Data filtering

[neolane]

Hello everyone. Is there a universal standard for availability filtering of raw wind data? Could it be found in IEC text? Or it differs in different countries? Thanks for answering.

[Niels Gylling Mortensen]

AFAIK, there is no universal standard for this. Measnet, for example, has described the general principles in their "Evaluation of Site specific Wind conditions", see http://www.measnet.com/wp-content/uploads/2012/04/Measnet_SiteAssessment_V1-0.pdf, but not with a lot of detail or examples. Some filtering criteria are described in Annex B though.


In addtion to the most simple checks, such as the time stamp integrity (observation interval) and checks for missing records in the data series, here are a few of the things you need to look out for in the raw wind data series:
1. Are there any spikes or sudden drops in the data series?
2. Are there periods of constant data values in the data series?
3. Are there periods of missing data in the data series?
4. Are there any unusual patterns in the data series?
5. Are there any unusual patterns in the polar scatter plot?
6. Do the wind speed time traces follow each other for different anemometers?
7. Do the wind direction time traces follow each other for different vanes?
8. Do the measured and Weibull-derived values of U and P compare well?
9. Does the calm class (0-1 m/s) in the histogram look realistic?
10. and so on and so forth...
Hope this helps a little.