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When
switchgear
malfunctions,
the
consequences
are
often
catastrophic.
Damage
to
the
switchgear
itself
can
be
extremely
expensive,
but
that
pales
in
comparison
to
corollary
damage
and
the
potential
hazards
to
people.
That’s
why
implementing
an
effective
switchgear
testing,
inspection,
and
maintenance
program
is
essential.
According
to
National
Fire
Protection
Association
(NFPA)
70B
Recommended
Practice
for
Electrical
Equipment
Maintenance,
a
switchgear
assembly
is
"assembled
equipment
that
includes,
but
is
not
limited
to,
one
or
more
of
the
following:
switching,
interrupting,
control,
metering,
protective,
or
regulating
devices
together
with
their
supporting
structure,
enclosure,
conductors,
electric
interconnections,
and
accessories.
They
might
be
found
outdoors
as a
part
of a
substation,
or
indoors
as a
power
distribution
center."
Recommended
frequency
of
maintenance
depends
on
environmental
and
operating
conditions
but
at
the
least
an
annual
inspection
of
the
entire
switchgear
assembly
is
recommended.
The
InterNational
Electrical
Testing
Association
(NETA)
Maintenance
Testing
Specifications
recommends
that
during
these
inspections
the
following
should
be
performed:
l
Inspect
physical,
electrical
and
mechanical
condition
including
evidence
of
moisture
or
l
corona
l
Inspect
anchorage,
alignment,
grounding,
and
required
area
clearances
l
Prior
to
cleaning
the
unit,
perform
as-found
tests,
if
required
l
Clean
the
unit
l
Verify
that
fuse
and/or
circuit
breaker
sizes
and
types
correspond
to
drawings
and
l
coordination study as well as to the circuit
breaker’s address for microprocessor
l
-communication
packages
l
Verify
that
current
and
voltage
transformer
ratios
correspond
to
drawings
l
Inspect
bolted
electrical
connections
for
high
resistance
l
Confirm
correct
operation
and
sequencing
of
electrical
and
mechanical
interlock
systems
l
Use
appropriate
lubrication
on
moving
current-carrying
parts
and
on
moving
and
sliding
l
surfaces
l
Verify
correct
barrier
and
sutter
installation
and
operation
l
Exercise
all
active
components
l
Inspect
mechanical
indicating
devices
for
correct
operation
l
Verify
that
filters
are
in
place
and/or
vents
are
clear
l
Perform
visual
and
mechanical
inspection
of
instrument
transformers
l
Inspect
control
power
transformers
for
physical
damage,
cracked
insulation,
broken
leads,
l
tightness
of
connections,
defective
wiring,
and
overall
general
condition.
Verify
that
l
primary and
secondary
fuse
ratings
or
circuit
breakers
match
drawings.
Verify
correct
l
functioning
of drawout
disconnecting
and
grounding
contacts
and
interlocks
l
Perform
as-left
tests
Also
during
the
annual
inspection
process,
the
following
electrical
tests
should
be
performed:
l
Resistance
measurements
l
Insulation-resistance
tests
on
each
bus
section,
phase-to-phase,
and
phase-to-ground
l
Overpotential
test
on
each
bus
section
and
each
phase-to-ground
l
Insulation-resistance
tests
on
control
wiring
with
respect
to
ground
l
Electrical
tests
on
instrument
transformers
l
Ground-resistance
tests
l
Insulation-resistance
test
on
control
power
transformers
l
Verify
correct
function
of
control
transfer
relays
l
Verify
operation
of
switchgear
heaters
and
their
controller
l
System
function
tests
Staying
on
top
of a
switchgear
maintenance
program
can
be
difficult.
Maintenance
is
often
considered
a
low
priority
and
deferred
or
ignored
until
a
failure
occurs.
However,
when
you
fail
to
conduct
the
proper
maintenance,
the
risk
of
loss
is
high
including
personnel
injury
or
death,
equipment
damage,
and
lost
production.
HVM’s
electrical
reliability
experts
can
work
with
you
to
develop
and
implement
a
solid
maintenance
program
to
ensure
the
safety
of
your
people
and
reliability
of
your
electrical
switchgear.
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