Analysis on cause of severe convection weather"4·19"in 2022 and its influence on distribution line faults in Longnan City
The distribution line is exposed to the natural environment for a long time,which is easy to be affected by strong convection weather.In the afternoon of April 19,2022,under the influence of high impact weather such as lightning and thunderstorms and gales,13 distribution lines in Longnan City broke down successively,causing adverse effects such as power outage and power load loss for us-ers.The extreme wind speed and lightning positioning data of from the automatic meteorological observation stations in Longnan City,Fengyun 4A(FY-4A)infrared cloud images,sounding data and Doppler weather radar data were used to analyze the severe convection weather process and the influence of power grid.The results are as follows:(1)The severe convective weather was dominated by light-ning and thunderstorms and gales,and a large area of power outage and power load loss had occurred in Xihe,Lixian,Wudu,Kangxian and other counties.(2)The development of severe convection weather was mainly influenced by the plateau trough and shear line.Un-der the unstable atmospheric junction of"cold above and warm below",the surface convergence line triggered strong thunderstorm and gale;Satellite cloud images and radar echoes also showed that the development of convective clouds coincided with surface thunder-storms and gales.(3)The fault range distribution of distribution lines was basically consistent with the occurrence time and transit path of severe convective weather.Using 10-minute extreme wind speed and lightning location data,it was discussed that when the extreme wind speed exceeded 15.0 m·s-1 or the positive lightning current exceeded 43 kA or the negative lightning current exceeded 26 kA,the possibility of distribution line faults was higher.
severe convection weatherthunderstorms and galeselectric power circuitimpact threshold
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