Research on cross-layer moisture diffusion process in oil-paper insulation structure of capacitor type bushing

Moisture intrusion which may lead to insulation deterioration is one of the main factors for the failure in oil-filled bushing. the internal structure of capacitor type bushing is multi-layered oil-paper insulation medium, moisture diffusion process can be very completed in this structure. Moisture diffusion process was compared under different temperatures by using eight-layered oil-paper insulation structure model in this work. Result shows that the diffusion time of moisture for cross-layer is slower than that for traditional oil-impregnated pressboard. The fit of the diffusion coefficient match best with the parameters of Foss’s data. Temperature is a vital factor on diffusion rate, every 10 ? Drop of temperature, double diffusion time is in growth.