Wind Turbine Rotor Positioning

Worldwide growth
VENSYS wind turbines that were built and tested in Saarbrücken, Germany, are currently turning in the Canadian Higgins Mountain Wind Plant, as well as in the German city of Grevenbroich. This year alone, Chinese partner Goldwind is planning to put three plants into operation with more than 1,000 wind turbines.

With regard to safety, the pitch control system is among the most important components of a wind turbine. The system measures, monitors and controls the working angle of the rotor blades on a wind turbine which can change the power consumption. For example, pitch control allows the rotor blades to turn into the wind when starting up. During operation, the output can be held constant despite changing wind conditions by adjusting the working angle. However, if a storm gets up, the pitch control rotates the rotor blades automatically out of the wind in order to prevent damage.

Sensors guarantee reliability
“A malfunction can have fatal consequences,” says Dr. Stephan Joeckel, Director of Electro-Technology at VENSYS. No wonder that the reliability of the measurement technology in this field is the highest priority. That is the reason why VENSYS Energy AG decided in favor of inductive sensors from Turck. In each wind turbine, six uprox+ sensors – two on each blade – simultaneously determine the precise position of the rotors. To do so, each sensor records the end position of the rotor blades. A seventh sensor determines the position of the maintenance hatch of the turbine. With the data from all the sensors, the control system then ensures that each rotor blade is in the correct position. The power is transmitted between the motor and the rotor blade via a lubricant-free and maintenance-free toothed belt. In this process, the power is distributed across several teeth, thus minimizing wear and increasing safety and reliability.

In 2007 alone, VENSYS equipped 60 wind turbines with Turck sensors without encountering any difficulties. “So far, we have only had good experiences,” confirms Dr. Joeckel. “In addition to the high level of reliability, high quality and an attractive price-performance ratio, the high resistance to the high EMC was also an important factor in the decision in favor of the uprox+ sensors. Because of their direct proximity to the generator of the wind turbines and the risk of lightening, the topic of EMC plays a significant role in this application area.”

Resistant and impermeable
Because wind power plants are frequently located in coastal regions with relatively high particulate concentrations, all plant components must meet particularly high requirements when it comes to impermeability. Here, too, the uprox+ series was able to score some points: In the standard design, the sensors are encapsulated in a chrome-plated brass housing with an IP68 degree of protection and meet the high requirements of the VENSYS developers.