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Longitudinal AC Breakdown Voltage of XLPE-XLPE Interfaces Considering Surface Roughness and Pressure

Abstract

The interfacial breakdown between two dielectric surfaces has been reported to represent one of the principal causes of failure for power cable joints and connectors; thus, a better understanding of interfacial breakdown mechanisms is vital. The primary purpose of this paper is to investigate the influence of the surface roughness and interfacial pressure on the tangential AC breakdown strength (BDS) of solid-solid interfaces experimentally. The three-dimensional surface texture parameters are utilized to characterize the morphology of the surfaces. Experiments were performed using samples made of cross-linked polyethylene (XLPE) at three different contact pressures. The surface roughness was varied by polishing the surfaces using four different sandpapers of different roughness. Each surface topography was then assessed using a 3-D optical profilometer. Next, the samples were assembled under ambient laboratory conditions. The experimental results showed a good correlation between the tangential BDS and the surface roughness. The results suggested that reducing the surface roughness resulted in decreased mean height of the surface asperities by nearly 97% and increased the real contact area of the interface considerably. As a result, the tangential BDS rose by a factor of 1.85 – 2.15 with increasing pressure. Likewise, the increased contact pressure yielded augmented tangential BDS values by a factor of 1.4 – 1.7 following the decrease of the roughness.
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Category

Academic article

Language

English

Author(s)

Affiliation

  • SINTEF Energy Research / Elkraftteknologi
  • Norwegian University of Science and Technology

Date

27.11.2017

Year

2017

Published in

IEEE transactions on dielectrics and electrical insulation

ISSN

1070-9878

Volume

24

Issue

5

Page(s)

3047 - 3054

View this publication at Norwegian Research Information Repository