normal Kraft paper

Ingredients

cellulose

Preparation Steps

Original Recipe Text

The Kraft paper is a cellulose-based insulation material used in transformer oil/cellulose insulation systems. For the study, it was subjected to drying in a vacuum chamber for 24 to 48 h at 90 °C and absolute pressure below 10 mBar, followed by impregnation with dry and degassed oil (p. 2). Wet experimental setups involved subjecting the strips to a wetting procedure in a wet chamber at defined temperatures and relative humidity (p. 2).

Evidence

"The results of the aging experiments of normal Kraft and thermally upgraded papers, two different types of transformer oil (mineral and natural ester), and copper are shown."

Remarks

Kraft paper serves as the baseline for comparing the quality and aging rates of insulation. The aging process is driven by hydrolysis, oxidation, and pyrolysis, which weaken cellulose fibers and cause depolymerization, decreasing the DPv value initially in amorphous regions and later in crystalline regions (p. 1). Experimental aging was performed in hermetically sealed stainless-steel vessels (p. 2).