Kerr electro-optic field measurement in palm oil fatty acid ester transformer insulation system

Yamamoto, S.; Katō, K.; Endo, Fumio; Hatta, Y.; Koide, Hidenobu; Ōkubo, H.

doi:10.1109/ceidp.2007.4451461

Cited by 11 publications

(9 citation statements)

References 6 publications

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“…From Fig.6, we found out a critical boundary between discharge and no discharge. The calculated boundary line designed by a dotted line can be expressed by (5) The dotted line coincides well with the experimental criteria. This result suggests that when the sum of E acc and E appl exceeds E BD , discharge can occur in the oil gap in a oil / PB composite insulation system.…”

Section: B Breakdown Behavior At Polarity Reversalmentioning

confidence: 87%

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Breakdown characteristics in oil/pressboard composite insulation system at HVDC polarity reversal

Ōkubo

Nara

Saito

et al. 2010

2010 Annual Report Conference on Electrical Insulation and Dielectic Phenomena

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By using Kerr electro-optic technique, electric field in oil / pressboard (PB) composite insulation system, which is the typical insulation system of a transformer, was investigated at polarity reversal of HVDC voltage. When the applied voltage polarity was sharply reversed, the applied electric field was superimposed by the electric field of accumulated charges on PB, and very strong field appeared right after the polarity reversal. This could cause the discharge in the oil gap and on the PB surface. The critical value of the discharge initiation at the polarity reversal was verified to be determined by the sum of the applied electric field and the electric field of accumulated charges on PB. The discharge was observed by a high-speed video camera. It was clarified that the surface discharge on PB did not overlap with each other, which was explained by that the surface discharge could neutralize the charges on PB.

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Section: B Breakdown Behavior At Polarity Reversalmentioning

confidence: 87%

“…The electric field strength in the oil gap E oil was measured continuously by Kerr electro-optic technique [4,5] when polarity reversal of applied DC voltage. By examining the various conditions of polarity reversal of DC voltage, discharge inception criteria in the oil gap was studied.…”

Section: Introductionmentioning

confidence: 99%

Breakdown characteristics in oil/pressboard composite insulation system at HVDC polarity reversal

Ōkubo

Nara

Saito

et al. 2010

2010 Annual Report Conference on Electrical Insulation and Dielectic Phenomena

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“…Note that only the situation with two crossed λ/4 wave plates is given in equation (10) (11)(12)(13)(14).…”

Section: Deducing the Electric Fieldmentioning

confidence: 99%

“…where n is the sequence space (0, 1, 2…n max ) of dark fringes or light fringes on CCD images which are counted from outmost where n=0 (generally, the electric field is also approximately 0), and the value n in situation "a)" always increases by 1 with the changing states in equations (11)(12).…”

Section: Deducing the Electric Fieldmentioning

confidence: 99%

“…Moreover, the electric field distribution can hardly be determined in the dielectric bulk, because the electric field cannot be easily calculated from the geometries alone when space charge appears. The Kerr electro-optic space charge measurement method can be used to measure space charge/electric field interactions in high voltage stressed liquid dielectrics [10][11][12][13]. Such as in the early 1980's, Kelley and Hebner [14]] used a CCD array to record the intensity variations, synchronized the detection interval to different times in the waveform, and made some explanation of space charge dynamics.…”

Section: Introductionmentioning

confidence: 99%

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Space charge dynamics investigation based on Kerr electro-optic measurements and processing of CCD images

Shi

Yang

Sima

et al. 2013

IEEE Trans. Dielect. Electr. Insul.

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The Kerr electro-optic technique is used to investigate electric field and space charge effects using large Kerr constant propylene carbonate as the dielectric liquid with Kerr constant B≈1.22×10 -12 m/V 2 . However, improved accuracy of this technique to measure space charge distributions remains an important goal. This paper describes inversion algorithm research on obtaining accurate space charge distributions from Kerr measurements. The original charge-coupled device (CCD) image of light intensity was converted into grayscale values for improved calculation. The grayscale CCD image was transformed into the frequency domain through a two-dimensional Fourier transformation. Butterworth filtering techniques were employed for edge enhancement algorithms. The most important parameter for calculation of space charge distributions are the integer fringe numbers n in the sequence of light and dark fringes measured by the CCD camera. Comparison of the improved algorithm and traditional methods for calculating electric field and space charge distributions between a pair of stainless steel parallel plate electrodes was investigated. The space charge dynamics were also calculated after processing the CCD images with some improvements. The results showed the electric field was essentially uniform at early times of pulsed high voltages. This uniformity indicated the absence of space charge during the early transient interval, while a bipolar charge injection was found in the central region between electrodes at later times. For longer times the electric field and space charge distributions slowly became uniform again. Grayscale processing and Butterworth filtering played an important role in the improvement of the algorithm for better image quality and edge enhancement.

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Design and investigation an optical modulator based on olive oil as a liquid crystal

Al-Ithawi¹,

Mohammad²

2020

2ND INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING &Amp; SCIENCE (IConMEAS 2019)

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Kerr electro-optic field measurement in palm oil fatty acid ester transformer insulation system

Cited by 11 publications

References 6 publications

Breakdown characteristics in oil/pressboard composite insulation system at HVDC polarity reversal

Breakdown characteristics in oil/pressboard composite insulation system at HVDC polarity reversal

Space charge dynamics investigation based on Kerr electro-optic measurements and processing of CCD images

Design and investigation an optical modulator based on olive oil as a liquid crystal

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