swiveling the nacelle by the nacelle swiveling mechanism based on a wind direction obtained from a measurement result of the anemoscope when a wind speed obtained from a measurement result of the anemometer exceeds {HEAD ~ a first threshold} which is lower than {TAIL ~ a cut} in wind speed; and 
swiveling the nacelle by the nacelle swiveling mechanism based on a wind direction obtained from a measurement result of the anemoscope when a wind speed obtained from a measurement result of the anemometer exceeds { HEAD ~ a first threshold } which is lower than { TAIL ~ a cut } in wind speed ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH