The presentation is about Accurately Assessing the Impact of Wind Turbines on Radar. It was given by Kai Folic on behalf of Pager Power at the British High Commissioner's Residence, Pretoria, South Africa in 2012.

1. British High Commissioner’s Residence, Pretoria
2012
+ 44 1787 319 001
kai@pagerpower.co.uk
www.pagerpower.com

2. Wind Turbines and Aviation Radar
Accurately Assessing the Impact of Wind Turbines on Radar

3. Considerations
• Understanding Impacts
• Terrain Based Assessments
• Application of Assessment Results – Wind Farm Design
• Risk Assessment
• Conclusions

4. Considerations
• Understanding Impacts
• Terrain Based Assessments
• Application of Assessment Results – Wind Farm Design
• Risk Assessment

5. Functional Diagram
Operator

6. Functional Diagram
Operator Display System

7. Functional Diagram
Operator Display System Radar

8. Functional Diagram
Operator Display System Radar Propagation

9. Functional Diagram
Operator Display System Radar Propagation Turbine

10. Functional Diagram
Operator Display System Radar Propagation Turbine

11. Understanding Impacts
• Characterisation of wave source – radar
• Behaviour of radar pulses
• Atmospheric effects – refraction
• Physical environment – reflection, earth curvature
• Terrain effects – diffraction

12. Terrain Based Assessments
• More than one approach
• Must consider whether approach is:
1) Accurate
2) Conservative
• Survey is ideal – not always practical (or necessary!)

13. Terrain Based Assessments – Nearest Neighbour
Nearest neighbour
Point
zPoint = zNearest neighbour

14. Terrain Based Assessments – Nearest Neighbour
• Simple to implement
• Low accuracy
• Appropriate for some assessments

15. Terrain Based Assessments – Weighted Average
Point
zPoint = Weighted average (z1 .. z4)
Closest point has highest weighting
z1 z2
z3 z4

16. Terrain Based Assessments – Weighted Average
• More complex to implement
• High accuracy
• Generally conservative

17. Terrain Based Assessments – 12 Point Average
Point
zPoint = Adjusted weighted average (z1 .. z4)
zPoint adjusted based on slopes determined to outer points
z1 z2
z4z3

18. Terrain Based Assessments – 12 Point Average
• Most complex to implement
• Highest accuracy
• Not necessarily conservative

19. Terrain Based Assessments

20. Terrain Based Assessments

21. Terrain Based Assessments

22. Terrain Based Assessments

23. • Must have accurate assessment tools
• Must understand limitations
• Radar LOS and Radar Detectability Analysis
Terrain Based Assessments

24. Application of Assessment Results

25. Application of Assessment Results

26. Risk Assessment
• Detailed analysis gives reliable assessments
• Results can easily be applied as GIS layers
• Maximise potential of available site area
• Quantified effects lead to quantified risk

27. Risk Assessment

28. Conclusions
• An accurate assessment process is important for the
industry for the following reasons:
1) Standard process understood and accepted by all
parties involved
2) Credible results based on this process
3) Efficient wind farm development

29. British High Commissioner’s Residence, Pretoria
2012
+ 44 1787 319 001
kai@pagerpower.co.uk
www.pagerpower.com

31. Doppler Effect
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32. Diffraction
Radar Line of Sight
Blocking Point
Treated as a
Knife Edge for
calculations
Strong signal
No Diffraction loss
0% Loss
Moderate signal
Some Diffraction loss
50% Loss Typical
Weaker signal
Diffraction Loss
75% Loss Typical
Weak signal
Diffraction Loss
99% Loss Typical
Diffraction losses also affect
Line of Sight signals above, but near or at,
The Blocking Point. (Typical separation 5m)
Diffraction losses are greatest for
Diffracted signals beneath the
Blocking PointReceived Radar Signals are
reduced twice due to losses
affecting both the transmitted
And received signals.

33. Protected Surfaces