IEC 61400-11:2002/AMD1:2006

Amendment 1 - Wind turbine generator systems - Part 11: Acoustic noise measurement techniques

General Information

• Status: Published
• Publication Date: 28-May-2006
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 88 - Wind energy generation systems
• Drafting Committee: MT 11 - TC 88/MT 11
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 07-Nov-2012

Relations

• Amends: IEC 61400-11:2002 - Wind turbine generator systems - Part 11: Acoustic noise measurement techniques
• Effective Date: 05-Sep-2023
• Revised: IEC 61400-11:2012 - Wind turbines - Part 11: Acoustic noise measurement techniques
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 61400-11
AMENDMENT 1
2006-05
Amendment 1
Wind turbine generator systems –
Part 11:
Acoustic noise measurement techniques
 IEC 2006 Droits de reproduction réservés  Copyright - all rights reserved
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– 2 – 61400-11 Amend. 1  IEC:2006(E)
FOREWORD
This amendment has been prepared by IEC technical committee 88: Wind turbines.
The text of this amendment is based on the following documents:
FDIS Report on voting
88/260/FDIS 88/264/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
_____________
INTRODUCTION
This amendment to IEC 61400-11:2002 addresses special cases where 95 % of rated power
is reached below 10 m/s speed at 10 m height and for sites where wind speeds of 10 m/s at
10 m height are very rare. Furthermore a clarification on regression analysis and frequency
weighting is included.
Page 8
4 Symbols and units
Add the following new symbol:
V  wind speed measured by the nacelle anemometer (m/s)
n
Page 9
5 Outline of method
Insert, after the fifth paragraph, the following text:
If this part of IEC 61400 is used for verification that actual noise emission is in accordance
with a reference/declared noise level, the verification measurement shall be made in
accordance with the present standard for a wind speed range given by:
– Annual average wind speed at 10 m height onsite ±1 m/s as a minimum. As a minimum,
three integer wind speed values and 8 m/s shall be reported (i.e. site average = 4,8 m/s,
use 4, 5, 6, and 8 m/s).
61400-11 Amend. 1  IEC:2006(E) – 3 –
– If the declaration measurements indicate that audible tones are present at other wind
speeds, these wind speeds shall be included as well.
Where local codes or contracts between parties involved (i.e. manufacturers, developers,
owners) require measurements at a different wind speed or wind speed range, this part of
IEC 61400 may be applied at those wind speeds.

Page 11
6.2.1 Anemometers
Add, at the end of the Subclause:
Because the nacelle anemometer is in situ calibrated during measurement, the demand for
calibration does not apply to the nacelle anemometer. The measurements from the nacelle
anemometer may be supplied from the wind turbine control system. The nacelle anemometer
shall not be used for background noise measurements.

Page 13
7.1.2 Wind speed and direction measurement positions
Add, at the end of the Subclause:
If 95 % of the rated power is reached below a standardized wind speed of 10 m/s and the
nacelle anemometer method is chosen, the wind speed from the nacelle anemometer shall be
measured. If no nacelle anemometer is available, an anemometer shall be mounted on the
nacelle. For wind turbines with a hub height below 30 m, all wind speed measurements may
be taken from an anemometer between 10 m and hub height.

Page 14
7.2.2.3 Narrow band measurements
Replace the text of this Subclause by the following new text:
For each integer wind speed, at least 2 min of A-weighted wind turbine noise and background
noise are required. These 2 min shall be as close as possible to the integer wind speeds.
If the A-weighting cannot be applied during measurement, linear spec
...