By Topic

Effect of ethylene content on bowtie trees and wet electrical performance in filled EPR insulation materials

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

5 Author(s)
Sarkar, A. ; Indianapolis Technol. Center, Gen. Cable Corp., Indianapolis, IN, USA ; Easter, M. ; Walcott, E. ; Temple, W.
more authors

The insulation for extruded medium voltage power cables currently used world-wide are based on two broad categories of polymeric materials: crosslinkable elastomers, consisting of Ethylene Propylene Rubber (EPR)*, and crosslinkable low density polyethylene, consisting of Crosslinked Polyethylene (XLPE) or Tree Retardant Crosslinked Polyethylene (TRXLPE). These two broad categories have over 40 years of proven field performance. A considerable amount of research has been done on water treeing in unfilled semi-crystalline and amorphous elastomers. Very little research has been done on filled elastomeric systems, as water trees are more difficult to detect. One paper reports a link between ethylene content and crystallinity in an unfilled EPR base resin and other ethylene base resins. In reality, unfilled EPR resin is not a commercially viable insulation material for high demanding medium voltage applications. In filled EPR resin-based insulation materials, surface-treated clays are chemically bonded to the polymer chains. This changes the whole interpretation of degree of crystallinity (related to ethylene content) with respect to bowtie tree formation and long-term wet electrical performance. This paper will report data that shows bowtie tree counts in carefully formulated higher ethylene content filled EPR insulation materials can be less than those for lower ethylene content and more amorphous EPR insulation materials in long-term wet electrical tests. This paper examines the influence of the ethylene content of base resins in suitably reinforced (with treated clay) filled EPR insulation materials with respect to its level of dispersion, formation of bowtie trees and ac voltage breakdown strength after accelerated wet-aged testing. However, the long-term wet ac breakdown strength testing via a step-rise high voltage time test (HVTT) after an accelerated water treeing test (AWTT) are found to be comparable in higher ethylene content (semi-crystalline) and lower ethy- - lene content (more amorphous) filled EPR insulation materials.

Published in:

Electrical Insulation (ISEI), Conference Record of the 2010 IEEE International Symposium on

Date of Conference:

6-9 June 2010