矿井电力电缆截面选择的一个基本条件,是使电缆实际流过的长期工作电流不超过它所允许的载流量。此电力电缆的允许载流量通常是从制造厂的说明书或电工手册提供的表格查得。这在用手工进行井下供电设计时是很方便的。但在采用计算机或可编程序计算器进行井下供电的辅助设计时,如仍用查表的方法就很麻烦了。这时,我们希望建立负荷的长期连续电流与电缆截面的数学关系式,使机器能根据负荷的长期连续电流直接要求出所需的电缆截面。电缆的长期连续负荷允许载流量由导电线芯的最高允许温度决定,并与导电线芯的材料、截面、电缆的结构、额定电压、周围介质种类和温度等因素有关。一般说来,已知 One of the basic conditions for the selection of the mine’s power cable cross section is that the long-term operating current through which the cable actually flows does not exceed the current carrying capacity it allows. The allowable current carrying capacity of this power cable is usually found on the form supplied by the manufacturer’s instructions or an electrical manual. This is handy for underground power supply design is very convenient. However, in the use of computer or programmable calculator for underground power supply design, such as still using the look-up table is very troublesome. At this time, we want to establish the mathematical relationship between long-term continuous current and cable cross-section of the load so that the machine can directly request the required cable cross-section according to the long-term continuous current of the load. The long-term continuous load of the cable allows the current carrying capacity to be determined by the maximum allowable temperature of the conductive core and depends on the material, cross-section, structure of the cable, rated voltage, type of surrounding medium and temperature of the conductive core. In general, it is known