Overview
IEC TS 61400-14:2005, titled Wind turbines - Part 14: Declaration of apparent sound power level and tonality values, is a technical specification published by the International Electrotechnical Commission (IEC). This document provides guidelines for the declaration of the apparent sound power level and tonality characteristics of batches of wind turbines. It is designed to complement IEC 61400-11, which details measurement techniques for acoustic noise emitted by wind turbines.
The specification addresses the need for more reliable and representative noise emission data from wind turbines by considering variations between individual units within a batch. This ensures enhanced accuracy in wind farm planning and supports regulatory assessments. IEC TS 61400-14 holds particular relevance in the context of Smart Grid development, where environmental noise and sound quality are critical factors influencing turbine integration and community acceptance.
Key Topics
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Declaration of Apparent Sound Power Level
The standard outlines statistical methods for declaring the apparent sound power level from several measurements of turbines within the same batch. It provides formulas to calculate mean values, standard deviations, and confidence intervals based on measurements from multiple turbines.
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Tonality Declaration
Tonality represents tonal noise components in the emitted sound, which can affect noise annoyance. The specification discusses the reporting of tonality values and their associated frequencies, though it notes that limited statistical data currently exist for tonality declarations.
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Measurement Batches
A batch refers to wind turbines of the same make and model with identical specifications. The standard emphasizes declaring noise values that represent the entire batch rather than individual units, accounting for turbine-to-turbine variability.
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Statistical Parameters
Important terms defined include:
- Standard deviation of reproducibility – variation of measurements on the same turbine under different conditions.
- Standard deviation of production – variation between different turbines within a batch.
- Total standard deviation – combined measure of variability for declaration and verification.
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Conversion for Hub Height Variations
Annex A provides a methodology to convert sound power levels to different hub heights based on logarithmic wind profiles, enabling consistent declarations across varying turbine installations.
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Reporting Requirements
Detailed information must be documented, including:
- Manufacturer and model details
- Measurement results (individual levels, means, deviations)
- Tonality data
- Manufacturer certificates for component differences
Applications
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Wind Farm Planning
By providing statistically sound declarations of noise emission, this standard assists planners and developers in accurately predicting environmental impacts and complying with noise regulations.
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Regulatory Compliance
Authorities can use these declarations to evaluate wind turbine noise compliance more reliably, minimizing disputes arising from measurement variability.
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Turbine Manufacturer Documentation
Manufacturers can create standardized noise profiles for batches of turbines, facilitating transparent communication with customers and regulators.
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Smart Grid Integration
Noise performance data contributes to smoother integration of wind turbines into smart grid systems where environmental and community considerations are intertwined with operational efficiency.
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Noise Comparison and Benchmarking
The standard supports consistent comparisons of noise emissions between different wind turbine models, aiding buyers and developers in informed decision making.
Related Standards
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IEC 61400-11:2002 – Wind turbines - Acoustic noise measurement techniques
Defines procedures for noise measurement essential for determining apparent sound power levels as per IEC TS 61400-14.
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ISO 4871:1996 – Acoustics - Declaration and verification of noise emission values of machinery and equipment
Provides foundational principles for noise declaration applicable to various equipment, referenced in this specification.
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ISO 7574 (all parts) – Acoustics - Statistical methods for determining and verifying stated noise emission values
Supplies statistical methods for noise emission declarations, supporting the procedures described in IEC TS 61400-14.
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Other Parts of IEC 61400 Series
Includes standards dealing with wind turbine design, safety, power performance, and other acoustical aspects contributing to comprehensive wind turbine standardization.
Keywords: IEC TS 61400-14, wind turbine noise, apparent sound power level, tonality declaration, wind farm planning, acoustic noise, IEC 61400-11, noise measurement, wind turbine standards, Smart Grid integration, environmental noise, turbine batch declaration, statistical noise analysis, wind turbine acoustics.