Siemens Static Trip III User Manual

Metering and
Extended
Protective
Relaying
Parameter
Description
kW
Demand
Kilowatt Demand Using
Fixed or Sliding
Window Approach
Range:
!7,2O0
Accuracy:
!2% ol
Reading
Provided
power
factor
is
greater
than
50%
and current
and
voltage
signals
are
within their sPeci-
fied accuracy
ranges.
BDU
DisPlaY:
kWD
=
XXXX
Power
Flow Sign Conventions
Static
Trip lllCP/CPX
model trip
devices are
capable
of
mea-
suring
real
(kW)
and
reactive
(kVAR)
power
flows
in both
directions.
The circuit
breaker and
trip unit
symbols
below
showthe
example
where the top
terminals
of the circuit
breaker
are
connected to
the normal
power
source,
and
the trip unlt
is
configured
with
"V
SOURCE'
set to
"TOP".
The term
"forward"
power
flow means that
kilowatts
(or
kiloVARS) are
being
consumed
by the
'LOAD";
"reverse"
flow means
power
is
being
supplied by the
"LOAD
. The sign conventions
used
for
kW kVAR and
PF are shown
in the
four
quadrants
of the
power
diagram below.
Extended
Protective
Relay
Functions
Extended
protective
relaying
functions
are
provided
with the
trip
unit
when the
"X"
model
type
is ordered.
There are
7
relaying
functions, described
below,
Each
function
is capable
of
tripping
the circuit
breaker
when the
proper
conditions
are
met.
To activate
a function,
f
irst set a
pickup
value and
a delay
value;
then enable
(turn
on)the
function,
When the
measured
conditions
relating
to the
appropriate
{unction
exceed
the
pickup
value, a
pickup
flag
will be set
and
the
value of
the
measured
conditions
will be
logged
into the trip
unit's
event
log.
lf the
pickup
stays
on for the
delay
value
time,
the circuit
breaker
will be tripped.
ln addition,
the
measured
conditions
at the
time
of the trip,
the
relaying
function
which
caused
the
trip, the
breaker
status,
and the
time of
the trip
will be
entered
into
a trip
1og. The data
in the
event
log and
trip
log can
be
viewed
from a
master device
using
the
R5-485 bus.
The trip
log
can also
be read
from the
BDU accessory,
but
without
time-
stamp
information.
Note:
All
relaying
functions,
except
current
unbalance,
are
prevented
f rom operating
unless
the
circuit
breaker
position
is
sensed
as
closed.
This feature
prohibits
repetitive
pickups
and
trip signals
from being
generated
on an
open
breaker,
Repeti-
tive
pickups
would result
in multiple
writes to the
event
logs
and
trip
logs;
repetitive
trip signals
would
result
in
multiple
drive
signals
being
sent
to the
actuator.
For example:
The
undervoltage
relay on an
open
feeder breaker
is enabled
with
a
pickup
of
440 volts and
a delay
of
1 second,
An
upstream
circuit
breaker
is opened.
Without the
above
feature,
the
undervoltage
relay
on the
feeder breaker
would
pickup,
time-
out, and
attempt
to trip.
This
process
would
repeat every
1
second
until
manually
stopped.
Therefore
for
proper
operation
of
the
relaying
functions, the
breaker
position
switch
must be
functioning
properly.
Current
Unbalance
-
Current
Unbalance
is a
protective
relay
function
that
protects
against
an
unbalance
in the
phase
currents.
Each
phase
current,
(la,
lb and
lc)
is compared
to
the
arithmetic
average
of the
three
phase
currents,
l*.
Tripping
occurs
when
any
phase
current
exceeds
the
programmed
unbalance
pickup
for a
period
of time
equal
to the
delay
time
setting.
The
pickup
must
remain active
for the entire
delay
time
for a trip
to occur.
lf the current
unbalance
condition
subsides
in less time than
the delay
time,
the
pickup
will
go
inactive
and
the
current
unbalance
protective
relaying
function
will be
reset.
When tripping
occurs,
the
actual
condition
that
caused
the trip
is
recorded
in the trip
unit's
nonvolatile
trip
log.
Programmable
settings:
Trip:
Yes, No or Clr
Pickup: 5%
lo 50%
in increments
of
I %
Delay:
1 to l5 seconds
in increments
of
1 second
Average
current
is defined
as
Ila
+ lb
+ lc]/3
=
l*
Pickup
occurs
if the absolute
value of
1
-
(lallX)
or
(lb/l*)
or
(lc/l>K)
X 100%
is
equal
to or
greater
than
the
pickup
setting
Current
unbalance
is disabled
for any
phase
current
less than
15%
of sensor
rating.
Data recorded
in
the
event
log:
Pickup
Active:
Time at
which
pickup
went active
and
la,
lb,
lc at
PickuP,
Pickup lnactive:
Time at
which
pickup
went inactive.
,V
SOUBCE"
Forward Power
(kwkvAR
consumed
by
the
"LOAD')
Circuit
Breaker/Trip Unit
symbols showlng
power
tlows
kVAR
(react
ve
power)
+kW
(forward
+kVAR
(forwa
+PF
(lagging)
kW
(real
kVAR
(fon
)F
(leadinr
vard)
t\t
II
kW
(revers
kVAR
(reve
-PF (laggir
III
e)
\
rrSe)
s)
IV
<W
(forwar
VAB
(rever
F
(leading
power)
+k\
PF
rrward)
(forward)
)rward)
reverse)
Power Diagram with Sign
Conventions
in each
quadrant
22

Siemens Static Trip III Specifications

General

Brand	Siemens
Model	Static Trip III
Category	Circuit breakers
Language	English