Title :
Studies on the improvement of breakdown strength of polyolefins
Author :
Niwa, T. ; Hatada, M. ; Miyata, H. ; Takahashi, T.
Author_Institution :
Fujikura Ltd., Tokyo, Japan
fDate :
2/1/1993 12:00:00 AM
Abstract :
Breakdown tests were conducted on a variety of polyethylenes and polypropylenes. High density polyethylene (HDPE) and polypropylene random copolymers (PPR) exhibited the highest breakdown strengths among the examined polyolefins. Model cables insulated with HDPE and PPR were manufactured, and the impulse breakdown strength of the HDPE cables made under some specific manufacturing conditions was 1.6×larger than that of conventional crosslinked polyethylene (XLPE). However, improvements were not observed in the impulse breakdown strength of PPR. The AC breakdown strength of HDPE and PPR cables also did not improve. The reason for the improvement in impulse breakdown strength of HDPE is the increased crystallinity of the insulating material, is brought about by the heat annealing applied to the cable in a manufacturing process
Keywords :
annealing; cable insulation; electric breakdown of solids; electric strength; impulse testing; insulation testing; organic insulating materials; polymer blends; polymers; AC breakdown strength; HDPE cables; PPR; PPR cables; XLPE; breakdown test; crosslinked polyethylene; crystallinity; heat annealing; high density polyethylene; impulse breakdown strength; insulating material; manufacturing conditions; manufacturing process; model cable; polyolefins; polypropylene random copolymers; Breakdown voltage; Cable insulation; Crystallization; Dielectric materials; Dielectrics and electrical insulation; Electric breakdown; Electrodes; Insulation testing; Polyethylene; Polymers;
Journal_Title :
Electrical Insulation, IEEE Transactions on
