多回路土壤直埋高压电缆温度场建模与载流量计算

Modeling of Soil Buried Multi-circuit Cables' Temperature Field and Ampacity Calculation

笔者研究了一种简单快捷的多回路土壤直埋电缆温度场及载流量的计算方法,导体温度作为判断电缆运行电流是否达到载流量的依据,是笔者的重点论述内容。对于多回路敷设的土壤直埋电缆,文中采用叠加原理建立导体温度计算模型,将每根电缆导体温度分为外部环境决定的初始温度、自身损耗产生的温升和其他电缆热源引起的导体温升3部分。综合运用解析法和有限元法对这3部分进行理论分析与建模,推导出导体温度计算公式。在此基础上进行了多回路土壤直埋电缆载流量计算与优化,并通过计算实例验证了文中所建电缆导体温度计算模型的准确性和实用性。

A kind of calculation method of temperature field and ampacity for direct buried cables is introduced in this paper. Cable conductor temperature as the key condition to determine whether current in operation reaches to the cables＇ampacity is the most important content. In order to gain conductor temperature of multi-circuit soil buried cables, this paper applies the superpose principle to establish calculation model of conductor temperature, and divide each conductor temperature into three parts： initial temperature decided by environment temperature, temperature rise caused by its loss, and conductor temperature rise generated by other cables heat source. It also analyzes the three parts by combining analytical method and the finite element method, and deduces formula of conductor temperature. On this basis, multi-circuit soil buried cables ampacity is calculated and optimized. Finally, the validity of conductor temperature field model and calculation formula proposed in this paper is verified by calculation examples.