Load Limiting Device

During normal operations, suspension towers in high-voltage transmission lines carry only the gravity loads of conductors and insulators. The lateral loads from conductors are negligible because of balanced tension on both sides of the tower. However, in the event of a sudden conductor snap, this equilibrium is disrupted, and towers are subjected to dynamic impact loads as high as two to three times the conductor's initial tension. Due to economic constraints, the suspension towers are designed to support only a fraction of the initial conductor tension to prevent cascading system failure upon conductor breakage. Thus, the current design practice accepts some tower damage as an unavoidable consequence of this phenomenon. In this study, a novel device is developed to mitigate damage to suspension towers during conductor breakage. The proposed device, intended to be installed between a tower's cross-arm and the insulator, integrates an energy-dissipating element with a triggering mechanism. It behaves as a rigid link during normal operation. In contrast, it undergoes large deformations to dissipate the energy released during a conductor breakage while limiting the force transferred to the tower within its lateral load capacity. The force-deformation behaviour of the device is experimentally characterized, which is further used to develop a trilinear model. The device's efficacy in protecting suspension towers is demonstrated through nonlinear dynamic analysis of a prototype transmission line system. Thus, the device provides a robust, low-cost solution for improving transmission line resilience against this hazard