Strukton completes extra 380 kV connection Borssele

Strukton signed an EPC contract for the work, which must be completed in a very short time. 

"Every year, there's a short period when the nuclear fuel is changed in Borssele nuclear power station. If any modifications are required to the electrical systems, that's when they need to be done. You can't say: sorry, it'll have to be a week later." Helmut Eder, project leader Strukton Systems

When it was awarded the contract in January 2016, after a process of creative brainstorming with client N.V. Elektriciteits-Productiemaatschappij Zuid-Nederland (EPZ), Strukton realised that besides safety, very tight planning management was key.

Difficult job
This in the knowledge that around a year is needed for the delivery of a transformer, the core device in the installation, which can handle 40 MVA. The transformer will be connected to TenneT's 380 kV grid (the highest voltage in the Dutch electricity grid) and will convert the voltage from this grid into a voltage of 6 kV, which it will deliver to the EPZ nuclear power plant.

Last May, the structural engineering work started, in partnership with contractors from the region. The installation had to be built against an existing switching station of grid operator TenneT. A 700 m long cable section links it to the power station.

On Friday 20 January, the transformer from Germany was lifted from the boat and raised on to its base.  A difficult job.

"This transformer has a transport weight of around 70 tons. But once the components are assembled and it's filled with insulating oil, it weighs 120 tons." Helmut Eder, project leader Strukton Systems

Coupling
Strukton has experience in expanding high voltage electrical equipment. Another project commissioned by TenneT is currently underway to create 110/220/380 kV spark coils in Eemshaven and Vierverlaten (Groningen). These will increase transport capacity with respect to the connection of wind power plants in the north of the Netherlands and Germany.

That experience led to an action plan which formed the basis for EPZ not only to award Strukton the Borssele project but also the technical coordination with third parties like TenneT. The grid operator also has an internal planning and imposes quality requirements for the connections.

'Always challenging'

"A situation like this, involving the integration of new technology into existing systems, is always challenging. Because you can't perform extensive 'dry' tests before everything becomes operational. When you encounter an unexpected problem in a test, there's immediately huge pressure to find a solution fast." Helmut Eder, project leader Strukton Systems

The critical phase starts during the spring, when the power station is switched off and the fuel exchange period begins. Then Eber and his people have a few weeks to create and test the coupling. In mid-June, the new connection must be operational.

This news item is based on the report from the Technisch Weekblad.