| In winter,transmission lines are easily galloped under ice and wind conditions,It can cause wire fatigue damage,broken strand and even inducing tower accident,which seriously affects the safe operation of power system.Because of its structural characteristics,the bundle conductor of high voltage line is more prone to instability than single conductor.Therefore,it is of great theoretical significance and application value to study the galloping characteristics of split wires and its influencing factors and anti dance measuresFirst of all,using the FLUENT fluid simulation software,the 2D plane mechanical analysis model of the external flow field of different split ice conductor is established.Using the RNG k-? turbulence control equation and the standard wall function to analyze and calculate the aerodynamic characteristics of each sub conductor which is under the conditions of different ice thickness,wind speed and wind attack angle.The accuracy of the simulation method is verified by comparing the calculation results of single conductor with wind tunnel test data.Providing the basic parameters for the study of galloping.In the nonlinear finite software ABAQUS,a beam element is set up with an ice coated wire unit with flexural stiffness and no compression.Write user defined load procedures that can apply alternating wind loads and electromagnetic force loads to each sub conductor.Taking the four bundle conductor spacer coupling model as an example,the influence of wake and electromagnetic force on the galloping of the bundle conductor under different working conditions is calculated and analyzed.The accuracy of the calculation model is verified by comparing the analytical values of the wire spacer system with the simulated modal values.Based on the simulation calculation method of the galloping,the influence of the wake of the bundle conductor on the overall amplitude under different wind speeds,the difference galloping of each sub conductor in the same phase conductor,and the influence of the electromagnetic force on the danced characteristics of bundle conductor under the different current intensity are analyzed.The result shows that,The bundle conductor wake has the greatest influence on the vertical direction of the traverse,which can reach two times when the tail flow is not considered,and the traverse wake makes the delay time of the wire premature,that is more likely to be danced when the tail flow is used.And the maximum displacement of the same sub conductor at the same wake can reach 40% of the overall amplitude.When the electromagnetic force between the sub wires is taken into account,the increase of the direction displacement of the traverse twist is maximum,reaching 43% of the amplitude of the direction,but the electromagnetic force has no obvious influence on the unstable vibration time of the wire.On the basis of the calculation results,the main reasons for the breaking of the catch rod in the galloping accident are analyzed.According to the characteristics of the influence of the conductor wake and electromagnetic force on the galloping,a new design idea of a new anti galloping equipment is put forward,that is to use the Pendulum damping structure with symmetry and consume the energy of the twisting and vertical direction when the conductor is galloped.The simplified calculation method of the main parameters of the new type anti galloping is given,and according to the calculated parameters to verified the anti galloping effect. |
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