DEME Offshore is a world leader in the construction of offshore wind farms. The company is responsible for, among other things, the pull-in operation in which the wind turbine is provided with the power cable. DROMEC has developed a specially designed and user-friendly pull-in system for this purpose.
With the help of the pull-in system, the cables for power and data are pulled from the ship into the wind turbine. It is a complex tool that DROMEC has developed specifically for this purpose. Specific versions have also been designed for various continental areas. For example, in the waters of the United Kingdom, additional safety standards such as Loler and Puwer are required.
Before the wind turbine is installed on the platform, the pull-in operation takes place. The cables are pulled from the ship into the platform over the seabed. The system has a constant tension function, which keeps the cable under a preset tension at all times, even when unexpected in- or decrease of cable force occurs. This prevents overload in the cable. This special tool has a nominal pulling force of 10 tons. The force is generated by the friction between the rope and the special warping head of the capstan. By the number of turns in combination with the back tensioner, the pulling force is guaranteed up to a holding force of 12 tons.
Pieter, engineer: ‘We designed this compact pull-in system specifically for this kind of operations, and the demand from various customers has since increased enormously. It is a user-friendly tool that can be installed on any platform for any pull-in operation. The combination of low weight and high pulling force in the system, using sophisticated control software, makes it a real time-saver for the customer. The system can be used both standing and hanging.’
Automatic back tension
The system works automatically. The back tensioner, which via the control works together with the special treated warping head, ensures that there is always sufficient-pretension between the back tensioner and the capstan. In this way the pulling force is guaranteed without need of a person holding the slack part. The system is electrically driven and is very compact, with a low weight of 475 kg. Once the operation is complete, the system is moved to the next wind turbine platform.