scope:

The series of standards VDI 3834 provides infor-mation about the measurement and evaluation of the mechanical vibration of WT and their compo-nents. It applies to horizontal axis WTs with rated generator outputs exceeding 200 kW and the fol-lowing design and operation characteristics:

• installation onshore or off the coast (offshore)

• installation on supporting systems (tower and foundation) made of steel and concrete

• horizontal-axis rotor with several rotor blades

• rotor bearing separate from or integrated into the gearbox

• generators driven via gearbox or direct driven

• generators of the synchronous or asynchronous type

• generators with only a fixed pole number or which are pole-changeable for speed adjustment

• output control by rotor blade adjustment pitch or stall • generator coupled to the power grid via con-verter or directly

• nacelle with active yaw system to align to wind direction

 This standard applies to on- and offshore WTs of Group 1. Section 5 covers the zone boundaries for evaluating vibration in the operating range de-scribed by Section 3.7. It has not yet been possible to collect sufficient data of offshore WTs. There-fore, zone boundaries for offshore WEA are not yet included in this standard.

VDI 3834 Part 2 for Group 2 WTs is currently in preparation and a small amount of measured data is already available.

The VDI 3834 standard series does not apply to acceptance measurements at gearboxes and genera-tors in the manufacturer's test facilities. These are assessed on the basis of the appropriate standards, namely, ISO 8579-2 and DIN EN 60034-14.

However, zone boundaries given in Section 5 are not suitable for the early detection of faults and diagnostic purposes.

The evaluation of balance quality of the slowly turning WT rotor requires special measurements and analysis. In addition to mass unbalance the rotor can also exhibit an unallowable aerodynamic unbalance. Information is given in Annex B.

The series of standards VDI 3834 does not apply to the evaluation of torsional vibration in the drive train nor to the condition of the rolling element bearings and gear meshes. Techniques to assist the detection of rolling element bearing and gearbox defects can be found in VDI 3832 and DIN ISO 13373-2. Explanations on failure diagnostic of machines are presented in the series of standards VDI 3839. Information on the type and implemen-tation of condition monitoring systems for WT is given in Section 7.2. Further information on condi-tion monitoring and diagnostics of WT will be presented in ISO 16079-1 (in preparation).