Three-core XLPE cables are commonly used in low-voltage distribution networks. However, studies on ampacity of three-core cable are rarely seen. Considering the structure difference between three-core cable and one-core cable, and based on IEC 60287 calculation standard, the thermal circuit model of 6 cable layers and 4 thermal circuit nodes is derived using transferring heat knowl-edge. Using the shape factor method to calculate thermal resistance, each layer temperature is obtained by calculation of cable surface temperature. For verification of calculation accuracy, current-rising test is designed with two kinds of laying methods: buried laying and air laying. In this test, the temperature of conduct, XLPE insulating layer, armor layer and cable skin are measured. And compar-ative analysis is carried out. The experimental temperature data and theoretical calculation reveals that the calculation error using the proposed model is within the acceptable range, Therefore, this method can be used for calculation of cable conduct temperature in en-gineering.%交联聚乙烯材料的三芯电缆广泛应用于低压配电网中，但长期以来，关于电缆载流量计算的研究多集中于单芯电缆。考虑到三芯电缆与单芯电缆的结构差异，在IEC 60287标准计算的基础上，利用传热学知识，理论推导了三芯电缆并联结构的6层4节点稳态热路模型。采用形状因子法计算热阻参数，利用外表皮温度反推计算得到电缆各层温度。为了验证计算的准确性，设计了空气敷设和土壤敷设两种敷设方式下的升流实验，测量得到稳态时导体线芯、绝缘层、铠装层和外表皮温度，并与理论温度计算值进行了比较分析。分析结果表明，利用提出的热路模型进行三芯电缆载流量计算的误差在允许范围内，可应用于工程实际。
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