Thermal expansion to the safe operation of the cable under each kind of constriction method

( Industry news] Various mode cable laying the safe operation of the thermal expansion on the threat posed by SXXLJT P with load current and the ambient temperature changes, the power cable thermal expansion, will happen because of thread core heat bilges cold shrink and produce very big thermal mechanical force, the greater the cable core section, the greater the heat generated by mechanical force; And wire core and metallic sheath will also because of the heat bilges cold shrink cycle for many times, and creep. Thermal expansion pose a big threat to power cable operation, will cause the displacement of cable operation and slide, even damage the cables and accessories. At present domestic has to choose one of the biggest cable for mm X =, therefore must attach importance to the thermal expansion of large cross-section cable problem. Regarding various mode cable laying the safe operation of the thermal expansion on the threat posed by a simple analysis: ( Directly buried installation), the cable by the limitation of the surrounding soil, the whole cable cannot produce displacement, so the wire core will be hot under the action of mechanical force in the two end of the line to produce a lot of thrust, cause end displacement, which pose a great threat to the safety of the cable accessories. ( ) About pipe laying, cable from lateral constraint, in hot cable will generate bending deformation under the action of mechanical force; Cable as the cable temperature changing, bending deformation appeared again and again, make the cable metal sheath produces strain fatigue. ( ) Tunnel, laying cable are usually on the bracket, not rigidly, therefore, the thermal expansion of the cable is larger, the slope sliding phenomenon is seen when laying; In the bend of the cable easy appear serious displacement; Cable as the cable temperature changing, also repeated bending deformation, make the cable metal sheath produces strain fatigue. ( ) Shaft installation, the gravity and thermal mechanical force of the cable may make the metal sheath produces excessive strain, thus shortening the service life of the cable. ( ) If municipal bridge installation, cable laying in the row in the bridge, there is the same as the exhaust pipe laying; If the cable laying in the box girder bridge, there is the same as the tunnel laying.