1 电力电缆的允许载流量 1 power cable allows carrying capacity 　 　电力电缆允许载流量的确定是保证电缆安全运行的关键,为了防止电缆过热,接头损坏和绝缘故障,在正常运行或短路时常用电力电缆的最高允许温度,绝缘导线 和电缆温度过高,可使绝缘损坏或引起火灾,这就要求导线和电缆的正常发热温度不得超过额定负荷时的最高允许温度,导线的允许载流量是指在规定的环境温度条 件下,导线能连续承受而不使其稳定温度超过允许值的最大电流,选择导线和电缆截面积时要通过相线的计算电流不超过允许载流量。 Power cable to allow determination of carrying capacity is the key to ensure the safe operation of the cable, in order to prevent cable overheat, joint damage and insulation fault, often used in normal operation or short circuit the allowable temperature of power cable, wire and cable insulation temperature is exorbitant, can make the insulation damage or cause fire, which requires the wire and cable of the normal heating temperature shall not exceed the rated load, the maximum allowable temperature of conductor allows article carrying capacity refers to the provisions of the environmental temperature parts, wire can not make its stability under temperature for more than the maximum current value, choosing a cross-section of wire and cable through the calculation of phase wire current does not exceed the permitted load flow. 　　2 根据允许载流量选择截面积 2 choose sectional area according to allow carrying capacity 　　允许载流量与环境温度有关,在实际环境温度与规定的环境温度不一致时,允许载流量乘以温度系数,进而求出实际载流量。 Allow the carrying capacity is related to the environment temperature, in the actual environment temperature and environmental temperature is not consistent, allowing carrying capacity multiplied by the coefficient of temperature, and then find out the actual carrying capacity. 　　3 电缆多根并列的情况 More than 3 cable joint 　　电缆多根并列的情况下,散热条件较单根敷设时差,允许载流量降低,所以要用电缆并列校正系数进行校正,得出在正常情况下的允许载流量。 Cable dogan tied for the case, the cooling condition is relatively single jet lag laying, allow the carrying capacity is reduced, so use cable joint correction coefficient of correction, it is concluded that under normal circumstances allow carrying capacity. 　　4 在土壤中敷设电缆 4 cable laying in the soil 　　在土壤中敷设的情况下,不同的土壤对应的土壤的热阻系数不同,散热条件也不同,允许载流量也应乘以土壤的热阻系数。 In the soil under the condition of laying, different soil corresponding to the thermal resistance coefficient of soil is different, the cooling condition is different also, allow carrying capacity should be multiplied by the coefficient of the thermal resistance of the soil. 　　5 电流的载流量与电缆的种类 5 the current carrying capacity and the types of cable 　　电流的载流量与电缆的种类,线芯截面积敷设方式和环境条件有关。在土壤中直埋的载流量的电缆高于在空气中敷设。 Current carrying capacity and the types of cable, wire core area laying way and environmental conditions. In the carrying capacity of soil directly buried cable above laying in the air. 　　6 电缆敷设时弯曲过度 Bending over 6 cable laying 　　电缆敷设时弯曲过度,易于使保护层和绝缘层受到损坏。产生裂纹,降低其机械强度。 When cable laying excessive bending, easy to damage to protective layer and the insulating layer. Cracks, reduce its mechanical strength. 　　1)铅护套铠装橡皮绝缘电缆20d;2)交联聚乙烯绝缘电缆铅包油浸纸绝缘电缆裸铅护套橡皮绝缘电缆15d;3)聚氯乙烯绝缘电缆橡皮或聚氯乙烯护套橡皮绝缘电缆10d。 1) lead sheath armored rubber insulated cable 20 d; 2) crosslinked polyethylene insulated cable as lead naked package of oil immersed paper insulated cable sheath rubber insulated cable 15 d; 3) rubber or PVC PVC insulated cable sheath rubber insulated cable 10 d.