Application of Order Analysis to Diagnose Fatigue within Wind Turbine Gearbox

One of the most expensive and critical component in wind turbines is the gearbox. Gearbox failure may have significant impacts on the network in terms of continuity of power supply especially in islanded areas where the majority of power demand is supplied by wind farms. As such, an effective condition monitoring technique for wind turbine gearbox should be adopted to avoid any catastrophic failure to the gearbox and maintain system reliability. This paper presents a technique to monitor the gearbox condition through monitoring the shaft torque and the gearbox vibration signals. Practical measurement is conducted on a test rig that emulating real wind turbine operation. Model based control technique using voltage slider by injecting a current through the induction generator stator terminals is applied to emulate real fault conditions on the wind turbine blades such as icing accumulation, wind share and gust wind. Order analysis technique is used to analyse and compare the obtained signals during normal and abnormal operating conditions.