For Tennet this was an important step towards the completion
□f its connection to the grid in the north-eastern section of the
North Sea, where the manned converter station, SylWin 1, reçoives the alternating current [AC] from three offshore wind
farms with a total capacity of 86^ mégawatts and a voltage of
155 kV and converts it to direct current [DC]. This direct current
is carried for a total distance of 205 kilométrés to the land-based
converter station in Büttel near Brunsbüttel in Southern Schleswig-Holstein. There the grid operators couvert the direct current
back to AC and feed it into the high-voltage grid.
The internai cables of the wind farm, which link turbines and
offshore transformer substation, are significantly smaller with
"only" 13 centimètres in diameter. The internai cabling of the
farm, however, is also exceptionally complex: "If you add it ail
up, there are 86 kilométrés of internai cabling", says Dirksmeyer
as he emphasises the point. Every cable is unigue in terms of
diameter and length. In principle, the cables are designed in the
shape of a tree with branches, twigs and the trunk: between four
and eight turbines are connected to the transformer substation
by one cable string; the doser they get to the transformer substation, the more turbines logically feed into the cable and the
thicker and more powerful it has to be.
wpd's contractual partner for the cable package was the Dutch
company Visser B Smit Marine Contracting [VSMC], Whilst the
team on board the cable laying vessel Stemat Spirit needed between eight and twelve hours to install a single cable, the crew on
board the Topaz Commander subseguently trenched the cables
into the sea-bed to a depth of around two métrés. "The work took
over eight months because they encountered problems", sighs
Dirksmeyer. Some cables had to be laid differently than planned.
"Fortunately, however, none of them was too short as each of the
cables, which were produced with lengths ranging from 800 métrés up to 2A kilométrés, had a five métré reserve. That was suffirent in every case to make the necessary course corrections",
he added.
18
□f its connection to the grid in the north-eastern section of the
North Sea, where the manned converter station, SylWin 1, reçoives the alternating current [AC] from three offshore wind
farms with a total capacity of 86^ mégawatts and a voltage of
155 kV and converts it to direct current [DC]. This direct current
is carried for a total distance of 205 kilométrés to the land-based
converter station in Büttel near Brunsbüttel in Southern Schleswig-Holstein. There the grid operators couvert the direct current
back to AC and feed it into the high-voltage grid.
The internai cables of the wind farm, which link turbines and
offshore transformer substation, are significantly smaller with
"only" 13 centimètres in diameter. The internai cabling of the
farm, however, is also exceptionally complex: "If you add it ail
up, there are 86 kilométrés of internai cabling", says Dirksmeyer
as he emphasises the point. Every cable is unigue in terms of
diameter and length. In principle, the cables are designed in the
shape of a tree with branches, twigs and the trunk: between four
and eight turbines are connected to the transformer substation
by one cable string; the doser they get to the transformer substation, the more turbines logically feed into the cable and the
thicker and more powerful it has to be.
wpd's contractual partner for the cable package was the Dutch
company Visser B Smit Marine Contracting [VSMC], Whilst the
team on board the cable laying vessel Stemat Spirit needed between eight and twelve hours to install a single cable, the crew on
board the Topaz Commander subseguently trenched the cables
into the sea-bed to a depth of around two métrés. "The work took
over eight months because they encountered problems", sighs
Dirksmeyer. Some cables had to be laid differently than planned.
"Fortunately, however, none of them was too short as each of the
cables, which were produced with lengths ranging from 800 métrés up to 2A kilométrés, had a five métré reserve. That was suffirent in every case to make the necessary course corrections",
he added.
18