| DESIGN The Nordex N54/1000 kW wind turbine was the first MW-class wind turbine in
series production. Through the successful operation since early 1995, the N54/1000 has
proved a high efficiency and reliability.
The N54/1000 kW wind turbine is designed as a 3-bladed, horizontal-axis, stall-regulated
wind turbine.
The distinct use of high quality components and the choice of leading sub-suppliers,
secures for the customer the optimum choice for his investment.
The wind turbine is designed for a survival wind speed of 70 m/s.
All components are therefore dimensioned with a high safety factor, which secures a long
lifetime of the entire turbine. Each component is designed for much higher loads than it
will normally be exposed to.
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ROTOR
The Nordex N54/1000 kW wind turbine has a rotor diameter of 54 m and a
swept area of 2290 m2.
The hub is made of cast iron, which gives a strong and robust construction. Furthermore
this material reduces transferred noise from the rotor to the turbine structure.
The Nordex N54/1000 kW turbine is stall-regulated, which means that the blades are fixed
to the hub in a predetermined tip-angle. The rotor is therefore generally maintenance
free, and contains a minimum of moving mechanical parts which could become worn during
operation. |
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BLADES
The blades are manufactured by one of the worlds leading blade
manufacturers, and are a development in which the blade profile as well as the material
are optimised. This is done in order to exploit the wind energy to a maximum, and in order
to reduce the blade surface and weight as much as possible, thereby reducing loads and
stress in the entire wind turbine.
The blades are manufactured primarily of fibreglass reinforced polyester. |
The surface is coated in a light grey
colour in order to prevent light reflections.The blade tips are pivotable, and can be
turned 85 degrees in relation to the rest of the blade, and thereby act as an aerodynamic
brake, and the primary braking system of the turbine. During normal operation of the
turbine, the blade tips are maintained in operational position by pressurised hydraulic
cylinders, which are located in each blade-root.
If unintentionally the rotor should exceed the nominal rotational speed, or if hydraulic
pressure is lost, the centrifugal force will cause the blade tips to deploy, thereby
slowing down the rotor and acting as a truly fail-safe system.
The blades are delivered as standard with a lightning protection system which, together
with the overall lightning protection system of the turbine, offers maximum security
against damage caused by a lightning strike. |
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MAIN SHAFT
The main shaft is manufactured in alloy steel. It has a state of the
art, 3-point support, with a solid spherical roller bearing supporting the shaft at the
rotor in order to absorb the rotor thrust. In the gearbox the shaft is supported by two
cylindrical roller bearings and the gearbox unit again rests on
two supports. The shaft is connected to the gearbox by a shrink-fit coupling.GEARBOX
The gearbox is delivered by one of the leading gearbox manufacturers for
the wind turbine industry. It is a custom designed 3-stage gearbox with the first stage as
high torque planetary gear and the second and third stages as helical stages. |
| The planetary stage is ideal for obtaining and
transferring the rotor torques of the shaft, and is at the same time a compact and robust
design. The gearbox is fitted in two strong rubber bushings in order to dampen the noise
and load peaks, so that when extreme loads occur, the gearbox and bearings are protected
against damage.The gear oil is cooled by a heat exchanger, connected to the cooling system
of the generator. Monitoring of the oil temperature ensure that the oil reaches its
optimum temperature as fast as possible, and at the same time is kept constantly at the
optimum temperature. The gears and bearings therefore obtain a constant and optimal
lubrication. |
GENERATOR
The generator is a doublewound 4/6 pole asynchronous machine with two seperate windings,
and a nominal effect of 1000 kW and 200 kW respectively. The generator is optimised for
the highest efficiency at 3/4 load, which under most wind conditions gives the optimum kWh
production. The generator is designed for insulation class F but is only operated to class
B. This together with the efficient liquid cooling of the generator, ensures an optimum
operating temperature, which again prolongs the lifetime of the generator considerably. |
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| The cardan coupling to the gearbox provides
a robust and low-maintenance solution. |
BRAKE SYSTEM
The Nordex N54/1000 kW turbine has two independent braking systems. The primary system is
the aerodynamic tip-brakes and the secondary system is the mechanical disk brake system
which is located on the high speed shaft of the gearbox. Both systems function fail-safe.
During normal operation of the turbine each blade tip is maintained in operational
position by a pressurised hydraulic cylinder located in the blade root.
The release of the hydraulic pressure on the cylinders, intentionally or by a failure in
the system, will cause the tips to deploy and the rotor to decrease the rotational speed.
When the rotor is slowed down to a certain speed, the mechanical disk brake system is
activated and the turbine is smoothly brought to a standstill.
The Nordex wind turbines utilise a soft braking system on the mechanical brake. This means
that the braking torque is controlled according to a rampload-function, which reduces the
strain on the drive train.
In this way the risk of pitting of the gearbox is minimised, and at the same time the
torque in blades and drive train is reduced.
During emergency braking both the aerodynamic and mechanical braking systems are activated
simultaneously.
By activation of the mechanical brake, the brake torque is controlled according to a
rampload-function.
After completed braking procedure, the system is activated by maximum torque to keep the
rotor at standstill. |
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YAW SYSTEM
The active yaw system which enables the wind turbine to be positioned correctly in the
wind, is based on a 4 point ball bearing slewing ring.
The yawing of the turbine is done by 2 planetary gears, which are each driven by a
thyristor controlled electric driven motor, resulting in the loading of the yaw gears
being equally distributed.
The yaw brake consists of a large disk brake activated by 6 hydraulic brake calibers.
Furthermore, each yaw gear has a separate brake built into the fast stage. |
The complete system ensures a smooth yawing procedure,
and that the nacelle is fixed when the yawing is inactive. In this way we ensure that
there is no load on the yaw gears and drives, when the turbine is not yawing.
Two mutually dependent wind vanes gives signals to themaster computer, which controls the
yawing procedure of the turbine.
The system ensures that the turbine is positioned correctly in the wind at all times,
thereby resulting in the optimal power production and minimum stress on the turbine drive
train. |
LIGHTNING PROTECTION
With the gradual increase in wind turbine tower height, the risk that the turbine could be
hit by a lightning strike also increases.
This fact has lead Nordex Balcke-Dürr to take the utmost precautions in order to minimise
the risk that a lightning strike will cause damage to parts of the turbine. |
The lightning protection system of the Nordex N54/1000
kW wind turbine is therefore designed according to the IEC 1024-1 standard. If a lightning
strikes the turbine blade or the nacelle, the advanced protection system will safely lead
the lightning current to the wind turbine earthing system, with minimum risk of damage to
any part in the turbine.
The electrical and electronic components in the turbine are protected by means of
varistors, and the turbine internal communication is performed via optical fibre
technique, which is immune to voltage peaks. |
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CONTROLLER
The wind turbine controller has two independent computers. The master-computer is located
in the switchboard in the bottom of the tower, and a slave is located in the nacelle. All
inputs from sensors and transducers are collected and assessed by the slave-computer and
transmitted to the
mastercomputer which supervises the overall operation of the turbine.
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The communication between the
master and the slave computer is via optic fibre technology, which enables a reliable and
fast exchange of signals.
A large amount of data can be read from the display-board connected to themastercomputer.
A keyboard in the front of the switchboard is utilised for changing between different
read-outs and at the same time it can be utilised to change parameter settings for the
turbine if required. |
REMOTE MONITORING
The Nordex N54/1000 kW wind turbine is fully prepared for remote monitoring and control. A
telephone-connection is all that is needed for this system to be functional. From a
Personnel Computer a full range of data can be read from the turbine.
In case of an error, the turbine controller automatically reports the event, and the data
in the controller is stored so that it is possible to see what happened just before, and
when the error occured. |
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WIND TURBINE
OPERATION
The Nordex N54/1000 kW wind turbine operates fully automatically.
This means that the turbine automatically starts (wind-start) when the wind speed reaches
3-4 m/s. When the rotor/generator reaches synchronising speed, the generator is connected
to the grid by a thyristor soft-connection. The turbine produces electricity for supply to
the grid, as long as the wind speed is between 3-25 m/s. At wind speeds between approx. 3
and 7 m/s the 200 kW generator is connected to the grid, and at wind speeds between
approx. 7 and 25 m/s, the 1000 kW generator is connected to the grid. At wind speeds
higher than 25 m/s, the turbine will be shut down for safety reasons.
The turbine will automatically re-start after any shut down if no error is present. If the
turbine has an error, this has to be analysed and reset before the turbine starts up
again.
Due to continuous development and improvement of our products, Nordex Balcke-Dürr GmbH
reserves the right to change the above specifications without notice. |
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