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March 1996
F
breaker. Settings available for ground fault
alarm are the same as for ground fault trip,
adjustable from 25 to 100 percent of the
rating plug value up to a maximum of
1200 amps. Once a ground fault alarm occurs
both local and remote signal indication
is available.
A peak demand exceeded alarm is available
with OPTIM 1050. For ensuring a minimum
degree of power quality, acceptable total har-
monic distortion levels can be set with OP-
TIM 1050 and an alarming feature can be
initiated should these levels be exceeded.
System Diagnostics
Whenever a circuit breaker trips it is impera-
tive that the cause of trip be determined
quickly, the faulty conditions rectified, and
the breaker put back into service. Digitrip OP-
TIM electronic trip units incorporate a com-
plete package of systems diagnostics to meet
this challenge.
OPTIM makes use of LED indicators on it
faceplate to help the user easily determine
the status of the circuit. A green LED blinks
on and off once per second to indicate that
the microprocessor is functioning normally.
A red LED on the face of the trip unit is pre-
set to flash on and off when an adjustable
high load level is exceeded. A time delay is
built in to avoid nuisance alarms. Four cause
of trip LEDs are embedded in the front of the
trip unit case indicating that the cause of trip
was either a long delay, short delay, instanta-
neous or ground fault.
A long-life lithium battery is included to pro-
vide power to the LED is following a breaker
trip and simultaneous loss of control power
to the power/relay module. The battery is lo-
cated in the rating plug and can be easily re-
placed from the front of the unit. Its normal
life expectancy would be between five and
eight years. A battery check pushbutton and
green LED are included to monitor battery
status.
Remote signal indication for cause of trip as
well as magnitude of trip information is also
available. The power/relay module, supplied
with all breakers using OPTIM trip units, uses
external control power (120Vac 50/60 Hz,
6VA
➀
) brought into the breaker’s secondary
contacts to operate the communications cir-
cuitry and reason for trip LED indicators. Sec-
ondly, it acts to provide signal relay contact
closures when conditions apply that warrant
advance warning alerts to potential problems
or actual trip conditions.
●
Programmable high load phase and neu-
tral alarm, adjustable between 50 and 100
percent of I
r
(LDPU setting).
●
Long delay trip alarm.
●
Short-circuit trip alarm.
●
Ground fault trip alarm (LSIG units) or
neutral overcurrent alarm if breaker has
provision for external neutral input.
●
A ground fault alarm adjustable between
25 and 100 percent of In (rating plug) will
alert user of a ground fault condition with-
out tripping the breaker (LSIA units).
●
Incom close contact for remote closing of
breaker via IMPACC.
Systems Monitoring
Digitrip RMS and Digitrip OPTIM electronic
trip units offer a complete menu of monitor-
ing capability to include current, power and
energy, power factor, power quality harmon-
ics, and other related parameters with a high
level of accuracy.
Current Monitoring - OPTIM 750 and 1050
Digitrip OPTIM 750 and 1050 trip units are ca-
pable of monitoring currents in individual
phases (A,B,C) as well as neutral and ground
currents.
Current values are displayed in kA on the
hand held OPTIMizer, the Breaker Interface
Module or on a remote personal computer via
IMPACC. Accuracy of the current monitored
values is
±
2 percent of full scale sensor
rating
➁
.
Power and Energy Monitoring - OPTIM 1050
For the trip unit to calculate true power and
energy values, a Potential Transformer Mod-
ule is required. This PTM is included the
power breaker and provides the voltage the
trip unit requires.
Digitrip OPTIM 1050 trip units are capable of
monitoring peak power demand, present
power demand, and reverse power flow in
kW. Additionally, both forward and reverse
energy consumption in kwh can be
monitored.
The accuracy of power monitored values is
±
4
percent of full scale sensor rating (sensor x
600 volts).
The accuracy of energy monitored values is
±
5 percent of full scale sensor rating (sensor x
600 volts).
Digitrip 1050 trip units have the additional
capability of monitoring line to line voltage as
well as system power factor.
Harmonics Monitoring
Digitrip OPTIM 1050 trip units are capable of
monitoring values of current harmonics. Per-
centage of total harmonic content can be
monitored on three phases plus neutral line
for each level of harmonic content up to the
27th harmonic. Additionally, a total harmonic
distortion (THD) value can be calculated and
displayed providing the user with total sys-
tem current harmonic monitoring capability.
With IMPACC, waveform capture gives the
ability to view the waveform on the computer
screen.
System Communications
The Westinghouse IMPACC monitoring, pro-
tection, and control communications system
is the most highly reliable, cost effective com-
munications system available. Digitrip OPTIM
750 and 1050 electronic trip units include a ca-
pability to communicate within an IMPACC
System. IMPACC system communications are
done over a shielded twisted pair communi-
cations cable that connects devices daisy
chain style.
OPTIM communications can be applied for
variable levels of sophistication as described
below.
Features
Control and monitoring features provided by
Digitrip OPTIM 750 or 1050 trip units include:
●
Breaker status (open, closed, tripped)
●
Address and baud rate
●
Trip event time
●
Trip event counter
●
View protection settings
●
Change protection settings
●
Load current values
●
Power and energy values
➂
●
Power Factor
➂
●
Line to line voltage
➂
●
Power quality current harmonic values
➂
●
Waveform capture
➂
●
Remote status messages
●
Remote control-trip/close/reset-reset
demand/energy/trip event
Further Information
I.L. 29C891 Instructions for OPTIM 750, 1050
Trip Units.
Power Circuit Breakers Type DSII and
Electronic Trip Units
➀
Optional 230 Vac available on SPB breakers.
➁
Accuracy applies when current is greater than 5%
of the primary sensor rating. Accuracy is of the
complete system which includes the sensors, aux-
iliary CTs and the OPTIM trip unit. When current is
less than 2% of sensor ratings, no current
reading is available.
➂
OPTIM 1050 only
