pwr_october-2024 - 18

FOCUS ON O&M
respond to any issues.
■ Automation and Artificial Intelligence
(AI). Utilizing automation and AI to enhance
operational efficiency. Automated
systems can handle routine tasks,
allowing human operators to focus on
more complex and strategic activities.
Building a Sustainable Future
Sustainability is another major initiative
for next-gen O&M solutions. As the energy
sector increasingly embraces renewable
sources, O&M providers must
adapt to the unique challenges and opportunities
presented by these technologies.
Among the items of concern are:
■ Integration of Renewables. Developing
expertise-including specialized
knowledge
and
operational
strategies-in
managing renewable energy
assets such as wind, solar, and energy
storage.
■ Environmental Compliance. Ensuring
that all operations adhere to stringent
environmental regulations by staying
abreast of changing regulations and
implementing practices that minimize
environmental impact.
■ Energy Efficiency. Implementing
measures to improve the energy efficiency
of power plants like optimizing
operational processes, upgrading
equipment, and utilizing energy management
systems.
■ Carbon Reduction Strategies. Developing
and integrating strategies to reduce
carbon emissions as the industry
moves toward a low-carbon future.
The power generation industry stands
on the cusp of a new era in O&M services.
The evolution from basic third-party
operations to comprehensive, value-driven
partnerships reflects the increasing
complexity and sophistication of the sector.
By embracing next-gen O&M solutions,
power plant owners can achieve
higher productivity, enhanced efficiency,
and a stronger competitive edge in an
ever-evolving landscape.
A robust strategic O&M partner will
not only provide the expertise needed
to mitigate operational and technological
risks, but also offer strategic value that
strengthens client companies and drives
industry innovation. As the industry continues
to evolve, the role of next-gen
O&M solutions will become increasingly
critical in ensuring the efficient and reliable
operation of power plants.
-Doug Machon is director of Business
Development at IHI Power Solutions Corp.
18
Minimize Risks with Robotic
Generator Inspections and
Comprehensive Testing
Historically, generator inspections require
rotor removal (Figure 3). There's a
significant level of risk during this process
due to possible generator damage
during the disassembly, and it also requires
additional outage time.
Robotic Inspections
But by combining robotic inspection technology
and field service experts, plant
managers can decrease outage duration
and reduce risks related to rotor removal.
For example, GE Vernova offers " stateof-the-art
Robotic Generator Inspection
Services " that are said to provide unparalleled
advantages, which include:
■ Reduced downtime.
■ Lowered risk, since the rotor is not
removed.
■ Reduced workforce needs for dismantling.
Among GE Vernova's offerings is a
generator air-gap robotic inspection with
rotor in-situ. This offline inspection solution
utilizes the company's latest robotic
tool technology, which can perform a
complete generator air-gap inspection
program. The inspection tool can visually
inspect both the rotor and stator
surfaces, as well as verify stator wedge
tightness and complete a stator low-flux
magnetic test, which is a non-destructive
method for evaluating the condition of a
rotating machine's stator. The test uses a
low level of excitation to detect faults in
the stator core's interlaminar insulation.
GE Vernova also has a generator retaining
ring scanner, which is a robotic
inspection tool engineered to detect
stress corrosion cracks without the need
to remove the retaining rings from the
generator. This is another inspection that
is performed offline, but it only requires
minimal dismantling and can be carried
out with the rotor in-situ or removed.
Generator Testing and Inspection
Program
Meanwhile, GE Vernova offers a test and
inspection program designed to thoroughly
assess the condition of a generator
during an outage. Based on decades
of experience across one of the largest installed
fleets, GE Vernova's diagnostic experts
provide customers with a detailed
analysis and recommendations for more
reliable operation as part of this program.
The inspection's scope tries to match
www.powermag.com
the allowed outage time, while accounting
for the generator's model to ensure all
identified areas of concern are inspected.
Examples of some electrical tests that
might be done in the process include insulation
resistance (IR), polarization index
(PI), and high-potential (hipot) tests, which
are used to assess the condition of a generator's
stator, rotor, and core plate insulation.
More specifically, the tests provide
the following information:
■ IR measures the electrical insulation's
resistance between the stator or rotor's
copper conductors and core. A
high IR value is ideal, as it indicates
that there is little leakage current. A
low IR value indicates that the insulation
has deteriorated.
■ PI is a variation of the IR test that measures
the ratio of IR after 10 minutes
to IR after 1 minute. A higher PI value
indicates better insulation condition.
A low PI value can indicate that the
winding has absorbed moisture or
been contaminated with dirt or oil.
■ Hipot testing determines if a generator's
stator winding insulation is strong
enough to withstand electrical stresses
during the machine's expected life.
Hipot testing is a standard factory acceptance
test for new machines, but it
can also be used to assess the condition
of existing generators. Hipot tests
can use AC at the power frequency,
very low frequency (VLF) at 0.1 Hz, or
DC. Typically, hipot tests increase voltage
slowly to a specified level, then
maintain that level for a minute. The
winding either passes or fails. A failed
hipot test indicates that the winding
needs to be rewound or the failed
component removed.
Other tests that might be performed
in conjunction with GE Vernova's generator
testing and inspection program
include stator low and high magnetic
tests, and a PULSAR test.
Stator Low Magnetic Test. This test
is performed at a relatively low magnetic
flux density in the stator core. Its main
purposes are to detect any interlaminar
insulation faults or short circuits between
laminations in the stator core, identify
any localized heating issues in the core,
and establish a baseline for future comparisons.
The test typically involves energizing
the stator core at about 3% to
4% of rated flux and using thermal imaging
or other temperature measurement
techniques to detect any hot spots.
Stator High Magnetic Test. This test
POWER | October 2024
http://www.powermag.com
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