Analysis on Transmission Tower Toppling Caused by Icing Disaster in 2008

By means of force condition check of three typical transmission towers,i.e.,the cup-type tower,drum-type tower and two-cross-arm tower,under the combination of different ice-coating thickness with different operation conditions,the causes of transmission tower toppling due to icing disaster in the year 2008 are analyzed and calculated in depth. Calculation results conform to actual field damage conditions,and it arrives at the conclusion that the principal reason of transmission tower toppling due to ice-coating lies in the ice-coating thickness exceeds the normal-designed ice load capacity of conductor and the excessive longitudinal unbalanced tension from the former. Finally,the suggestions and measures to strengthen the ice-coating resisting ability of transmission lines are given.