The Fuhrländer AG, German manufacturer of wind turbines with the slogan: "Friendly Energy - Friendly World" is developing wind projects in cooperation with partners and customers all over the world, from the small individual turbine to turnkey multi-megawatts parks. The company is happy to provide know-how in this respect and offers cooperation opportunities for partners. Recently, the company has developed a new wind turbine, the speed variable FL 2500, which will be presented as an example for technological development of wind turbine technology. This turbine of the 2,5 MW class, developed by the experienced W2E-team, offers optimum adaptation to all location conditions and wind zones. Three rotor sizes of 80, 90 and 100 m are available for regions with high, normal and low wind. With steel towers of 65 to 100 m and lattice towers of up to 160 m hub height, inland as well as coastal locations can be developed economically. Use in forest areas is also possible.
But very economic wind power production requires more: An integrated crane/winch concept and the maintenance friendly design of the turbine provide for reduced operational and insurance costs. The replacement of components is possible without expensive heavy load mobile crane. This lowers stoppage periods and repair costs.
References of the Nacelle picture:
The new drive line concept of the FL 2500 has several aims: It renders the turbine less noisy, more compact and lighter and reduces the installation times during manufacture and erection. This is made possible by a new anti-slip hardened rotor bearing located between rotor hub and machine rest. Lateral and transverse forces of the rotor do no longer put stress on the gear bearing but are diverted directly via the strengthened machine rest in the tower. This concept has a positive effect on the life of the gear. In addition, the access to the hub is possible without leaving the power house and results in improved air conditioning of the hub technology.
Test phase completed successfully: The more than 90 ton heavy power house
of the FL 2500 with installed hub just prior to practical testing. © Fuhrländer
The FL2500 offers a new safety system which already meets the requirements of the European machine guidelines and the specifications of Germanische Lloyd. For the first time, the safety concept was carried out on the basis of a risk analysis to increase personal safety (service technicians, operators, visitors) and the machine. The design meets category 3 of the machine guidelines. The safety system reacts selectively to triggering equipment and signals such as emergency off, vibration switch, performance and speed limit relays, overload protection, transposition of wiring, pitch system and operational faults, transformer protection, fire protection. An event-related, differentiated triggering of the actuator level reduces stresses and torques as extreme loads, which results in a significantly lower mechanical wear, e.g. of the brakes and the gears and a higher durability as well as cost reduction by savings on materials or longer operational periods.
Hub of the FL 2500 with its large anti-slip hardened rotor bearing and
the blue shaft coupling for the connection to the compact gear. © Fuhrländer
Even if one of the principal components such as rotor blade, bearing, gear, generator should fail, the operator does not require an expensive mobile crane to replace these heavy parts. The turbine has lifting beams in the power house. The associated crane only needs to be acquired once per service location or is provided by the turbine manufacturer. The up to 25 t heavy components are lowered or hoisted into the power house via a large floor flap directly behind the tower. This concept, for which a patent has been applied for, offers significantly lower costs and shorter repair periods. This also reduces insurance premiums, for example.
All components of the FL 2500 can be lowered through the floor
flap with the 25 t onboard crane plus handling winch
The developers have given the pitch system of the FL 2500 an intelligent control process, with which the weather side pitch of the tower head typical for pitch controlled turbines and which creates peak loads is reduced during quicker, more positive blade adjustment processes. The process also reduces stresses during braking procedures as well as during the reaction to gusts. Also new: the „Pitch Logic Unit“ located in the hub allows early detection of overspeed situations and avoids high turbine thrusts. In contrast to standard controls, the FL 2500 can react to such conditions without having the turbine run at overspeed.
A completely unique process reduces the loads of the machine components of the FL 2500 by up to 25%. This allows the realisation of comparatively significantly larger rotor surfaces on the basis of the same machine components. The process is based on complex regulating structures which set new technological standards. Extensive simulations have demonstrated that these new innovative approaches work.
The new Pitch Logic Unit (PLU) offers the advantage of realising a modular, safe, robust and simple pitch system. All pitch functions are combined in the PLU independent of the operation. The adaptation to different bus systems is possible. A few simple interfaces go to robust standard industrial units. A Li-ion battery guarantees highly available, durable, maintenance-free backup, which can be operated in a wide range of temperatures. In contrast to standard systems, chargers, brake choppers and connection units are not required. The input rectifier does not have to be adapted for the peak load. The very good energy-weight ratio allows the highest safety and availability during network outages.
All cable connections of the FL 2500 are designed as tested finishes with high quality Harting Industry plugs. This reduces installation times. As control boxes, lines and aggregates are tested up to the interface by the manufacturer, the failure rate during installation of the nacelle and the hub is reduced to almost zero.
In September 2006, the prototype of the FL 2500 was erected in Brandenburg, Germany (160 m lattice tower).