The effect of the polypropylene film on the impulse breakdown strength of the laminated oil-impregnated papers

PPLP (polypropylene laminated paper) used for oil-filled cables in high-voltage transmission systems was studied to determine the effect of the PP film on the impulse breakdown strength. The dielectric breakdown of PPLP was compared with that of Kraft paper alone. It was found that the impulse breakdown strength was affected by the relative position of the PP film and Kraft paper. For this kind of laminated oil-impregnated paper, the most essential factor in the impulse breakdown mechanism is the effect of the electric charges, especially the positive charge, trapped on the surface of the PP film.<
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