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of active network devices (switches and
hubs), the overall cost is reduced thanks
to the decentralised architecture, the
standardised equipments and protocols,
the reduced cabling (only ethernet, bus
topology) and the network synchronisation
of devices. thirdly, the fully
ethernet-based network increases operational
and maintenance facilities and
the performance is higher. At last, the
use of standard ethernet technologies
will make it possible to follow ethernet
evolution without additional R&D cost
thanks to the benefit from R&D investments
of the entire ethernet community.
pOWeRLINK being a pure software solution
based on standard ethernet components,
it has the great advantage to be
fully compatible with standard ethernet
devices. For example, one advantage is
that it allows for the use of fibre technology
to access distant equipment (several
kilometres). The use of fibre also has the
huge advantage of permitting networks
to be located in electromagnetically disturbed
areas.
Evolution by Alstom in POWER-
LINK: High availability
Alstom has contributed to the pOWeR-
LINK evolution by including the “High
Availability” feature in the standard.
thanks to the openness of the ethernet
pOWeRLINK Standardisation group
Redundancy demo
(epSg), Alstom was
able to share its
long-time expertise
on highly available
control systems.
The “High Availability”
technical working
group headed by
Alstom has been set
up with the objective
to release High Availability
features. One
of the most important
requirements was to
avoid modifying the
current pOWeRLINK
specification and maintaining full compatibility
with existing devices. the technical
working group achieved this target
and introduced High Availability features
as an add-on of the existing pOWeRLINK
standard.
thus, Alstom was able to implement a
pOWeRLINK network that reaches the
necessary level of availability to control
the processes of a power plant. Indeed,
critical applications must be secured in
a way that prevents functional disruptions
in case of control hardware failures
or cable damage. If one IpC with control
functions breaks down, a second unit
needs to immediately “notice” the malfunction
and assume the tasks of the
failing unit, preventing risk-entailing delays
in operation. the cable redundancy
implemented by Alstom allows easy
localisation detection of the failure and
avoids any loss of data (no cycle loss, no
reconfiguration time).
the High Availability feature of pOWeR-
LINK has been validated by a state-ofthe-art
model-checking approach. After
completing all models and technical developments,
Alstom went into an intense
simulation phase in order to confirm
calculations. the simulation was also
an opportunity to test the functionality
of the system in a range of critical scenarios.
the system was put into opera-
Alstom:
Technology
tion after a long and intensive validation
phase to verify that the High Availability
of the system was ensured.
Conclusion
With the integration of pOWeRLINK in
the field networks, Alstom has demonstrated
the industrial advantages of using
ethernet technologies in power control
systems. Alstom is confident in the
emergence of the pOWeRLINK standard
and very enthusiastic about the results
as it has all the required qualities for critical
process control.
With the recent announcement of the
release of an open-source pOWeRLINK
solution (openpOWeRLINK), Alstom is
also convinced that it will push more and
more third party device manufacturers
to adopt this technology.
the highly distributed architecture of
control system sets the network as the
heart of the system. that is why using
a high-performance ethernet network,
based on standard ethernet devices, is
a fundamental choice. moreover, Alstom
offers a system which is standard, proven
and reliable.
By improving the technology, Alstom
has gained more expertise and can
push for further developments if necessary.
thanks to this development, the
whole community can profit from it, as
the new functionalities have been be
standardised within the epSg and are
open to everyone. using ethernet technologies
is not only a technology breakthrough
for the present, it also ensures
investment for future evolutions.
Founded: 1928
Employees: more than 80,000
Turnover: 18.7 b euR
Locations: In more than 70 countries
Products & Services: Alstom is a
world leader in the transport and
energy infrastructure industry
www.alstom.com
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