Fracture Analysis on Four Split Interphase Spacer of 500 kV Transmission Lines Based on X-ray DR Technology

Through macroscopic examination, chemical composition analysis, mechanical property test, X-ray digital radioscopy (DR) detection, metallographic analysis, fracture analysis and other methods, the fracture failure causes of the four split interphase spacer of 500 kV transmission lines were analyzed. The results show that because of the insufficient modification treatment and the poor casting quality, the microstructure of material of the interphase spacer, ZL102 casting aluminum alloy, was abnormal and there were a lot of defects in it, so the bearing capacity of the interphase spacer bracket was seriously insufficient. Under the action of wind pendulum, dancing and other loads during the running of the lines, a great stress concentration formed at the severe defect site of the bracket. When the stress exceeded the bearing limit of the interphase spacer braket, fracture would occur, and that was the primary cause for the failure.