Cable failure threatens to cripple North Sea wind farm but 'meshed grid saves the day'
Rotary kept online by secondary connection to Belgian offshore hub, although output must be cut during high winds
A Belgian offshore wind farm has remained online despite suffering a sudden cable failure thanks to its “meshed” connection to the mainland, says the country’s grid operator.
A cable connecting the 309MW North Sea Rentel wind farm to the mainland suddenly failed earlier this month, grid operator Elia reported.
However, the farm was able to remain online as it has a second export cable running to Elia’s offshore power hub.
Since three other wind farms are connected to the hub, Elia said their electricity output is now being “restricted slightly” during periods of very high wind to “prevent the export cables from being overloaded”.
The wind farms involved – Rentel, Mermaid, Northwester 2 and Seastar, which together boast around 800MW of capacity – will be compensated for times when their generation is restricted, said Elia.
Elia said the cause of the cable incident is still being investigated but reassured that “Belgium’s security of electricity supply is not in jeopardy.”
Elia admitted that repairing the Rentel cable will be “very challenging and complex” given this is 34km off the coast and “winter is a far from ideal time for offshore operations, given the high winds and waves.”
The Rentel wind farm is owned by Belgian developer Otary and boasts 42 Siemens Gamesa SWT-7.0-154 turbines.
When it was commissioned in 2018, Elia said that like all first-generation Belgian wind farms Rental had just one cable connecting it to the mainland.
However, when the grid operator developed a “meshed transmission grid” for the next three wind farms developed nearby Elia said Rentel was added to this project.
“A meshed grid saves on cables – which is more sustainable – and enhances the security of supply of the wind farms in the event of an incident, such as the one Rentel is currently experiencing,” said Elia.