DONG Energy: Analyses of the temperature profile of 33kV array cables in foundations of Offshore Wind farms

As part of a DONG Energy R&D project this project contains analyses of the actual temperature conditions of 33kV subsea cables in founda-tions of offshore wind farms.

In the dimensioning process towards an optimal square size of 33kV subsea cables in offshore wind farms the temperature conditions around the cable have to be taken into account. The hot spots lie typically in the foundations. The cables hang inside the foundations in so called J-tubes (tubes formed like a J). Since air has a low thermal conductivity, the hotspot of the cables lies typically in the upper part of the J-tube, where the cable is surrounded by air.

The intention of this project is to evaluate and verify the dimensioning criteria's for 33kV cables in offshore wind farms. The evaluation will primarily be based on analyses of temperature measurements, which have been measured for the duration of approx. 1 year in an existing offshore wind farm. Based on the measurements, a typically maximum temperature profile of the cable and its surroundings should be calcu-lated.

The project will be undertaken in cooperation with the student’s university and the department of Electrical Power engineering in DONG Energy, and should contain the following elements:
Investigate and analyze the temperature conditions in offshore wind farm foundations based on measurements.
Evaluate the existing dimensioning criteria´s.
Provide recommendations for future offshore wind farm cable projects
The project can be extended into the next face of the R&D project where DONG Energy in November 2008 is going to install new measurement equipment on an existing offshore wind farm. The equipment measures the temperature via optical fibers.
Necessary skills / studies
Interest in Offshore Wind Power
Understanding of Power Engineering
Basic statistics
Fundamental thermodynamics
Gains / experience
The project will give a practical understanding of different electrical conditions in offshore wind farms. The job can be carried out either as a one day per week student job or as a full-time student project. Office location will be university (preferred) and/or DONG Energy location in Copenhagen or Århus.

Contactperson:
Willi Christiansen
Email: willi@dongenergy.dk
phone: +45 9955 6365
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