Development and
operating experience of
the WEC Winwind WWD-1
G.Böhmeke, WINWIND OY
Concept origin
 Direct drives appeared on the market 1994-’95
 Comparative study on direct drives, including slowspeed drives with single-stage gearing at aerodyn
GmbH in 1996-’97
 First publication EWEC ’97 Dublin
Study results, facts...
 Direct drive leads to very high generator mass and
cost , the machine is not competitive if bought from
ready-made components
 The situation becomes worse with increasing size
 This can only be partially neutralized by making the
generator and inverter in large series in the own
workshop
 A newcomer can not start on this basis
... Facts
 Large-scale gearbox failures from 1999 to 2002
 Investigations partially confidential. Published
results leave many questions open
 Damages seem to concentrate on high-speed parts
 A newcomer should not take the risk of using a
conventional gearbox
Aim
 Reliable and competitive wind turbine, suitable also
for arctic and remote locations
 Concept scaleable up to several MW
 Components bought from well-known component
deliverers, but own test and assembly
 Avoiding all gearbox problems known today
 Avoiding the cost and mass problems of direct
drives
Solution
 Low-speed drive train, planetary gearbox with
comparatively slow generator
 Gearbox and generator risk analysis and measures
against possible problems
 Further measures to increase overall reliability
Patents, co-operation, funding
 Slow-speed integrated drive train concept called
MULTIBRID and patented by aerodyn GmbH
 WinWinD and its cooperation partner Pfleiderer
Wind Energy GmbH hold the utilisation rights.
 Pfleiderers 5MW-MULTIBRID is in parallel under
development
 TEKES subsidy to WINWIND for the development of
the 1MW wind energy converter WWD-1
WinWinD
 Founded in March 2000, share company
Largest share holders
 Powest Oy, A subsidiary of biggest Finnish
power company, Pohjolan Voima Oy
 Head Future Technologies Oy, Venture capital
company, member of the Head Team
 Presently 20 employees, three locations
Location
Workshop, assembly and test
Ii-Raasakka
Main office and administration
Oulu
Machine design and development
Helsinki
WWD-1 Main component deliverers
Blades EUROS
Inverter ABB
Hub and
mainframe
casting METSO
FOUNDRY
Generator ABB
Tower steel
RAUTARUUKKI
Main bearing
HRE
Gearbox METSO
DRIVES
WWD-1 drive train
WWD-1 drive train (simplified)
WWD-1 Basic data
Rated power
Rotor diameter
Classification
Tower height
Cut-in wind speed
Cut-out wind speed
Rated wind speed
Top mass
1 000 kW
56 (60) m
IEC 2-A (3-B)
56 - 70 m
3 m/s
25 (20)m/s
12.5 m/s
53 to
Rated rotor speed
Rated gen. speed
Gear ratio
25.6 rpm
146 rpm
5.71
Temperature range
First machine (Oulu)
Series
-30C to +25C
site-specific
Diagram from
WWD-1 Basic data
aerodyn GmbH
E112 ca.
500t
50
mk = a * D
45
Technologie Faktor
a = 0.7 to 1.1
40
rel. Turmkopfmasse [kg/m²]
2.75
MOD 5b
35
E 66
schwere WEA
25
NTK 1500
E 40
E 30
MD 70
20
V 47
15
bwu 750
M 5000 » 300 t
N 80
WWD3
V 66
NTK 300
GE 3.6 » 268 t
Aeolus II
30
WWD1
leichte WEA
10
5
0
25
35
45
55
65
75
85
Durchmesser [m]
95
105
115
125
Design rules gearbox
Bearings and gears
Own crosscheck and neutral expert approval
No high-speed parts
FEM analysis of bearing influence on gearing
Load peaks
Variable speed and pitch concept, defined torque
Slip clutch against short circuit torque peaks
Brake dynamics torque peaks
Brake acts with only rated torque
Reaction forces and casing deformations
Concentric structure and FEM analysis
Spherical roller bearing problems
Only cylindrical roller bearings
Oil quality and temperature
Ample cooling and fine filtering
Design rules generator
Winding temperature level
Inherently large surface per kW of loss
Water jacket cooling
Permanent excitation saves losses and heat
Dielectric winding stress dU/dt
Adequate filter
Salt, water, erosion
Preformed coil winding, no round-wire
No ambient air through generator
Air gap collision
Conventional length/diameter ratio, stiff casing
No direct influence of rotor loads on air gap
Sensor and supervision
Magnet degrading
Quality control
Thick glassfibre sleeve
Current limiting
WWD-1 assembly
WWD-1 back-to-back test
WWD-1 test and running-in
WWD-1 site assembly
WWD-1
August 2001
First machine erected in Oulu
April 2003 two units
to Kokkola
June 2003 three units
To Oulunsalo
September 2003 three units
to Kristiinankaupunki
1Q 2004 two units to France
Operational experience...
Power curve
As predicted, pitch control needed parameter refinements
Noise
First results Lpa= 103 dBA
No measured single tone content
Gearbox silent
Dominant machine noise is generator slot frequency
No elastic suspension/insulation needed anywhere
Grid interference
As designed and predicted by inverter manufacturer
EN-SFS 50160 limits are fulfilled
Dynamics
As designed
... operational experience
Site
Some days of downtime due to rime ice
Blade heating system not justified
Generator air cooling => water jacket for series machine
Preheating procedure needed optimization
Temperature level during operation
Gearbox oil max. 60C so far, est. 80C with 25C ambient
Generator winding max. 85C so far, est. 100 C
Conclusion
No problems related to the drive train concept
Low temperature levels, no unexpected loads,
high reliability and long lifetime can be expected.
From WWD-1 to WWD-3
 Same drive train concept, but increased gear
ratio to cancel the lower rotor speed
 Still more compact structure and special
measures against structure-born noise
 Machine development is under work,
prototype scheduled for spring 2004
 First machine to be sited near Oulu
WWD-3 preliminary base data
Rated power
Rotor diameter
Tower height
Cut-in wind speed
Cut-out wind speed
Rated rotor speed
3 000 kW
90 m
85-90 m
4 m/s
25 m/s
15.9 rpm
Aim: MULTIBRID 1, 3 and 5 MW
product family