Power fluctuations from large offshore wind farms Poul Sørensen Wind Energy Systems (VES) Wind Energy Division Project was funded by Energinet.dk PSO 2004-6506
Geographical spreading 2
Wind turbine sites in Denmark Horns Rev 3 Risø DTU, Technical University of Denmark Energinet.dk advisory meeting on control
Validation available data February 2005 January 2006 January 2006 May 2007 6152500 Horns Rev Horns Rev 160 MW 6051000 Nysted 165,6 MW 72 WT 6151500 80 WT 6050000 6150500 6049000 6149500 Wind Turbines 6048000 Wind Trubines Mast 6148500 6047000 6147500 6046000 6146500 422500 423500 424500 425500 426500 427500 428500 429500 430500 6045000 671000 672000 673000 674000 675000 676000 677000 678000 679000 - acquisition made through the control system, with 1Hz sampling frequency; - wind speed, power, power set point and yaw position used - 2-hour segments were selected, with normal operation - 1110 2-hour segments (92,5 days) in Horns Rev and 1989 (165,75 days) in Nysted - wind speeds from 1 to 19 m/s (Horns Rev) and from 1 to 24 m/s (Nysted) 4
Validation ramp rates The ramp rate * (load following) is defined as the change in the mean value from one period to another and specifies the ramp rate requiremet that the wind farm power fluctuation causes to other power plants P ramp ( n) = Pmean ( n+ 1) Pmean ( n) Three time scales were investigated: 10 min, 30 min and 1 min * This definition specifies the ramping of the wind farm power. Thus, negative ramp rate means decreasing wind power and requires positive ramping of other power plants. The result were binned according to the initial power P mean (n), because the statistics will depend strongly on the initial power. A power bin size of 0.1 p.u. has been selected. Duration curves are obtained by sorting the ramping in each power bin. 5
Validation ramp duration curves Horns Rev duration curves, 0.8-0.9 p.u. 1 min 10 min 30 min Nysted duration curves, 0.8-0.9 p.u. 6
Validation 99% percentiles ramp 10 min 30 min 1 min 7
Validation reserve requirements The reserve requirement * (regulation) is defined as the difference between the initial mean value and the minimum value in the next period. P ( n) = P ( n) P ( n + 1) res mean min P ramp ( n) = Pmean ( n + 1) Pmean ( n) Three time scales were investigated: 10 min, 30 min and 1 min * with this definition, positive reserves means decreasing wind power that requires positive reserve from other power plants The result were binned according to the initial power P mean (n), because the statistics will depend strongly on the initial power. A power bin size of 0.1 p.u. has been selected. Duration curves are obtained by sorting the ramping in each power bin. 8
Validation reserves duration curves Horns Rev duration curves, 0.8-0.9 p.u. 1 min 10 min 30 min Nysted duration curves, 0.8-0.9 p.u. 9
Validation 1% percentiles reserves 10 min period 30 min period 1 min period 10
Future potential offshore sites 11
Climate model resolution 12
Simulated wind speeds - smoothing 24 22 20 Wind speed (m/s) 18 16 14 Turbine (A1) Wind Farm Weather model 12 10 00:00 02:00 04:00 06:00 08:00 10:00 12:00 Time 13
Wind farm (aggreg.) power curve 1.2 1 0.8 Power (pu) 0.6 0.4 Simulated farm Input turbine 0.2 0 0 5 10 15 20 25 30 35 Wind speed (m/s) 14 Risø DTU, Technical University of Denmark Energinet.dk advisory meeting on control
Study cases Djursland Anholt O Djursland Anholt P Horns Rev B Horns Rev A Horns Rev 2 Horns Rev 15
Study cases - wind farms data Name Symbol Wind turbine power Total power Annual mean wind speed Horns Rev HR1 80 2.0 MW 160 MW 9.6 m/s *) Horns Rev 2 HR2 91 2.3 MW 209 MW 10.4 m/s *) Horns Rev A HRA 40 5.0 MW 200 MW 10.6 m/s *) Horns Rev B HRB 40 5.0 MW 200 MW 10.5 m/s *) Djursland Anholt O DAO 40 5.0 MW 200 MW 9.0 m/s *) Djursland Anholt P DAP 40 5.0 MW 200 MW 9.0 m/s *) 16
Simulated wind speeds (wf averages) 40 35 30 Wind speed (m/s) 25 20 15 10 HR1 HR2 HRA HRB DAO DAP 5 0 28/01-2000 29/01-2000 30/01-2000 31/01-2000 01/02-2000 Time 17
Power fluctuations the 2 cases 800 700 600 Horns Rev B Horns Rev A Horns Rev 2 Djursland Anholt O Djursland Anholt P Power (MW) 500 400 300 200 HRB HRA HR2 HR1 Horns Rev 100 0 28/1-2000 29/1-2000 30/1-2000 31/1-2000 1/2-2000 800 Time 700 600 Horns Rev B Horns Rev A Horns Rev 2 Horns Rev Djursland Anholt O Djursland Anholt P Power (MW) 500 400 300 200 DAP DAO HR2 HR1 100 0 28/1-2000 29/1-2000 30/1-2000 31/1-2000 1/2-2000 Time 18
Conclusions Efficient simulation tool for simulation of wind power fluctuations in power system region Calibration to sites should be looked more into, especially for onshore applications Applications planning of offshore sites control development 19