Finding functional redundancies in offshore wind turbine design

Offshore operational conditions for wind farms differ from onshore especially because of their exposure to extreme weather, their remote locations and their inaccessibility in certain periods of the year. This brings a new challenge for the wind energy industry, which faces the need of more reliable systems. A common approach to improve reliability is to use component redundancies. Although this may be a good solution in some cases, it can also give undesirable consequences such as additional weight, need of additional space and cost increase. Another approach is to look at the functional capabilities of existing components to accomplish functions not initially intended to do so. In the event of a fault, these additional capabilities may be used to substitute the function of a faulty component and to have the system available for operation. This paper presents a new design philosophy based on functional redundancies and reconfiguration that can help to increase availability of wind turbines. It has a special impact on offshore applications where, in addition to the difficult accessibility, energy output per unit is more significant because of the continuous increase in sizes. An example is presented using a conceptual design of a wind turbine, showing how to find potential functional redundancies that can provide fault-tolerant solutions and bring flexibility to the system's operation, at no significant additional weight and cost. The methodology is implemented in a software tool named Knowledge Intensive Engineering Framework, which supports functional representation and, more specifically, function-behavior-state modeling.