IEEE Power & Energy Magazine - March/April 2016 - 32

These aging assets are still as important as they were
when first commissioned, which is why refurbishment
is such an important tool to the industry.

devices will often have an extremely high rate of use, thus
needing more frequent maintenance or replacement. the
filter equipment itself should be monitored for general condition. It is also important that the operator talk with the filter equipment manufacturer about spare components. some
manufacturers have decided to no longer make items such
as replacement capacitor cans, which caused the owner to
replace the entire capacitive portion of the filter. In another
instance, replacement resistors were no longer available, causing the owner to scramble to find something from nontraditional sources to keep the filter operational.
In addition, the adequacy of the filters needs to be periodically checked. system characteristics change over time,
and that can change the filtering requirements. periodic
measurements of harmonics and harmonic studies should be
performed to ensure filter adequacy. It is common to have to
adjust the tuning (with new equipment), add new filtering,
or replace filters in their entirety to ensure compliance with
system harmonic standards.

hVdc or Facts installation based on detailed design and
construction documentation of the scheme, operational data,
maintenance records, and industry accepted practices. this
type of investigation requires proven expertise on the part
of the investigators, following proven methodology, and it
doesn't hurt having the skills of a sherlock holmes when sifting through the age-old records. the investigation isn't simple,
but it will provide the owner and operator options rather than
replacing the entire system. the investigation will also serve
as the basis for a detailed specification that can improve the
performance of the equipment, provide new control strategies,
and reduce maintenance costs. owners are usually surprised
to find that the most cost-effective method of extending the
life of the facility may not be the complete replacement of that
facility but rather the strategic replacement of the individual
components at the end of their service life. making old hVdc
and Facts installations new again provides engineers the
opportunity of renovating the grid for the future.

Conclusions

r. Johnson, d. woodford, w. mele, b. lavier, g. wolf, r.
wachal, and d. torgerson, "life extension guidelines of existing hVdc systems," tech. Update 1012516, eprI, palo
alto, ca, 2007.
r. Johnson, d. woodford, w. mele, b. lavier, g. wolf, l.
recksiedler, r. wachal, and d. torgerson, "life extension
guidelines of existing hVdc systems," Final rep. 1013976,
eprI, palo alto, ca, 2007.
r. Johnson, d. woodford, g. wolf. r. wachal, s. maruvada, w. litzenberger, and d. torgerson, "life extension
guidelines of hVdc systems, phase II," Final rep. 0628191, eprI, palo alto, ca, 2008.
r. Johnson, d. woodford, w. mele, g. wolf, w. litzenberger, r. wachal, and d. torgerson, "life extension guidelines static Var compensators," tech. Update 1017868,
eprI, palo alto, ca, 2009.

the generic reasons for the use of hVdc and Facts technology have not changed, but the application of specific facilities can change as the network evolves. there remains a need
for stabilizing the grid, meeting changes in load levels and
characteristics, and providing voltage support and control.
the load may grow or decline or change electrical characteristics (different types of load and ramp rates). there is also
the need to integrate variable resources, such as photovoltaics and wind, that requires the increased flexible response
possible with hVdc and Facts facilities.
these aging assets are still as important as they were
when first commissioned, which is why refurbishment is
such an important tool to the industry. refurbishment has
proven to have many benefits both for cost and time, but
there are other considerations that should also be weighed.
Interfacing new technology with old technology is not easy.
It requires more specialized knowledge and experience than
needed with the installation of a totally new facility, but the
rewards are a more cost-effective life extension completed
more quickly than a total replacement.
deciding whether to do a replacement or a refurbishment
is best determined by conducting a detailed assessment of the

march/april 2016

For Further Reading

Biographies
Ruth Johnson is with high energy Inc., denver, colorado.
Gene Wolf is with lone wolf engineering llc, albuquerque, new mexico.
p&e

ieee power & energy magazine

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