Long-Time D-C Conductivity of Oil-Impregnated Paper Capacitors Under High Field Stresses

The electrical conductivity of thin oil-impregnated paper insulation at high electric fields_> 100 kv/cm (kilovolts per centimeter)_has been measured as a function of temperature and voltage. Assuming that the dominant part of the conduction takes place in the oil by means of ions, a theory has been developed which permits the approximate determination of mobility of the charge carriers_10-9 to 10-6 cm2/v-sec (square centimeters/voltsseconds) between 35 C (degrees centigrade) and 145 C.