以单根直埋敷设的10 kV 三芯电缆为研究对象，建立了电缆暂态热路模型，并将其简化等效为一阶RC 热路，根据所建立模型推导了应急时间与线芯温度的关系式。同时，设计了直埋敷设电缆加载不同应急负荷时的温升实验，实测了各组实验的应急时间。通过与应急时间计算值的对比，分析实验结果与误差，验证了理论计算的正确性，并得到不同应急负荷下的电缆应急时间变化规律，为电力部门指导电力电缆的运行提供理论支持．

transient thermal circuit model of 10kV three-core cables directly laid in soil is established and simplified into an equivalent first-order RC thermal circuit.Then,the relationship between the emergency time and the core temperature is deduced by using the established model,and the temperature rising experiments of the cable are designed and carried out to measure the emergency time under different emergency loads.Finally,the measured values are compared with the calculated ones to verify the correctness of the theoretical calculation,discover the causes of error and reveal the variation of cable's emergency time under different emergency loads.The present study provides a theoretical foundation for the operation of power cables in power sectors.