THE BREAKDOWN VOLTAGE OF INSULATION OIL UNDER THE INFLUENCES OF HUMIDITY, ACIDITY, PARTICLES AND PRESSURE

摘要: The breakdown voltage of mineral insulation oil was systematically investigated under the influences moisture, acidity, pressure and particles. standards IEC156/95 (VDE0370/Part5/96 ASTM D1816) specified test conditions. Moisture provides charge carriers, therefore a moisture saturation 0 to 20 % decreases from 72 down 61 kV. Acids as aging products decrease dielectric strength too for same reason. Not total acid number TAN, but low molecular acids effect major decrease. Since process starts with microscopic bubble, an increasing increases too. observed asymptotic behaviour seems come maximal end value at around 150 Under-inflation supports bubble generation, decreasing withstand strength. Dry particles (cellulose fibres) only under-inflation, nearly no influence atmospheric pressure.