| 摘要 |
Plastics-insulated heavy-duty power cable for high and very high voltages in protected against the action of humidity by a metal jacket surrounding the insulation and the superposed outer conductor. Underneath this closed mantle there is a helically wound metal tape, spaced away from the core, whose thickness is appropriate to the thermal expansion characteristics of the plastics used for insulation. The thickness of the tape S min = alpha. DELTA delta d where alpha is the coefficient of thermal expansion of the core, DELTA delta is the temp. difference between average temp. of the core at max. load and room temp. and d = dia. of the core at 20 degrees C. The space between jacket and tape winding is packed with vaseline (RTM). |
