Validation of full-scale and small-scale transmission line test results on dynamic loads with numerical modeling

Tucker, Kyle B. (2007) Validation of full-scale and small-scale transmission line test results on dynamic loads with numerical modeling. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (30MB)

Abstract

This research presents the numerical validation of two different failure test data. These are: (1) suspension insulator failure test and (2) conductor failure test. The first failure scenario deals with the study of the effect of dynamic load on adjacent towers due to a broken suspension insulator; while the second scenario deals with the effect of dynamic load on a tower when the adjacent tower has failed due to conductor rupture. The published data were gathered from full scale as well as scale model tests for model validations. A finite element model of the line was developed using three different element types. Incremental nonlinear dynamic analysis was carried out in the time domain using a commercially available software package. -- Using full-scale test data from broken insulator at the suspension point, a numerical model was developed. Upon validation of the numerical model with the test results, a sensitivity study was carried out for various insulator lengths, ice thicknesses and initial tensions to determine the effects of these parameters on the impact loads on the tower cross arm. Results of the study show that the impact loads are less sensitive to the change in insulator length and initial tension but they do vary significantly when the ice loads are increased. The magnitude of the effect of incremental ice thickness has not been quantified in any previous study. A coordination of strength study showed that a suspension insulator failure can increase the conductor tension considerably thus initiating conductor rupture and therefore, a possible cascade failure in the longitudinal direction. -- Using the scale model test data for broken conductor, a numerical model was developed where a number of towers were allowed to fail (one at a time) in a preferred sequence and the peak forces predicted on the surviving tower. This predicted peak force was compared to the experimental results and a reasonable correlation was established. Results show clearly that by allowing a few structures to fail, the longitudinal peak load on the surviving tower can be reduced significantly. This information can then be used in the design of the anti-cascading tower for proper cascade failure containment. -- The study results show clearly that the analysis of dynamic load assessment on transmission system is possible and is cost effective using commercially available finite element software.

Actions (login required)

View Item