Analysis Of Fatigue Fracture Mechanism Of Transmission Conductors And Clamps In Strong Wind Environment

There have been many wire break events and clamp fracture events occurred in transmission and transformation equipment in strong wind area of Xinjiang.The service time is significantly shorter than the prescribed years,which greatly affects the normal operation of transmission lines.In this paper,the fracture surface of the failed wire were analyzed by scanning electron microscopy;the resistivity,microhardness and nanoindentation hardness of the failed wire and the new wire were tested and compared;the anemometer and the wire swing detection device were installed on the wire to investigate the relationship between wind speed and wire swing.Abaqus software was used to simulate the stress condition of the wire in service and analyze its mechanical behavior;a wire swing test machine was built to simulate the wire swing under wind load.The results show that the corrosion has little effect on the normal operation of the wire;the wind speed and the swing angle of the wire satisfy a certain functional relationship;causes of wire breakage are low-cycle swing fatigue.Similarly,metallographic observation,hardness and tensile strength of wire clamp were carried out.Abaqus finite element software was used to simulate the mechanics of wire clamp and to build a fatigue test platform of wire clamp for swing test.Several improvement schemes of wire clamp were put forward.The results show that the material and performance of the clamp conform to the general national standard;the finite element simulation and fatigue test show that the clamp has yielded under 7-8 wind load,i.e.,the fracture form is low cycle fatigue;at the same time,the scheme of thickening the terminal plate and adding stiffeners can effectively improve the wind resistance and service life of the clamp.