1.4 Operational Predictions - Converter Station
1.4.1 Prediction Method Modelling of the converter station for East Anglia ONE has been undertaken using CadnaA noise modelling software, which incorporates prediction methodology within ISO 9613: 1993 Acoustics - Attenuation of sound during propagation outdoors. The ISO 9613 method predicts a long-term equivalent continuous A-weighted sound pressure level (LAeq) under meteorological conditions favourable to propagation at distances from a variety of sources of known emission. The method is defined for octave bands for 63 Hz to 8 kHz.
1.4.2 Prediction parameters
The model assumes downwind propagation, within +/- 45 degrees of direction connecting dominant source and receiver, wind speeds between 1 and 5 m/s at heights between 3 and 11 m above the ground. The following parameters have been used within the modelling:
• 0.01 absorption coefficient on site ground assuming concrete and 0.8 absorption coefficient outside of site as per Datakustik methodology for fields/grassland/arable;
• Temperature of 10◦C and humidity of 70% for worst case sound propagation; and
• Site buildings and barriers reflective surfaces. 1.4.3 Noise Source Parameters
The following section describes the noise sources as they have been modelled within the CadnaA computer noise model representing the main noise emitting plant for a converter station of the type proposed for East Anglia ONE. Sources of data to be used in the modelling were as follows:
• Converter Cooling Fan Banks - Datasheet from thermofin GmbH, HelWin II, #711362, 11.04.2012.
• Air Handling Unit - Datasheet from thermofin GmbH, BorWin 2, Stat. Diele, # 88434 - 5000024064, 21.10.2010.
• Transformer Bank - Siemens 'Sound power level spectra used for HVDC plus Station acoustical 3D model, for the main equipment'.
• Transformer Cooling Radiator Fans -Siemens 'Sound power level spectra used for HVDC plus Station acoustical 3D model, for the main equipment'.
Transformer Bank (height of 5 metres) x 6
This source has been modelled as a composite of vertical and horizontal area sources surrounding a core structure. As such, the supplier Lw data could not be inputted directly into the source. The Lw input requirements have been back calculated by calibrating modelled receptor points (representing the Lp) 1m perpendicular to each of the transformer sides and top (as would be measured to calculate the Lw in accordance with ISO 3747:2010 Acoustics - Determination of sound power levels and sound energy
EAOW
Noise Prediction Methodology P41388
5
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46