Characterising wind fluctuations at the Horns Rev offshore wind farm. Claire Vincent and Gregor Giebel (Risø-DTU) Pierre Pinson (DTU-IMM). Introduction. Episodes of severe wind variability are observed at Horns Rev.
Claire Vincent and Gregor Giebel (Risø-DTU)
Pierre Pinson (DTU-IMM)
Introduction wind farm
Examples from 2000 and 2001
Methodology wind farm
Observational Data wind farm
The Hilbert-Huang Transform wind farm
1. Decompose the data, so that each component is a mono-component signal.
2. Use the Hilbert transform to calculate the instantaneous frequencies and their amplitudes at each time.
Empirical Model Decomposition wind farm
Fastest oscillations in the time series
Quick response to non-stationarities in the data
Original time series
Amplitude Modulation wind farm
Frequency Modulation wind farm
Period: 2.4 hours
1/2.4 = 0.4 cycles per hour
Episode of enhanced variability
More intense fluctuations in winter and autumn
Results: The effect of wind direction wind farm
What does the wind wind farm‘see’ from different directions?
Results: Variability and Precipitation wind farm
Rmax at time t is the maximum observed 10 minute rain amount within the interval [t – 90mins, t + 90 mins]
Rain is observed in discrete 0.25 mm quantiles.
Contours show probability density function of variability for each Rmax value.
Results: Variability and Stability wind farm
10 minute cup anemometer data: 4 year time series
12 Hz sonic anemometer data: 10 month time series
Summary of Results wind farm
A wind farm‘classic’ event
Conclusions wind farm
Acknowledgements wind farm