As soon as the installation vessel is jacked up after turbine installation, the commissioning work will start. A work which will take approximately 14 efficient days before the wind turbine can be connected to the grid as a producing unit.
Here, Siemens wind turbine technicians are securing the commissioning of the wind turbines in the wind farm; DONG Energy helps connect the wind turbines to the power grid as DONG Energy is responsible for the coupling of the 33kV cable grid connecting the wind turbines to the substation in the wind farm.
The wind turbines are connected to the power grid in groups of 9-10 wind turbines in one string, and therefore power supply to the entire group is affected by the coupling. Consequently, this operation is often carried out at night in order not to interfere with the commissioning of other wind turbines.
When the string is disconnected, measured to be de-energised and connected to earth, the Siemens technicians can connect the wind turbine to the string.
When this has been carried out, the string is reconnected, power is established, and the mechanical and electrical works can be completed. Among other things, these works include assembly of the cable sections in the two tower parts and the nacelle; then, a thorough test of all the electrical and control-related equipment begins.
When the wind turbine is ready to produce power, the temporary monitoring systems are replaced by permanent systems. This requires disconnection and securing of the wind turbine again. The wind turbine is now ready to produce power for many years to come.
This work naturally requires safe access for the technicians to the wind turbines, and as for other activities in the wind farm, the work is subject to the vagaries of weather.
[mappress]
Press release, March 07, 2013; Image: dongenergy