This technical note outlines the importance of surge protection for automatic transfer switches (ATS) in oilfield operations to prevent damage from lightning and static discharges. It identifies four primary sources of transient damage and recommends the installation of surge protective devices (SPDs) to mitigate risks. Proper selection, sizing, and installation of SPDs are critical for the protection and longevity of ATS systems during electrical crises.

1. Technical
Note_005
Lightning
&
Static
Protection
for
Oilfield
Assets
015-­‐0108
Rev
1
Jan
2015
www.petroguardian.com
Disclaimer:
This
engineering
recommendation
is
based
on
industry
standards
and
practices.
This
guideline,
when
applied,
does
not
guarantee
a
production
location
will
not
be
susceptible
to
lightning
strikes
or
static
discharge
events.
By
using
these
guidelines
and
industry
practices,
the
likelihood
of
lightning
or
static
related
damage
will
be
decreased
but
not
eliminated.
Technical
Editors:
Chief
Technical
Officer:
Terry
Charrier
Jr
Director
of
Engineering
Services:
Harshul
Gupta
©
2015
Petro
Guardian
LLC
Page1
BEST
PRACTICES
FOR
LIGHTNING
PROTECTION
ON
ATS
INTRODUCTION
Automatic
Transfer
Switch
(ATS)
surge
protection
is
critical
for
the
operation
of
the
switch.
The
modern
ATS
has
circuit
boards,
electronic
controls,
relays
and
sensors
that
are
sensitive
to
transients.
Transient
damage
to
an
ATS
switch
and/or
controller
can
result
in
failure
of
the
ATS
to
perform
during
an
electrical
crisis.
Cumulative
damage
from
transients
can
cause
minor
problems
in
the
programming
or
logic
controls
for
the
switch.
This
can
result
in
the
false
operation
of
the
transfer
switch
and
operation
of
the
generator
when
no
problem
exists,
and
even
worse
the
failure
to
make
the
transfer
in
the
event
of
an
actual
crisis.
Catastrophic
damage
can
destroy
the
switch
and/or
controller
and
take
the
entire
system
off-­‐line.
This
technical
note
outlines
best
practices
that
can
be
used
as
a
guideline
during
UPS
installation
and
operation
start-­‐up.
BACKGROUND
There
are
four
main
sources
of
potential
transient
damage
that
can
impact
an
ATS.
• The
first,
and
most
common,
is
the
utility
power
line.
Lightning,
generator
switching
at
the
utility
power
station
or
sub-­‐station,
capacitor
bank
switching
on
the
grid,
or
nearby
facilities
producing
their
own
large
transients
can
cause
catastrophic
as
well
as
cumulative
level
transients
at
the
ATS.
A
properly
installed
Surge
Protective
Device
(SPD)
at
the
power
utility
line
side
of
the
ATS
can
prevent
the
damage
from
this
source.
• The
second
source
of
transients
is
the
generator,
or
back
up
power
source
line.
The
quality
of
the
power
produced
by
a
back-­‐up
generator
is
dependent
on
many
factors.
The
age
of
the
generator
and
motor,
the
quality
and
frequency
of
the
maintenance
performed
on
the
motor
and
generator,
the
load
to
capacity
ratio
of
the
generator,
how
frequently
the
generator
is
run
and
for
how
long,
the
quality
and
maintenance
of
the
connections
from
the
generator
to
the
ATS,
and
more
all
have
an
impact
on
the
ability
of
the
generator
to
provide
clean
quality
power
to
the
electrical
system
during
a
power
utility
outage.
Problems
in
any
of
these
areas
can
result
in
the
generator-­‐
producing
transients
with
the
capability
of
causing
everything
from
a
minor
nuisance
to
catastrophic
failure.
A
properly
installed
SPD
at
the
generator
line
side
of
the
ATS
can
prevent
the
damage
from
this
source.
• The
third
source
of
transients
is
the
down
line
electrical
system.
Internally
generated
transients
can
travel
back
up
line
to
the
ATS
and
cause
cumulative
as
well
as
catastrophic
damage
to
the
switch
and
controller.
A
properly
installed
SPD
at
the
load
side
line
of
the
ATS
can
prevent
the
damage
from
this
source.
• The
last
source
of
transients
is
the
actual
physical
switch
within
the
ATS
itself.
The
blades
that
switch
from
the
power
utility
line
input
to
the
generator
line
input
will
cause
arcing
and
transients
when
they
disconnect
from
one
and
make
contact
with
the
other.
A
properly
installed
SPD
at
the
blades
of
the
ATS
can
prevent
the
damage
from
this
source.
COMMON
MODES
OF
LIGHTNING
DAMAGE
TO
ELECTRONICS
• Lightning
strike
to
the
network
of
power,
phone
and
communication
cable
wiring.
This
network,
especially
if
it
is
elevated,
is
an
effective
collector
of
lightning
induced
surges.
The
wiring
conducts
the
surges
directly
into
the
facility,
and
then
to
the
connected
equipment.
• Lightning
travels
through
the
ground
(soil),
reaching
underground
cables
or
pipes.
This
is
another
route
for
lightning
to
enter
a
facility.
Surges
are
induced
in
underground
cables
and
into
the
ground
reference
for
electrical
and
electronics
systems.

2. Technical
Note_005
Lightning
&
Static
Protection
for
Oilfield
Assets
015-­‐0108
Rev
1
Jan
2015
www.petroguardian.com
Disclaimer:
This
engineering
recommendation
is
based
on
industry
standards
and
practices.
This
guideline,
when
applied,
does
not
guarantee
a
production
location
will
not
be
susceptible
to
lightning
strikes
or
static
discharge
events.
By
using
these
guidelines
and
industry
practices,
the
likelihood
of
lightning
or
static
related
damage
will
be
decreased
but
not
eliminated.
Technical
Editors:
Chief
Technical
Officer:
Terry
Charrier
Jr
Director
of
Engineering
Services:
Harshul
Gupta
©
2015
Petro
Guardian
LLC
Page2
• Lightning
strikes
to,
or
near,
the
external
wiring
network
common
to
most
outdoor
facilities.
Power
Generators,
satellite
dishes,
exterior
lights,
gate
control
systems,
flare
control
panel,
drive
panel,
RTU
Panel,
and
security
systems
can
all
be
struck
by
lightning,
allowing
lightning
surges
to
be
carried
by
the
wiring
damaging
critical
circuits
and
operations.
• Lightning
may
strike
nearby
objects
(open
field,
trees,
or
another
facility)
that
are
close
to,
but
not
directly
connected
to
the
facility.
In
this
scenario,
the
lightning
strike
radiates
a
strong
electromagnetic
field,
which
can
be
induced
into
the
wiring
of
power
and
instrumentation
cables,
producing
large
voltage
spikes
that
can
damage
equipment.
• A
direct
lightning
strike
to
the
structure.
This
type
of
strike
is
rare.
It
can
severely
damage
a
structure
without
a
lightning
protection
system
(LPS)
and
will
generally
damage
most
electronic
equipment
connected
to
the
facility.
The
structural
damage
can
normally
be
prevented
by
a
properly
installed
LPS
,(network
of
air
terminals,
lightning
conductor,
bonding,
grounding)
but
the
LPS
alone
provides
little
protection
for
the
electronic
equipment.
PROTECTING
ATS
FROM
SURGES
Installing
four
separate
SPDs
on
a
transfer
switch
would
not
be
practical
or
cost
effective.
The
most
cost
effective
solution
is
to
place
one
properly
sized
SPD
at
a
location
on
the
ATS
that
will
provide
the
best
"path
of
least
resistance"
for
any
transients
coming
from
any
of
the
four
sources.
This
best
location
is
usually
the
load
side
output
terminals
of
the
ATS.
Their
proximity
to
the
switching
blades,
sensors
and
electronics
in
the
ATS,
as
well
as
the
power
utility
and
generator
lines,
will
usually
make
them
the
closest
common
junction
point
to
connect
the
SPD.
Selecting
type
of
SPD
Device:
Because
the
ATS
is
controlled
with
electronics,
the
use
of
a
SPD
integrated
with
an
EMI/RFI
filter
is
required.
The
oscillatory
ring
wave
transients
that
are
generated
by
the
operation
of
electronic
equipment
on
the
system
can
have
a
particularly
damaging
effect
on
the
controller,
sensors
and
relays
within
the
ATS.
An
All
Mode
SPD
with
an
EMI/RFI
Filter
will
provide
protection
from
these
oscillatory
ring
wave
transients
as
well
as
providing
brute
force
protection
from
the
generally
stronger,
but
less
frequent
electrical
switching,
impulse
type
transients.
The
SPD
should
have
the
ability
to
provide
both
impulse
and
oscillatory
ring
wave
protection
in
every
mode,
i.e.
line-­‐to-­‐neutral,
line-­‐to-­‐ground,
neutral-­‐to-­‐ground
and
line-­‐to-­‐line.
Selecting
SPD
Rating:
Proper
sizing
of
the
SPD
for
the
correct
peak
surge
current
is
essential
to
ensuring
the
survival
of
the
SPD
and
its
ability
to
protect
the
ATS
over
time.
Even
if
there
is
a
properly
sized
SPD
at
the
service
entrance
up
line
from
the
ATS,
the
SPD
at
the
ATS
will
effectively
become
the
service
entrance
protection
from
the
time
the
source
power
is
switched
from
the
utility
line
to
the
generator
line,
to
the
time
it
is
switched
back
to
the
utility
line.
Because
this
increases
the
potential
for
catastrophic
surge
activity
at
this
point
on
the
system,
the
SPD
should
be
"up-­‐sized"
one
level
of
peak
surge
current
to
ensure
continued
operation
under
all
but
the
most
severe,
direct
strike
type
situations.
Correct
installation
of
SPD:
Installation
of
the
SPD
should
be
accomplished
with
the
device
positioned
to
provide
the
shortest,
straightest
leads
to
the
load
side
buss
or
output
terminals
of
the
ATS.
For
this
reason,
an
integral
type
SPD
installed
inside
the
ATS
cabinet
may
be
the
best
solution.
The
integral
unit,
having
no
exposed
metal
parts,
can
be
installed
in
close
proximity
to
the
bus
or
lugs
and
allow
for
extremely
short
leads.
The
use
of
an
external
remote
indicator
lamp
kit
mounted
to
the
front
of
the
ATS
will
alert
the
user
of
any
problems
with
the
SPD.
ABOUT
PETROGUARDIAN
Petro
Guardian
engineers
systems
to
protect
your
oil
and
gas
field
assets
from
damage
caused
by
lightning
strikes
and
static
discharge.
Petro
Guardian’s
experienced
engineering
team
works
alongside
your
operations
and
engineering
team
to
develop
a
standardized
plan
that
prevents
ignition
from
lightning
strikes
and
static
discharge.
Contact
team@petroguardian.com
to
schedule
an
appointment.