DIN ISO 20816-21:2025-12

This part of DIN ISO 20816 specifies the measurement and evaluation of the mechanical vibration of wind turbines and their components through measurements taken on non-rotating parts. It applies to horizontal axis wind turbines with a generator rated output exceeding 200 kW. It deals with both horizontal axis wind turbine installations with generators coupled to the rotor via a gearbox and horizontal axis wind turbine installations with generators coupled to the rotor without a gearbox (direct drive wind turbines). The vibrations of various types of wind turbines are clearly identified and the measurement locations are graphically displayed. In addition, the evaluation tables have revised and standardized, and the descriptions of the technical operation of wind turbines clarified. A proposal for protocols for acceptance measurements has also been added. This part of DIN ISO 20816 recommends zones for evaluating the vibration at continuous load operation specifies evaluation zone boundaries based on vibration data collected from thousands of wind turbines with rated generator outputs of 5 MW or less, which can be helpful in facilitating discussion between users and manufacturers. Although the type and implementation of broad-band vibration monitoring of wind turbines are discussed, this document does not apply to diagnosis or fault detection through condition monitoring of wind turbines. Evaluation of the unbalance of the slowly turning wind turbine rotor, which requires special measurements and analyses, is not covered by this part of DIN ISO 20816. Furthermore, this document does not apply to the acceptance measurements for wind turbine gearboxes and generators taken in the manufacturer's test facility. The responsible national standardization committee is Working Committee NA 001-03-03 AA "Messung und Beurteilung von Maschinenschwingungen" ("Measurement and evaluation of vibration of machines") at DIN/VDI Standards Committee Acoustics, Noise Control and Vibration Engineering (NALS).