重冰区超高压输电塔线体系安全性研究

重庆大学硕士学位论文ABSTRACT500kV Extra-high Voltage (EHV)transmission technology has been widely usedin power transmission system.Due to its characteristics of high tower and long span,theEHV transmission line is sensitive to ice and wind loads,which in extreme cases lead tobreakage of conductor line and collapsing of tower.The Investigation on safety oftransmission line in heavy icing area is very important for the safe operation of powersupply system.The dynamic responses of typical sections of 500 kV transmission tower-linesystem in heavy icing area after ice-shedding and wire-broken are numericallyinvestigated comprehensively in this thesis.Firstly,the finite element models,includingtransmission towers,conductor lines,ground wires,insulators and spacers,of thetransmission tower-line system are created in ABAQUS/CAE.The static load generatedby the weight of the ice accreted on the transmission tower-line system and the dynamicloads induced by the ice-shedding from the electric lines are simulated by means of themodification of the density and the gravity acceleration of the lines.The safety of thetransmission system is analyzed based on the dynamic response after ice-shedding.Thewire-broken is simulated by setting the element to"death"in the finite element analysis.I addition,the numerically determined dynamic responses of the transmission tower arecompared with those obtained using the Chinese transmission tower design code and theIEC code,and it is indicated that the load simplification in the case of wire-brokenproposed in the Chinese and IEC code for transmission tower design may underestimatethe dynamic effect and need to be investigated further.It is suggested that the dynamiceffect of the load induced by wire-broken has to be taken into account.Finally,thedynamic process of transmission line system and the breakage of the tower after wire'sbreaking are numerically simulated by introducing the failure criterion of structurecomponents.The results obtained in this thesis may provide a technique reference for the designof power transmission lines.Keywords:EHV transmission line,Tower-line coupling system,Numerical simulation,Safety