Cause Analysis on Fracture of Overhead Ground Wire Based on Consideration of Crimping Quality

Overhead ground wire of a 110 kV high voltage transmission line fractured in alpine region of Inner Mongolia. The fracture causes of overhead ground wire were analyzed by means of macroscopic analysis, fracture analysis, metallographic examination, mechanical property test and crimping quality examination of splice tube. The results show that there was a full decarburization layer on the steel wire surface of the overhead ground wire, and there were a lot of cracks in the decarburization layer, which seriously reduced the fatigue resistance of the steel wire. The joint crimping quality of the overhead ground wire was unqualified, the bending deformation of the splice tube was serious, and a large fatigue stress formed at the contact part between the end of the splice tube and the overhead ground wire. The combination of the two caused fretting fatigue cracks on the surface of the steel wire of the overhead ground wire, which eventually led to the fracture of the overhead ground wire.