导线临界防冰电流及其影响因素分析

导线覆冰是影响输电线路安全运行的主要问题之一,基于焦耳热效应的临界电流防冰方法可行且有效。为此,基于焦耳热效应和导线在临界覆冰状态下的传热过程,并考虑了集肤效应、导线几何外形及其表面水膜对传热过程的影响,建立了临界防冰电流模型,其计算结果与人工气候室试验结果符合。另外,还研究了在覆冰环境下,导线直径及几何外形、环境温度、风速、液态水含量(LWC)、中值体积直径(MVD)对输电线路临界防冰电流的影响。仿真结果表明,临界防冰电流随温度的降低或风速的增加而迅速增大,随LWC的增大或MVD在0～100μm区间增大而缓慢增大,而当MVD>100μm时,临界防冰电流无明显变化。

Analysis on Critical Anti-icing Current of Conductor and Its Impacting Factors

Conductor icing is one of major factors which affect the safe operation of the transmission line,and the anti-icing method based on the Joule heating effect is feasible and effective.Taking the skin effect,the effect of geometric shapes,and water film covering conductors on heat transfer process into consideration,we established a mathematical model of critical anti-icing current on the basis of Joule heating effect and the heat transfer process of conductor under critical icing condition,and its calculations were consistent with the test results in artificial climate chamber.The proposed model is more accurate compared with other current models.We also studied the effects of the geometrical parameters of conductor,environment temperature,wind velocity,liquid water content(LWC),and median volume diameter(MVD) on critical anti-icing current of conductor.The simulation results show that the critical current increases rapidly with decreasing temperature,and increases rapidly with increasing wind velocity.The critical current slowly increases with increasing LWC,and increases slowly with increasing MVD when MVD is in the range of 0~100 μm.