Publication: Assessment of the failure of an electrical transmission line due to a downburst event

All || By Area || By Year

Title Assessment of the failure of an electrical transmission line due to a downburst event
Authors/Editors* A.Y. Shehata and A.A. El Damatty
Where published* Electrical Transmission Line and Substation Structures: Structural Reliability in a Changing World - Proceedings of the 2006 Electrical Transmission Conference,
How published* Proceedings
Year* 2006
Volume 218
Pages 27-38
Keywords downburst- failure- wind
In September 1996, Manitoba Hydro reported damages of about US $ 12 Million due to failure of 19 transmission towers during a downburst event. As a result, a research program has been recently initiated in Canada to study the performance of transmissions tower under high intensity wind loads associated with localized events such as downbursts and tornadoes. This study focuses on assessing the failure of one of the towers that collapsed in Winnipeg as a result of a downburst event. The study is conducted numerically using a numerical code that was developed in-house at the University of Western Ontario specifically for the analysis of transmission towers under the effect of downbursts. The numerical model combines wind field data for downbursts generated using a Computational Fluid Dynamic (CFD) model together with non-linear finite element formulation that accounts for the large displacement behaviour of the conductors. Failure criteria for the tower members associated with both compressive and tension forces are incorporated into the model. As such, the non-linear finite element model is capable of predicting the progressive failure of a tower that can initiate once one of its members reaches its ultimate capacity. Based on an optimization scheme, the numerical model can determine the downburst parameters, such as its radius and location relative to the tower, that are most critical for the structure in terms of failure. Using these parameters, the velocity of the downburst is gradually increased till one of the member towers reaches its ultimate capacity. Failures of other members progressively occur till the structure looses its overall stability. The study provides an insight about the mode of failure of transmission tower structures under downburst loading. This is compared to the field observation detected during the collapse of the Manitoba tower.
Go to Structural Engineering
Back to page 74 of list