Radial Oil Flow and Pressure Differences in Cable Insulations

During temperature change pressure differences across cable insulations can be considerable. Rigorous relations are derived for the calculation of the pressure differences in accordance with Miller and Wollaston´s method. In addition, approximate relations are derived, which lead to less laborious calculations than the rigorous method. Validity of both methods was checked by comparing calculated and experimentauy observed pressure differences in the insulation of a 220-kv cable. Fair agreement was found for both methods.