Ready for 66 kV - Solutions for modern Offshore Wind Farms

Energy distribution and energy transmission have been PFISTERER core competences for almost 100 years. As experts for interfaces in energy networks, we supply connection components and turnkey cable systems for all voltage levels as a complete system. Our PLUG, CONNEX and SEANEX pluggable systems as well as our SICON connector connect all system parts of the wind farm reliably and quickly. All system components are made specifically for maritim operation: weather-resistant, salt-water resistant and designed for offshore environment.

Constructing cable systems on offshore substations requires the ultimate discipline of cable-laying. Highly complex cable routes must be installed in a confined space around many corners and on several levels. Considerable time pressure and the construction of other subsections at the same time further complicate the task. Successfully overcoming this challenge requires meticulous planning and specialists with solid experience in the industry. PFISTERER has been there from the very beginning. We have closely accompanied the process from the idea of a power station on the high seas to the construction of the first offshore wind farm. PFISTERER has set industry standards, our project management and our products are state-of-the-art today. With SEANEX up to 72,5 kV and CONNEX for higher voltage levels offers PFISTERER dry pluggable connection systems for all offshore requirements.

The interface to the wind farm network, the cable connection between the static tower and moving nacelle, and the connection to the generator - these are the challenges involved in every single wind turbine in the wind farm. PFISTERER has the right solution for all challenges. SICON screw connectors can connect all different kinds of cable easily, without using special tools. The pluggable PLUG system connects the generator, individual tower segments, converter and transformer into a complete electrical system. SEANEX is used for the connection to the inter-array cabling and the CONNEX system is for all converter station applications.

Turnkey Cable Systems up to 245 kV from the Specialists


The services we at PFISTERER provide include the entire project management, the evaluation, the installation and assessment of the cable systems including high-voltage cable systems with XLPE cablesup to 245 kV.

  • Engineering, project work for all AC cable lines, including planning and feasibility analyses
  • Preparing technical guidelines, taking systemspecific cable types into account, as well as laying and operating methods
  • Calculating static and dynamic current carrying capacity in accordance with IEC, and overload operation, using own software
  • Computer-assisted calculation of tensile forces
  • Project realisation / site management including commissioning

The dry pluggable CONNEX connection system connects the transformer, MV and HV GIS without timeconsuming SF6 gas work. CONNEX connection joints in cast resin technology up to 170 kV enable pluggable connections that can be separated quickly if necessary. The longitudinal water barrier prevents water penetration as a result of cable faults.The solid-insulated CONNEX connections aremaintenance-free and the only ones on the market with DNV-GL certification.

  • No gas monitoring
  • Fully submersible and salt water resistant

66 kV: Proved Connections for modern Wind Farms

Connecting the Transformer and the Switching Station

Whether it is 33 kV or 66 kV, aluminium or copper cable: All connections are easy to connect. On the low-voltage side with the PLUG, on the high-voltage side with SEANEX. Installation is quick and easy, and maintenance times are significantly reduced. Due to our close cooperation with the transformer manufacturers very compact device designs can be realized. 

  • Quick and easy installation
  • No on-site oil work required
  • Esters for insulation
  • DNV GL offshore certification
  • Pre-manufactured and tested cables possible
  • For all highly flexible copper cablesat all voltage levels
  • According to the new standard EN 50673

Interface to the Wind Farm Network

The solid-insulated SEANEX connection does not require SF6, it is reliable and maintenance-free and can be easily disconnected whenever necessary.

  • No gas monitoring
  • Fully submersible and salt-water resistant
  • The vertical barrier prevents water penetration as a result of cable faults
What´s SEANEX?

SEANEX is a dry pluggable inner cone connection and contact system specifically for offshore applications. It is based on the CONNEX system by PFISTERER for voltages up to 550 kV. SEANEX components have been optimised for requirements at sea, are DNV GL certified and meet the new IEC 63026 offshore standard.

All Connection Components from a single Source

Connection from generator, converter and between gondola and tower

The PLUG system's high-quality materials and sophisticated technology guarantee reliable contact during the entire service life of the system. The low profile PLUG connectors are quick and safe to install and maintenance-free. The connection can be quickly and easily unplugged whenever necessary. More than 4,100 PLUG connections are installed on the Global Tech I.

  • Short assembly time onshore
  • Quick plugging offshore
  • Low contact resistance
  • No creep corrosion
  • Low space requirement
  • Coding prevents faulty connections.

Connection of different Cables

With the patented SICON screw connectors, ultra-flexible copper and cost-effective aluminium conductors can easily be connected to one another.

  • Reliable contact of all conductors
  • Installation with standard tools
  • Stepless share off of the SICON bolt without torque wrench

Offshore Products

[Translate to en:]

High-voltage connection for inter-array cabling


Turn-Key Cable Systems from the Specialist


The plug-in high current connection for trains, wind power plants and industrial applications


Unique connectors with stepless shear bolts


The universal connection system for cables, transformers, and GIS


A good connection guaranteed for high-voltage cables


Top-class technology from the inventor of the inner cone system


State-of-the-art protection – Everything you need from a single source.


Offshore Case Studies

This project is unique worldwide. DolWin gamma is one of the first and largest commercial offshore converter stations in the German North Sea. As part of the DolWin network connection project, it has been connected to another platform via a bridge system, using a new kind of flexible high-voltage cable with a conductor cross-section of 800 mm².


Q7 is the Netherlands’ first off-shore wind farm outside of the territorial zone (12 nautical miles). Here, CONNEX cable connections are not the only things that need to show off their sea legs. PFISTERER experts have to showcase their bravery, too.


The cable system in the dry dock, the test transformer far away on the back of the truck. HV tests for off-shore systems can be pretty tricky. A PFISTERER-developed adapter solves this problem.


14 staff, 13 weeks, 5,800 meters of cable: PFISTERER installed the first ever cable system certified for off-shore use at the Global Tech I off-shore wind farm.