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| Electrical Power Systems Studies
Electrical
Power System
Studies
Mid-South
Engineering
now has the
ability to
perform
Electrical
Power System
Studies
Focusing on
the
following:
Ø
èShort
Circuit
Analysis
Ø
èCoordination
Analysis
What is a
Power System
Study?
Data
relating to
the existing
electrical
power
distribution
system is
gathered
including:
Ø èShort
Circuit
Capacity &
Impedance of
Utility
Supply
Ø èHi
Voltage Fuse
Types, Sizes
& Ratings
Ø èTransformer
Evaluation
(Quantity,
Size, etc)
Ø èSwitchgear
Evaluation
(Amp rating,
Short
Circuit
rating,
Breaker
quantities &
sizes, etc)
Ø èMotor
Control
Centers (Amp
rating,
Short
Circuit
rating,
Connected
Loads, etc)
Ø èCable
Sizes &
Raceway
types
(Steel,
Aluminum,
PVC or Tray)
Ø è480
Volt Fuse
Types, Sizes
& Ratings
Ø èShort
Circuits
Ø èPower
and/or
Current Flow
at various
load factors Ø è Coordination of protective devices èArc Flash Energy in cal/cm^2 and Personal Protection Equipment "PPE" requirements
What does a
Power System Study
give you?
Short-circuit
current
magnitudes
are
calculated
for possible
faults at
each
switchboard,
motor
control
center and
distribution
panel to
verify
adequate
short
circuit
ratings of
the existing
electrical
equipment
and to
provide data
for any
future
electrical
equipment
additions.
Time versus
current
curves are
plotted to
determine
the
coordination
between
circuit
protective
devices.
The object
of proper
coordination
is to
minimize the
disruption
of service
by tripping
only
protective
devices as
close as
possible to
an overload
or fault
condition on
the
electrical
system. A
written
summary
report
outlining
the study
results will
be
generated.
Arc Flash Study informs the electrician of what level of PPE is required for maintenance, and also provides NEC 2008 article 110.16 Arc Flash Labeling compliance. This study also includes suggestions on how to reduce fault energy to a level that would reduce the required level of PPE.
Why should
you conduct
a Power
Study?
Equipment
installed at
time of
original
plant
construction
may have
been
properly
rated, but
with the
passage of
time, the
utility
company may
have
significantly
increased
the amount
of short
circuit
current that
could flow
into the
customer’s
mill.
Equipment
may have
unknowingly
been
installed
that is not
rated for
the
available
short
circuit
current, or
that is not
properly
coordinated.
The Power Study will also allow minimum ratings for future electrical equipment to be established.
Arc Flash events occur almost daily, and more that 2,000 people are admitted to burn centers every year due to them. This study will provide qualified personnel a visual reference to what the proper level of PPE is required to work on a specific labeled piece of equipment. It will also provide the employer the level of compliance required by the NEC and the NFPA70E. Contact: Don Elrod PE, Electrical Engineering Services Group Manager
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