WP4 - Development of new tools for lifetime assessment

This WP is led by DTU. Two sets of analysis will be made: 1) for ageing turbines using inspection methods, site wind conditions and power production and 2) Turbines where component load measurements are also available.  Several wind turbines  nearing end of certified design life including NEG Micon, Vestas V-52/850, Nordtank NTK 500/37, Suzlon S88 /2.1MW will be inspected and various levels of data will be recorded. Besides inspection records, other available data from the turbines such as SCADA measurements, wind conditions recorded on the site will also be analyzed. These operational wind turbines that are nearing the end of design life will be inspected with specific instruments to gather data from 1) blades, 2)Yaw bearing and tower top flange and 3) gearbox (endoscopy) to determine their condition. These critical components are often the cause of major repair costs, if found to have serious deterioration.

Thus measurements from a significant set of operational wind turbines nearing end of certified design life will be analyzed in this project, from which statistical models for each component can be derived to represent the relationship between remaining life to the damage level. These Bayesian based statistical models provide updated quantification of the fatigue degradation from inspection records with measurements such as crack lengths on blades, cracks on gear teeth, bearing temperatures etc. and thereby the remaining life of the inspected components.

The end result of this work package will be software tools to determine the remaining life of different turbine types, conditional on the level of data available on the turbines and based on which it can be verified if the requirements listed in WP2 for certifying life extension are met.