IEC TS 61400-11-2:2024

Wind energy generation systems - Part 11-2: Acoustic noise measurement techniques - Measurement of wind turbine sound characteristics in receptor position

IEC TS 61400-11-2:2024 presents measurement procedures, that enable the sound characteristics of a wind turbine to be determined at receptor (immission) locations. This involves using measurement methods appropriate to sound immission assessment at far-field locations of a wind turbine or wind farm. The procedures described are different in some respects from those that would be used for noise assessment from other industrial sound sources in environmental noise impact assessments. The procedures present methodologies that will enable the sound immission and sound characteristics of wind turbines to be described in a consistent and accurate manner.

General Information

• Status: Published
• Publication Date: 26-Mar-2024
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 88 - Wind energy generation systems
• Drafting Committee: PT 61400-11-2 - TC 88/PT 61400-11-2
• Current Stage: PPUB - Publication issued
• Start Date: 05-Apr-2024
• Completion Date: 27-Mar-2024

Standards Content (Sample)

IEC TS 61400-11-2 ®
Edition 1.0 2024-03
TECHNICAL
SPECIFICATION
colour
inside
Wind energy generation systems –
Part 11-2: Acoustic noise measurement techniques – Measurement of wind
turbine sound characteristics in receptor position

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IEC TS 61400-11-2 ®
Edition 1.0 2024-03
TECHNICAL
SPECIFICATION
colour
inside
Wind energy generation systems –

Part 11-2: Acoustic noise measurement techniques – Measurement of wind

turbine sound characteristics in receptor position

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.180  ISBN 978-2-8322-8405-6

– 2 – IEC TS 61400-11-2:2024  IEC 2024
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 Symbols and units . 15
5 Outline of method . 16
6 Instrumentation . 17
6.1 Acoustic instruments . 17
6.1.1 General . 17
6.1.2 Equipment for the determination of the equivalent continuous
A-weighted sound pressure level . 17
6.1.3 Equipment for the determination of A-weighted or Z-weighted
1/3-octave band spectra . 17
6.1.4 Equipment for the determination of narrow band spectra . 17
6.1.5 Acoustical calibrator . 17
6.1.6 Audio recording and playback systems . 18
6.2 Non-acoustic instruments . 18
6.2.1 General . 18
6.2.2 Wind speed measurement systems . 18
6.2.3 Other instrumentation (temperature, humidity, rain, pressure, distance,
temperature gradient, satellite positioning system) . 18
6.3 Traceable calibration . 18
6.4 Acoustic field calibration . 19
6.5 Time synchronization . 19
7 Test planning . 20
7.1 General . 20
7.2 Planning acoustic measurements . 20
7.2.1 Sound characteristics . 20
7.2.2 Sound sources to be considered . 20
7.3 Determination of representative conditions . 21
7.4 Effects of site conditions on measurements . 22
7.5 Acoustic measurements . 22
8 Setup of acoustic measurements . 23
8.1 Measurement locations . 23
8.1.1 General . 23
8.1.2 Proxy location . 23
8.1.3 Mounting . 23
9 Non-acoustic measurements . 24
9.1 General comments . 24
9.2 Data sampling . 24
9.3 Wind speed . 24
9.3.1 General . 24
9.3.2 Binning wind speed related to wind farm operation, V . 26
bin
9.3.3 Binning wind speed related to background sound . 27
9.4 Wind direction . 28

9.5 Precipitation . 28
9.6 Temperature, humidity, etc . 29
9.7 Wind turbine parameters (optional if necessary for assessment) . 29
10 Data reduction . 29
10.1 Bin analysis . 29
10.2 Data recommendations . 29
10.3 Uncertainty . 30
10.3.1 General . 30
10.3.2 Calculation of average sound pressure level and uncertainty per bin

based on measurements . 30
10.3.3 Calculation of average values and uncertainty per bin based on
measurements – Arithmetic averaging . 32
10.3.4 Calculation of average sound pressure level and uncertainty per bin
when using the sound power level based regulatory scheme . 32
11 Sound pressure level . 33
11.1 Outline . 33
11.2 Instrumentation . 33
11.3 Acoustic measurements . 34
11.3.1 General . 34
11.3.2 Equivalent continuous A-weighted sound pressure evel, L . 34
Aeq
11.3.3 Statistical level, L . 34
Axx
11.4 Non-acoustic measurements (SCADA, wind speed, temperature, humidity). 34
11.5 Data processing and analysis . 35
11.5.1 Data requirements . 35
11.5.2 Data binning . 35
11.5.3 Handling extraneous sound data . 35
11.5.4 Determination of representative conditions . 36
11.6 Measurement methods . 36
11.6.1 Long term measurements of wind turbine operation without shut down . 36
11.6.2 Short term measurements including periods of wind turbine operation
and shut down . 36
11.6.3 Long term measurements including periods of wind turbine operation
and shut down . 37
11.6.4 High background sound situation . 38
11.7 Guidance on background sound correction . 38
11.8 Sound power level based regulatory scheme . 39
11.8.1 General . 39
11.8.2 ISO 9613-2 . 39
11.8.3 Nord2000. 40
11.9 Reporting of results . 42
12 Tonal audibility . 42
12.1 Outline . 42
12.2 Overview of the ISO/TS 20065 method . 43
12.3 Instrumentation . 43
12.4 Acoustic measurements . 44
12.5 Non-acoustic measurements . 44
12.5.1 General . 44
12.5.2 Implementation specifics . 44
12.5.3 Data binning . 47

– 4 – IEC TS 61400-11-2:2024  IEC 2024
12.5.4 Uncertainty . 47
12.6 Reporting . 47
13 Amplitude modulation .
...