Full-scale Field Test And Finite Element Simulation Of Ice-coated Conductors Under Galloping Condition

Electric energy is an important material basis of modern society and plays an important role in people's production and life.With the development of the national economy and the increase of electricity demand,China's power grid has gradually formed a situation of west-to-east power transmission,north-south mutual supply and national interconnection,and the high-voltage overhead transmission lines with large capacity and long distance are increasing day by day.In the normal operation of high voltage transmission lines,conductor galloping is a phenomenon of low frequency and large amplitude self-excited vibration caused by irregular icing of conductors.Galloping will cause wire breaking,wire flashover,hardware damage,overhanging insulator wire clamp slip,spacer bar fracture,transmission tower cross pole distortion,tower bolt loosening,tower collapse and other problems,leading to a wide range of power supply interruptions,and even threaten the stability of the national social situation.So far,fruitful progress has been made in the research on galloping analysis and prevention of overhead transmission lines at home and abroad.However,due to the complexity of dance generation and action mechanism,the existing research results can not fully meet the needs of the project.In recent years,with the completion and continuous improvement of test lines in the comprehensive test base of real transmission lines in China,it is possible to study the galloping response of ice-covered wires based on real tests,and this is the most direct and effective research approach.various response parameters of conductor galloping can be easily obtained,which can provide reference for the anti-dance design of practical engineering.Therefore,taking the test line of a real test base as an example,this paper uses the method of field test and simulation to study the galloping response of single wire and split wire.The main contents and conclusions of this paper are as follows:(1)Relying on the real transmission line galloping test base established by State Grid Corporation in Henan Province,the artificial simulated ice galloping field test of small span test lines was carried out.The acceleration response of conductors with different splits under different natural wind excitation and the strain response of tension tower are tested and analyzed.The observation shows that under the natural wind excitation,due to the wake interference effect of the upstream wire,the downstream conductor is significantly affected by the upstream conductor;for the same measuring point in the wire,the average in-plane acceleration response is about 20% compared with the out-of-plane response,indicating that when galloping occurs,the in-plane response of the wire is slightly larger than the out-of-plane response.(2)the aerodynamic characteristics of the small span test line are numerically simulated,and the aerodynamic coefficients of D-shaped ice-covered double-split conductors under different wind speeds and different wind angles of attack are analyzed according to the experimental data.focus on the impact of upstream sub-conductors on downstream sub-conductors.The analysis shows that due to the interference of the wake of the upstream conductor to the downstream conductor,the three-component coefficient of each sub-conductor of D-type ice-covered double-split conductor is very different,and the lift vibration and resistance vibration of the sub-conductor are also different.(3)On the basis of the above work,the overall finite element model of the small span test line is established,and the dynamic response of the line system under different wind speed is analyzed,including the displacement,strain,trajectory,tension and other data of each split conductor.and the stress and strain of the tension tower.The analysis shows that the maximum displacement response of the upstream and downstream conductors of each split wire is about 0.5m under high wind speed,and the strain response fluctuates between 0.00105 and 0.00115,and the value is very small.Even at higher wind speed,the dynamic tension at the mid-span node of the wire is still much less than its calculated breaking force,and the stress of the main material of the tension tower is also much lower than the yield strength of steel,indicating that the design of this small span line system is appropriate.it can meet the needs of galloping test of ice-covered wires under various working conditions.