The repair work on the cable which connects the 309 MW Rentel offshore wind farm to the Belgium’s mainland has been completed approximately four months after the failure.
The fault was located just below the Rentel transformer platform. A new section of cable, approximately 400 metres long, was attached to the platform and connected to the existing cable under the seabed.
The four connected wind farms were still able to generate electricity throughout the repair work, because they are part of the meshed offshore high-voltage grid, via Elia's MOG or offshore power hub.
These include Rentel, Northwester 2, Mermaid and Seastar.
Their electricity output was capped slightly during periods of very high winds to prevent the operational export cables from being overloaded.
Despite this, another offshore and onshore wind energy production record was broken in the first few months of this year.
The repair work was very technically complex and challenging due to the location of the fault and the weather conditions, according to Elia.
The alternative transmission route via Elia Transmission Belgium's MOG worked perfectly and ensured that all wind farms continued to generate electricity, despite the fault
The windy weather conditions in recent months hampered the repair work but did allow very high levels of wind energy to be produced
The cause of the fault is still being investigated.
The Rentel turbines are operational and produce green energy since 2018.
The project was developed by Rentel, a consortium of eight Belgian shareholders, including DEME Group, Otary Offshore Energy and Elicio.
It comprises 42 Siemens turbines of 7.35 MW and supplies CO2-friendly electricity to approximately 285,000 households.
The wind turbines are installed on monopile foundations and connected through 33 kV inter array cables to an offshore transformer station (OTS). The substation is connected by a 220kV submarine cable to the onshore substation of Stevin in Zeebrugge. Water depths range between 26 m and 36 m below LAT.