Stability Analysis Study on Diameter-Expanded Conductor With Fewer Inner Wires

The structure stability of the diameter-expanded conductor with fewer inner wires is the principal limitation in its large-scale use at present. As the traditional design method cannot be adopted to solve this problem, the instability properties of the diameter-expanded conductors were studied in this paper. To perform this analysis, different typical diameter-expanded conductors with fewer inner wires were chosen for the sheave tests under different working conditions at first. Then the simulation model as well as the instability criterion was established to analyze the influence factors of the structure stability. Finally, the synchronous stringing tests were carried out to assess the correctness of the model proposed. The results showed that the weakened support of the inner layer(s) and the local buckling of the external wires are the main causes of the wire jumping phenomenon. Therefore, a reasonable increase in the outmost wire's gap and decrease in the inner wire's gap are feasible to improve the load-carrying ability of the diameter-expanded conductor.