Overview
ISO 10816-21:2015 - Mechanical vibration - Evaluation of machine vibration by measurements on non-rotating parts - Part 21: Horizontal axis wind turbines with gearbox - defines how to measure and evaluate vibration of wind turbines by taking measurements on non-rotating parts (tower, nacelle, gearbox housing, etc.). It applies to horizontal-axis wind turbines with a mechanical gearbox and rated generator output exceeding 200 kW, and covers turbines with common design and operational characteristics such as blade pitch/stall control, synchronous/asynchronous generators, and tower/foundation constructions of steel or concrete.
Key topics and technical requirements
- Scope and applicability: turbines with gearbox, rotor bearings integrated or separate from gearbox, grid-coupled generators (direct or via converter).
- Measurement principles: guidance on measurement locations, mounting and connection of vibration transducers, required measurement equipment quality, and appropriate operating conditions during measurements.
- Characteristic quantities and averaging: specifies measurement quantities, averaging methods and evaluation periods tailored to wind turbine dynamics (including low-frequency content from blades, tower and wind excitation).
- Component-specific guidance: instructions for measuring and interpreting vibration at the nacelle and tower, rotor bearing, gearbox and generator.
- Evaluation and alarm concepts: defines evaluation practices including evaluation zones and procedures to set operational limits (ALERT / ALARM / TRIP concepts) - note: the standard does not prescribe universal numeric zone boundary values due to fleet variability.
- Informative annexes: Annex A provides example evaluation zone boundaries for onshore turbines based on data from about 1 000 turbines (up to 3 MW) to support discussion between users and manufacturers.
Practical applications and users
ISO 10816-21 is a practical reference for:
- Turbine manufacturers - to design acceptance/tests and define vibration pass/fail criteria in supplier agreements.
- Asset owners & operators - for commissioning, routine vibration assessment, and setting condition-based maintenance thresholds.
- Maintenance and service providers - to standardize measurement methods and interpret vibration signals for troubleshooting gearbox, bearing and generator issues.
- Condition monitoring and vibration analysts - to integrate non-rotating-part measurement methods into predictive maintenance programs.
- Certification bodies and financiers - to evaluate machine condition consistently during due diligence.
Key use cases include commissioning checks, periodic inspection, baseline vibration surveys, setting alarm limits for SCADA/integrated monitoring systems, and comparative evaluation across turbine models.
Related standards
- ISO 10816 (series) - General guidance (Part 1) and multiple machine-specific parts (e.g., ISO 10816-3).
- Planned: ISO 10816-22 for horizontal-axis wind turbines without gearbox (direct drive).
Keywords: ISO 10816-21:2015, wind turbine vibration standard, mechanical vibration, gearbox, horizontal axis wind turbines, vibration monitoring, non-rotating parts, evaluation zones, condition monitoring.