Vindkraft i kraftsystemet
Transcription
Vindkraft i kraftsystemet
Vindkraft i kraftsystemet Kjetil Uhlen og John Olav G. Tande SINTEF Energiforskning john.o.tande@sintef.no kjetil.uhlen@sintef.no SINTEF Energiforskning AS 1 Oversikt Vindkraftteknologi Styring og kontrollmuligheter Systemutfordringer Eksempler: Balansehåndtering Energi- og effektbidrag Storskala offshore vindkraft - systemkonsekvenser SINTEF Energiforskning AS 2 Norwegian wind energy potential Very good wind conditions – wind farms may produce +3000 full load hours Theoretical potential +1000 TWh/year (annual el consumption in Norway ~120 TWh) Official target is 3 TWh annual wind energy production by year 2010 Development is ongoing: 320 MW (~1 TWh) was installed by mid 2006; +15 TWh is in planning Financial support is low: 0.08 NOK/kWh and probably not sufficient for many projects A realistic goal for wind energy use in Norway is 20 TWh by 2020 (on land and offshore) Norway has also a potential for developing a wind industry – especially related to deep sea offshore technology. SINTEF Energiforskning AS Smøla 150 MW wind farm 3 Oversikt Vindkraftteknologi Styring og kontrollmuligheter Systemutfordringer Eksempler: Balansehåndtering Energi- og effektbidrag Storskala offshore vindkraft - systemkonsekvenser SINTEF Energiforskning AS 4 From wind turbines to wind power plants 1980’s: typical wind turbine size 50 - 300 kW few installations – marginal influence on distribution grids grid connection was allowed using simple rule of thumbs 1990’s: typical wind turbine size 300 – 1500 kW more and larger installations – significant impact on voltage quality national guidelines suggest limits for flicker emission etc, and that WTs shall stop in case grid conditions outside 0,9<U<1,1 pu and 48<f<52 Hz IEC 61400-21 (ed 1 – 2001) gives basis for rational assessment of impact on voltage quality of wind turbines in distribution grids 2000’s: typical wind turbine size is in MW’s large wind farms constitute significant part of power system grid codes require wind farms to ride-through temporary grid faults, and also support voltage and frequency control wind farms are becoming power plants - IEC 61400-21 is updated accordingly to facilitate power quality test on modern wind turbines SINTEF Energiforskning AS 5 Teknologi - Vindkraftverk Foto: Hydro Horisontalakslede (tre-bladede) vindturbiner for kraftproduksjon Elektromekaniske konfigurasjoner Regulering SINTEF Energiforskning AS 6 Main types of wind turbine technologies Fixed speed, stall/pitch Gear box Control system Variable slip Gear box Control system IG Doubly-fed induction generator Gear box Control system DFIG ~ ~ Full converter, gear/no gear Gear box Control system G ~ ~ Total wind technology market ~ EUR 12 billion (2005) Top 5 manufacturers: Vestas, Enercon, Gamesa, GE, Simens SINTEF Energiforskning AS 7 Major wind turbine manufacturers Vestas (DK) Opti-slip and Opti-speed NTE: Vikna og Hundhammerfjellet SIEMENS-BONUS (DK) Traditional AG/active stall Statkraft: Smøla (150 MW), Hitra (55 MW) and Kjøllefjord Enercon (DE) Multi-pole synchronous generator, direct drive TE: Valsneset and Bessakerfjellet Nordex (DE) DFIG Havøygavlen: 16 x 2.5 MW GE wind (USA) DFIG og frequency converter ScanWind (N) NTE: Hundhammerfjellet SINTEF Energiforskning AS 8 Slik kan de se ut.. Her mangler det et bilde av en ”konvensjonell” vindturbingenerator Vestas V80-2MW nacelle Stator i Enercons 4.5 MW SINTEF Energiforskning AS 9 Oversikt Vindkraftteknologi Styring og kontrollmuligheter Systemutfordringer Eksempler: Balansehåndtering Energi- og effektbidrag Storskala offshore vindkraft - systemkonsekvenser SINTEF Energiforskning AS 10 Reguleringsformål Maksimal utnyttelse av tilgjengelig vindenergi Følge driftsoptimum. Redusere belastninger Aktiv demping av mekaniske svingemodi. Bidra i systemsammenheng Effekt, frekvens og spenningsregulering SINTEF Energiforskning AS 11 Regulering av vindkraftverk Hensikt: Optimalisering av elproduksjon Effektbegrensning Redusere effektfluktuasjoner og mekaniske påkjenninger, pga: Hurtige vindvariasjoner Strukturelle modi, 3P-variasjoner, osv. (Forstyrrelser fra nettet) Overholde krav til elkvalitet Dempe effekten av hurtige vindvariasjoner på spenning. Redusere flimmer Reaktiv støtte / spenningsregulering SINTEF Energiforskning AS 12 Additional wind farm controls Control of power output from wind farm. Setpoint control within the available power range Frequency and voltage control Control functionality enabling wind farms to contribute with primary active and reactive reserves SINTEF Energiforskning AS 13 Available power Power Power Modern wind farm control droop Set-point power Available power Reserve power Frequency Reactive power Power Time Time droop Voltage SINTEF Energiforskning AS 14 Energi og effekt i vinden Turbineffekt: Pwind 1 3 C p air Arotor v wind 2 www.windpower.org Betz-Lanchester: v1 3 For en ideell rotor Cpmax=0.59 hvis v2 Typiske verdier for effektkoeffisient for trebladede vindmøller ligger i dag omkring Cp=0.5. Effektfaktoren er avhenging av: - Antall blader i rotor. - Blad – design. SINTEF Energiforskning AS 15 Regulering av vindkraftverk Effektregulering Mulighetene avhenger av systemkonfigurasjon (turbin og el-konverteringssystem) Prinsipper for effektregulering: ”Stall” ”Pitch” Turtall Vha. frekvensomformer Vha. asynkrongenerator og variabel sakking ”Yaw” SINTEF Energiforskning AS 16 b PW vw w Pel Gearbox Nett f1 f2 Turbineffekt: PW = ½ Cp(l ,b ) A vw3 ,”Tip speed ratio” l = w r / vw - Turtall - Pitch - Yaw SINTEF Energiforskning AS 17 Effektregulering Variabelt turtall Begrensninger i pitch-regulering knyttet til hastighet (båndbredde) og ytelse. Ved å regulere turtall oppnås: Ytterligere optimalisering av virkningsgrad. Kan utnytte energien i roterende masser (korttids energilager). Hurtigere og nøyaktigere regulering Turtallsregulering kan implementeres på ulike måter vha. asynkrongenerator med variabel sakking vha. dobbeltmatet asynkrongenerator vha. full frekvensomformer (uavhengig av generator) SINTEF Energiforskning AS 18 Oversikt Vindkraftteknologi Styring og kontrollmuligheter Systemutfordringer Eksempler: Balansehåndtering Energi- og effektbidrag Storskala offshore vindkraft - systemkonsekvenser SINTEF Energiforskning AS 19 Hva er systemutfordringene? (Økonomi og pålitelighet) Driftssikkerhet Risiko mht utfall/blackouts (pålitelighet, spenningskvalitet) Overvåking og kontroll i drift Tekniske og funksjonsmessige krav til anlegg som tilknyttes nettet Effektbalanse Risiko for effektsvikt (rasjonering, osv.) Driftsplanlegging Balansehåndtering Energiplanlegging Risiko for energimangel (høye priser) Langsiktig planlegging og investering i nett og produksjon SINTEF Energiforskning AS 20 SINTEF Energiforskning AS 21 Exchange capacity (MW) 100 MW 740 MW 1200 MW 1600 MW 200 MW NORWAY FINLAND 500 MW 2000 MW SWEDEN 500 MW= 1050 MW= 740 MW= 270 MW= 1350 MW 350 MW= EST DENMARK 600 MW= 700 MW= NED <1200 MW 600 MW= 600 MW= POL GER SINTEF Energiforskning AS 22 Current challenges Source: Statnett Large scale integration of renewable energy: • Positive contribution to the energy balance • Main challenges: – Market solutions – Bottlenecks and transmission capacity – Voltage and frequency control and support – Failure tolerance and protection (FRT) – Reactive power support SINTEF Energiforskning AS 23 Hva skiller vindkraftverk fra andre kraftverk? Aktiv effekt Frekvens Spenning Reaktiv effekt Energi input: -Brensel -Magasin G Nett Aktiv effekt Frekvens Spenning Reaktiv effekt Energi input: -Vind vw G Nett Vindkraftverk mangler energilager ”bak” turbinen Vanskeliggjør produksjonsplanlegging SINTEF Energiforskning AS 24 Uregulert produksjon? Begrep fra vannkraft Kraftverk med liten eller ingen magasinkapasitet (elvekraft) Karakterisert ved at kraften må produseres når det er tilsig mindre frihetsgrader mht produksjonsplanlegging Definisjonen passer også godt for vindkraft Og i noen grad for kombinerte kraft- og varmeverk (CHP) Uregulert kraft betyr at energitilgangen er variabel og ikke fullt styrbar Ikke at produksjonen er uforutsigbar SINTEF Energiforskning AS 25 Annual and seasonal wind generation (% of annual) Normalised annual production (%) 140 7 120 6 100 5 80 4 60 3 Wind Hydro 40 Wind Power Hydro inflow Consumption 2 1 20 0 0 1960 1965 1970 1975 Year 1980 1985 1990 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 Week of year Wind and hydro – a win-win case: Combining wind and hydro provides for a more stable annual energy supply than hydro alone, and wind generation will generally be higher in the winter period than in the summer. SINTEF Energiforskning AS 26 Hour by hour variations of wind generation Std of delta wind power (pu) 0.25 Estimate Observation 0.2 0.15 0.1 0.05 0 0 5 10 # of sites 15 20 Wind impact on need for balancing power: 10 % wind energy supply of gross demand in the Nordic power system gives an extra balancing power of 1.5%-4% of the installed wind capacity, corresponding to a cost of about 0,8 øre per kWh wind, and about half if investment in new reserve capacity is not needed. [Holttinen 2005] SINTEF Energiforskning AS 27 Capacity Capacity value (%) 20 10 Wind capacity value 0 200 400 600 Installed wind power (MW) c) 800 1000 40 Simple scaling of wind production Summation of three wind farms 30 20 10 0 2 4 6 8 10 Penetration level (%) 12 14 Wind capacity value = average generation at low penetration The smoothing effect of distributed wind is significant SINTEF Energiforskning AS 28 Wind generation impact on power system Wind will replace the generation with the highest operating cost, and reduce the average Nord Pool spot market price. 20 TWh/y wind generation will reduce the average system price with about 3 øre/kWh and CO2 emissions by 12-14 million tons per year for the case of replacing coal, and about 6 million tons per year for replacing natural gas. Replacing gas turbines on oilrigs with wind generation would give higher savings of CO2 and NOx emissions. NOK/MWh Demand (buy) Supply (sale) System price MWh Volume SINTEF Energiforskning AS 29 Oversikt Vindkraftteknologi Styring og kontrollmuligheter Systemutfordringer Eksempler: Balansehåndtering Energi- og effektbidrag Storskala offshore vindkraft - systemkonsekvenser SINTEF Energiforskning AS 30 Example related to congestion management and balancing control in Nordel Frequency control reserves Balancing control Congestion management Reserves Illustrating Nordic collaboration and sharing of reserves across synchronous interconnections (UCTENordel) Example is from 8. January 2005 nearly 2000 MW wind power disconnected due to severe storm in Southern Scandinavia SINTEF Energiforskning AS 31 Denmark West MW GWh Central power plants 3,516 16,161 Decentralised CHP units 1,567 6,839 Decentralised wind turbines 2,374 4,363 Offshore wind farm Horns Rev A 160 Consumption 21,043 Maximum load 3,780 Minimum load 1,246 Capacity export to UCTE 1,200 Capacity import from UCTE 800 Capacity export to Nordel 1,560 Capacity import from Nordel 1,610 Key counts of the power system of Eltra for the year 2003 (Source: Energinet.dk) SINTEF Energiforskning AS 32 Elspot areas and transmission capacities NO3 NO2 NO1 1000 MW FI SE 950 MW DK1 DK2 1200 MW 800 MW To Germany SINTEF Energiforskning AS 33 NO2 Real life case – balance handling At 8 January 2005 a strong storm crossed over Denmark The wind farms of western Denmark at first produced close to rated power, but then started to cut out due to the excessive wind speed (+ 25 m/s) – the wind production were reduced from about 2200 MW to 200 MW in a matter of 10 hours Data for DK1, west Denmark 2003 +/-1000 MW 670/630 MW SE MW Central power plants 3,516 Decentralised CHP units 1,567 Decentralised wind turbines 2,374 Offshore wind farm Horns Rev A NO1 DK1 DK2 160 Maximum load 3,780 Minimum load 1,246 Germany 800/1200 MW SINTEF Energiforskning AS 34 8 January 2005 2500 2250 2000 MWh/h 1750 1500 1250 1000 750 500 250 0 -250 Exchange DK1 -> NO1 -500 -750 Balancing power (NO1) Windpower DK1 -1000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Hour Source: NORDPOOL The case demonstrates that the existing marked based mechanisms can handle large variations in (wind) generation and demand SINTEF Energiforskning AS 35 Oversikt Vindkraftteknologi Styring og kontrollmuligheter Systemutfordringer Eksempler: Balansehåndtering Energi- og effektbidrag Storskala offshore vindkraft - systemkonsekvenser SINTEF Energiforskning AS 36 Wind impact on system adequacy - Case study Total import capacity 14 TWh / 1600 MW (4x400 MW) 13 TWh hydro / 2250 MW (6x375 MW) 0,18 TWh wind / 62 MW (3 wind farms) 18 TWh annual load / 3180 MW max load Increasing to 21 TWh / 3780 MW Options A: 3 TWh wind / 1000 MW (3 wind farms) B: 3 TWh gas / 375 MW C: 3 TWh wind + 3 TWh gas SINTEF Energiforskning AS 37 Normal year load and generation 35000 GWh 30000 25000 Import 20000 Gas Wind 15000 Hydro 10000 Load 5000 0 Base (1.0 %) A (15.2 %) B (0.9 %) C (15.2 %) SINTEF Energiforskning AS 38 Base case 30 years week by week import (result of Multi-Area Power Market Simulation) Import per week (GWh) 400 300 200 100 0 -100 -200 -300 1 6 11 16 21 26 31 36 41 46 51 Week of year SINTEF Energiforskning AS 39 Cumulative distribution of weekly import 100 90 CDF of import (%) 80 70 Base Case A Case B Case C 60 50 40 30 20 10 0 -400 -200 0 200 400 Import per week (GWh) SINTEF Energiforskning AS 40 Annual variations in import 10000 Import (GWh) 8000 6000 Base Case A Case B Case C 4000 2000 0 -2000 -4000 1961 1966 1971 1976 1981 1986 Year Wind and gas contributes equally to the energy balance SINTEF Energiforskning AS 41 Case study max load and generating capacity 6000 5000 Wind 4000 MW Gas 3000 Import Hydro 2000 Max load 1000 0 Base A B C SINTEF Energiforskning AS 42 Loss of load probability (LOLP) LOLP is here probability of exceeding N-1 criterion Capacity value = load carrying capacity LOLP (%) Wind capacity value (%) Gas capacity value (%) Wind penetration (%) Base 0.11 31.5 1.0 A 7.2 14.7 15.2 B 1.43 34.3 95.2 0.9 C 0.35 13.6 94.7 15.2 Without new generation in case A, B and C the LOLP=26% SINTEF Energiforskning AS 43 Oversikt Vindkraftteknologi Styring og kontrollmuligheter Systemutfordringer Eksempler: Balansehåndtering Energi- og effektbidrag Storskala offshore vindkraft - systemkonsekvenser SINTEF Energiforskning AS 44 Integration of large-scale offshore wind power in the Norwegian power system Magnus Korpås, Thomas Trötscher, John Olav Giæver Tande SINTEF Energy Research magnus.korpas@sintef.no SINTEF Energiforskning AS 45 Project: Deep sea offshore wind power Installation at deep sea far from shore: Unlimited potential and high energy output Minimized negative environmental impact Challenges: Bigger, lightweight and strong wind turbines Foundation / floater Grid connection (AC, HVDC, multi-terminal) Grid connection and power system integration SINTEF Energiforskning AS HYWIND 46 25 TWh/y wind generation for supply to oilrigs, mainland grid and trans-national connections Floating offshore wind turbines – a sustainable energy future Use Norwegian oil and gas industry know-how. Large scale commercial use of floating offshore wind turbines is viable by year 2020. The market is global. Hot political subject in Norway. SINTEF Energiforskning AS 47 Simulation study 5 simulation cases describing possible situations in 2025: A: 10 TWh load increase B: …added 25+10 TWh offshore+onshore wind C: …added 20 TWh new hydro D: …added new wind in DE and DK E: …added 3200 MW new exchange capacity SINTEF Energiforskning AS 48 Wind data Normalised production [p.u.] 1 MYKEN 66 oN NORDØYAN FYR 63 o N ONA II KRÅKENES 60oN UTSIRA FYR 0.6 0.4 0.2 0 LISTA FYR 3 oE 6o E o 9 E o 12 E 1000 o 2000 3000 4000 5000 Duration [hours] 6000 7000 8000 15 E 1 LISTA FYR UTSIRA FYR KRÅKENES ONA II NORDØYAN FYR MYKEN 0.8 0.6 p.u. of installed power 57oN Estimated 5 offshore wind farms, NO Estimated 5 onshore wind farms, NO Historical onshore, DK-W 0.8 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 0.5 1 1.5 2 2.5 Hours 3 3.5 4 4 x 10 SINTEF Energiforskning AS 49 Power market model SINTEF Energiforskning AS 50 Wind impact on hydro reservoir B: Added 25+10 TWh wind 100 100 90 90 80 80 70 70 Reservoir level [%] Reservoir level [%] A: 10 TWh load increase 60 50 40 30 60 50 40 30 20 20 10 10 0 1000 2000 3000 4000 5000 Time [hours] 6000 7000 8000 0 1000 2000 3000 4000 5000 Time [hours] 6000 7000 8000 Median Median 2005 reference SINTEF Energiforskning AS 51 Wind impact on prices Wind reduces winter price peaks in dry years 1400 Reference case Case A: 15 TWh load increase Case B: Added 35 TWh wind NO price [NOK/MWh] 1200 1000 800 600 400 200 0 2 4 6 8 10 12 14 Hydro inflow year 16 18 SINTEF Energiforskning AS 20 22 52 Wind impact on prices 1400 A B C D E NO price [NOK/MWh] 1200 1000 800 load increase add wind in NO add hydro in NO add wind in DE+DK 3200MW new HVDC 600 400 200 0 0 10 20 30 40 50 60 Duration [%] 70 80 90 100 Hours with zero price caused by full hydro reservoirs SINTEF Energiforskning AS 53 Wind impact on power exchange A B C D E Net export from Norway [TWh/yr] 60 50 40 30 20 10 0 -10 -20 -30 2 4 6 8 10 12 14 Hydro inflow year 16 SINTEF Energiforskning AS 18 20 54 Conclusions Deep sea offshore wind power has very high potential in Norway Unlimited areas Very high wind speeds Wind power relieves constrained energy situations in winter Adding 25 TWh offshore wind, 10 TWh onshore wind and 20 TWh hydro is a plausible scenario Exchange capacity should be increased to avoid hydro spillage SINTEF Energiforskning AS 55 Further work Include year-to-year variations in wind speed Increase number of price areas Further tuning of water-value calcualtions Analysis and optimization of offshore grid layout SINTEF Energiforskning AS 56 MYKEN 6 6 oN NORDØYAN FYR 6 3 oN ONA II KRÅKENES 6 0oN UTSIRA FYR LISTA FYR 5 7o N 3 oE 6 oE 9oE o 12 E o 15 E SINTEF Energiforskning AS 57 Normalised production [p.u.] 1 Estimated 5 offshore wind farms, NO Estimated 5 onshore wind farms, NO Historical onshore, DK-W 0.8 0.6 0.4 0.2 0 1000 2000 3000 4000 5000 Duration [hours] 6000 7000 SINTEF Energiforskning AS 8000 58 1 LISTA FYR UTSIRA FYR KRÅKENES ONA II NORDØYAN FYR MYKEN 0.8 p.u. of installed power 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 0.5 1 1.5 2 2.5 3 3.5 Hours SINTEF Energiforskning AS 4 4 x 10 59 Summing up: Wind generation impact on power system operation and adequacy will be overall positive. Wind contributes with energy and capacity value. Combining wind and hydro provides for a more stable annual energy supply than hydro alone, and wind generation will generally be higher in the winter period than in the summer. Wind impact on the need for additional balancing power is moderate, i.e. the extra balancing cost is about 0,8 øre per kWh wind, and about half if investment in new reserve capacity is not needed. The real life example from 8 January 2005 demonstrates that existing market based mechanisms can handle large amounts of wind power Wind power has a capacity value starting from average power and decreasing at high penetration 35 TWh wind will reduce the average spot market price with about 5-8 øre/kWh. Wind generation is a cost-effective means to reduce emissions of greenhouse gasses Impact of integrating wind power in the Norwegian power system SINTEF Energy Research, April 2006, TR A6337. www.sintef.no/wind SINTEF Energiforskning AS 60 Nordic power system Power system (see www.nordel.org): Synchronous Nordic interconnection: Norway, Sweden, Finland and Denmark East Denmark West is synchronously connected to UCTE Iceland Main players: Power exchange: NordPool TSOs: Statnett (NO), SvK (SE), Fingrid (FI) and Energinet.dk DNOs, generators, consumers, traders, etc. SINTEF Energiforskning AS 61 Nordic power system Markets and services (see www.nordpool.com): Financial market and clearing services Hourly day-ahead market: ELSPOT Intra-day market ELBAS (individual hours, up to one hour prior to delivery): Intra-hour/real-time balancing market: RK (Regulating power market) Operated by the TSOs Some characteristics of the Nordic power system (that motivates present ancillary services): Strong and weak grids, long distance interconnections, many players, distributed generation, high share of hydro power, close cooperation. SINTEF Energiforskning AS 62 Key figures for 2006 Population Total consumption Maximum load1 Electricity generation mill. TWh GW TWh Nordel DK Fin Icel. Nor Swe 24.8 405.4 66.8 393.9 5.4 36.4 6.3 43.3 5.3 90.1 14.2 78.6 0.3 9.9 1.1 9.9 4.7 122.6 19.9 121.7 9.1 146.4 25.4 140.3 0 86 14 - 14 28 58 0 - 73 0 27 98 1 1 - 44 46 9 1 - Breakdown of electricity generation: Hydropower Nuclear power Other thermal power Wind power Geothermal power % % % % % 1) Measured 3rd Wednesday in January 51 22 24 3 - - = Data are non-existent 0 = Less than 0,5 % SINTEF Energiforskning AS 63 Source: Nordel Generation capacity in Nordel (GW) 27.6 16.2 NORWAY 10.8 2.6 2.9 9.5 0.6 0.3 5.0 9.2 0.1 FINLAND 0.5 3,1 Conv. thermal Nuclear Hydro Wind SWEDEN DENMARK SINTEF Energiforskning AS 64 Electricity Generation in Nordel 2006 (TWh) 120 46 64 62 22 NORWAY 11 1 1 37 FINLAND 13 6 1 Conv. thermal Nuclear Hydro Wind SWEDEN DENMARK SINTEF Energiforskning AS 65 Floating offshore wind turbines Installation at deep sea far from shore: Unlimited potential and high energy output Minimized negative environmental impact Cost competitive renewable generation Challenges: Bigger, lightweight and strong wind turbines (10 MW, 160 m wingspan ~ twice a jumbo jet) Develop floater (design, installation, O&M) Power system integration of large scale wind HYWIND Key Norwegian industry stake-holders: ScanWind; large wind turbines Hydro and Sway; floater concept Aker Kværner, Nexans, Devold AMT, Umoe Ryving etc; sub-supplies of components Statkraft etc; wind farm developers SINTEF Energiforskning AS 66 Power control “Pitch” versus “stall” and speed control b PW vw w Gearbox Pel AG Nett fn Power is a function of torque and speed: P = T · w Turbine speed is determined by grid frequency, gear ratio and slip of induction generator. ”STALL”: Passive torque regulation, determined by the turbine’s aerodynamic properties. ”PITCH”: Active torque control through pitching of rotor blades (applied for both optimization and power output limitation) SINTEF Energiforskning AS 67 Effektregulering ”Stall” og ”Pitch” b PW vw w Gearbox Pel AG Nett fn Turtall gitt av nettfrekvens, giromsetning og sakking i asynkrongenerator. ”STALL”: Passiv effektregulering, gitt av turbinens aerodynamiske karakteristikk. ”PITCH”: Aktiv effektstyring gjennom regulering av bladvinkel. Benyttes for optimalisering og effektbegrensning SINTEF Energiforskning AS 68 Regulering av mekanisk moment Pitch/Stall www.windpower.org Source: Lubosny SINTEF Energiforskning AS 69 Power control “Pitch” versus “stall” and speed control www.windpower.org Source: Lubosny SINTEF Energiforskning AS 70 Power versus windspeed curves 120 Pitch regulated 100 Power (%) 80 Stall regulated 60 40 20 0 0 5 10 15 20 25 30 Wind speed (m/s) SINTEF Energiforskning AS 71 Conventional pitch control 25 Pitch angle [degrees] 20 15 3000 kW 2500 kW 2000 kW 1500 kW 1000 kW 500 kW 0 kW 10 5 0 -5 -10 Power limitation Optimisation -15 0 5 10 15 20 25 Windspeed [m/s] SINTEF Energiforskning AS 72 Active stall control 25 Pitch angle [degrees] 20 15 3000 kW 2500 kW 2000 kW 1500 kW 1000 kW 500 kW 0 kW 10 5 0 -5 -10 Power limitation Optimisation -15 0 5 10 15 20 25 Windspeed [m/s] SINTEF Energiforskning AS 73