Theoretical Calculation of Ultimate Bearing Capacity and Fatigue of Safety Pin of Transmission Tower

In this paper, the hazard of normal operation power lines caused by transmission lines icing is analyzed. On the basis, several technology means of preventing the hazard of transmission lines icing in power grid in China are summarized. A new kind of overload protection fitting which is safety pin is designed in this paper, which can make transmission line dissociate from tower when ice thickness exceed the numerical value that ultimate load related. And then collapse of power transmission tower and disconnection of transmission are prevented and the goal of avoiding and decreasing the ice disasters is achieved. Ultimate bearing capacity of safety pin is researched based on elastic-plastic theory and elastic limit load and plastic limit load of safety pin are obtained. Finally, applying Palmgren Miner linear fatigue damage accumulation rule, fatigue life of safety pin is calculated.