HV cable termination with forced cooling - with terminal coolant separated from cable coolant and impregnant

摘要

The cable termination (19) is insulated and covered by a concentric sheath (4). The terminal coolant flows over the outside of this sheath to remove heat generated at the termination. Thus the cable cooling and impregnation circuit is isolated from the terminal cooling. The latter can therefore be more easily maintained in a high state of purity reducing the risk of electrical breakdown, due to contamination, in a highly stressed area. A typical arrangement comprises two further concentric tubes (13, 14). The space between the sheath (4) and inner tube (13) has turbulence promoters (11, 12) to disturb the flow and thus improve heat transfer. Coolant return is between the two concentric tubes. The space between the outer tube (14) and the terminal insulator (1) is filled with a dielectric, for example sulphur hexafluoride. The terminal cooling system has its inlet (9) at a spiral (8) outside the insulator (1). Coolant drains (7) are typically in the base of the insulator (10).