土壤直埋电缆群额定载流量的计算

当多根电缆埋地敷设时,电缆之间热的相互影响使每根电缆的载流量不同程度的降低。每根电缆的载流量由IEC60287给定公式计算,其环境温度由土壤环境温度和其他电缆在该点的温升迭加所决定。其他电缆在该点的温升可以采用镜像法计算。这样,每一根电缆额定载流量将由其他电缆决定,用高斯-赛德尔迭代法对以额定载流量为变量的方程组进行求解,计算了电缆群等负荷、不等负荷以及环境因素对载流量的影响。试验结果表明,计算结果符合工程实际要求。

Ampacity Calculation for Groups of Buried Cable

When several cables are buried in soil,there is thermal infection among cables.This effect makes the ampacity of every cable reduced.The ampacity of every cable can be calculated by the formula introduced by IEC 60287.The environment temperature in the formula is the sum of soil temperature and temperature rise caused by other cables.The temperature rise caused by other cables can be calculated by the method of mirror image.So,the ampacity of every cable will be decided by other cables,Gauss-Seidel iterative method is used to solve the equation group which is consisted of ampacity of different cables,and calculate the ampacity of equally load and unequally load and different environment condition.The test result shows that the calculating result conform to the request of project.