Assessment of condition monitoring techniques for offshore wind farms

This paper discusses the results of an extensive investigation to assess the added value of various techniques of health monitoring to optimise the maintenance procedures of offshore wind farms. This investigation has been carried out within the framework of the EU funded CONMOW project (Condition Monitoring for Offshore Wind Farms) which was carried out from 2002 through 2007, [5]. A small wind farm of five turbines has been instrumented with several condition monitoring systems and also with the “traditional” measurement systems. Analyses of these measurements and of data collected by the turbine's SCADA systems have been performed to assess (1) if failures can be detected; (2) if so, if they can be detected at an early stage and their progress over time can be monitored; and (3) if criteria are available to assess the component's health. Several data analysis methods and measurement configurations have been developed, applied, and tested. This paper first describes the use condition monitoring to change from scheduled and corrective maintenance to condition based maintenance. Second, the paper describes the CONMOW project, and the major results. viz. the assessment of the usefulness and capabilities of condition monitoring systems and algorithms for identifying early failures. Finally, the economic consequences of applying condition monitoring systems have been quantified and assessed.