Wind systems offer a promising alternative to meet the needs of electricity consumers by exploiting the benefits of renewable natural sources. The work presented in this paper focused on the study of a stand-alone wind system based on a Permanent Magnet synchronous generator for the production of electrical energy in isolated sites. This study aims to detect and isolate the different sensors faults that can affect a wind turbine using a sliding mode observer. The proposed observer is synthesized and implemented in Matlab/Simulink environment. Simulation results are presented and analyzed up.