淋雨量对绝缘子串雨凇覆冰的影响

Effect of Rainfall on Glaze Ice of Insulator Strings

计算了在不同条件下过冷却雨滴的冻结时间γ及不同淋雨量下过冷却水滴碰撞同一区域的时间间隔△γ。在人工气候室内模拟了不同喷水量对绝缘子串覆冰的影响。在温度、雨滴直径、覆冰水电导率、风速等参数不变的情况下,通过控制喷头的喷水量达到模拟自然环境中不同降雨强度下绝缘子串覆冰的目的。通过计算及观察实验现象和分析实验结果知:如果γ<△γ,则覆冰为"干增长";如果γ>△γ,则覆冰为"湿增长";在相同的覆冰时间内,当淋雨量为20mm/h时,绝缘子串覆冰为干增长;当淋雨量为40mm/h时,绝缘子片间及伞裙间有大量冰凌桥接;当淋雨量为86.4mm/h时,绝缘子串上覆冰柔软,在整个覆冰过程中一直有均匀水膜的存在,冰凌较少且短。

The cooling raindrops freezing time（τ）in different conditions and the time interval （△τ） that cooling water collides the same area under the different rainfall conditions were calculated in this paper. The different water quantities and theirs influences on icing on the insulator strings had been simulated in an artificial climate chamber. With the temperature, raindrop diameter, covered ice water conductivity, wind speed and other parameters unchanged, simulation of icing on insulator strings under different rainfall intensities in the natural environment was realized by controlling water sprinkling through a nozzle. Calculation and analysis of the experiments and its results indicate： if τ〈△τ, and then the ice cover is ＂dry growth＂; if τ〉△τ,and then the ice cover ＂wet growth＂. In the same time of icing, when the rainfall reaches 20 mm/h, the icing on insulator strings is dry growth; when the rainfall reaches 40 mm/h, each piece of insulators and the umbrella of insulator strings have a large number of icicles and serious ice-bridge phenomena; when the rainfall reaches 86.4 mm/h, the insulator string is covered with ＂soft ice＂, there is an uniform water film in the whole process of ice, and the icicles are fewer and last shorter.