Simulation study on slippage of preformed helical suspension clamps for ground wires in overhead transmission lines

Abstract The preformed helical suspension clamps have been widely applied in overhead transmission lines due to their fatigue resistance. However, slippage at the interface between the clamp and the ground wire can lead to fitting failure, threatening grid safety. This paper addresses this issue by establishing 3D finite element models for three typical preformed helical suspension clamp types (CL-12-150BG, CLS-16-150BG, and CLS-21-240BG). The explicit dynamics method was employed to analyze their contact pressure and slippage characteristics in both the pre-tightened state and unbalanced tension conditions. The study shows that, in the pre-tightened state, the clamp generates high stress concentration points due to cylindrical surface contact. The contact pressure exceeds 560 MPa and increases with higher failure load, accompanied by minor slippage. After unbalanced tension is applied, all clamps exhibit significant displacement imbalance. However, the anti-slippage performance of twin-clamp structures (especially CLS-21-240BG) is significantly superior to that of single-clamp structures (e.g., CL-12-150BG). Full-scale test of the CLS-21-240BG clamp compared with simulation results verifies the model’s accuracy in predicting both deflection and maximum slip displacement.