Modeling And Analysis Of Pre-Tightening Conditions For Cable Erection

Transmission lines play a vital role in the power system.It is very meaningful to ensure the normal operation of transmission lines.The problem of cable line erection is also one of them.At present,there are few studies on the cable erection process at home and abroad,and most of the construction parameters are derived from engineering experience.The traditional structural finite element has problems in dealing with large deformation,large displacement motion,inefficiency,inaccuracy,and difficulty in establishing accurate and complex constraints.It is difficult to study the cable erection problem.In this paper,a new coupled coupling dynamics model of transmission tower line system is established by combining structural finite element method and absolute node coordinate method,which is applied to the research of cable line breaking condition during pre-tightening and pre-tightening of cable erection.The structural finite element dynamic equations of the transmission towers with space complex and the cable dynamics equation based on the absolute node coordinate method are established.The nonlinear coupling sliding pair and the hinge sub-constraint equation of the transmission tower and cable are derived.Based on the matrix,the dynamic equation of the transmission tower line system of the hybrid model is established by the augmented Lagrangian multiplier method.The simulation results show that the dynamic equations established in this paper have higher precision and more accurately describe the large deformation and large displacement of the cable and the nonlinear coupling constraint between the tower cables.Based on the analysis of the working principle of the tensioning machine on the cable,a preloading kinematics constraint equation based on iterative solution is established,which realizes the simulation of the preloading condition and obtains different preloading speed and preloading angle.The required maximum preload force;the solution method for the existence of multiple sliding pairs in the system is introduced,and the simulation of the existence of multiple sliding pairs in the system is realized.The two working conditions of cable breakage in the pre-tightening process are calculated.The step of ensuring the energy conservation of the system during the calculation of the equation is discussed.The response of the transmission tower and the cable line is obtained,which can guide the protection span.Frame design.The modal synthesis method is used to reduce the degree of freedom of the transmission tower,and the reduced system dynamics equation is obtained.The calculation of the pre-tightening and breaking conditions of the two cables of the two towers is carried out.The calculation efficiency and results of the reduced system dynamics equation are compared with the non-reduction equations.The results show that the calculation efficiency of the system can be greatly improved after the reduction.And can guarantee a certain precision;get the pre-tightening force and transmission tower response for reference.