Research On The Mechanical Characteristics Of The Conductor At The Exit Of The Suspension Clamp Of Transmission Line

The breeze vibration in the transmission line is a common form of vibration of the transmission line.When the transmission conductor is exposed to the breeze vibration for a long time,problems such as strand breakage may occur,If the strand breaks,it will threaten the safe operation of the transmission line project.It is necessary to carry out relevant research on the problem of conductor breakage.Based on the fact that most of the conductor breakage occurs near the suspension clamp,this paper mainly conducts experimental and simulation research on the mechanical characteristics of the conductor at the exit of the suspension clamp of the transmission conductor under breeze vibration conditions.The main research work is as follows:(1)Preliminary suggestions for correcting the calculation formula of the dynamic bending stress of the conductor at the exit of the suspension clamp are proposed.As the current research on the calculation formula of the dynamic bending stress of the conductor,the assumption of the minimum bending stiffness of the conductor is basically used,and the change of stiffness is ignored.Therefore,considering the change in the bending stiffness of the conductor,through numerical simulation calculation,the relationship between the equivalent bending stiffness and the equivalent diameter of the conductor is proposed and used for the correction of the formula.The comparison of the results shows that the correction can further improve the calculation accuracy of the formula.(2)Experiments and simulation analysis are carried out on two kinds of conductor specimens and the conventional conductor clamp system.In order to study the mechanical characteristics of the conductor at the exit of the suspension clamp of a large span,a comparative analysis was carried out with the conventional conductor,and it was found that the stress distribution of the two conductors was consistent.Therefore,the stress distribution law of the conventional conductor installation suspension clamp is studied,and the comparative test and simulation results show that:considering the tension and amplitude conditions,the stress of the outer aluminum strand at the outlet of the suspension clamp is larger than that of the inner layer due to the influence of the clamp.And the stress of the KE section is larger than that of the LPC and 89mm sections.(3)A test model of the conductor strand at the exit of the suspension clamp is constructed to conduct a mechanical test study.Because the force of the conductor strand at the exit of the suspension clamp is relatively complicated,in order to further understand the force characteristics of the conductor strand,a single-strand adjacent layer,a simplified test model of the same layer and a secondary outer layer aluminum strand test model are proposed.The adjacent layer model test research shows that the dynamic bending strain of the conductor strand at the exit of the suspension clamp is mainly affected by the tensile strain,and the dynamic bending strain of the conductor strand far away from the clamp exit tends to be affected by the bending strain;the same layer model test research shows that:Under the horizontal condition,the dynamic bending strain of the strands of the same layer model is smaller than that of the adjacent layer model under the influence of the amplitude,and the linear dynamic bending strain of the same layer model is larger than that of the adjacent layer model at the same frequency;the test study of the secondary outer layer aluminum strand model shows that:aluminum strand The linear stress distribution law is the same as that of the outer layer,and the maximum stress is also located in the KE section,but the overall stress is smaller than that of the outer layer.(4)The mechanical characteristics of the conductor at the exit of the suspension clamp are tested and studied considering the suspension angle.Because the current study on the conductor mechanics at the exit of the suspension clamp rarely considers the influence of the suspension angle,the stress test of the conductor at the exit of the suspension clamp is carried out with consideration of different suspension angles.The research shows that the suspension angle and the stress of the aluminum strands are linear,and the stress of the aluminum strands of the KE section is greatly affected by the suspension angle.