Failure Analysis of Transmission Line Tower: A Case Study

Extra high and ultra high voltage transmission lines are widely used by the power industry. Towers are vital components in transmission system and their failure results in power disruption and economic losses. These towers are subjected to heavy loads and undergo larger displacements. The current industry practice for the analysis of towers does not consider the secondary effects of tower displacement which may affect the tower strength. In this paper, 400 kV S/C horizontal configuration tower, which has failed in the field, is modeled and analyzed using NE NASTRAN FE software. The result of nonlinear analysis is compared with the conventional linear static analysis. Both geometric and material nonlinearities are considered in the analysis. The study indicates that nonlinear analysis forces are more in comparison to the conventional linear analysis forces. In this study, the instability present in the system is determined and remedial measures are suggested.