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Wind and Structures
  Volume 33, Number 3, September 2021 , pages 251-264
DOI: https://doi.org/10.12989/was.2021.33.3.251
 


Probabilistic failure analysis of 400 kV transmission tower-line system subjected to wind and ice hazards
Amir Mahmoudi, Kourosh Nasrollahzadeh and Mohammad Ali Jafari

 
Abstract
    Transmission line (TL) structures are exposed mostly to particular environmental conditions, which are likely to damage the line. Long experience in power systems shows that the reliability of TLs in nature is closely related to climate conditions. The purpose of this study is to develop a probabilistic framework for estimating the annual failure probability of 400 kV TL components considering the coincidence of multiple hazards with the Scenario Sampling method. Regression equations are presented to account for two sources of uncertainty including the eccentricity of connection in tower modeling, and the temperature effect on the conductor's ultimate tension in loading. The correlation matrix for maximum wind speed, maximum radial ice thickness, and temperature in the studied line is presented by analyzing local meteorological data. These correlation coefficients impose a constraint on the magnitudes of the occurrence models. The tower system used in the reliability analysis is addressed by eliminating critical members and studying changes in demand-to-capacity ratios in other members. Bi-modal bounds are used to estimate the annual failure probability of the TL system. Finally, the TL towers' fragility curves for various wind speeds as well as for different values of radial ice thickness at a constant wind speed are presented within the proposed framework.
 
Key Words
    fragility; ice thickness; load coincidence; scenario sampling; system reliability; temperature effect; transmission line; wind speed
 
Address
Amir Mahmoudi:Amir Mahmoudi:Department of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran/ Power Industry Structures Research Department, Niroo Research Institute (NRI), Tehran, Iran

Kourosh Nasrollahzadeh:Department of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran

Mohammad Ali Jafari: Power Industry Structures Research Department, Niroo Research Institute (NRI), Tehran, Iran
 

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