CASE STUDY: HVDC
South West Link
Balancing the power supply between central
and southern Sweden with HVDC
In 2011, Svenska kraftnät
procured Alstom's
HVDC MaxSineTM voltage
source converter solution
for the construction of
converter stations at Hurva
and Barkeryd.
The Hurva station in southern Sweden will have a unique
architectural design established in conjunction with local residents
to allow the station to blend in with the rural surroundings.
HVDC MaxSineTM valve at the
manufacturing centre in Stafford, UK
GRID/CASE//EN/3.2014/FRA/2020 © ALSTOM 2014. All rights reserved.
THE CHALLENGE
Balancing power supplies: Svenska
kraftnät (Swedish national grid) is
the state-owned public utility that
transmits electricity from major power
plants to regional electrical grids via the
national grid.
The network managers at Svenska
kraftnät looked at innovative solutions
to solve a long-term energy issue in
the country - how to balance the price
of electricity between the northern and
southern sectors. It needed to move
more power more efficiently to the
south where electricity on occasions
can get more expensive.
THE SOLUTION
The South West Link power line project
is the single most important investment
in Sweden's electricity infrastructure.
The overall project has a budget of SEK
7.3 billion and is unique in terms of
both scope and technical implementation. The South West Link project
also marks an important technological
milestone, with the introduction of high
voltage direct current technology
(HVDC VSC) within the national grid.
The South West Link comprises two
720 MW ±300 kV HVDC transmission
links interconnecting Barkeryd in
central Sweden and Hurva in the south:
One AC-line that encompasses about
180 km of overhead lines and one DCline that encompasses a total of 250 km
of powerlines.
This project will bolster reliability and
improve power transmission capacity.
The South West Link will reduce the
risk of price differences between
southern Sweden and the rest of the
country, which is particularly important
following the introduction of bidding
areas in Sweden. The South West Link
will be built with the potential of
becoming part of a future multiterminal HVDC grid.
Grid-PEA-L5-South-West_Link_VSC-2974-2014_02-EN. Information contained in this document is indicative only. No representation or warranty is given or
should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is
provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly
prohibited. Alstom contributes to the protection of the environment. This leaflet is printed on environmentally friendly paper.
CASE STUDY: HVDC
ALSTOM'S EXPERTISE
Alstom has been providing HVDC
solutions for 50 years and remains one
of the pioneers in HVDC technology.
Alstom’s high voltage valve and control
technology has been used for HVDC
transmission schemes worldwide.
VSC controls real and reactive power in
one power electronics device, effectively
acting as a generator. It generates its
own voltage waveform, meaning that it
can ‘blackstart’ a network.
Alstom is one of only three companies
capable of delivering large, complex
power electronics projects. The South
West Link project coordination calls
upon teams made up of excellence
centres and delivery units based all
around the world. This expertise,
together with Alstom’s extensive R&D
activities over the past few years,
positions Alstom to deliver these
technologically advanced VSC
converters for Sweden’s national grid.
Under the terms of the contract, Alstom
will deliver four converter stations, two
each at Barkeryd in central Sweden and
Hurva in southern Sweden. The
stations will incorporate valve halls
with HVDC MaxSineTM VSC valve
modules and control systems from the
HVDC excellence centre in Stafford, UK,
13 transformers manufactured by
Alstom factories, wall bushings from
Alstom’s unit in Italy as well as
instrument transformers. Alstom in
Sweden will handle all civil works
and delivery.
Alstom’s HVDC MaxSineTM voltage
source converter (VSC) technology, a
relatively new innovation in HVDC
technology, is more compact than
traditional line commutated converters
(LCC) HVDC.
The four converter stations will be
connected by two sets of OHL and
underground cables (for a total of
250 km) and will transmit a total of
1440 MW at ±300 kV between the
two sites.
The Nordic Supergrid
When utilities start meshing
alternating and direct current in one
network, this meshed system is
known as a Supergrid. This
particular contract has two
important attributes. HVDC brings
exceptional stability to AC systems
when they are interconnected. DC,
unlike AC, is completely controllable.
The DC link can be a help to stabilise
the grid at fault conditions.
In addition, because this project will
be utilising VSC technology, it allows
for the extension of an additional link
to other regions (future project
planned by Svenska kraftnät).
"The South West Link project is
important for Alstom because it is
the first application of the new
HVDC MaxSineTM in Europe," said
Claes Scheibe, Vice President of the
Power Electronics Product Line at
Alstom. "Alstom was also awarded
GRID/CASE//EN/3.2014/FRA/2020 © ALSTOM 2014. All rights reserved.
the DolWin3 offshore windfarm
connection project by TenneT
offshore GmbH in 2013, while the
first project to select this
technology was the Tres Amigas
SuperStation located in Clovis,
New Mexico in the USA."
For more information
please contact Alstom Grid:
Alstom Grid Worldwide Contact Centre
www.alstom.com/grid/contactcentre/
Phone: +44 (0) 1785 250 070
The Barkeryd converter station in central Sweden
Grid-PEA-L5-South-West_Link_VSC-2974-2014_02-EN. Information contained in this document is indicative only. No representation or warranty is given or
should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is
provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly
prohibited. Alstom contributes to the protection of the environment. This leaflet is printed on environmentally friendly paper.
Visit us online: www.alstom.com