TWS invests in series pull-in systems

Tension Winding Solutions, originally a subsidiary specializing in rentals at DROMEC, is investing in a new series of pull-in systems.

Gerrit Drost says,
“With TWS, we aim to continue innovating and distinguishing ourselves in equipment for offshore applications. Having successfully completed two projects, the pull-in operation at the Luchterduinen wind farm in the North Sea and Windplan Blauw in Urk, in collaboration with a reputable offshore contractor, we now aim to contribute to a sustainable future with these new systems!”

Pull-In System

TWS intends to rent out pull-in systems for various operations at wind farms and provide coaching for operators. The pull-in system is used to pull power and data cables from the vessel into the wind turbine. It’s a complex tool specifically developed by DROMEC Winches for this purpose. Specific variations have been designed for different continental regions. For instance, additional safety standards such as Loler and Puwer are required in the waters of the United Kingdom.

Constant Tension

Before installing the wind turbine on the platform, the pull-in operation takes place. The cables are pulled from the vessel through the seabed onto the platform using the pull-in system under constant tension. This means the cable is always kept at a predetermined tension, even in the event of unexpected increases or decreases in cable force, preventing cable overload. This special tool has a nominal pulling force of 10 tons. The force is applied through friction between the rope and a special capstan head. By adjusting the number of windings in combination with a tensioner, the pulling force is ensured up to a holding force of 12 tons.

TWS plans to deploy the pull-in systems in sets of 4 to 10.

Gerrit Drost adds,
“With DROMEC, we can strengthen each other in collaboration. If a system fails during the pull-in operation, as a rental company, we can immediately arrange a backup. We also assess on-site whether any improvements can be made. With DROMEC, we can quickly adapt and create innovative solutions for each other. From TWS’s perspective, once the market experiences these pull-in systems, they become indispensable. Since the operation can only be performed during certain times of the year due to weather conditions, we also aim to focus more on operator training. The right expertise benefits both ways. Equipment remains in better condition, ensuring continuity in operations, which is crucial. Our focus is more on the service and maintenance of the product. Eventually, we’d like to build a test tower to simulate real-life pull-in operations, enabling us to expand rentals to Germany, Denmark, Belgium, and France!”

Automatic Tensioning

The system operates with automatic tensioning. A tensioner synchronized with the capstan head ensures there is always sufficient tension between the tensioner and the capstan. This guarantees the pulling force through the capstan without requiring a person to continuously hold the slack end. The system is electrically powered, very compact, with a low weight of 550 kg. Without the detachable tensioner, it weighs 475 kg. Once the operation is complete, the system is moved to the next wind turbine platform, making it highly suitable for rental by TWS.

Pieter, engineer at DROMEC, comments,
“This compact pull-in system is a user-friendly tool that can be installed on any platform for pull-in operations. The combination of low weight with high force, using advanced control software, is a real time-saver for the customer. The system can be used both in a standing and hanging position. Several improvements have been made for the new series, such as the nominal pulling force and the hard-anodized capstan head, which is more resistant to corrosion. The frame is also more user-friendly, with an integrated lifting eye and additional guide bracket, allowing the cable to be wound on and off at a 70-degree angle.”

DROMEC builds series of Pull-In Systems

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!”

Pull-In System

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.

Constant Tension

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.”

Automatic Tensioning

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.

DROMEC Service Worldwide

As the DROMEC Winches team, we take care of on-site commissioning. Our experts are the ultimate support for our customers. With their technical expertise in special winches, we can provide valuable insights in complex situations. Whether there’s a breakdown on land, at sea, or high in the sky, we’re ready to respond. And yes, we may make mistakes from time to time, but we don’t shy away from fixing them! That’s the essence of DROMEC Service worldwide!”

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