Van Oord is a leader in offshore wind farm construction. The company is responsible for the cable pull-in operation for the Sofia Offshore Wind Farm project located on the Doggersbank in the North Sea. This operation involves providing the wind turbine with power cables to transport the generated energy. In 2019, DROMEC delivered a special series of 10 user-friendly pull-in systems for this application and is now supplying another series of 10 systems.
Stefan Graat, Project Engineer at Van Oord:
“Dromec provides Van Oord Offshore Wind with equipment, support, and services that make a significant contribution to successful cable projects!”
The pull-in system, developed specifically by DROMEC, is used to draw the thick power cable from the ship into the wind turbine. It is a complex tool designed for this purpose. Specific variants have been designed for different continental areas. For instance, in the waters of the United Kingdom, additional safety standards are required, such as LOLER and PUWER.
Before installing the wind turbine on the platform, the pull-in operation takes place. The cables are pulled from the ship through the seabed into the platform using the DROMEC pull-in system. This system features a constant tension function, ensuring that the cable is always kept at a preset tension, even when unexpected changes in cable force occur. This prevents cable overload. This special tool has a nominal pulling force of 10 tons, which is maintained through friction between the rope and a special capstan head. The combination of the number of wraps and a fairlead ensures the safety of the pulling force up to a holding force of 12 tons.
Pieter, engineer DROMEC:
“We designed this compact pull-in system specifically for operations of this kind, and since then, the demand from various customers has significantly increased. It’s a user-friendly tool that can be installed for any pull-in operation on a random platform. The combination of its low weight and high force, along with advanced control software, provides real time savings for the customer. The system can be used both in a standing and hanging configuration. Various improvements have been made for the new series, such as the nominal pulling force and the hard-anodized capstan head. This material is more resistant to corrosion. The frame is also more user-friendly with an integrated lifting eye and an additional guide bracket, allowing the cable to wind on and off at a 70-degree angle.”
The system operates with automatic tensioning. A fairlead that runs in sync with the capstan head through the control system ensures a consistent tension between the fairlead and the capstan, guaranteeing the pulling force by the capstan without the need for a person to hold the loose end continuously. The system is electrically powered, compact, and lightweight, weighing 550 kg. It weighs 475 kg without the detachable fairlead. Once the operation is complete, the system is moved to the next wind turbine platform.