Transcript Slide 1
Blue font and lines – need to know These are all lift-type (the sweep surface faces the wind)
These are suitable for utility-scale generation Too much interference from tower Not high enough above ground
Wind
Drag-Type - not suitable for serious power
4 m/s cut-in 12.5 m/s rated power 25 m/s cut out 56 Pmax region, pitch regulated to hold Pmax cubic 25 1 mile = 1609 m
Desert Sky Wind Farm - Map
•
Dallas - 400 Miles
•
San Antonio - 266 Miles
•
Odessa - 90 Miles
•
Ft. Stockton - 50 miles
•
McCamey - 20 Miles
•
Iraan - 12 Miles
Desert Sky Wind Farm (approx 300 miles due west of Austin)
330 ft 215 ft At least 100 wind turbines in a wind farm Approx. 10 wind turbines (15 MW) per square mile. Thus, a farm needs at least 10 square miles.
Metric units – about 6 MW per square km.
115 ft Operate at 10 – 20 RPM, with wind speed range 8 – 56 MPH
GE 1.5S Wind Turbine Operation
•
Operates in 8-56 mph wind speeds
•
Each turbine is a self-contained independent power plant, no operator intervention required
•
Onboard weather station, yaw control facing wind
•
Variable speed, operates from 10 20 RPM rotor/blade assembly, generator speeds 850 to 1440 RPM
Nacelle Layout
O&M - Non-Routine Corrective Maintenance
• •
Blade repairs, lightning damage & leading edge erosion.
• Blade inspections and repairs are completed annually. • About 25 lightning related repairs per year.
25 lightning-related repairs per year per 100 turbines
• Since commissioning, three blades have required replacement due to lightning damage.
Gearbox failures and subsequent replacement.
• Gearbox life cycle appears to be 5-8 years.
Note: The repairs mentioned above require two cranes, a large 300 ton crane and a smaller 100 ton crane. Crane availability and expense are serious issues facing wind farm owners. Demand for crane service is currently outpacing availability.
x
K
.
E
.
1 2
mv
2 ,
P
d dt
K
.
E
.
1 2
v
2
dm dt P
1 2
v
2
A dx dt
1 2
Av
3
Better performance when cold Ideal gas law, PV = nRT.
P
1
V
1
T
1
P
2
V
2
T
2
For constant P,
V
2
V
1
T
2
T
1
so as T ↑, V ↑. As V ↑ , then ρ ↓ . Result is as T ↑ , then ρ ↓.
K T
273 .
15 15 273 .
15
K
P
(
z
)
P
(
z
dz
)
g
Adz A dP
g
dz
P
MW
10 3
RT
MW = molecular weight R = gas constant T = degrees K
dP dz
gP
MW RT
10 3 1 .
185 10 4
P P
P o e
1 .
185 10 4
z
P o = 1 atm, T = 15 ºC, z meters
o
o e
1 .
185 10 4
z
, 1 .
225
kg
/
m
3
K A
Drops about 0.1 per 1000m, and about 0.1 per 30 º C Relative Air Density ( Nominal 1.0 at Sea Level, 15 Deg C) 1.15
1.10
Sea Level 1.05
1.00
500 m 1000 m 0.95
0.90
0.85
0.80
1500m 2000 m 2500 m 0.75
0.70
-20 -15 -10 3000 m -5 0 5 10 Temp - C 15 20 25 30 35 40
v v o
H H o
Variation of Wind Speed with Height above Ground
v o , H o : velocity and height at reference position, usually 10 meters above ground.
1 7
th
power law
Betz Limit – Max theoretical turbine energy capture = 59.3% of swept area when downwind is slowed to 1/3 rd of the upwind speed.
swept
Betz Limit – Max theoretical turbine energy capture = 59.3% of swept area when downwind is slowed to 1/3rd of the upwind speed.
TSR
Tip Speed v wind
rotor
(
rad
/ sec)
R rotor
(
m
)
v wind
(
m
/ sec)
Moderate: 6.4 - 7 m/s Good: 7- 7.5 m/s Excellent: >7.5 m/s
GE 1.5MW Turbines