Condition based maintenance for offshore wind turbines : the effects of false alarms from condition monitoring systems

As wind turbines increase in size and move offshore, operations and maintenance procedures need to be optimised to increase reliability, safety and maximise cost effectiveness. The practice of installing condition monitoring systems to allow the real time monitoring of assets as a means to achieve these goals is becoming more wide-spread. This allows operators to adopt a condition based maintenance approach that theoretically allows reduced costs over both preventive and corrective maintenance strategies. There have been several studies into the possible benefits and cost advantages of using a condition based maintenance strategy. However, few have examined the implications of system detection rates or false alarms. Many studies have assumed that condition monitoring systems will detect all the faults they are designed to observe. This will not be the case. Investigating false alarms or ignoring false positives in a remote offshore environment will incur costs that may alter the cost benefit of condition monitoring systems. Probabilistic models are used in the paper to determine the possible benefits of using condition monitoring systems and the effect that system detection rates and false positives have on the reliability of the system. The methods used include Markov chains and time-series modelling. © 2014 Taylor & Francis Group, London.