RWE Innogy has commissioned the Dutch company Fabricom Offshore Services BV to maintain the inter-array substation of the Nordsee Ost offshore wind farm for the next five years.
The contract covers the inspection as well as the structural and mechanical maintenance of the auxiliary systems and the maintenance of the steel structure starting in August 2015.
“The transformer substation is the nerve centre of the wind farm which makes it an essential element for its safe and economically efficient operation. The stresses acting upon the components at sea are much higher than on land. Wind, waves and salt water require more maintenance work than what is usually needed” , explains Florian Würtz, Head of Operation Management Central Europe at RWE Innogy .
Inside the substation, the energy generated by the 48 wind turbines at a medium voltage of 33 kV is transformed to a transmission voltage of 155 kV. The electricity is then transmitted through two high-voltage submarine cables to the HelWin alpha converter platform of the system operator.
This is where the AC voltage is converted to 250 kV DC voltage and transported to the nearest onshore grid access point at Büttel. From here, the power generated at sea is transmitted to the consumers. With its installed capacity of 295 megawatts the Nordsee Ost offshore wind farm can provide enough electricity to supply some 320,000 residential households with ecofriendly power per year. This is equivalent to about a third of all households in Hamburg.