架空导线动态增容的热路法稳态模型

Steady-state Model of Thermal Circuit Method for Dynamic Overhead Lines Rating

应用动态增容技术提高现有架空导线的输送能力,需要准确计算架空导线的隐含容量。为此,首先分析了架空导线动态增容的基本原理并比较了各种传统动态增容模型的优缺点。然后,根据传热学理论建立了架空导线动态增容的热路法稳态模型,该模型仅需监测导线温度以及环境温度,并根据该模型推导了架空导线允许载流量的计算方法。最后,设计了室内、室外架空导线加载不同阶跃电流的温升实验。实验结果表明:在室内较稳定条件下,随着导线温度升高等效热阻RX逐渐减小,当温升达44°C时RX减小了7.7%;室外实验中根据模型计算的允许电流与实际值相对误差为-1.7%。可见,根据架空导线热路法稳态模型可实现对架空导线隐含稳态载流量的准确评估。

When applying dynamic monitoring capacity-increase technologies to increase the transmission capacity of lines,it is necessary to accurately calculate the implied capacity of transmission lines.Thus,firstly,we analyzed the basic principle of dynamic overhead lines rating,and summarized the pros and cons of several traditional dynamic overhead lines rating models.Then,by the heat transfer theory,we established a steady-state type of dynamic overhead lines rating model,in which only the temperatures of conductor and environment were required to be monitored;thereby,a calculating method of allowable current was derived.Finally,temperature rise experiments of outdoor and indoor overhead lines carrying different step-currents were designed and carried out,respectively.The experimental results show that the equivalent thermal resistance（RX） decreases gradually with the increase of temperature of overhead lines under relatively stable indoor condition： RX is decreased by 7.7% when the temperature rises by 44°C.For outdoor experiments,the correlation’s calculation numerical value has a relative error of-1.7% compared with the experimental results.Therefore,it is concluded that the steady loading implied-current of overhead lines can be evaluated accurately by the presented thermal-circuit-method-based steady-state model.