Acoustic propagation effects were calculated using the ISO 9613 method;
Free field noise levels were calculated at first floor height for each receptor, as the results were slightly higher than at ground floor level; and
A +5dB ‘acoustic feature’ penalty, as defined in BS 4142, was added to the noise level calculated at each receptor. This is to account for the tonal nature of noise from converter stations, and represents a conservative approach.
60.
The noise levels were calculated at the closest noise sensitive receptors to the converter station sites.
Scenario 2: Trenching and ducting 61.
Under construction Scenario 2, operational noise impacts arise from the operation of a single DC converter station constructed in the location provided in Figure 26.1 in close proximity to the existing National Grid Bramford sub–station.
62.
In this scenario it is considered appropriate to use the converter station modelling results obtained in the East Anglia ONE ES as an accurate representation of the noise impact associated with the construction of the identical East Anglia THREE converter station (full details of the assessment is provided in Appendix 26.1).
63.
The noise from the converter station has been predicted by modelling the noise sources using CadnaA noise modelling software. CadnaA incorporates prediction methodology within ISO 9613: 1993 Acoustics - Attenuation of sound during propagation outdoors.
64. A three-dimensional model of the proposed surrounding area was constructed, based on topographical data, ordnance survey mapping and indicative layout plans of the converter stations. Typical noise emission data for the items of electrical equipment and their typical locations was obtained from a potential supplier.
Operational vibration from the converter stations 65.
Ground borne vibration may potentially arise from the operation of electrical substations and associated plant. There is a very large separation distance between the converter stations site and residential properties. Where properties are located outside of the 100m buffer zone, the distances are deemed large enough to protect receptors from operational related ground borne vibration. It is considered that given the separation distances of over 100m that ground borne vibration could not be expected to adversely affect receptors. As a result ground borne vibration from
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm
Chapter 26 Noise and Vibration Page 20
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 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58