输电线路单导线覆冰形状对直流大电流融冰时间的影响

The Impact of Ice Accumulation Shape on the DC High Current Ice-Melting Time for a Single Conductor on Power Transmission Line

直流大电流融冰是输电线路冰灾防御的有效手段。根据实际运行条件下输电线路单导线覆冰形状在导线各处不一的情况,计算分析单导线圆形覆冰和翼形覆冰的直流大电流融冰时间。计算结果表明,翼形冰融冰时间仅为圆形冰融冰时间的10%左右。在重庆大学雪峰山能源装备安全国家野外观测研究站对LGJ—300/50和LGJ—400/35两种型号单导线进行直流大电流融冰实验。实验结果表明:LGJ—300/50导线翼形冰融冰时间为圆形冰融冰时间的10.6%,LGJ—400/35导线翼形冰融冰时间为圆形冰融冰时间的8.3%。基于此,该文提出抑制导线形成圆形冰促使其生长为翼形冰可降低直流大电流融冰时间,减少融冰能量消耗。

In winter,the icing of transmission lines has emerged as a significant threat to power grid safety.Scholars have diligently researched and developed numerous de-icing methods,categorizing them based on their working principles into mechanical,thermal melt-icing,passive,and other methods.Despite these alternatives,DC high current melt-icing technology remains the preferred choice for transmission line de-icing.This study focuses on the actual operating conditions of single wire icing shapes on transmission lines,using three wire types(LGJ-240/30,LGJ-300/50,and LGJ-400/35)to calculate and analyze the DC high current melt-icing time for both circular and wing-shaped ice.Under the same wire type,an increase in melt-icing current density leads to a shorter melt-icing time for circular ice.For instance,when the current density increased from 1.5 A/mm^(2)to 3 A/mm^(2),the melt-icing time for circular ice decreased by 21.78%,22.13%,and 22.55%for the three wire types.Similarly,with the same melt-icing current density,a larger wire cross-section results in a shorter circular ice melt-icing time.Comparing wire types from LGJ-240/30 to LGJ-400/35,the latter's melt-icing time was 70.73%,72.26%,and 73.25%of the former across the three current densities.The impact of melt-icing current density on circular ice melt-icing time is more significant than the wire type under the same ice-covered environment.The pattern of melt-icing time variation with current density and wire type for wing-shaped ice mirrors that of circular ice,but numerically,the melt-icing time for wing-shaped ice is notably smaller.The ratioβ,representing the wing-shaped ice melt-icing time to circular ice melt-icing time,ranges from 9.27%to 11.55%,with an average of 10.49%.In natural DC high-current melt-icing,LGJ-300/50 wire's wing-shaped ice melt-icing time was 10.6%of the circular ice melt-icing time,and for LGJ-400/35 wire,it was 8.3%.Consequently,the paper suggests inhibiting circular ice formation to promote wing-shaped ice growth as a means to reduce DC high current melt-icing time and decrease energy consumption.