Wind energy generators convert the kinetic energy of the wind into electrical energy. The rotary motion of the rotors generates mechanical energy in the process which the generators then convert into electrical power. Power generated in this manner is fed into the grids of electrical utility companies.
High-power, industrial wind turbine generators (WTG) today have output powers in the megawatt range. Large plantsare generally installed in windy regions and wherever there is a higher demand for energy. Wind turbine generators consist of: the rotor, the rotor blades, the nacelle with generator and (frequently) a gearbox and the tower. Monitoring, regulation and control engineering technology – as well as the power feed to the grid – are decisive for the efficiency of these systems.
Adaption to grid with frequency inverters
Power should be generated at every wind speed and supplied to the grid. Frequency inverters assume this task. They match the power to the respective grid frequencies. Continuous correction to facilitate wind speeds and grid states requires frequent switching. Here the control and feedback systems optimise the operating parameters.
Eaton products have long been tried and tested in this application field: such for example as the combination of DIL contactors up to 2,200 A (up to 2.500 A with the new DILH 2500) and compact circuit-breakers NZM, as well as the IZM series up to 6,300 A. Their compact and low-maintenance construction has convinced leading wind energy plant manufacturers.
We have optimised our products in conjunction with the manufacturers of Wind energy generators to take their special requirements into consideration. They meet the challenges of high switching cycles and guarantee a long, maintenance-free operation.
Rotor blade adjustment with xStart
Rotor and generator speed must be adapted to the wind speed. Speed control systems assume this task. Variable speed controlled pitch systems are steadily increasing their market share. The pitch control adapts the angle of incidence of each rotor blade to the wind speeds. Should it prove necessary to suddenly aerodynamically brake the wind energy plant – for example in an emergency – the rotor blade pitch adjustment will rotate the rotor blades to take them fully out of the wind.These kinds of operating situations make very high demands on the functionality and operating safety. Motor starter combinations from Eaton have demonstrated consistent and sustained performance when switching and protecting the pitch controls and motors. The contactors and motor-protective circuit-breakers of the xStart series are not just ideally suited for pitch control applications, but also for wind direction tracking of the nacelle by means of azimuth drives.
Arc-fault protection system ARCON®
WEP manufacturers rightly demand high levels of performance in terms of malfunction-free operation and protection of the plant. The task involves mastery of high short circuit currents in electrical plants and systems. One of the greatest damage events results when an arc-fault occurs. This is a short circuit which results between active conductors of different potentials. An unobstructed arc occurs in the switchgear system. The disastrous effects result from the rapid rise in pressure and temperature. In extreme cases the complete switchgear system can catch fire resulting in a fire in the nacelle.
In addition to special switching equipment for short circuits, we have developed the arc-fault protection system ARCON® for these extreme cases. ARCON® detects and quenches the arc before it even has the opportunity to develop its destructive effects. ARCON® is used in many Wind energy generators and has more than proven its effectiveness in these applications.
Control of obstruction beacons with PLC
Wind energy generators higher than 100 meters must be clearly visible for flight safety reasons. This is prescribed by current safety standards. In addition to coloured daytime and night-time marking systems, signalling beacons must be installed on the nacelle. A PLC controls the beacon management system to ensure operational safety. It takes the available visibility into consideration and controls the power supply to the beacons.
The high-performance PLCs of the XC series from Eaton perform this task on a daily basis. The data is transmitted via fibre-optic cables to other WTG control systems.