Numerical Investigation on the Dynamic Response and Fatigue Analysis of the Tension Insulator String Under Stochastic Wind

The tension insulator string is an important component for transferring the load of the conductor to the transmission tower. The damage of tension insulator strings may dramatically affect the operation safety of the grid power. In this paper, the dynamic response and fatigue life of the tension insulator strings under stochastic wind were systematically studied. Firstly, finite element models of conductors and the tension insulator string upon the actual transmission lines were established. The effects of height difference ratios on the dynamic tension of conductors and the dynamic response of tension insulator strings under a 10 m/s stochastic wind were investigated, respectively. Secondly, a simplified calculation method of stress time history is proposed to simplify the fatigue life analysis for tension insulator strings. Finally, based on the Rayleigh distribution, wind farms with the annual mean wind speed of 7 m/s were established to evaluate the fatigue life of tension insulator strings. The stress results revealed the at-risk parts in tension insulator strings and their failure modes. The fatigue life results showed 17.1 and 33.4 years for the GD (Guan Dian)-fittings and the upper U-shackles, respectively. This study can provide a useful guideline for optimization and safety evaluation of fittings.