Safety of Deicing Dynamic Response for Ground Wire Support of Ultra-high Voltage Transmission Tower in Heavy Ice Area
In order to explore the safety of ground wire support of ultra-high voltage(UHV)transmission tower in heavy ice area under the action of deicing dynamic load,based on the deicing numerical theory of computation,the deicing numerical models of two kinds of ground wires and two kinds of tower line coupling numerical models were established.The deicing dynamic response of ground wire under different working conditions and the bearing capacity safety of tower ground wire support under different deicing conditions of ground wire were studied.Research on deicing shows that the greater the height difference,the greater the uplift force generated by deicing;the larger the span,the greater the longitudinal unbalanced tension;the thicker the ice cover,the greater the longitudinal unbalanced tension generated by the ground wire's deicing,and the smaller the uplift force generated by the deicing.Research on tower line coupling deicing shows that under the multi stage model,when the ground wire is deicing,there is a stress ratio exceeding the limit on the front and bottom inclined materials of the suspension tower ground wire support,and existing design methods tend to be unsafe.The tension tower ground wire support is not controlled by the deicing dynamic response.It is recommended to consider only the uplift force generated by the deicing of the ground wire during the design of the ground wire support in the heavy ice-covered area.The uplift force should be taken as 1.0%-5.0%of the maximum working tension of the ground wire.The thicker the ice-covered area,the smaller the uplift load can be.The uplift force can be taken as 4.0%-5.0%,3.0%-4.0%,2.5%-3.0%,2.0%-2.5%and 1.0%-2.0%of the maximum working tension for ice areas with thicknesses of 20 mm,30 mm,40 mm,50 mm and 60 mm,respectively.
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