The contribution of oil-flow electrification to the leakage current of multi-point gaps under direct and alternating voltages

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Abstract

This paper demonstrates the effect of oil-flow electrification (OFE) on the leakage current in oil-cooled electric power apparatus using a closed cycle model. The current in multi-point gaps is measured as a function of oil-flow velocity and temperature, type and polarity of the applied voltage, number of points and their interspacing, and type of the solid insulating material used in such composite insulation system. The results reveal that OFE phenomenon exists for both energized and unenergized cases. It causes a polarity reversal for the current under positive direct voltage, while it augments that current for negative voltage case. The measured current increases exponentially with temperature and/or voltage. Higher number of points or interspacing between points leads to higher current under both direct (both polarities) and alternating voltages for both stationary and flowing conditions. Also, the experimental results are interpreted and discussed in the light of electric field computation using a package based on the charge simulation method. The electric field profiles, corona inception voltage and number of streamers are invoked to explain the trend of the experimental results.

Original languageEnglish
Pages (from-to)47-52
Number of pages6
JournalEuropean Transactions on Electrical Power
Volume12
Issue number1
DOIs
Publication statusPublished - Jan 2002

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Leakage Current
Leakage currents
Voltage
Electric potential
Polarity
Electric Field
Charge Simulation Method
Electric fields
Corona
Insulating materials
Experimental Results
Reversal
Flow velocity
Oils
Insulation
Composite
Cycle
Closed
Temperature
Composite materials

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

Cite this

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title = "The contribution of oil-flow electrification to the leakage current of multi-point gaps under direct and alternating voltages",
abstract = "This paper demonstrates the effect of oil-flow electrification (OFE) on the leakage current in oil-cooled electric power apparatus using a closed cycle model. The current in multi-point gaps is measured as a function of oil-flow velocity and temperature, type and polarity of the applied voltage, number of points and their interspacing, and type of the solid insulating material used in such composite insulation system. The results reveal that OFE phenomenon exists for both energized and unenergized cases. It causes a polarity reversal for the current under positive direct voltage, while it augments that current for negative voltage case. The measured current increases exponentially with temperature and/or voltage. Higher number of points or interspacing between points leads to higher current under both direct (both polarities) and alternating voltages for both stationary and flowing conditions. Also, the experimental results are interpreted and discussed in the light of electric field computation using a package based on the charge simulation method. The electric field profiles, corona inception voltage and number of streamers are invoked to explain the trend of the experimental results.",
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AB - This paper demonstrates the effect of oil-flow electrification (OFE) on the leakage current in oil-cooled electric power apparatus using a closed cycle model. The current in multi-point gaps is measured as a function of oil-flow velocity and temperature, type and polarity of the applied voltage, number of points and their interspacing, and type of the solid insulating material used in such composite insulation system. The results reveal that OFE phenomenon exists for both energized and unenergized cases. It causes a polarity reversal for the current under positive direct voltage, while it augments that current for negative voltage case. The measured current increases exponentially with temperature and/or voltage. Higher number of points or interspacing between points leads to higher current under both direct (both polarities) and alternating voltages for both stationary and flowing conditions. Also, the experimental results are interpreted and discussed in the light of electric field computation using a package based on the charge simulation method. The electric field profiles, corona inception voltage and number of streamers are invoked to explain the trend of the experimental results.

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