IEEE Power & Energy Magazine - March/April 2016 - 16

guest editorial

Michael Henderson

refurbish or replace?
what's best for aging HVdc and FACTS

ApplicAtions of high-voltAge
(hv) dc and flexible ac transmission
systems (fActss) present opportunities for improving the utilization of the
grid. hvdc construction can maximize
power transfers on limited rights-of-way.
Underground and submarine applications
of hvdc can provide creative options for
routing transmission by mitigating adverse
environmental impacts and facilitating siting. likely areas of growth include longdistance hvdc that bypasses congested
interfaces, asynchronous applications of
hvdc, and point injection of hvdc power
at brown field sites of retired power plants.
hvdc and fActs applications increase
transfer limits of existing facilities and enable flexible operation of the grid under a
wide variety of operating conditions.
the use of power electronics will
continue to grow worldwide. hvdc and
fActss provide economical transmission
solutions that minimize adverse environmental impact. the industry anticipates
building transmission to successfully integrate the system with renewable resources,
often at remote locations. A number of
conceptual hvdc overlays have already
been discussed. greater transfer capability over existing and planned transmission
facilities can also be achieved through the
proper application of fActss.
the case studies discussed in this
issue of IEEE Power & Energy Magazine provide important lessons to existing and future owners of hvdc and
fActs facilities, who must consider the
operational and economic costs over the
Digital Object Identifier 10.1109/MPE.2015.2505380
Date of publication: 18 February 2016

ieee power & energy magazine

full life of the installation. Refurbishment and replacement of hvdc and
fActs facilities present challenges and
opportunities. Decisions are never easy
and must answer the questions of why,
what, where, when, and how.
Decision makers often establish the
need to refurbish or replace facilities based
on the condition and age of existing facilities. the historical and projected performance of equipment accounts for outage
rates, lost opportunity costs, and operation
and maintenance costs. the human factor
is also vitally important, especially at a
time when qualified personnel may not be
readily available to operate and maintain
existing facilities or construct new ones.
the need and operational requirements for hvdc and fActs facilities
change with the evolution of system
strength, resource mix, and fuel prices.
Modifications to system topologies and
operating conditions may present opportunities for retiring or upgrading
hvdc and fActs facilities. the following factors must be considered:
✔ the need for robust operation and
flexibility under a wide variety of
future network expansion scenarios
✔ the timing of hvdc and fActs
upgrades
✔ construction, operations, and maintenance issues
✔ environmental impact and siting
✔ the physical and economical risks
of the hvdc/fActs option versus other possible solutions.
Modern technology and control systems offer new options for maximizing
the benefits of hvdc and fActss, but

a very organized process with sufficient time allowed for performing studies and constructing and testing the
facility is required. effective communication is essential for planning, engineering, constructing, and operating
the system. extensive planning studies
and adequate modeling of the control
systems capture interactions between
the ac and dc systems and between
the interconnecting systems. field tests
confirm the design and performance of
the installation, and a shakedown period provides additional benefits prior
to beginning commercial operation.
system events and future system improvements should be analyzed to verify and update models and to revisit operating procedures. Monitoring system
protection and control system designs
and responses, especially as the system
evolves, ensures consistency with desired performance.
the increased use of power electronics on the system is giving rise to new
interactions, which require detailed
studies of multiple system conditions.
Modern software and modeling now permits analyses that capture both electrical
transients and stability performance.
Acknowledgement of the extraordinary work done by the power & energy society (pes) hvdc and fActs
Working group (Wg) 15.05.08 is in
order. the pes general Meetings featured Wg panel sessions on hvdc and
fActs operating and economic issues,
with over 150 attendees participating in discussions on refurbishments
and replacements. the Wg reports to
march/april 2016

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2016