Key Facts
•
Principal:TenneT TSO B.V.
•
Location of the project:
Delft (The Netherlands)
•
Construction period:
April 2011 to October 2012
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Completion date:
November 2012
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Cable route length:
approx. 11 km
Supply:
•132 km of 380 kV XLPE cable, conductor size 2500 mm², partly with integrated optical fibres
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132 joints with screen separating insulations
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24 outdoor terminations with composite insulators
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68 link boxes for earthing and cross-bonding of cable screens
•High-voltage surge arresters, current transformers,
fixing material and supporting structures
380 kV cable connection which fulfils special criteria:
•
High-voltage cables and accessories produced at one place, Cologne (Germany)
•Turnkey project including engineering, production and delivery of cables and
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Tailor-made logistics concept
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Innovative solution for horizontal drillings
Member of the NKT Group
accessories, civil engineering, civil works, installation, cable laying and testing
•Mastering challenges caused by the varying ground conditions, like peat layers, high water table and subsidence
•
Taking care of the environment during laying and installation works
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Special system design with double circuits and parallel installations
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Maintaining high safety and quality standards
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Successful high-voltage tests including online partial discharge measurements
nkt cables GmbH & Co. KG
Düsseldorfer Strasse 400
Chempark
51061 Cologne
Germany
Tel.: +49 221 676 0
[email protected]
www.nktcables.com
Cable Laying
Installation Works
09.2014 copyright © 2014 nkt cables
The World’s Largest 380 kV
Turnkey Cable Project
Randstad380 Zuidring
Completing the picture
www.nktcables.com
Extremely varying ground conditions with soft peat layers at
different levels, high water table and expected subsidence,
here and there exceeding 0,5 m, continuously made high
demands on the engineering teams employed by nkt cables.
Another point with respect to protection of the environment
was the occupied space during installation. A working area
only 35 m wide was sufficient for nkt cables and the civil
contractor to make the trenches and transport routes,
for temporary storage of excavated material and laying of
the cables.
The Project
The Solutions
The world’s largest 380 kV turnkey project.
Ensuring the future power supply of the Randstad region in The Netherlands.
Meeting special project requirements in an excellent way.
Efficient solutions demonstrating competence and providing flexibility.
The Randstad region is a conurbation forming a ring which
comprises the four largest cities of The Netherlands:
Amsterdam, Rotterdam, The Hague and Utrecht. Two
new 380 kV connections, Zuidring and Noordring, are
designed to ensure the future electricity supply in this area.
The Zuidring connects the two stations Wateringen and
Bleiswijk. It is about 25 km long. Around 11 km are installed
as underground cable system while the remaining part
consists of overhead lines. The cable connection comprises
two double circuits which means that twelve single-core
cables are laid in parallel. In total 132 km of the 380 kV cable
are installed.
380 kV Cable
In 2008 the Dutch transmission system operator TenneT
TSO B.V. placed an order with nkt cables to install the
cable connection within the Zuidring. Presently, the 380 kV
cable connection of the Zuidring is the largest in the world.
According to the scope of this turnkey project nkt cables
provided project management and system engineering
works. The 380 kV cables and accessories were produced,
tested and delivered by nkt cables. Furthermore, installation
of accessories and commissioning tests were done by nkt
cables’ personnel. Civil engineering and cable laying were
carried out by nkt cables’ subcontractor.
Location Map
In 2009, nkt cables started production of cables and
accessories in Cologne, Germany. Within a tailor-made
logistics concept, nkt cables delivered extra-wide cable
drums to The Netherlands. The drums were able to carry
more than 1000 m of cable, resulting in a gross weight of
up to 50 t. To support a smooth work flow and to provide
high flexibility and short construction time, an interim storage
facility was set-up in The Netherlands.
nkt cables and the relevant authorities joined their forces
to find the optimum solutions for crossing the obstacles.
Horizontal directional drilling technology was applied to avoid
open trenches. Plastic pipes were installed in the drillings
so that the cables could be pulled in. Interference with rail
and road traffic and disturbance of neighbourhood and
landscape were reduced to a minimum. The environment
was preserved as far as possible.
During the engineering phase various different tasks and
challenges were to be mastered.
For example, the cable route crosses two railway lines, the
motorway A13, some sports facilities, several dikes, the
river Schie and numerous smaller watercourses. TenneT,
About 40 % of the cable route has been realized with
horizontal directional drillings. The longest drilling length was
530 m. All drillings add up to more than 50 km. Maintaining
a distance of 3 m between the parallel drillings was a special
challenge and an innovative solution to provide optimum
conditions within the limited space available.
380 kV Double Cable Circuit
Cross-bonding Joints
In April 2011, nkt cables started construction works in the area
near Delft. The 380 kV cable connection consists of two double
circuits. In total they comprise 132 km of 380 kV XLPE insulated
single-core cables with 2500 mm² copper conductor, 132 joints
and 24 terminations. Some of the cables are equipped with
optical fibres for temperature measurement. All accessories
were installed by nkt cables’ own specialists. Several teams
worked in parallel to meet the ambitious time frame of the
project. Due to compliance with high occupational safety
standards and adherence to certified quality management
procedures, no serious incidents occurred during the
construction period.
For the on-site high-voltage tests nkt cables used two own
test trailers plus two additional ones. With the four mobile
test sets it was possible to apply the AC test voltage of
374 kV for one hour each to the twelve cable lines of the two
double circuits. All accessories were permanently monitored
for partial discharge during the high-voltage test. The
successful commissioning after 1 ½ years of construction
can be seen as an outstanding performance and the best
possible prerequisite for the energizing of the connection in
the first quarter of 2013.
By completing the cable installation within the Zuidring of the
Randstad380 project, nkt cables has established another
excellent reference in the field of high-voltage turnkey
projects. The described cable solution is a proof for the
successful integration of cable connections within overhead
lines. It demonstrates the outstanding capability on the part
of nkt cables to act in a solution-oriented and ecological
manner according to customer’s needs. With the realization
of this project, nkt cables could provide an economically
attractive solution. TenneT’s Randstad380 project is a new
step for high-voltage cable solutions and a remarkable
milestone – not only for nkt cables.
Continuous Partial Discharge Measurement
HV Test Trailers in Position
Preparation for HV Testing