Research On Buckling Characteristics Of V-shaped Composite Insulators Used In 500KV Compact Transmission Line

Insulators are electrical insulation devices to hang and support overhead transmission lines, they play a crucial role in the protection of the safe operation of transmission lines. Due to its good performance in antifouling flash, composite insulators have been widely used in the power grid. At the same time, the fault of the rupture destruction have also occurred, resulting in transmission lines out of string, dropped accidents, threatening the safety of the grid operation.In 2010, Chang-Fang Compact 500kV line occurred buckling failure fracture accident of composite insulators, which was recorded in the country for the first time. The failure mode is completely different from the fracture under axial tensile force in hanging string and string insulators. Therefore, it is necessary to depth study buckling mechanical properties of V-shaped composite insulator string, in order to provide a reference for its process improvement and replacement cycle. By ANSYS modeling and simulation, respectively, based on linear and nonlinear large deformation theory, buckling deformation conditions and mechanical properties of V strings are studied in this paper.Typical weather conditions of the line corridor approach regional are analyzed, vertical and horizontal external loads of V strings hanging points are calculated, the maximum wind angle under extreme weather conditions are determined and also its impact on the force of V strings. Describes the production process characteristics of composite insulators, Based on Halpin-Tsai equations theory, the finite element model of glass fiber reinforced epoxy material is established in ANSYS environment. Numerical method and analytical method are used to obtain the critical buckling load of composite mandrel, the nonlinear buckling analysis is also used. For the V series overall buckling deformation were simulated.The results showed that:the maximum wind angle is larger than half of the V series angle, downwind insulator buckling occurs under axial pressure; numerical solution and analytical solution of the critical buckling load don’t differ by more than 0.2%, the modeling is verified,the 3rd-order buckling mode shape is close to the actual deformation; For the V series overall instability deformation, when middle-linked board deflection angle is 12 °, its eigenvalues vector graphics consistent with the actual working conditions.Among studies on V string buckling deformation in the domestic, this article is first concerned about the impact on deformation of middle-linked board deflection angle, deformation, stress cloud are consistent with the actual working conditions. On this basis, can carry out further research, adjustment test ideas, improve test equipment.