CONNEX: Powerful system for strong interfaces in power grids


With the CONNEX connecting and jointing system for voltages up to 550 kV, constructors and operators of power grids benefit from advanced means and many options for the optimized use of transformers, gas-insulated switchgear (GIS) and cable systems. 

CONNEX offers the widest range of modular connecting and jointing components in plug-in technology accompanied by many practical extra tools. The list on the right gives you an overview of the CONNEX product range. This variety combines elementary properties and unique advantages for resilient power grid operation. Indoors and outdoors, above and below ground. In cities and made caverns, on land and at sea:


  • Versatile in use, flexible for repurposing
  • Minimizes installation workload and risks
  • Enables compact and environmentally conscious equipment designs
  • Safe, robust and reliable in lifelong operation
  • Certified for offshore, proven in use worldwide



CONNEX for GIS and transformers

CONNEX streamlines operations, protects existing equipment and makes the use of transformers and GIS more flexible in all life cycle phases.

Transformers and GIS form a unit with built in CONNEX sockets and can therefore be delivered in a closed state, factory tested, ready for transportation and connection. Transformers and GIS remain also closed when CONNEX cable connectors, bushings or surge arresters are installed on them. This is done efficiently by a plug-in process – without interfering with the equipment, without handling insulating oils or gases.

Likewise, CONNEX components can be dismantled and replaced at any time, for example to switch from bushings to cable connectors or vice versa. CONNEX extra tools for current and voltage testing or earthing and short-circuiting are also easy to connect. In addition, CONNEX sockets enable variable treatments of star points for protective measures on the transformer.

All these positive effects may also be achieved for equipment in operation - CONNEX can be retrofitted.



CONNEX system: Everything for connecting, jointing and more

Pluggable CONNEX components:
  • Solid-insulated cable connectors
  • Solid-insulated bushings
  • Surge arresters
For operating resources and CONNEX components with integrated CONNEX interfaces:
  • Transformers and GIS with built-in CONNEX sockets
  • Solid-insulated CONNEX outdoor cable terminations
  • Solid-insulated CONNEX epoxy resin sockets
  • CONNEX joints insulated with conventional or alternative gases for straight, right-angle and branch off connections
With complementary tools for many purposes, for example:
  • Pre-assembly, routing and support of cables
  • Component protection
  • Current and voltage tests
  • Earthung and short-circuiting
  • Fixing and moving gas-insulated CONNEX joints

CONNEX for cable systems

Modular cable systems with CONNEX components ensure optimum operational readiness for plannable work and unexpected applications with sustainable solutions.

Quick Deploy systems can be used as quickly as possible and as versatile as necessary. To this end, they are made in needs-based configuration levels and for specified areas of application: As basic systems consisting of highly flexible cables with prefitted CONNEX cable connectors. Flexibly expandable to Plus systems with various CONNEX joints. Both for numerous applications such as construction work, testing, as bypasses in the event of equipment failures, etc.

Or as complete solutions for extensive applications and complex requirements, including complementary tools and consumables, with installation and application training. Two examples: The Universal Repair Kit enables high-voltage cable routes to be repaired as fast as possible. It can be used flexibly on all specified cable types and also permanently as a lasting solution. The efficient and safe use of mobile units is made possible by comprehensive CONNEX connecting and jointing systems, whether for single transformers and GIS or for complete substations.

Pre-assembled CONNEX systems are also in demand offshore: They can be integrated into prefabricated modules ready for connection and can implement all equipment connections and cable jointings in and to offshore wind farms - from wind turbine nacelles and offshore platforms to equipment in onshore substations.



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PFISTERER developed the first universal cable repair system suitable for all XLPE-insulated cables – regardless of type and cross-section – for Schleswig-Holstein Netz AG, the largest electricity network operator in the German state of Schleswig-Holstein and partner to some 900 municipalities.


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.


Just 36 hours from installation to switch-on – New York’s first mobile emergency transformer went online in record time. PFISTERER was involved from the outset in planning this new type of transformer, and supplied the dry pluggable CONNEX connection technology that forms a key element of the integrated solution.


The new power transformers from AVU Netz GmbH are universal in their application. This network operator in western Germany is already implementing three connection versions using identically constructed transformers and thus remaining flexible for future demands. This is made possible by the versatile CONNEX connection system.



Space-saving, innovative, underground. The Oerlikon substation uses intelligent, vertical connection technology by PFISTERER to free up building space.


When designing the Klus substation, personal safety was given number one priority because quick maintenance means maximum reliability, just as you would expect in Switzerland. CONNEX also reduces costs, just as you would expect from PFISTERER.


Kraftwerke Oberhasli AG (KWO), a Swiss energy supplier, runs some of the most powerful hydropower plants in Europe but some of the plants have started to show their age. For the upgrades, the operators relied on PFISTERER technology.



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.


The Park Substation built by Anaheim city council in California is the USA’s first distribution station to be built underground. Also in on the action: the CONNEX connection system by PFISTERER.


Quick and long-lasting renovations? All it takes is a few steps thanks to the IXOSIL joints by PFISTERER. No clamping rings, no pipes, no flanges. Simply remove, fit, and save time.