The consortium around Cofely Fabricom GDF Suez subcontracted
countless suppliers to produce components forthe offshore substation. Hundreds of welders, fitters and painters worked round
the clock for many months in the dockyard in Hoboken [Belgium] in order to finalise construction from summer 2013 to
March 2014. After completion, jacket and topside were heaved
onto a large barge and brought to the wind farm - from Belgium
to the North Sea off Sylt - to be installed in depths of around 17
métrés. The three storey topside stands a proud 65 métrés in
length, 31 métrés wide and 30 métrés high. On the inside, there
are two transformers as big as houses each weighing 170 tons
and standing in an enclosed oil bath for safety reasons. They
transform the power generated at the wind farm from a voltage
of 33 kilovolts [kV] to 155 kV. The latter is then sent from Tennet
to the SylWin 1 convertervia two export cables..
The manufacturer of the transformer units is CG with its head
office in the Belgian town of Mechelen. "For us the order for Butendiek represents a milestone for further activities in the field
of offshore wind power", said CG's Managing Director, Laurent
Demortier, in 2013, underlining the strategie significance of this
Project for his company.
Beside the transformers the interior of the transformer substation also houses two diesel generators each with an output of
1.2 mégawatts and a 280,000 litre diesel tank. "In an emergency, these power units can generate enough electricity to keep
the wind farm running if the connection to the grid should fail",
explains Germann. After around two years of planning and preliminary work on land, the critical phase for him and his colleague,
Craig Langhorn, who, as an electrical engineer, was responsible
for ail things electrical in Butendiek's transformer substation,
started in March 2014. Because the commissioning of Tennet's
SylWin converter took longer than planned, the power required
for the Systems in the offshore substation had to be externally
supplied by diesel generators for a period of three months.
"The endless number of technical interfaces which hâve to be defined to enable us to guarantee that the unmanned transformer
substation can be safely operated, represents the major challenge", explains Germann. He knows the subject-matter very well
and is more than aware of the tightly synchronised schedules. "In
the Butendiek project, Fabricom did not manage to complété the
electrical and mechanical fittings in the dockyard as planned and
as a resuit some works had to be finalised offshore at some cost
in terms of time and logistics", he says, referring to the many
impondérables which had to be overcome by close interaction of
ail concerned parties.
A high level of improvisation artistry was also needed to install
Tennet's second export cable on the sea bed in time. While the
first cable with a 20 cm circumference was laid, trenched and
pulled-in to the topside at the transformer substation in the
summer of 2014, the second cable only followed in December
2014 after a considérable delay. "The responsible project manager at Tennet sent me an email reporting the loss of a cable",
says Dr. Jochen Dirksmeyer, who was in charge of internai cabling
within the farm and for connecting to the grid - as he recalls "an
extremely délicate matter".
What had happened? The barge which was supposed to transport the two three-phase cables from the manufacturer Prysmian in Naples to the North Sea, capsized in a heavy storm and
sank with its cargo - and it just happened to be at the deepest
point of the Mediterranean. Recovering the export cable from the
depth of the océan was impossible. But Tennet managed to find
another way out of its dilemma: it proved possible to partially replace the lost cable with an export cable, which had already been
produced for the Nordergründe offshore wind farm. This cable
was in fact planned to transfer electricity from the site of wpd's
next offshore project in the Weser estuary to Wilhelmshaven at
the coast of Lower Saxony. As this distance is only 30 kilométrés,
it was necessary to produce an additional ten kilométrés of cable
to make it fit for Butendiek. Cable technicians used a joint to link
the sections at sea. "We finally managed to add this second cable
to our transformer substation in February 2015", says Dirksmeyer, revealing the positive outcome of a difficult operation.
14
countless suppliers to produce components forthe offshore substation. Hundreds of welders, fitters and painters worked round
the clock for many months in the dockyard in Hoboken [Belgium] in order to finalise construction from summer 2013 to
March 2014. After completion, jacket and topside were heaved
onto a large barge and brought to the wind farm - from Belgium
to the North Sea off Sylt - to be installed in depths of around 17
métrés. The three storey topside stands a proud 65 métrés in
length, 31 métrés wide and 30 métrés high. On the inside, there
are two transformers as big as houses each weighing 170 tons
and standing in an enclosed oil bath for safety reasons. They
transform the power generated at the wind farm from a voltage
of 33 kilovolts [kV] to 155 kV. The latter is then sent from Tennet
to the SylWin 1 convertervia two export cables..
The manufacturer of the transformer units is CG with its head
office in the Belgian town of Mechelen. "For us the order for Butendiek represents a milestone for further activities in the field
of offshore wind power", said CG's Managing Director, Laurent
Demortier, in 2013, underlining the strategie significance of this
Project for his company.
Beside the transformers the interior of the transformer substation also houses two diesel generators each with an output of
1.2 mégawatts and a 280,000 litre diesel tank. "In an emergency, these power units can generate enough electricity to keep
the wind farm running if the connection to the grid should fail",
explains Germann. After around two years of planning and preliminary work on land, the critical phase for him and his colleague,
Craig Langhorn, who, as an electrical engineer, was responsible
for ail things electrical in Butendiek's transformer substation,
started in March 2014. Because the commissioning of Tennet's
SylWin converter took longer than planned, the power required
for the Systems in the offshore substation had to be externally
supplied by diesel generators for a period of three months.
"The endless number of technical interfaces which hâve to be defined to enable us to guarantee that the unmanned transformer
substation can be safely operated, represents the major challenge", explains Germann. He knows the subject-matter very well
and is more than aware of the tightly synchronised schedules. "In
the Butendiek project, Fabricom did not manage to complété the
electrical and mechanical fittings in the dockyard as planned and
as a resuit some works had to be finalised offshore at some cost
in terms of time and logistics", he says, referring to the many
impondérables which had to be overcome by close interaction of
ail concerned parties.
A high level of improvisation artistry was also needed to install
Tennet's second export cable on the sea bed in time. While the
first cable with a 20 cm circumference was laid, trenched and
pulled-in to the topside at the transformer substation in the
summer of 2014, the second cable only followed in December
2014 after a considérable delay. "The responsible project manager at Tennet sent me an email reporting the loss of a cable",
says Dr. Jochen Dirksmeyer, who was in charge of internai cabling
within the farm and for connecting to the grid - as he recalls "an
extremely délicate matter".
What had happened? The barge which was supposed to transport the two three-phase cables from the manufacturer Prysmian in Naples to the North Sea, capsized in a heavy storm and
sank with its cargo - and it just happened to be at the deepest
point of the Mediterranean. Recovering the export cable from the
depth of the océan was impossible. But Tennet managed to find
another way out of its dilemma: it proved possible to partially replace the lost cable with an export cable, which had already been
produced for the Nordergründe offshore wind farm. This cable
was in fact planned to transfer electricity from the site of wpd's
next offshore project in the Weser estuary to Wilhelmshaven at
the coast of Lower Saxony. As this distance is only 30 kilométrés,
it was necessary to produce an additional ten kilométrés of cable
to make it fit for Butendiek. Cable technicians used a joint to link
the sections at sea. "We finally managed to add this second cable
to our transformer substation in February 2015", says Dirksmeyer, revealing the positive outcome of a difficult operation.
14