Optimized design of welding techniques for grading ring brackets used on UHV lines at high altitudes

In this paper, the welding techniques for brackets and rings of grading rings used on UHV transmission lines in high altitude areas are optimized, and four new welding methods, including strengthening the surface of ring welding, single side drilling of ring welding, bending welding of bracket and combination welding, were proposed. The conventional welding method was used as the control group to carry out tensile and torsion tests. According to the test results, the two welding techniques essentially produce the same results as the conventional welding technique when the specimens are in their tensile state. The technique of punching on one side of the ring significantly outperforms the conventional welding technique when the specimens are in their torsion state. The technique of welding a reinforced surface on the ring has a less favorable effect than the conventional welding technique because of the increased welding area and consequently, a larger heat-affected zone. The test results indicate that the technique of punching on one side of the ring is advised for grading rings used in high altitude and thick ice cover areas.