基于FEM的直埋电缆载流量与外部环境关系的计算

Calculation of ampacity reduction factors for buried cables with surroundings based on FEM

利用有限元法对有外部热源的直埋电缆区域进行剖分,计算了给定电缆负荷的温度场。利用对分法计算了导体温度等于绝缘长期耐受温度时的电缆负荷,确定了有外部热源和地表空气温度变化时的直埋电缆的载流量。计算结果给出了电缆载流量随电缆与外部热源间距的变化规律,以及电缆载流量随地表空气温度的变化规律,为工程实际提供了参考依据。

Finite element method （FEM） was used to partition the area of buried cables with outer heat sources and calculate the temperature field with given cable load. Bin-search method was used to calculate the cable load until the temperature of conductor is equal to the long endurable temperature of insulation and obtain the ampacity of buried cables with outer heat source and variation of temperature of air. The resuh gives out the relationship of the ampacity with the distance between outside of cables and outer heat source and the relationship of the ampacity with the variation of temperature of air. The result gives out a reference for practice.