Title :
Electrical treeing properties of polyethylene degassed and impregnated with SF6
Author :
Xie, H.K. ; Vester, M. ; Gockenbach, E. ; Beyer, M.
Author_Institution :
Schering-Inst. for High Voltage Eng. & High Voltage Plants, Hannover Univ., Germany
Abstract :
The electrical treeing properties of low-density polyethylene (LDPE) degassed and SF6-impregnated have been studied for a needle-plane configuration. The experimental results show that the electrical treeing properties of LDPE can be improved by impregnating with SF6, depending on the impregnating pressure and duration, i.e. the amount of SF6 dissolved in LDPE, and improved more by degassing in a vacuum of 10-6 bar for 170 h. On the basis of the results obtained, a model for tree inception and propagation of polyethylene in a divergent field is proposed which suggests that the tree initiation is due to the breakage of bonds of the polyethylene chain by injected high-energy charge carriers and the rapid reaction between energy-enriched singlet oxygen and polyethylene. Therefore, impregnating with SF6 and decreasing the concentration of oxygen in polyethylene can inhibit the initiation and the propagation of trees
Keywords :
composite insulating materials; electric breakdown of solids; insulation testing; organic insulating materials; polymers; SF6; bond breakage; degassing; electrical treeing properties; energy enriched singlet O; impregnated LDPE; impregnating pressure; injected high-energy charge carriers; model; needle-plane configuration; polyethylene; tree inception; tree propagation; Cable insulation; Dielectric losses; Dielectrics and electrical insulation; Electrons; Manufacturing processes; Needles; Polyethylene; Sulfur hexafluoride; Trees - insulation; Voltage;
Conference_Titel :
Properties and Applications of Dielectric Materials, 1991., Proceedings of the 3rd International Conference on
Conference_Location :
Tokyo
Print_ISBN :
0-87942-568-7
DOI :
10.1109/ICPADM.1991.172017
