In this paper, the problem of fault diagnosis in wind turbines will be addressed applying a setmembership approach. Fault detection is based on the use of parity equations and unknown but bound description of the noise and modelling errors. Fault detection test is based on checking consistency between measurements and the model by finding if there is parameter in the feasible parameter set (approximated by a zonotope) that is compatible with modelling and noise bounds. The fault isolation algorithm is based on analyzing the observed fault signatures on-line and matching them with the theoretical ones obtained using structural analysis. Finally, the proposed approach will be tested using the wind turbine benchmark proposed in the context of the WT FDI competition.