Investigation of static electrification phenomenon due to transformer oil flow in electric power apparatus

Radwan, R.M.; El-Dewieny, Reda M.K.; Metwally, I.A.

doi:10.1109/14.135599

Cited by 42 publications

(16 citation statements)

References 7 publications

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“…One can also notice that for aged oil 1, the current is more influenced by the temperature than by the rotating velocity in the considered range; the current variation shows some stabilisation when the velocity is changed. For the temperature of oil of 80°C, one observes some decrease in the current when the velocity increases Similar results have been obtained by Radwan et a1 [6] with PerspexT" and TeflonT" disk materials. Let us consider now a disk coated with pure aluminium (5N), we remark that all the measured current are negative for a new oil (Fig.4) whereas they are all positive for aged oil 1 (Fig.5).…”

Section: Resultssupporting

confidence: 87%

Influence of thin layers on static electrification phenomena of materials for power transformers

Rottenberg

Fleszyński²,

Béroual³

Conference Record of the 1998 IEEE International Symposium on Electrical Insulation (Cat. No.98CH36239)

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The static electrification phenomenon is investigated, using a test cell with a rotating metallic disk coated on both sides with thin layers (0,5 and 2 pm) of conducting, semiconducting and insulating materials, obtained by magnetron sputtering. The current characterising the static electrification is studied as a function of the nature of the coating material and the oil, the temperature and the rotating velocity of the disk. Modification of the surface properties has a decisive influence on the static electrification of insulating oils, the sign and the amplitude of the currents are strongly affected.

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Section: Resultssupporting

confidence: 87%

Influence of thin layers on static electrification phenomena of materials for power transformers

Rottenberg

Fleszyński²,

Béroual³

Conference Record of the 1998 IEEE International Symposium on Electrical Insulation (Cat. No.98CH36239)

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“…The vessel (7) is inserted in the loop and constitutes of a relaxation zone for the remaining charges and may be used either for pressurisation with gas or for oil recovering under vacuum. Oil resistivity and moisture content are measured online by a laboratory-made conductivity cell (8,9,10) and a moisture measurement device (Panametrics) (11,12), respectively. The capacitive sensor (5) and the streaming vessel (6) are shielded by a grounded steel 'Faraday' cage (13) [9][10][11][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Behaviour of electrical double layer under oil flow and voltage application inside a capacitive sensor

Metwally

LeBlanc

Paillat

2015

IET Science, Measurement & Technology

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This study presents an experimental investigation of the behaviour of electrical double layer (EDL) under oil flow and voltage application inside a capacitive sensor. This sensor is incorporated in a closed-loop filled with fresh transformer oil. The sensor configuration allows a potential application for risk assessment. The behaviour of EDL is investigated by recording the streaming and the capacitive current waveforms for grounded and energised middle copper-electrode cases and at different oil-flow velocities and temperatures. The effect of direct and alternating voltage energisation is examined for different wave shapes and frequencies. In addition, the physicochemical reaction coefficient, the wall space-charge density and the accumulated charges inside the sensor are calculated by the static and the dynamic methods. The results are interpreted in terms of EDL evolution, physicochemical reaction at the solid-liquid interface, relaxation time of charges and electron emission from the negatively energised electrode. The results reveal that the calculated wall space-charge density slightly decreases with the increase in the oil-flow velocity, contrary to the physicochemical reaction coefficient. For the case of AC energisation, the results show that there is an innocuous effect of the generated harmonic voltages on the oil-flow electrification phenomenon.

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“…The entire electric field reaches its peak value when AC voltage is in the phase between 180 • and 360 • . Thus, partial discharges take place around 270 • at first in Figures 10 and 12 [25,26].…”

Section: The Influence Of Ac/dc Proportion On the Prpd Patternsmentioning

confidence: 99%

“…As shown in Table 1, AC electric field intensity decreases with the decrease of AC component in AC-DC combined voltage. Therefore, the intensity of the DC electric field needs to be increased to reach the condition of the initial discharge for the needle-plane defect, and DC component in combined voltages should be raised [24,25].…”

Section: The Influence Of Ac/dc Proportion On the Pdiv And Breakdown mentioning

confidence: 99%

Partial Discharge of Needle-Plane Defect in Oil-Paper Insulation under AC and DC Combined Voltages: Developing Processes and Characteristics

Sun

Zhu

et al. 2017

Energies

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Partial discharge (PD) behaviors of oil-paper insulation is distinctive in AC and DC combined electric fields in converter transformers from PD behaviors in pure AC or DC electric fields. The present study focuses on the PD developing processes and characteristics of oil-paper insulation systems with needle-plane defects under different AC/DC proportions. The degradation of oil-paper insulation can be accelerated by PD pulses incurred by needle-plane defects. AC-DC combined voltages are applied to the needle-plane defect model simultaneously in the established experimental platform, and the proportions of AC/DC voltages are decided according to the cases in actual converter transformers. The developing processes from the initiation of partial discharge until final breakdown were observed for each AC/DC proportion. PD parameters and patterns were acquired by a detector using the pulse current method. The test results indicate that the inception and breakdown voltages increase with the increase of the DC component in AC-DC combined voltages. However, pulse repetition rate and amplitude of PD shows a descending trend when AC/DC proportion decreases. Meanwhile, the PD recurrence rate in the phase between 180 • and 360 • becomes higher than that in the phase between 0 • and 180 • at the initial stage as the DC proportion increases; high-amplitude discharges mainly occur in the phase range between 180 • and 360 • when the pressboard is close to breakdown. The current study is useful in further research on fault diagnosis in converter transformers.

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Investigation of static electrification phenomenon due to transformer oil flow in electric power apparatus

Cited by 42 publications

References 7 publications

Influence of thin layers on static electrification phenomena of materials for power transformers

Influence of thin layers on static electrification phenomena of materials for power transformers

Behaviour of electrical double layer under oil flow and voltage application inside a capacitive sensor

Partial Discharge of Needle-Plane Defect in Oil-Paper Insulation under AC and DC Combined Voltages: Developing Processes and Characteristics

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