台灣風場特性與離岸風電技術 - 蔡原祥 助理教授

台灣風場特性與離岸風電技術 - 蔡原祥 助理教授

Transcript

1. 1 Yuan-Shiang Tsai, Ph.D. 2019/11/22 National Kaohsiung University of Science and Technology 台灣風場特性與離岸風電技術 成功大學能源講堂
2. Outlines ◼ Wind features in Taiwan ◼ Wind measurements ◼ In terms of power generation and wind turbine safety ◼ Turbulence effects ◼ Extreme winds 2
3. Wind energy in Taiwan Strait 3 ◼ Potential wind energy Shallow water (5-20m) Deep water (20-50m) Potential 9 GW 48 GW feasible 1.2 GW 5 GW From ITRI (2007) ⚫ Taiwan Strait is one of the best sites for wind energy development
4. Wind patterns in Taiwan 4 Typhoon ◼ Diurnal variation ◆ Sea-land (land-sea) breeze ◆ Mesoscale and extension for hundred kilometers ◼ Typhoons ◆ Extreme wind conditions ◆ Mesoscale and extension for hundred kilometers Northeast monsoon Southwest monsoon ◼ Seasonal variations ◆ Northeast trade wind ◆ Southwest trade wind ◆ Very large-scale and extension for thousands of kilometers H Winter L Summer
5. Funnel effect 5 ⚫ Wind speed is increased when passing a contract section wind h v1 v2 ◼ Venturi effect ◼ Wind passes a valley
6. Distribution of wind direction 6 Mar. - May Jun.- Aug. Sep. – Nov. Dec.- Feb. Annual ◼ Wind rose offshore of Jhonghua ⚫ Majority of the wind energy from northeast monsoons
7. Wind-speed variations 7 Typhoons sea-land/land-sea breeze Southwest monsoon ◼ NE wind in dominance ◼ SW wind in dominance ⚫ Observed at Yongan Taoyuan ⚫ Dry and cold winds Cold fronts ⚫ Warm and humidity winds abrupt wind increase ⚫ Observed At Singda Harbour
8. 8 Various scales in winds ✓ Typhoon Wind power Diurnal cycle Synoptic scales Turbulence, gusts Spectral gap Time scale Without significant wind energy ◼ Spectrum of Von der Hoven (1956)
9. Wind measurements 9
10. Conventional measurements 10 ⚫ Accurate measurements after calibration ⚫ Difficult to construct over 100 m ⚫ Not easy to maintain ◼ Meteorological mast cup anemometer wind vane Taiwan generations Corp. IEC 61400-12-1 propeller anemometer Ultrasonic anemometer PTH sensor
11. 11 ⚫ Easily to measure a greater height (for example between 40- 200m) with self-defined different levels ⚫ Ease of installation and maintenance Lidar measurement ◼ Leosphere WindCube v2 200 m 40 m 50 m 60 m 80 m 100 m 120 m 140 m 160 m 180 m
12. 12 Principle of Lidar measurement Aerosols V fo fo +2f  Radial velocity • Assuming aerosols moving with wind =   : Doppler frequency shift ◼ Lidar (Light Detect and Ranging )
13. Wind studies using Lidar 13 ◼ Observation at intertidal zone, Hanbour, Changhua 13 ⚫ SW wind measurement (P2) ⚫ NE wind measurement (P1) Observation sites 600 m P1 P2
14. Site assessment 14 ◼ Use of floating Lidar https://www.ieawindtask32.org/about/objectives/site-assessment/
15. In terms of power generation and wind turbine safety 15
16. A wind turbine under wind action Wind Foundation Tower Hub Nacelle Blade Rotation Pitch Yaw Waves & currents Power generation Upper part Structural safety Lower part Integration Hub height
17. Inside the nacelle 17 ◼ Power generator and mechanical components Lynn (2012) ⚫ Very import devices to control the wind turbine and power performance, however, installed behind the rotor
18. Power performance 18 Wind velocity (m/s) Generated power (KW) ◼ Wind-speed distribution ◼ Power output curves • Wind-Speed distribution • Wind shear (boundary layer) • Turbulence • Wind veer • Inflow direction (horizontal & vertical) ◼ Factors to affect power output Weibull distribution
19. 19 Verification of power curve ◼ Single point measurement 2-4D D: diameter of rotor Hub height Electric power (kW) Hub height wind speed (m/s) IEC 61400-12-1 ◼ Observed power curve ⚫ Wind speed & direction ⚫ Pressure ⚫ Temperature ⚫ Humidity
20. 20 Size growth of wind turbines 2020 ◼ GE 12 MW future wind turbine power generation effective power generation =  () = () : power coefficient
21. As becoming large-scale wind turbines 21 ◼ Importance of wind-speed profile (wind shear) ⚫ Wind power estimation ⚫ Wind turbine design- need to know wind loading from the wind shear Approx. 200 m Mean wind profile Wake turbulence turbulence ⚫ Wakes- influence the power generation behind
22. 22 Formulation of the boundary layer ◼ Logarithmic law (neutral stability) () = ∗ : surface roughness length ∗ : friction velocity () ( ) = ( ) ◼ Power law : power exponent  =0.14 for a flat terrain, 0.11 over the sea ◼ Both profiles are used for international standards IEC for wind turbine designs ⚫ for the surface layer approximately below 100 m
23. Jet-like profiles 23 ◼ Observed at Hanbour using the Lidar ⚫ NE wind ⚫ SW wind ⚫ Sometimes different from conventional profiles
24. Wakes in the wind farm 24 Horns Rev Offshore Wind Farm, Denmark (http://i.imgur.com/qruVcnu.jpg /)
25. 25 Wake measurements ◼ Observations nearby Gaomei Wetland, Taichung ◼ Wind-speed profiles ◼ Wind-direction profiles
26. Turbulence effects 26
27. 27 Intermittency of wind ◼ Significant fluctuations in natural atmospheric airflow Turbulence intensity I=U  /U ◼ Pitch control ◼ Decrease of power generation abrupt wind increase
28. 28 Outputs varying with wind fluctuations ◼ NERL 5 MW reference wind turbine dynamic behaviour wind speed (m/s) Gen power (kw) Gen toque (N/m) Pitch (deg) Lackner (2009)
29. IEC international standard ◼ IEC 61400-1, wind turbine classes 29 Vr: the reference wind speed averaged over 10 minute ◼ Turbulence standard deviation (NTM model) ◼ Turbulence intensity (NTM model)
30. To have better control 30 upwind downwind wind wind ⚫ Following the wind passively ⚫ Flexible material ⚫ However, strong turbulence effect ◼ Upwind and downwind wind turbine
31. Nacelle wind Lidar 31 ◼ Development of nacelle wind Lidar FREA ( https://www.aist.go.jp/fukus hima/en/unit/WPT_e.html) ◼ Prototype
32. Extreme winds (typhoons) 32
33. Tracks of typhoons 33 ⚫中央氣象局颱風 路徑分類統計
34. 34 Impact of typhoon ◼ Typhoon Dujuan (2015) observed at Hsingda Harbour ⚫ Wind direction ⚫ Wind speed approaching leaving ⚫ Wind direction rotation 180o in a day , depending on the typhoon moving speed. ⚫ Have to carefully consider yaw control
35. 35 Takahara et al. (2005) Damaged types ◼ Wind turbine damaged by the typhoon
36. 36 Typhoon wind-speed profile ⚫ Power law Typhoon approaching Typhoon leaving =0.18 =0.24 ⚫ Log law 100 m Significant Coriolis effect Surface friction effect Tsai, Miau, Yu, and Chang (2019), Boundary Layer Meteorology
37. Decomposition 37 ◼ EMD method Curtesy of ANCAD Diurnal cycle
38. Waves induced by wind 38 ⚫ Wave patterns over the sea are highly correlated to winds NW wind SW wind NW wind SW wind Typhoon ◼ Buoy observation Typhoon
39. 39 Structural safety ⚫ Parameters over the sea under typhoon conditions are not fully understood. (NCREE 2018)
40. Summary 40 ◼ Long-term observations are needed. ◼ Required to validate the consistency of wind and wave characteristics between Europe experiences and Taiwan. ◼ Aware of typhoon wind effect on offshore wind farm.
41. Thank you for your attention! 41