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Vol.7 No.1previous AASP14 (87-88-89-90-91-92-93-94-95-96-97-

Academic Articles
Regular Paper Vol.7 No.1 (2015) p.102 - p.107

A Study on Insulation Degradation in Thermally Aged Ethylene Propylene Rubber Using Volume Resistivity Measurement


1 School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan
2 Nuclear Professional School, The University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Ibaraki 319-1188, Japan


This study presents electrical condition monitoring technique aiming at measuring volume resistivity (ρ) precisely for the tubular-shaped cables insulators. Tubular electrodes were designed to detect ρ for nuclear grade flame retardant ethylene propylene rubber (FR-EPR) insulated cables that underwent thermal accelerated ageing. FR-EPR insulated cables were heated at 125 °C for 5040 hours by two methods: with jacket and without jacket, while only FR-EPR cable with jacket was heated at 150 °C for 336 hours. ρ in insulators heated with jacket sharply decreased at ageing times 800-3480 hours and 300-336 hours during ageing at 125 °C and 150 °C respectively, hence obeying “induction-time” behavior as confirmed from elongation at break degradation curves at similar ageing conditions. Reduction of ρ in insulators heated at 125 °C without jacket is less significant compared to ageing with jacket.

Thermal ageing, cable insulator degradation, volume resistivity, elongation at break, and ethylene propylene rubber
Full Paper: PDF EJAM Vol.7No.1 pp.102-107 "A Study on Insulation Degradation in Thermally Aged Ethylene Propylene Rubber Using Volume Resistivity Measurement"
Article Information
Article history:
Received 21 November 2014
Accepted 27 March 2015