NEESR-II: A Seismic Study of Wind Turbines for Renewable Energy

Ian Prowell

Presenter, Graduate Student Researcher

PI: Prof. Ahmed Elgamal Co-PI: Prof. Joel Conte

Prof. J. Enrique Luco

Prof. Chia-Ming Uang

Background and Motivation

Source: Sandia National Laboratories

Background

65 kW Nordtank (15 m rotor diameter), 900 kW NEG Micon 52m (52 m rotor diameter), and 3 MW Vestas V90 (90 m rotor diameter)

Background

Enercon 4.5MW 112 Meter RotorSource: Sandia National Laboratories

Construction of Modern Turbine BladeSource: LM Glassfiber

Motivations for Research• Coincidence of wind

resource and seismic hazard– Pacific Rim: US West

Coast, Japan, China, etc

– Mediterranean: Greece, Turkey, etc

• Require combined wind, operational, and seismic load case

Field Vibration Testing: NEES@UCLA

In-Situ Vibration Experiments• 900 kW NEG Micon• 2 hours of data while

operating• 46 hours of parked data• Tower and surrounding soil

instrumented• Forced vibration up to 15 Hz• Data recorded while rotor and

gearbox were removed• Wind speed and operational

data recorded simultaneously with vibration data

In-Situ Vibration Experiments• 1.5 MW NEG Micon• 45 hours of data while

operating• 1 hour of parked data• Tower and surrounding soil

instrumented• Wind speed and operational

data recorded simultaneously with vibration data

In-Situ Vibration Experiments: Outcomes

Side View

Front View

Side View

Front View

Side View

Front View

(a) 1st Side-to-side at 0.54 Hz (b) 1st Fore-aft at 0.56 Hz (c) 2nd Side-to-side at 3.94 Hz

Side View

Front View

Side View

Front View

Side View

Front View

(d) 2nd Fore-aft at 4.00 Hz (e) 3rd Fore-aft at 8.86 Hz (f) 3rd Side-to-side at 10.9 Hz 1

Mode Type Orientation Mean Frequency

Std. Dev. of Frequency

Mean Damping

Std. Dev. of

Damping

1st Bending Side-to-side 0.54 Hz 0.01 Hz 3.4 % 1.2 %

Fore-aft 0.56 Hz 0.01 Hz 4.0 % 1.4 %

2nd Bending Side-to-side 3.94 Hz 0.03 Hz 1.0 % 0.5 %

Fore-aft 4.00 Hz 0.03 Hz 0.9 % 0.4 %

3rd Bending Fore-aft 8.86 Hz 0.10 Hz 1.8 % 0.7 %

Side-to-side 10.9 Hz 0.04 Hz 0.7 % 0.4 %

Shake Table Testing: NEES@UCSD

Shake Table Testing• Dense instrumentation

with in- and out-of-plane components

• Input motions in two perpendicular orientations relative to nacelle

• Input motions in operational and parked conditions

SimulationExperiment

Shake Table Testing: Outcomes• Experimental validation of operational effects

and accurate simulation in using updates to NREL code for turbines

Overall Project Outcomes• Numerous publications sharing results• Provide valuable experimental evidence

supporting seismic behavior of wind turbines• Field work and shake table tests provide

basis for applying results across entire range of existing turbines

• Contributed and validated updates to NREL simulation code for turbines to simulate combined earthquake, operational, and wind loads

• Project personnel provided guidance on seismic loads in development of forthcoming AWEA/ASCE turbine permitting guidelines

Acknowledgements – Organizations • NSF - Grant No. CMMI0830422

• Oak Creek Energy Systems

• NEES@UCLA

• NEES@UCSD

• Sandia National Laboratories

• National Renewable Energy Laboratory

• Harvey Mudd College

Thank You