IEEE Power & Energy Magazine - March/April 2016 - 66

plan, after 15 years of the installation when purchasing new systems.
✔ Cost of replacement control systems. The price to
replace a control system does not simply depend on
the cost of the cabinets and the software but must also
take into account other commercial and technical risk
factors. These additional factors may even make the
replacement of the control system alone not viable.
✔ Valves replacement. Replacement of the thyristor
valves alone is not normally possible due to the interface differences with the control systems. The signals
and the hardware that were historically generated by
the control system to fire the thyristors may not be
the same as those required for today's thyristors, especially when considering the involvement of different
manufacturers.
✔ Valves and controls replacement. This is the more
common approach to refurbishment, since this is the
cleanest solution with least complexity in matching
old and new technologies. Everything can then be
designed and delivered by one manufacturer with the
least commercial and technical risk.
✔ Commercial and operational issues. Budget, outage duration, risk strategy, and power contract commitments are all factors that influence the owner's
decision to refurbish. If the existing link is heavily
utilized, with a high dollar value against loss of transmission capacity, then it will be necessary to develop
a solution that minimizes the outage duration. This is
easiest to implement with the construction of a parallel replacement HVdc link or FACTS installation,
although clearly this is a relatively high cost solution. An outage duration of only a few weeks can be
achieved with a design that allows unimpeded power
flow on the existing link throughout the construction
period for the new installation. Where the outage costs
are relatively low, then with an extended shutdown
of three months or more, it is possible to replace the
entire valves, control, and cooling plant.
There are several other refurbishment projects being
planned at this time, many involving the thyristor valves
originally supplied by GE in the United States and Canada,
since these were all built in the same period around 1980,
and all are therefore now reaching their end of life. Some
are being planned as valves and controls only replacements,
while others are being considered for total replacement.

Conclusion
What is clear from all of the refurbishment projects discussed
here is that there is no single solution that fits all HVdc or
FACTS installations. In just the same way as the original
installations were created as unique power electronics systems

march/april 2016

for that particular owner, with many individual design features and constraints, similarly, the refurbishment process
must be addressed with that particular system and owner in
mind. New technologies in control hardware and software,
converter power electronics, and other areas of the plant bring
existing owners the prospect of not only extending the life but
also of enhancing the functionality of their system.
HVdc and FACTS facilities have been put into service
since the 1960s. An ever-increasing number of these systems
will reach the end of their design life soon and that means
there will be an increasing amount of attention focused on
how to refurbish these installations to make best use of the
existing system.

For Further Reading
N. M. Kirby, C. Horwill, N. M. Macleod, and D. R. Critchley, "Konti-Skan HVDC refurbishment and life extension
methods for other HVDC projects," in Proc. 2008 IEEE
PES General Meeting, Pittsburgh.
G. L. Brewer and B. A. Rowe, "Operational experience with the convertor valves of the UK terminal of the
2000 MW cross channel link," in Proc. IEEE Regional
Conf., Winnipeg, MB, Canada, 1989.
S. Kim ll, S. Lee, J. L. Haddock, and M. H. Baker, "System design characteristics for the 300 MW submarine link to
Cheju," in Proc. CIGRE Regional Meeting (Southeast Asia
and Western Pacific), 1993.
P. E. Marken, J. P. Skliutas, P. Y. Sung, K. S. Kim,
H. M. Kim, L. H. Sailer, and R. R. Young, "New synchronous condensers for Jeju island," presented at the IEEE PES
General Meeting, San Diego, CA, July 2012.
D. Ingemansson, T. Kiiveri, H. Nurminen, B. Pääjärvi,
and K.-G. Danielsson, "New Fenno-Skan 2 HVDC pole
with an upgrade of the existing Fenno-Skan1 pole," in Proc.
CIGRE, Paris, France, 2012, Paper B4-105.
B. Mehraban, D. Reed, R. Gutman, B. Depommier, R.
Hariharan, S. R. Mendis, and S. Shah, "SVC refurbishment
for smart grid power quality enhancement and life extension," in Proc. IEEE PES Expo, Chicago, IL, 2014.

Biographies
Neil M. Kirby is with GE, United States.
Paul E. Marken is with GE, United States.
Michael Paradis is with ATCO Electric Ltd., Canada.
Pei Wang is with Manitoba Hydro, Canada.
Ian Plowright is with National Grid, United Kingdom.
Hyoung-Bae Moon is with KEPCO-Alstom Power Electronic Systems, South Korea.
Dag Ingemansson is with Svenska-Kraftnät, Sweden.
Reginald Mendis is with GE, United States.
Ben Mehraban is with AEP, United States.
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