单芯电缆热路模型的改进及其在载流量计算中的应用

Improvement of the Thermal Circuit Model for Single-Core Cable and Its Application in Ampacity Computation

基于IEC 60853的理论基础,减小传统热路模型中用集中性参数代替分布性参数所带来的误差,并充分考虑电缆实际结构中,缓冲层存在一定的空气介质,通过建立改进的热路模型,自行编制计算载流量的应用程序。在计算电缆载流量程序中,将动态的电缆热参数代入计算,减小了利用传统的经验公式和估算值计算各层热参数所引起的误差。为了进一步提高电缆载流量求解精度,利用分布式光纤测温系统(DTS),测量电缆表面温度大小,进而代入程序中求解。该计算程序能够处理各种不同型号的电力电缆,以电缆的实际运行条件为依托,方便了电缆载流量的计算。

Based on the theory of IEC 60853, this thesis reduces the errors caused by replacing the distributed pa-rameters with the concentrated parameters in the traditional thermal circuit model. What,s more, we take full consid-eration of the existence of air medium in the actual structure of cushion. Based on which, the improved thermal model is used to develop the application of ampacity computation. On the use of the dynamic thermal parameters in the cal-culation ,the calculation errors caused by traditional empirical formulae and the estimated thermal parameters are re-duced in the ampacity program. In order to further improve the accuracy of the calculation, distributed temperature sensor （DTS） is used to measure the surface temperature of the cable, and this program can conveniently calculate the capacity of various types of cables.