Effect of Different Dielectric Coatings in Divergent Fields
Dielectric coatings are widely used in electric power equipment to increase the breakdown voltage and to reduce the insulation distance.
Two different coating materials, epoxy and polyamide, and two different coating thicknesses, 3 and 5 mm, were experimentally investigated in divergent field gaps (coated rod — bare plane arrangements). The experimental campaign was performed in air at 100 kPa.
Previous measurements referring to bare electrodes, under the same experimental conditions, have been used as reference for calculating the increase in the breakdown voltage U50% as well as modification in the standard deviation σ.
The streamer inception model was also used to work out predictions of the breakdown voltage.
Discrepancies as well as similarities are put in evidence and discussed in the conclusions.
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