Extensible catenary approach in analyzing transmission line’s conductors under downbursts

Abstract

The objective of this paper is to develop a mathematical approach that can predict the structural performance of a cable with end points unaligned both vertically and horizontally. The approach takes into account the extensibility of the cable. Moreover, it considers the analysis of a multiple span cable, the flexibility of the cable’s supports and the effect of both in plane and out-plane loads. An important application of this model is related to the performance of transmission line conductors under High Intensity Wind (HIW) such as downbursts. The localized nature of those events can lead to failure of one tower, which results in misalignment of the end points of the adjacent spans. The developed model can be used in predicting the performance of an entire line post the failure of one tower during a downburst event. The validation of this mathematical model is conducted by comparing its numerical predictions to the results of the analysis of multi-span conductors conducted using non-linear Finite Element Analysis (FEA). The main advantage of the mathematical model compared to FEA is the efficient computational time, which is very important for predicting the progressive failure of transmission lines under downbursts as this requires conducting a large number of analyses by varying the location and size of the localized wind event.