Life extension for wind turbine structures and foundations

  • Tim Rubert

Student thesis: Doctoral Thesis


This thesis explores economic and technical lifetime extension considerations of wind turbine generators. The research unveils that onshore support structures will likely have suffcient fatigue reserves left, beyond the initial design life, to support an extended operation. However, suitability is strongly dependent on the difference between the designand encountered load profile, asset maintenance activities, operational knowledge, and the policy environment. A lifetime extension decision model is developed and input parameters are scrutinised revealing the feasibility to replace the entire drive train of a wind turbine and yet, be profitable when exposed to a non-subsidised environment. The designed decision modelis further applied based on operational data of two wind farms in the UK to derive anasset specific lifetime extension strategy. In addition, a methodology and field trial is presented to monitor operational foundationstresses based on optical sensor networks aimed at reducing conservative designassumptions, enabling the reuse of foundations for greater rated turbines as well as tosupport the lifetime extension decision-making. Furthermore, this thesis provides guidance on how to evaluate and obtain the strategic lifetime extension decision-making at an early stage (year 10-14) by means of a fatigue analysis of tower strain measurements. Fatigue tower findings in conjunction with operational data of an asset are subsequently assessed to define the turbine's/wind farm'sunique economic lifetime extension boundaries.
Date of Award1 Oct 2018
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde & EPSRC (Engineering and Physical Sciences Research Council)
SupervisorPawel Niewczas (Supervisor) & David McMillan (Supervisor)

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