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تفاصيل البطاقة الفهرسية

BREAKDOWN STRENGTH OF IMPREGNATED POLYPROPYLENE FILMS AGED UNDER HIGH A.C. FILEDS

مقال من تأليف: Gadoum, A. ; Gosse, B. ; Gosse, J. P. ;

ملخص: Electrical breakdown measurements were performed on polypropylene films impregnated with benzyltoluene and aged for different electric field values (100 Vrms [mu]m-1 Ea rms [mu]m-1). Two films of 13.6 [mu]m thickness were sandwiched between two plane electrodes and immersed in the liquid at 80[deg]C and with substantial 02 concentrations. For this arrangement, the threshold voltage discharge (Vth) was ca 6-7 kVrms. The results show that for a given ageing time the films breakdown strength dependence on the ageing voltage Va is different for Va Vth and Va > Vth. This result is a confirmation of the occurrence of electrical discharges in the capacitor for Va > Vth. The area of degradated film is also different in both cases. For Va Vth the region with lower breakdown strength is restricted to the part of the film sandwiched between the electrodes. For Va > Vth the region with lower breakdown voltage is larger (about 1 mm) than the electrode diameter (8 mm). This is the result of the radial propagation of discharges or streamers. The influence of an epoxy additive which is an effective stabiliser of impregnated PP films was also investigated.


لغة: إنجليزية