In the process of storage, transportation, laying and operation of cables, they may be subject to external damage, especially if the cables are already buried and are easily damaged in the construction of other projects. Such accidents often account for 50% of cable accidents. In addition to enhancing the quality of work in all aspects of cable storage, transportation, and laying, it is more important to strictly implement the groundless system to avoid such accidents.
PROTECTIVE LAYER CORROSION
Electrochemical corrosion of underground stray currents or chemical corrosion of non-neutral soils invalidates the protective layer and loses its protective effect on insulation. The solution is to install drainage equipment in areas with stray electric current concentration. When the local soil on the cable line contains chemical substances that damage the cable lead package, the cable should be installed in the pipe, and the neutral soil should be used for cable cushioning and covering the cable with asphalt.
OVERVOLTAGE AND OVERLOAD OPERATION
Improper selection of cable voltage and sudden high pressure in operation or long-term overloading may damage the cable's dielectric strength and break down the cable. This needs to be stepping by stepping up inspections and improving operating conditions.
OUTDOOR TERMINAL HEAD SOAKED IN WATER
Due to poor construction, the insulating glue was not filled, causing the terminal head to be flooded and finally exploded. Therefore, it is necessary to strictly implement the construction process regulations and seriously accept and inspect; strengthen inspection and timely maintenance. The terminal head leaks oil, destroys the sealing structure, causes the draining of the impregnant at the end of the cable to dry, increases the thermal resistance, accelerates the aging of the insulation, easily absorbs moisture, and causes a thermal breakdown. When it is found that the terminal head is leaking oil, inspections should be intensified, and when it is severe, the power should be cut off and redone.