Lecture By Prof S S Murthy 19 th Feb.2015 Silicon Institute of Technology, Bhubaneswar National Workshop on

Transcription

1 WIND ENERGY SYSTEMS (WES) FOR POWER GENERATION Lecture By Prof S S Murthy 19 th Feb.2015 Silicon Institute of Technology, Bhubaneswar National Workshop on Emerging Technologies in Electrical Engineering,

2 THERITICAL POTENTION of Renewable Energy

3 RENEWABLES ARE SOMETIMES DESCRIBED AS THE DREAMS OF THE 1970S, REALITIES BUT LUXURIES OF 2000, AND THE NECESSITIES OF 2020 AND THEREAFTER INCLUDE HYDROPOWER, BIOMASS, SOLAR, WIND, GEOTHERMAL AND OCEAN RESOURCES

4 RENEWABLE POWER CAPACITIES(GW) IN WORLD, EU -27, BRICS, AND TOP SIX COUNTRIES, 2012

5 ALL INDIA GENERATING INSTALLED CAPACITY (MW) (As on ) (source: CEA)

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7 GE Wind Energy 1.5 MW Turbine WIND ENERGY

8 GRID CONNECTED WIND ENERGY SYSTEM CHITRADURGA-KAR

9 Global cumulative growth of wind power capacity

10 Global investment to 2050 (USD billion)

11 Progress in wind power since 2008

12 Global wind map, installed capacity and production for lead countries

13 Wind generation is significant In 2010 alone, new global wind power installations equaled the capacity of 66 large conventional power plants.

14 World Wind Energy Scenario TECHNICAL POTENTIAL OF ONSHORE WIND ENERGY IS ABOUT TO TWH PER YEAR AGAINST THE TOTAL WORLD ELECTRICITY CONSUMPTION OF TWH ECONOMIC POTENTIAL DEPENDS ON FACTORS LIKE AVERAGE WIND SPEED, STATISTICAL WIND SPEED DISTRIBUTION, TURBULENCE INTENSITIES AND COSTS OF WIND TURBINE SYSTEMS

15 WORLD WIND ENERGY SCENARIO AS ENERGY OF WIND IS PROPORTIONAL TO THIRD POWER OF WIND SPEED, ECONOMIC CALCULATIONS ARE SENSITIVE TO LOCAL AVERAGE WIND SPEED BECAUSE THE WIND ENERGY IS INTERMITTENT, WIND TURBINES MAINLY DELIVER ENERGY BUT VERY LITTLE CAPACITY. TYPICAL CAPACITY VALUES BEING OFTEN LESS THAN 20% OF INSTALLED WIND POWER

16 WINDIEST REGIONS, POTENTIAL COASTAL REGIONS OF AMERICAS, EUROPE, ASIA, AUSTRALIASIA TOTAL RESOURCE IS VAST- ONE ESTIMATE PUTS IT AS A MILLION GW Even if only1% of area used with a low load factor of 15-40%, wind potential correspond to total capacity of all elec. Generating plants Offshore resource HUGE- capable of supplying all EU electricity without going further than 30km offshore.

17 World Wind Energy Scenario AS THE PENETRATION OF WIND TURBINES INCREASES THE PERCENTAGE FALLS FURTHER, REQUIRING EVEN MORE BACK UP POWER FOR A RELIABLE ENERGY SUPPLY IT IS POSSIBLE TO TRANSFORM WIND- GENERATED ELECTRICITY FROM INTERMITTENT TO BASE LOAD POWER IF IT IS COMBINED WITH COMPRESSED AIR ENERGY STORAGE. THUS A HIGHER CAPACITY FACTOR CAN BE ACHIEVED WITH SMALL ECONOMIC PENALTY

18 World Wind Energy Scenario BY OPTIMIZING THE TURBINE CHARACTERISTICS TO THE LOCAL WIND REGIME, CAPACITY FACTOR CURRENTLY OFTEN AT 20-25% CAN BE OPTIMIZED WITHOUT LOOSING TOO MUCH ENERGY OUTPUT. HOWEVER EXTREME CAPACITY FACTORS OF ABOUT 40% AUTOMATICALLY MEAN A LARGE LOSS OF POTENTIAL ENERGY OUTPUT

19 World Wind Energy Scenario BECAUSE OF SCARCITY OF LAND IN URBAN CENTERS, THE COUNTRIES LIKE DENMARK, NETHERLANDS, UK AND SWEDEN ARE DEVELOPING OFFSHORE PROJECTS A UNDP STUDY ESTIMATES THAT AROUND 3000 TWH PER YEAR OF ELECTRICITY COULD BE GENERATED IN THE COASTAL AREAS OF EUROPEAN UNION

20 World Wind Energy Scenario: Wind Turbine Sizes THE CURRENT WIND ENERGY ERA BEGAN IN MID 1970S WITH A TYPICAL SIZE OF A WIND TURBINE OF 30 KW WITH A ROTOR DIAMETER OF 10 METERS THE LARGEST UNIT INSTALLED TODAY HAS A CAPACITY OF 1650 KW WITH A ROTOR DIAMETER OF 66 METERS

21 ATTRACTIVE WIND REGIONS Europe- North/West coasts, Mediterranean Asia- East coast, some inland areas Africa- North, Southwest coast North America- Most coastal regions, some mountainous central zones S. America- Best Towards south

22 Wind Energy Scenario TECHNICAL POTENTIAL OF ONSHORE WIND ENERGY IS ABOUT TO TWH PER YEAR AGAINST THE TOTAL WORLD ELECTRICITY CONSUMPTION OF TWH ECONOMIC POTENTIAL DEPENDS ON FACTORS LIKE AVERAGE WIND SPEED, STATISTICAL WIND SPEED DISTRIBUTION, TURBULENCE INTENSITIES AND COSTS OF WIND TURBINE SYSTEMS

23 World WIND ENERGY Scenario WIND ENERGY WAS USED AS A SOURCE OF POWER BEFORE THE INDUSTRIAL REVOLUTION DISPLACED BY FOSSIL FUELS BECAUSE OF COST AND RELIABILITY OIL SHOCKS OF 1970S SAW RENEWED INTERESTS IN WIND ENERGY FOR APPLICATIONS LIKE GRID- CONNECTED ELECTRICITY, WATER PUMPING AND POWER SUPPLY IN REMOTE AREAS

24 Wind Power Global Capacity,

25 Wind Power Capacity and additions, Top 10 Countries, 2012

26 Wind Turbine Suppliers Introduction Sinovel Nordex 3.4% 3.4% Goldwind 4.2% Acciona 4.4% Others Vestas 22.8% Siemens 7.1% GE Wind 16.6% Suzlon 10.5% Enercon 14.0% Gamesa 15.4% Top 10 wind turbine suppliers in 2007 Account for around 95% of the total supply in 2007 Asian manufacturers improve their shares (Goldwind & Sinovel in China, Suzlon in India) 26

27 Wind Power in India Estimated Potential as per CWET: GW Renewable share (31 GW) in overall Power Capacity (234 GW) amounts to more than 13% Share of Wind power generation in Indian Renewables is 65 %. India is fifth after USA, Germany, Spain, China NOTE: Only about 20% is the maximum utility factor of installed wind capacity based on local wind conditions.

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29 WIND POWER State Wise Analysis in INDIA

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42 Wind Power Potential in India

43 Estimated Gross Potential

44 NAPCC - National Action Plan on Climate Change REC - Renewable Energy Certificate

45 SERCs - State Electricity Regulatory Commissions SNA - State Nodal Agency IPP - Independent Power Projects

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49 Wind Turbine Technology Wind turbine size Year Capacity (kw) Rotor Diameter (m) , , ,500-5, ,

50 MODERN WIND TURBINES Early machines (20 Yrs. Ago) kW, 15-20m dia Present trend-upto 2MW and above, 60-70m dia Offshore upto 5MW and 110m.dia

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52 Wind Turbine Technology Horizontal- and vertical-axis wind turbines Rotor blade Rotor Diameter Generator Nacelle Rotor Diameter Gearbox Tower Tower Rotor blade Gearbox Generator Horizontal-axis wind turbine (HAWT) Vertical-axis wind turbine (VAWT) 52

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54 Wind Turbine

55 Offshore Wind Farm

56 Fixed-bottom foundation and floating offshore concepts

57 Wind farms

58 REQUIREMENTS Area required per Wind Turbine = 5Acres (approx) Grid availability. Accessibility for commissioning. Strong terrain / soil for proper foundation / civil work Favorable environmental condition to prevent corrosion & not prone to cyclone.

59 Wind farms Cluster of tens of machines or many single machines Economy of scale dictates wind farmscivil Engg and grid connection cost decreases

60 SITING AND CLEARANCES

61 GCIG IN WIND SYSTEM

62 INSIDE NECELLE(RRB VESTAS)

63 Enercon System(SYN.GEN)

64 GENERATORS AND SYSTEMS FIXED SPEED INDUCTION GENERATOR(MOSTLY) SYNCHRONOUS GENERATOR VARIABLE SPEED WITH POWER ELECTRONIC CONVERTORS-AC/DC/AC Doubly Fed Induction Generator (DFIG) Permanent Magnet Synch. Generator- Direct Driven Gearless

65 Wind Energy Conversion WES without using power converters Up to 2.3 MW SCIG Soft starter Squirrel Cage Induction Generator Gearbox Capacitor Transformer Grid Advantages Low manufacturing cost Robust, low maintenance cost Drawbacks Low conversion efficiency Large fluctuation in output power 65

66 Wind Energy Conversion Doubly fed induction generator with rotor converter Up to 5 MW DFIG Gearbox Reduced-capacity converter Transformer Grid Advantages Extended speed range High system efficiency and low cost because Decoupled active & reactive power control Enhanced dynamic performance Drawbacks Limited grid-fault operation capability 66

67 Wind Energy Conversion Wind energy systems with full-power converters Up to 5 MW (PMSG) Gearbox SCIG WRSG PMSG Full power converter Transformer Grid Advantages The generator fully decoupled from the grid Wide speed range Smooth grid connection Reactive power compensation Capability to meet the strict grid code Drawbacks 67

68 FIXED SPEED WIND SYSTEMS

69 SCHEMATIC OF A CONSTANT SPEED WIND SYSTEM WIND P INDUCTION 415V 11kV P 11kV GRID TURBINE GEAR BOX GENERATOR Q TRANSFORMER CAPACITOR

70 Enercon wind system E-48 TECHNICAL DATA Rated capacity : 800 kw Rotor diameter : 48 m Hub height : 56.85m and m Rotor with Pitch Control Type : Upwind rotor with active pitch control Direction of rotation : Clockwise Number of blades : 3 Length of blades : 20.7 m

71 DATA Swept area : 1810 m² Blade material : Fiberglass (reinforced epoxy) with integral lightning protection Rotor speed : Variable, rpm Tip speed : m/s Pitch control : Three synchronized blade pitch system with battery back-up

72 Enercon System. Generator : Synchronous - Type Hub : Rigid Bearings : Tapered roller bearings Grid Feeding : AC-DC-AC through Convertor - Invertor Braking System : 3 independent Aero Brakes with emergency back up supply. Yaw Control : Active through adjustment gears, friction damping Cut-in Wind Speed : 2 m/s Rated Wind Speed : 14 m/s Tower : Steel Tubular / Concrete

73 POWER RELATION-WIND P= ρc p D 2 w 3 ρ = AIR DENSITY C p= CONSTANT D = BLADE DIA w =WIND SPEED

74 POWER Vs WIND SPEED Pitch Control.p.u 1.0 power Cut out speed Wind speed, m/s Cut in speed

75 DOUBLY WOUND SCIG AS WIND GENERATOR (NO CONVERTOR) GRID

76 DATA ON A WIND MACHINE Rated Power:1.65 MW Blade dia: 63m Cut in speed:3-5 m/s Cut out speed: m/s

77 Energy production (MWh) Wind speed (m/s) Energy at 60 m height- 5m/s m/s m/s 4800

78 GRID INTERFACE SEVERAL PROBLEMS OF EVACUATION OF ENERGY INTO THE GRID HIGH WIND AND LOW LOAD CONDITIONS WEAK, UBNORMAL GRIDS SEVERAL STUDIES MADE

79 GRID CONNECTED INDUCTION GENERATOR

80 COMPARISON- MOTOR Vs GEN MOTOR GENERATOR STATOR VOLTAGE V S V S STATOR CURRENT I S -I S MAGNETIZING CURRENT I M I M AIRGAP VOLTAGE V G V G

81 MOTOR Vs GEN. MOTOR GENERATOR ROTOR CURRENT I R -I R SLIP s -s(=s') AIR GAP POWER (P g ) 2 R r 3Ir s 2 R r 3Ir s'

82 Motoring and Generating MOTOR GENERATOR P shaft P out 3I ω 2 r s R s r 1 s P in 3I ω 2 r s opp top R s' out r 1 s' DEVELOPED TORQUE (T d ) 3I ω 2 r s R s r 3I ω 2 r s R s r 3I ω 2 r s R s' r SPEED (pu) υ 1 s υ 1 s'

83 Motoring/Generating P mech MOTOR 3I R r 1 s ωss 3Vs Iscos s P elec 2 GENERTOR 3V 2 3Ir R ω s s s I s 1 cos s' s

84 ν MOTOR GENERATOR Pelec Pg Td Pelec ν TL Pout Pg Td Tin Pm Pin Pmech Load PRIME MOVER

85 GRID CONNECTED INDUCTION GENERATORS DRIVEN BY WIND/HYDRO TURBINES

86 Induction Generators ( I G ) are used for low and medium power generation, as they have certain inherent advantages over conventional alternators Low unit cost Less maintenance Rugged and brushless rotor Asynchronous operation

87 THE INPUT POWER TO THE GENERATOR CAN BE NORMALLY KEPT CONSTANT WITH HYDRO TURBINES. THE WIND TURBINE ON THE OTHER HAND PROVIDES VARYING POWER INPUT DEPENDENT ON THE WIND SPEED. CAPACITORS ARE CONNECTED TO THE GENERATOR TERMINALS, TO IMPROVE THE SYSTEM POWER FACTOR AND TO REDUCE THE VAR DRAIN FROM THE GRID

88 PROBLEM WITH THE GRID GRID FAILURE SINGLE PHASING TURBINE OVERSPEED WITH LOAD THROW OFF(ABOVE 2pu) GENERATOR THERMAL OVERLOAD POOR POWER QUALITY OF GRID-VOLTAGE, FREQUENCY SELF EXCITATION DUE TO CAPACITOR DUE TO GRID FAILURE AND TURBINE OVERSPEED

89 Grid connected induction generator

90 EQUIVALENT CIRCUIT OF IG

91 FIND RESPONSE AT CONSTANT POWER INPUT AND GRID VOLTAGE USE THEVENIN EQ. CIRCUIT

92 THEVENIN EQUIVALENT CIRCUIT

93 P in =- 3I r 2 R r (1-s)/s (1) V th + (R th + R r /s +j X th ) I r =0.(2) ABOVE ARE TWO EQS WITH TWO UNKNOWNS s AND I r

94 FROM FIG. I r = V th / {[R th + R r /s ] 2 + X th2 } 1/2

95 SIMPLIFYING As 2 +Bs + C =0 A= R th 2 + X th 2-3V th 2 / P in B=2R th R r +3 V th / P in C= R r 2

96 P in =- 3I r 2 R r (1-s)/s SINCE s IS NEGATIVE P in IS POSITIVE

97 SOLVE FOR s, FOR GIVEN POWER INPUT AND GRID VOLTAGE SOLVE EQ. CIRCUIT GET ACTIVE POWER REACTIVE POWER POWER FACTOR EFFICIENCY

98 DATA ON PRACTICAL FIELD SYSTEMS GENERATOR- 415V, 50 Hz GRID-11kV, 50 Hz TRANSFORMER IMPEDANCE- (0.021+j0.382)p.u HV- TRANS. LINE IMPEDANCE- (0.021+j0.382)Ohm/km SC MVA OF GRID = 250 LENGTH OF HV LINE=10km (HYDRO), 2km(WIND)

99 EQ. CKT. PARAMETERS(pu) M/C Rs Rr xls xlr xm Rc

100 CHARACTERISTICS OF WIND TURBINE DRIVEN 55/11KW INDUCTION GENERATOR

101 EFFECT OF VARIATION OF GRID VOLTAGE

102 EFFECT OF VARIATION OF GRID VOLTAGE

103 EFFECT OF VARIATION OF GRID VOLTAGE

104 EFFECT OF VARIATION OF TERMINAL CAPACITOR

105 EFFECT AT VARYING POWER INPUT

106 EFFECT AT VARYING POWER INPUT

107 EFFECT AT VARYING POWER INPUT

108 EFFECT AT VARYING POWER INPUT

109 References.. S.S.Murthy (with C.S.Jha and P.S.N.Rao), "Analysis of Grid Connected Induction Generator driven by Hydro/ Wind Turbines under Realistic System Constraints ", IEEE Trans. on Energy Conversion, March, 1990 Volume 5, No. 1, pp 1-7 S.S.Murthy (with A.H.Ghorashi, B.P.Singh & Bhim Singh), 'Analysis of Wind Driven Grid Connected Induction Generators under unbalanced Grid Conditions', IEEE Trans. on Energy Conversion Vol.9, No.2, June, 1994 pp S.S.Murthy (with C.S.Jha, A.H.Ghorashi, P.S.Nagendra Rao), 'Performance Analysis of Grid Connected Induction Generators Driven by Hydro/Wind Turbines including Grid Abnormalities', presented at Inter Society Energy Conversion Engg. Conference (IECEC at Washington DC, Aug., 1 989).

110 VARIABLE SPEED WIND SYSTEMS

111 DOUBLY FED INDUCTION GENERATORS:

112 DOUBLY FED IND. MACHINE GRID Pe f Pcur Pg Pcus TRANSFORME Pr DFIG Pm fr f CONVERTOR(BIDIRECTIONAL))

113 EQUIVALENT CIRCUIT of DOUBLY FED WOUND ROTOR I.M- MOTRING I s R r +jsx lr R s jx ls I 0 I r V s V g R c x m sv g E j I c I m

114 sp g = P r + P cur P g = P r + (1-s) P g +P cur

115 ROTOR EQUATION sv g - I r (R r +jsx lr )-E j =0 sv g = I r (R r +jsx lr )+E j sv g -E j = I r (R r +jsx lr ) (E j REF. TO STATOR TURNS)

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117 DFIG

118 DFIG (COVERTOR IN ROTOR)

119 POWER SPEED CURVES

120 Turbine Power (kw) 80 Vw=11m/s Maximum Power Line V w =10m/s V w =9m/s V w =8m/s Generator Speed (rad/sec) V w =7m/s V w =6m/s V w =5m/s Mechanical power output of the wind turbine vs. generator speed for different wind speeds

121 PHASOR DIAGRAM WITH INJECTED EMF Ej β Φr svg Ir

122 RESOLVE VOLTAGES AND DROPS ALONG Ir AXIS sv g cos Φ r = I r R r + E j cos (Φ r + β) sv g I r cos Φ r = I 2 r R r + I r E j cos (Φ r + β)

123 ON 3- PH BASIS Pg= 3 V g I r cos Φ r P cur =3 I r 2 R r P r = POWER FED TO CONVERTOR =3 I r E j cos (Φ r + β)

124 AIRGAP POWER= ROTOR COPPER LOSS+ POWER FED TO CONVERTOR + MECHANICAL POWER

125 EXAMPLE s= P g =+100 P m, = +120 P r =-20 (POWER FED TO ROTOR) P e, = +100 POWER DRAWN FROM GRID =P grid = 120

126 MODE-I, SUBSYNCHRONOUS, MOTORING 0<s <1, s IS +VE P g, P m, P e, P r POSITIVE P m =(1-s) P g IS POSITIVE NEGLECT LOSSES Pcur, Pcus

127 EXAMPLE s= +0.2 P g =+100 P m, = +80 P r =+20 P e, = +100 POWER DRAWN FROM GRID =P grid = 80

128 MOTORING AT s=0.2 GRID (80) Pcur Pe (100) Pg f Pcus TRANSFORMER (100) Pr DFIG Pm(80) (20) fr CONVERTOR f

129 MODE-II, SUPERSYNCHRONOUS, MOTORING -1<s <0, s IS NEGATIVE P g, P m, P e, POSITIVE P r NEGATIVE P m =(1-s) P g IS POSITIVE NEGLECT LOSSES Pcur, Pcus P m IS MORE THAN P g

130 MOTORING AT s= -0.2 GRID (120) Pcur Pe (100) Pg f Pcus TRANSFORMER (100) Pr DFIG Pm(120) (-20) fr CONVERTOR f

131 MODE-III, SUBSYNCHRONOUS, GENERATING 0<s <1, s IS +VE P g, P m, P e, P r NEGATIVE P m =(1-s) P g IS NEGATIVE P m IS LESS THAN P g

132 EXAMPLE s= P g =-100 P m, = -80 P r =-20 (POWER FED TO ROTOR) P e, = -100 POWER FED TO GRID =P grid = 80

133 GENERATING AT s= +0.2 GRID (-80) Pcur Pe (-100) Pg f Pcus TRANSFORMER (-100) Pr DFIG Pm(-80) MOTORING (-20) fr CONVERTOR f GENERATING

134 MODE-IV, SUPERSYNCHRONOUS, GENERATING -1<s <0, s IS NEGATIVE P g, P m, P e, NEGATIVE P r POSITIVE P m =(1-s) P g IS NEGATIVE P m IS MORE THAN P g

135 EXAMPLE s= P g =-100 P m, = -120 P r =+20 (POWER DRAWN FROM ROTOR & FED TO GRID) P e, = -100 POWER FED TO GRID =P grid = 120

136 GENERATING AT s=-0.2 GRID (-120) Pcur Pe (-100) Pg f Pcus TRANSFORMER (-100) Pr DFIG Pm(-120) GENERATING (+20) fr CONVERTOR f

137 POWER Vs SLIP (MOTORING) Pr Pm Pg s 0 s -1

138 POWER Vs SLIP, GENERATING 0 Pr s Pm 0 s Pg -1

139 Pg Pm Pr MOTOR SUB SYNC MOTOR SUPER SYNC GENERATOR GENERATOR SUB SYNC SUPER SYNC

140 PM GENERATORS

141 TRANSFORM WIND SYSTEM WITH PM GENERATOR RECTIFIER INVERTER

142 WHAT IS IN STORE FOR FUTURE?

143 FUTURE IN WIND ENERGY FIXED SPEED SCIG (UPTO 1 MW) VARIABLE SPEED SCIG (WITH CONVERTOR/INVERTOR BETWEEN MACHINE AND GRID DFIG (FEW MW) SYNCH GEN LOW SPEED GEARLESS WITH AC-DC-AC PM SYNCH GEN WITH AC-DC-AC

144 FUTURE IN INDIA NEW PREDICTION: 100GW INCREASE HEIGHTS RETROFIT OLD FARMS WIND FORECASTING OFF-GRID OFF-SHORE (HUGE POTENTIAL)

145 FUTURE DEVELOPMENTS GERMANY, DENMARK- SLOWED DOWN USA, SPAIN,INDIA, CHINA FORGING AHEAD CANADA, MIDDLE EAST, FAR EAST, S. AMERICA HAVE GOOD PLANS At current growth 150GW of wind power expected in 2010

146 FACTORS FOR GROWTH POLITICAL SUPPORT INTERNATIONAL COMMITMENT CONCERN FOR CLIMATE CHANGE, EMISSIONS TECHNOLOGY FAIRLY MATURE PERFORMANCE AND COST ARE NOW CRUCIAL

147 THANK YOU