Thermal Analysis of Cable Sealing Ends
A general analytical method for thermal analysis of high-voltate oil-filled cable sealing ends is presented. Oil flow within the conductor oil duct, longitudinal heat flow through the conductor and conductor losses variation with temperature are taken into consideration. The method is successfully applied for a sealing end of a 300 kV, 2000 mm2 integral sheath cooled oil-filled cable. A companion paper where cable joints are analyzed, is referenced.
A New Method for Cable Joints Thermal Analysis
A general analytical method for thermal analysis of a joint in an oil-filled high-voltage cable is presented. Oil flow within the conductor oil duct, longitudinal heat flow through the conductor, and conductor losses variation with temperature are taken into consideration. The method is applied for a straight joint in a 300 kV, 2000 mm2 integral sheath cooled oil-filled cable. The theoretical temperature distributions along the conductor from joint to cable are in good agreement with the corresponding experimental results.
Steady-state thermal analysis of a 400 kV-cable through joint
Temperature distributions in a 400kV through joint and associated cable, as used in directly buried transmission circuits, are obtained for natural cooling and various forms of artificial cooling. The joint, rather than the cable, is seen to limit the current rating for all forms of cooling. With the higher ratings resulting from artificial cooling, the joint limitation becomes more severe. In all the cases considered, including the use of water jackets around the glass-fibre box surrounding the joint, the conductor temperature at the centre of the joint is above 85°C when the rating is decided by the cable alone. A thermal resistivity of the soil of 120degCcm/W, and a maximum coolant-temperature rise of 20degC are assumed. Investigation into joint power factors in the. range 0.004-0.008 shows a large temperature dependence with natural cooling, but small dependence with artificial cooling.