Analysis on fracture of steel foot of suspension insulator used in 110kV transmission line

The fractured steel foot of suspension insulator used in 110 kV transmission line was investigated by means of Macro-morphology inspection, chemical composition analysis, microstructure analysis, fracture morphology analysis, hardness test and numerical simulation. The results show that the terrain of the area where the transmission line passes through is relatively flat and the wind speed is uniform and stable. At the same time, the climate characteristics of low temperature in winter and large temperature difference between day and night cause the conductor tension to rise, resulting in slight vibration of the conductor without anti vibration device. Finally, under the action of cyclic bending stress, fatigue cracking occurs along the joint of ball joint and rod of the steel foot used in suspension insulator.