04-DESIGN AND LAYOUT OF WIND FARM.pdf

DESIGN AND LAYOUT OF
WIND FARM
K.Boopathi
Director & Division Head
Offshore Wind Development,Data
Analytics & Forecasting and IT
National Institute of Wind Energy
Chennai
boopathi@niwe.res.in
V
S
D
P

WIND FARM
➢Profitable wind resources are limited
to distinct geographic areas
➢Increases total wind energy
production
➢Economic point of view: The
concentration of repair and
Maintenance of equipment and spar
parts reduces cost
➢Dedicated maintenance personnel can
be employed
➢Resulting in reduced labour
costs/turbine and financial saving to
WT owner
V
S
D
P

Need of wind farm design ?
• The use of large areas of land for harvesting wind energy requires careful
design of the location of turbines, roads and electrical cables
• If wind farms are sited and designed well, the capacity of the landscape to
incorporate this type of development will be maximized
• Conversely, if they are poorly located and designed the scope for further
development in the future will be greatly reduced.
• improper design will increase generation losses and load on the turbine
V
S
D
P

Preliminary Site Investigation
•Basic understanding about the proposed
site
•Collecting the maximum possible
information
•Investigation to mitigate the risk
V
S
D
P

Wind Resource Map of India
V
S
D
P

Historical information required
Risk mitigation
Force majeure cases
•Cyclone,
•Typhoon,
•Earthquake,
•Lightening.
Risk mitigation
Force majeure cases
V
S
D
P

Plateau and Complex need more attention
Risk mitigation
Site conditions
Classification of terrain
•Plain.
•Plateau ( Raised and flat Surface).
•Semi complex.
•Complex:
irregular topography, such as mountains or coastlines
generates local circulations, or modifies
ambient synoptic weather features
V
S
D
P

Managed through efficient wind farm
design / micro-siting
Risk mitigation
High wind shear
Negative wind shear
Flow separation
High turbulence
High vibration
Huge Wake loss
V
S
D
P

• Preliminary Geotechnical
Investigation:
• Desktop site selection & field
mapping
• Assessment of the geological
variability across the study area
• Assessment of the nature and
strength of the near surface
materials at selected turbine
locations
• Assessment of slope stability in
the proposed wind farm
location
▪ Preliminary assessment of design
parameters for turbine footing
foundations and anchor support
▪ Preliminary advice for the construction
of roads
▪ that provide access to the turbines
▪ Undertake investigations on historical
▪ developments within the lease area
▪ Detail and design site drainage
requirements around both access roads
and footing foundations
▪ Provide a detailed Geotechnical report,
for use in the attainment of building
permits etc
V
S
D
P

Siting
Main Objective: Identify viable wind
project sites
Main Attributes:
• Adequate winds
• Generally > 7 m/s @ hub height
• Access to transmission
• Permit approval reasonably
attainable
• Sufficient land area for target
project size
• 30 – 50 acres per MW for arrays
• 8 – 12 MW per mile for single row on
ridgeline
V
S
D
P

Design parameters and impact parameters
• Parameters that are used when designing a wind farm include
❑wind farm design parameters and
❑ meteorological design parameters.
• the production of a wind farm is optimal and minimize the load. These include hub
height, rotor diameter and nominal power of the wind turbines, as well as distance
between the turbines and distance to other wind farms.
• The meteorological design parameters on the other hand are given constraints which
characterize the wind climate at a site.
These include the geostrophic velocity (that is a wind speed which is independent of
what happens close to the surface), the height where that velocity is reached, and
the surface roughness length (that is the length scale which characterizes the
roughness of the surface).
V
S
D
P

IMPACT PARAMETERS
❑measure the impact of a wind farm on the velocity.
❑Impact parameters include velocity deficit, velocity recovery
distance, minimum safe distance, and disturbed sectors in the
wind rose.
❑The distance where the velocity reaches a given fraction, for
example 99%, of the upstream value is the velocity recovery
distance. The minimum safe distance is a similar measure,
indicating the distance beyond which the velocity deficit is less
than 0.5 m/s..
V
S
D
P

What is micro siting ?
Micro siting is a way to optimize the park layout in any given site to give the optimum production on site.
- Production estimate, incl. wake losses to other turbines
- Calculate sound emission from the turbines to the
nearest neighbor.
- Create a visualization of the park.
All this is something that is done before the park is erected
so you can calculate the feasibility of the project.
- Load calculation to ensure a 20 year design lifetime
- Calculate shadow flickering
- Wind measurements
-Recommend another turbine type, turbine layout, hub height,
wind sector management or measurement campaign
- Wind resource estimate
- Turbine layout
- Roughness, Obstacles, Orography
V
S
D
P

For a good micrositing is needed:
• Min. 1 year of wind data measured on site
• Wind direction measurements
• The wind speed measurements must be
conducted for at least 2 heights → wind shear
• The measuring height should be as close to
hub height as possible
• Standard deviation measurements →
turbulence
• If possible temperature measurements → air
density
• A digital 3-D contour map covering an area of
a radius of 5 – 10 km from the site centre
V
S
D
P

• Wind Data Short and Long term with
Equipment and Mast details,
• Temperature and Pressure details,
• Maps with Coordinate System (Contour,
Roughness and Background maps),
• Aerial Photographs,
• Gps Co-ordinates for Masts and
propose WTGs,
• Site boundary details, local regulations
and set backs.
• Minimum spacing between WTGs ?
For a good micrositing is needed:
 Wind Monitoring Stations:
◦ Preferably at Hub height
◦ Anemometers at different
heights,
◦ Wind vane,
◦ Temperature and pressure,
◦ Data logger.
 Site inspection is required to
understand the impact of the
instrumentation on the data
measured.
V
S
D
P

In order to do a proper wind assessment
on-site wind measurements are necessary!
Wind rose
• One full year of measurements are needed in order
to take all seasonal variations into account.
• If more than one year of raw data are used the year
to year uncertainty is taken into account.
• If the temperature is measured simultaneity with the
wind speed, it is possible to estimate weather or not,
a high/low temperature turbine is needed.
• On site measurements are needed in order to
investigate the wind regime on site. Wind shear,
turbulence, wind rose, and wind speed are factors
that can easily change with the complexity of the
landscape.
V
S
D
P

What does Micro Siting include?
Wind measurements
Wind speed
Turbulence, Roughness, Obstacles
Turbine and park layout
Production estimate
Load calculation
Sound emission
Visualization
Shadow casting
V
S
D
P

Wind data analysis and climatic condition
◦ Average Annual Wind Speed,
◦ Temperature and pressure,
◦ Air density,
◦ Turbulence,
◦ Wind frequency distribution,
◦ Wind Shear, (Power Law
Index)
◦ Extreme Wind Speeds,
◦ 3 Sec Extreme Gust.
V
S
D
P

Turbine selection and suitability of turbine
Page
22
Design Turbulence intensity@ 15 m/s
A = 18%
B = 16%
C = 14%
 IEC 1:
◦ v10 min. avg.< 10 m/s.
◦ v10 min. ext.< 50 m/s.
◦ v3 sec. survival < 70 m/s.
 IEC 2:
◦ v10 min. avg.< 8.5 m/s.
◦ v10 min. ext.< 42.5 m/s.
◦ v3 sec. survival< 59.5 m/s.
 IEC 3:
◦ v10 min. avg.< 7.5 m/s.
◦ v10 min. ext.< 37.5 m/s.
◦ v3 sec. survival< 52.5 m/s.
IEC S:
v 10 min. avg.< Specified by manufacturer.
v 10 min. ext.< Specified by manufacturer.
v 3 sec. survival< Specified by manufacturer.
Turbulence int: Specified by manufacturer.
All wind speeds are at hub height.
V
S
D
P

Maps preparation
Contour Map – minimum 5 kms from the site boundary
Preferably 2m resolution for project site and for rest of the area 5m to 10m resolution
V
S
D
P

Maps preparation
Roughness
Page 24 Site visit is required to prepare a quality roughness map
V
S
D
P

Power Curve and Air-density
Page 25
Thrust curve is required along with the power curve for Wake modeling.
V
S
D
P

Software tools Wind data Analysis
Windographer
Windpro
Excel
MATLAB
Wind Farm Layout and
Energy Estimation
WAsP
Wind farmer
Windpro
Windsim
MeteoDYN
Openwind
Turbulence, Inflow angle and
slope calculation
WAsP Engineering
Windsim,Meteodyn,
Openwind, Surfer
V
S
D
P

WAsP – Wind Atlas Analysis and Application Program
WAsP is developed and distributed by the Wind Energy and Atmospheric Physics
Department at Riso National Laboratory, Denmark.
WAsP is a PC program for the vertical and horizontal extrapolation of wind climate
statistics, predicting wind climates and power productions from wind turbines and wind
farms.
Horizontal extrapolation
V
S
D
P

 Orography
 Roughness
 Obstacles
V
S
D
P

- Obstacle
Observed Wind Climate
V
S
D
P

- Obstacle
- Roughness
V
S
D
P

- Obstacle
- Roughness
- Contour
V
S
D
P

Generalized Wind Climate / Atlas
V
S
D
P

+ Contour
V
S
D
P

+ Roughness
+ Contour
V
S
D
P

+ Roughness
+ Contour + Obstacle
V
S
D
P

Predicted Wind Climate
V
S
D
P

Key technical aspects
• Deciding the right orientation
of turbine array
• Good understanding of macro
characteristics of wind profile
• Minimum inter turbine spacing
• Wake loss
• Turbulence
• Loads
• Selecting model in general
• Matching site wind class and
turbine design wind class
• Extreme load
• Extreme winds
• Positioning of turbines
• Terrain
• Turbulence
• Deflections
• Skewed wind flow
• Selecting models at specific
locations
• Fatigue loads
• Wind shear
• Veer
• Flow angle
V
S
D
P

What is Turbulence
Turbulence is variations in wind
speed
•Back ground turbulence
•Wake turbulence
V
S
D
P

What is a simple and Complex Site?
Minor relief
Negligible influence of
orography
Charecterized by
orographic features
with terrain slope >17
deg
Dominant influence on
wind conditions
V
S
D
P

Windmill Packing Density
• As it extracts energy from the wind, the turbine leaves behind
it a wake characterised by reduced wind speeds and increased
levels of turbuence
• A turbine operating in the wake of a turbine will produce less
energy and suffer greater structural loading
• Rule of thumb is that windmills cannot be spaced closer than 5
times their diameter without losing significant power
V
S
D
P

Wake Effect
Since a wind turbine generates electricity from the energy in
the wind, the wind leaving the turbine must have a lower
energy content than the wind arriving in front of the
turbine.
This follows directly from the fact that energy can neither be
created nor consumed.
A wind turbine will always cast a wind shade in the downwind
direction.
In fact, there will be a wake behind the turbine, i.e. a long trail
of wind which is quite turbulent and slowed down, when
compared to the wind arriving in front of the turbine. You
can actually see the wake trailing behind a wind turbine, if
you add smoke to the air passing through the turbine, as
was done in the picture on the right.
Wind turbines in parks are usually spaced at least three rotor
diameters from one another in order to avoid too much
turbulence around the turbines downstream. In the
prevailing wind direction turbines are usually spaced even
farther apart, as explained on the next page.
V
S
D
P

Windmill Packing Density
• Power that a windmill can
generate per unit land area
= Power per windmill / land
area per windmill
= (Cp x ½ ρv3 x (π/4)d2) /
(5d)2
d
5d
V
S
D
P

a) The distance between the proposed WEG with
adjacent existing WEG, formed in row should be
minimum three times (3D) the diameter of the rotor.
Row should be formed in such way that it is
perpendicular to the predominant wind direction. The
distance between the rows should be at least five times
diameter (5D) of the Rotor, so that performance of the
WEGs should not be affected in any manner.
b) In general, the developer shall leave boundary
clearance to avoid arial trespass of the wind mill
blades into the neighboring land of the property a
distance of 2D perpendicular to the predominant wind
direction and 3D distance in the pre-dominant wind
direction.
c) It is also possible that certain WEGs are / would be
erected nearer to residential places, school buildings
etc., hence considering the safety aspect, a minimum
fall on distance for such case should be kept at least
‘Tower Height + ½ Rotor Diameter + 5m’.
V
S
D
P

WRD 45
Array loss
• Wake effect
Prevalent
wind
1st row 2nd row 3rd row 4th row
V
S
D
P

Developing and improving Tools
• Complex Sites
• Met Masts
• Wind Analysis
Tools
• Site Check
• Reporting
Tools
V
S
D
P

Site ID
X-
locatio
n [m]
Y-
locatio
n [m]
Elevati
on
a.s.l.
[m]
Wake
loss
[%]
P50
GWH
P75
GWH
P90
GWH
P95
GWH
1 2.3 1.23 4.68 4.22 3.8 3.55
2 2.2 3.16 4.59 4.13 3.72 3.48
3 4 4.42 4.56 4.11 3.7 3.46
4 1.9 4.85 4.51 4.06 3.66 3.42
5 0.2 4.79 4.47 4.02 3.62 3.39
6 3.3 4.83 4.51 4.07 3.66 3.42
7 2.4 5 4.46 4.02 3.62 3.38
8 4.8 5.05 4.47 4.02 3.63 3.39
9 5 4.75 4.48 4.03 3.63 3.39
10 4 4.8 4.41 3.97 3.58 3.34
11 3.9 4.36 4.43 3.99 3.59 3.35
12 4 3.82 4.42 3.98 3.59 3.35
13 2 3.45 4.43 3.99 3.59 3.35
14 1.4 3.4 4.43 3.99 3.6 3.36
15 2.7 3.34 4.45 4.01 3.61 3.37
16 2.1 3.09 4.43 3.99 3.6 3.36
17 0.7 2.85 4.42 3.98 3.58 3.35
18 2 3.72 4.42 3.98 3.59 3.35
19 4.8 4.46 4.39 3.96 3.57 3.33
20 3 5.44 4.32 3.89 3.51 3.28
AEP/GWH 4.46 4.02 3.62 3.38
PLF (%) 25.48 22.95 20.68 19.31
Wind
Speed
(m/s)
Power
[MW]
Thrust
coefficient
4 0.079 0.831
5 0.181 0.812
6 0.335 0.812
7 0.55 0.811
8 0.832 0.8
9 1.175 0.758
10 1.53 0.674
11 1.816 0.562
12 1.963 0.44
13 1.988 0.335
14 1.996 0.261
15 1.999 0.209
16 2 0.171
17 2 0.142
18 2 0.12
19 2 0.102
20 2 0.088
21 2 0.077
22 2 0.067
23 2 0.06
24 2 0.054
25 2 0.048
V
S
D
P

Wind Resource map generated in Kayathar Existing wind farm
boundary
V
S
D
P

Calculating power output ■ two important prerequisites:
► thoroughly measured and evaluated wind data for the
site(s) in question, and
► an exactly measured power curve, according to
international standards, so that turbines on the world
market can be compared
■ but still ...
► for both power curve and wind data evaluation error
margins exist, which make an absolute certainty for
output estimation impossible
► in addition - annual variations of wind resource for a
given region can be substantial (+/- 20 % normal, up to
40 % ...)
V
S
D
P

Methodology for energy yield assessment
V
S
D
P

Influences on Uncertainty
Measured Speed
Shear
Climate
Resource Model
Plant Losses
Sensor Types, Calibration & Redundancy,
Ice-Free, Exposure on Mast, # of Masts
Height of Masts, Multiple Data Heights,
Sodar, Terrain & Land Cover Variability
Measurement Duration, Period of Record @
Reference Station, Quality of Correlation
Microscale Model Type, Project Size, Terrain
Complexity, # of Masts, Grid Res.
Turbine Spacing (wakes), Blade Icing &
Soiling, Cold Temp Shutdown, High Wind
Hysteresis, etc.
(2-4%)
(Typical Range of Impact on Lifetime Energy
Production)
(1-3%)
(4-9%)
(5-10%)
(1-3%)
V
S
D
P

Uncertainties
➢ Meteorological input data:
➢ Gaps in the recorded data
➢ Poor or not calibrated anemometer
➢ Damaged or malfunctioning sensors
➢ Change of obstacles in the vicinity of the met mast
(trees, buildings, etc.)
➢ Calculation methods:
Not suitable for complex terrain
Input of roughness, obstacles and orography
V
S
D
P

WRD 60
Recommended approach
V
S
D
P

Step 1: Collate data
• Technical spec of your turbine
• Rotor diameter
• Hub height
• Power curve
• Cp, Ct data
• Technical spec of surrounding
turbine (same as above)
• Detailed survey of site
• Contour
• Land-use
• Infrastructure
• Position of existing turbines
• Wind profile
• Wind Rose
• Maximum speeds
• Known Government regulations WRD 61
Step 2: First big decision
• Derive the general wind class of the site
• Decide which model
• Complex decision in case of
multiple model in same class
• Basic check of viability of the model
Step 3: Spacing game
• Maintain a rule of bare minimum of 3D spacing in any
direction
• Based on site extents decide single row or multiple row
• In case of multiple row increase the minimum
spacing to 4-5D
V
S
D
P

Step 4: When game gets tough…
• Use optimization tools
• WindFarmer, Garrad Hassan, U.K.
• WindPro, EMD, Denmark
• WindFarm, ReSoft Ltd., U.K.
• OpenWind, AWS Truepower, USA
• Provide as much of site inputs as possible
• Use high resolution wind resource grid “wrg”
data for optimizing – especially in complex
terrain
• Use your own judgment to re-check the output
of these tools
WRD 62
• Marking and verification at site
• Use G.P.S., Siting compass
• Carrying Laptop with Micro-siting map
recommended
• Carry detailed Micro-siting map
• To thrash out minor local nuances
• Normally not captured in survey
• Try for fine adjustment to improve output / array
efficiency
• In case of major shifting – 1/2D or more, re-run
the tools
• Pick up the final locations from site
• Re-survey
• Final run of program for estimated output.
Step 5: Positioning of WTGs…
V
S
D
P

WRD 63
Step 5: Positioning of WTGs…
• Marking and verification at site
• Use G.P.S., Siting compass
• Carrying Laptop with Micro-siting map recommended
• Carry detailed Micro-siting map
• To thrash out minor local nuances
• Normally not captured in survey
• Try for fine adjustment to improve output / array
efficiency
• In case of major shifting – 1/2D or more, re-run the tools
• Pick up the final locations from site
• Re-survey
• Final run of program for estimated output.
V
S
D
P

Step 6: Study each location…
• Analyze each location for suitability of the selected WTG
model
• More critical in complex sites
• Harmful location need either correction or cancellation
• Use of advanced modeling tools (CFD) will help in decision
making
V
S
D
P

Locating
Wind Farms
Using GIS to Optimize
Wind Farm Locations
V
S
D
P

GIS and Wind Farms
• GIS services provide the basis for wind farm siting at all stages of
development.
• As wind farms grow, more applications will appear to transform the
process into real-time field applications.
Wind Availability
Transmission Availability
Choosing a Wind Farm Location
V
S
D
P

Preperation of rougness map
V
S
D
P

Land Use Land Cover Map
V
S
D
P

Oops...
• What’s wrong with this picture?
• Proximity of turbines
• Orientation w.r.t.
prevaling winds
• Ignoring local
topography
• …
Near Palm Springs, CA
V
S
D
P

Conclusions
• Wind farm has to be carefully designed as it involves huge
investment
• Improper design will reduce energy generation ,increase the load on
the turbine and reduce the life of the turbine.
V
S
D
P

04-DESIGN AND LAYOUT OF WIND FARM.pdf

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to 04-DESIGN AND LAYOUT OF WIND FARM.pdf

Similar to 04-DESIGN AND LAYOUT OF WIND FARM.pdf (20)

Recently uploaded

Recently uploaded (20)

04-DESIGN AND LAYOUT OF WIND FARM.pdf