Title :
Migration of vinyl acetate from semiconductive to insulation of power cables
Author_Institution :
AT Plastics Inc., Brampton, Ont., Canada
Abstract :
Semiconductor compounds based on ethylene vinyl acetate (EVA) copolymers were used along with ultraclean insulation to form an ideal interface for diffusion studies. The interface was analyzed before and after diffusion at different temperatures, using micro-Fourier-transformed infrared spectroscopy. Migration of vinyl acetate species was detected at these interfaces using their characteristic absorptions at 1742, 1240, and 1025 cm-1. The results were verified for semiconductive formulations with different carbon blacks and different EVA copolymers and for actual cable samples. The diffusion profile was obtained for an ideal case by choosing an antioxidant system other than the phenolic and thio esters for the insulation. Low-molecular-weight EVA was found to migrate across the interface between the semiconductives and cross-linked polyethylene (XLPE) of power cables. A correlation is established between the tree counts and EVA detected at the interface between the conductor shield and the XLPE of a 15-kV-rated power cable
Keywords :
Fourier transform spectroscopy; ageing; cable insulation; insulation testing; materials testing; organic insulating materials; polymer blends; polymers; power cables; 1025 to 1742 K; 15 kV; 15-kV-rated power cable; EVA copolymers; EVA diffusion; XLPE; antioxidant system; cable samples; carbon blacks; characteristic absorptions; conductor shield; cross-linked polyethylene; diffusion at different temperatures; diffusion profile; ethylene vinyl acetate; ideal interface for diffusion studies; low-molecular-weight EVA; micro-Fourier-transformed infrared spectroscopy; power cables; semiconductive formulations; tree counts; ultraclean insulation; Absorption; Aging; Cable insulation; Conducting materials; Conductors; Power cables; Semiconductor materials; Spectroscopy; Temperature; Trees - insulation;
Conference_Titel :
Electrical Insulation, 1990., Conference Record of the 1990 IEEE International Symposium on
Conference_Location :
Toronto, Ont.
DOI :
10.1109/ELINSL.1990.109756
