Power Circuit Breakers Type DSII and
SPB with OPTIM Trip Units
Electronic Trip Units
General Description
OPTIM 750
OPTIM 1050
Cutler-Hammer offers the most comprehensive range of electronic trip units in the industry for power circuit breakers. The UL listed
OPTIM electronic trip units are true RMS
sensing and can be applied in any SPB or
DSII breakers.
Digitrip electronic trip units are ac devices
that employ microprocessor-based technology that provides a true RMS current sensing
means for proper correlation with thermal
characteristics of conductors and equipment.
The primary function of the Digitrip electronic trip unit is to provide circuit protection.
This is achieved by analyzing the secondary
current signals received from the circuit
breaker current sensors and initiating trip
signals to the circuit breaker trip unit when
pre-set current levels and time delay settings
are exceeded. By sampling the current waveform at various points on the wave and calculating true RMS current, the Digitrip is able to
reduce nuisance tripping events due to nonsinusoidal wave shapes.
Electronic trip units are applied to distribution systems when high standards of protection and coordination are called for. In
addition, electronic trip units can provide further enhanced features such as alarming,
diagnostics, system monitoring and
communications.
Cutler-Hammer RMS sensing trip units for
power breakers fall into two main categories:
● Front adjustable trip units: Digitrip RMS
510, 610, 810, 910
● Programmable trip units: Digitrip OPTIM
750, 1050
Programmable Trip Units
OPTIM trip units are electronic trip units that
have up to ten time-current setting options
that are programmed electronically by the
use of a programming device. Trip units are
readily accessible from the front of the breakers. Programmability means more settings,
better accuracy, faster configuration, remote
accessibility, higher system security, and the
ability to apply limitless software. The application for programmable trip units would be
high integrity distribution systems that require superior levels of system coordination
coupled with system alarming, diagnostics
and monitoring.
Digitrip OPTIM for power breakers are available in three configurations:
- Long time, short time, and instantaneous (LSI)
- Long time, short time, instantaneous
and ground fault protection (LSIG)
- Long time, short time, instantaneous
and ground fault alarm (LSIA)
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RMS Sensing
10 Functions
Programmable
Load Monitoring
Diagnostics
Communications
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RMS Sensing
10 Functions
Programmable
Load Monitoring
Diagnostics
Communications
Power and Energy Monitoring
Harmonics
For maximum selectability, OPTIM trip units
allow the user to disable either short time or
instantaneous functions, but not both.
selectable on DS breakers and on SPB breakers are equal to the breaker frame rating. The
plug value is referred to as In.
Rating Plugs
Time-Current Curve Shaping
Rating plugs provide a means to establish
the breaker’s continuous current rating. Rating plugs are unique to a particular breaker
type, and are color coded to make it easy to
match the correct rating plug with the correct
circuit breaker type. Rating plugs are fixed
type, and are interchangeable so that amp
ratings can be changed simply by changing
from one plug to another in a given breaker.
The same rating plug can be applied to both
50 and 60 Hz distribution systems. SPB plugs
are interlocked with the breaker frame to prevent putting the wrong plug into the wrong
frame size.
All Digitrip OPTIM settings are continuously
adjustable, allowing virtually an infinite number of possibilities within setting ranges.
Ranges are based on the plug rating In and
the long delay pickup setting Ir. For ease of
use all pickup values are programmed in
amps rather than in multiples of In or Ir.
Table 1 illustrates available setting ranges.
For improved system coordination OPTIM
features a new setting not available on previous models of Digitrip. The I4t long delay
slope will provide superior coordination with
upstream fuses and transformer damage
curves.
Rating plugs are available down to an ampere
value of half the sensor rating. Sensors are
Interchangeable rating plugs establish the circuit breaker’s continuous ampere rating. Different types and
ratings are available to match the desired ampere rating and type of circuit breaker into which a Digitrip
RMS trip unit is installed. The rating plugs are suitable for use on either 50 or 60 Hz system applications.
Rating plugs may be applied as low as 50% of sensor rating.
March 1996
Power Circuit Breakers Type DSII and
SPB with OPTIM Trip Units
Electronic Trip Units
10 Curve Shaping Adjustments
Function
1
Multiplier/
Setting
Setting Range
Overload
1. Long Delay Pickup
2B
2A
2
XIn
0.4 - 1.0
2A. Long Delay Time I2t
@6Ir
2 - 24 sec.
2B. Long Delay Time I4t
@6Ir
1 - 5 sec.
Short Circuit
3
Time
4B
XIr
1.5 - S max.*
XIr
0.1 - 0.5 sec.
4B. Short Delay Time I2t Response
XIr
0.1 - 0.5 sec.
5. Instantaneous
XIn
2.0 - M max.*
Ground Fault
4
4A
6
3. Short Delay Pickup
4A. Short Delay Time Flat Response
6. Ground Fault Pickup
XIn
0.25 - 1.0 (1200 A max)
7A. Ground Fault Delay Flat Response
XIn
0.1 - 0.5 sec.
XIn
0.1 - 0.5 sec.
7B. Ground Fault Delay I2t Response
5
In = Rating Plug Rating
Ir = LDPU Setting
* Varies with Breaker Type and Frame –
See small table this page.
7B
7
7A
Current in Amperes
Breaker Type
Frame
S max.
SPB
SPB
DSII
400A - 3000A
4000A - 5000A
All
8
6
10
M max.
10
6
12
F
Figure 1. OPTIM Trip Curve Settings
Protective function settings are described
below. See Figure 1.
Long Delay (L)
1. Long Delay Pickup
Determines the continuous ampere
rating of the breaker.
2.
Long Delay Time
Determines the amount of time the
breaker will carry a low level overload
before tripping.
2A. I2t Response
I2t in: For coordination with other circuit
breakers with electronic trip devices and
for coordination with thermal magnetic
circuit breakers.
2B. I4t Response
I4t in: For coordination with fuses and upstream transformer damage curves.
Short Delay (S)
3. Short Delay Pickup
Determine or set the level of fault current
at which the short time trip delay countdown is actuated.
4.
Short Delay Time
Sets the amount of time the breaker will
carry both low level and high level fault
currents before tripping.
4A. Flat Response
I2t out: For coordination with other circuit
breakers with electronic trip devices.
This setting is used when I4t Long Delay
Time is selected.
March 1996
4B.
I2t
I2t
Response
in: For coordination with fuses and
thermal magnetic breakers.
Instantaneous (I)
5. Instantaneous Pickup
Determines the level of fault current
which will actuate a trip with no time
delay.
Ground Fault (G)
6. Ground Fault Pickup
Determines the level of fault current at
which the ground fault trip delay countdown is actuated.
7.
Ground Fault Delay
Determines the amount of time the
breaker will carry a ground fault before
tripping.
7A. Flat Response
I2t Out: For coordination with other circuit breakers with electronic ground fault
settings.
7B. I2t Response
I2t In: For coordination with zero
sequence ground fault relays.
dent curve shaping provides a wider range of
available settings. OPTIM offers virtually infinite settings to allow the user to optimize coordination for a selectively coordinated
distribution system. Time-current set points
can be downloaded via a handheld programmer or a communication system from a central personal computer. Digitrip OPTIM is
normally applied to electrical power systems
where system integrity is very important.
Zone Selective Interlocking
Zone selective interlocking capabilities are
available with Digitrip OPTIM 750 and 1050
trip units. Zone selective interlocking provides positive system coordination by allowing the breaker closest to the fault to trip
without any preset time delays. This is
achieved by setting up the distribution system as shown in Figure 2. The hard wired
connection between the trip units sends a restraining signal upstream allowing the breaker closest to the fault to interrupt instantaneously, while the upstream breaker times
out per its programmed settings. Zone selective interlocking reduces stress on the distribution system by isolating faults without
time delays, and provides the ultimate in system selective coordination.
Programmable Dependant Curve Shaping
Digitrip OPTIM 750 and 1050 trip units offer
programmable dependent curve shaping via
ten curve shaping choices that are programmed electronically into the trip unit. The
trip curves are interactive so that changing a
long delay setting (Ir) moves the whole curve
including the short time portion to provide
closer protection for bus and cables. Depen213
Power Circuit Breakers Type DSII and
SPB with OPTIM Trip Units
Electronic Trip Units
Figure 2. Zone Selective Interlocking
made to close a breaker on a faulted circuit.
The discriminator (or making current release)
is set at 11 times the rating plug ampere rating and is enabled for approximately the first
10 cycles of current flow. Should a fault condition exist upon closing, the breaker will trip
with no intentional time delay, protecting the
user from a potentially unsafe condition. The
discriminator function can be enabled or disabled by the user.
In addition to a discriminator, an instantaneous override is present in all SPB insulated
case circuit breakers to provide additional
protection for the breaker. The instantaneous
override is factory set just below the breaker
withstand rating to ensure rapid clearing under conditions of fault currents greater than
the short time withstand rating of the breaker
in which the trip unit is installed.
Fault 1
There are no interlocking signals. The
main breaker trip unit will initiate the trip
instantaneously.
Fault 2
The feeder breaker trip unit will initiate the
trip instantaneously to clear the fault; and
Zone 2 will send an interlocking signal to
the Zone 1 trip unit. The Zone 1 trip unit
will begin to time out, and in the event
that the feeder breaker in Zone 2 would
not clear the fault, the main breaker in
Zone 1 will clear the fault in 0.5 seconds.
Fault 3
The branch breaker trip unit will initiate
the trip instantaneously to clear the fault;
and Zone 3 will send an interlocking
signal to the Zone 2 trip unit; and Zone 2
will send an interlocking signal to Zone 1.
Zone 1 and Zone 2 trip units will begin to
time out, and in the event that the branch
breaker in Zone 3 would not clear the
fault, the feeder breaker in Zone 2 will
clear the fault in 0.3 seconds. Similarly, in
the event that the feeder breaker in Zone 2
would not clear the fault, the main breaker
in Zone 1 will clear the fault in 0.5
seconds.
Digitrip OPTIM electronic trip units can operate reliably in ambient temperatures that
range from -20C to + 95C. In the unlikely
event that temperatures exceed this ambient,
the trip unit has a built-in overtemperature
trip to protect the trip unit from operating
outside its design parameters.
Non-Volatile Memory
After an overcurrent trip operation, the trip
unit retains information in E2 prom. Values
indicating the cause of trip, currents through
the breaker at time of trip, time when trip occurred, total number of times the trip unit has
tripped the breaker, and voltage and power
quality related data when applicable are
automatically stored. The data will remain in
memory even if 120 Vac control power to the
power/relay module is lost. These values can
be displayed when control power is restored
prior to resetting the trip unit.
Thermal Memory
Digitrip OPTIM electronic trip units incorporate powered thermal memory. The units
remember recent overcurrent events which
may have initiated the trip timing sequence
and then returned to nominal levels, halting
the sequence prior to trip initiation. If a
trip occurs, OPTIM remembers the heating
effect of this overload. In the event that the
current levels again exceed the pickup setpoint before the circuit has had time to cool
from the original pickup, the unit's memory
recalls the previous trip or near trip and automatically imposes a shorter delay time. In
effect, the trip unit treats multiple time
related events as a single continuous event
thereby preventing system damage due to
cumulative overheating.
As a further enhancement, the trip units incorporate an unpowered thermal memory
feature. In the event that current levels cause
the breaker to trip and the breaker is then reclosed following a loss of control power, the
trip unit remembers the previous overcurrent
trip and again imposes a shorter delay time
should a further overcurrent occur before a
sufficient cool-down period has elapsed.
Thermal Memory protects the distribution
system from cumulative overheating caused
by repeated overcurrent conditions. Both
powered and unpowered thermal memory
can be programmed in or out by the user.
System Alarms
Digitrip OPTIM electronic trip units offer a
high load alarm capability but with more flexibility than was previously available. OPTIM
trip units have a high load alarm that can be
programmed to operate between 50% and
100% of Ir.
In some cases users want to know when a
ground fault exists, but want to continue to
operate without tripping due to ground fault.
Digitrip OPTIM electronic trip units incorporate a ground fault alarm capability. Units
equipped with LSIA will alert the user to a
ground fault condition without tripping the
Additional Protection Features
Digitrip RMS Electronic Trip Units are designed and built with safety and reliability in
mind, both to protect the user and the equipment as well as making sure the trip functions within its design parameters. Following
a trip, the OPTIM trip unit should be reset via
the highly visible red “trip reset” button on
the front of the unit.
By providing a SURE Start discriminator circuit in Digitrip OPTIM 750 and 1050 trip units
that do not have an instantaneous setting,
the user is protected should an attempt be
214
Breaker Accessories Pictured From Left to Right: Power Relay Module, Potential Transformer Module, and
Auxiliary Power Module.
March 1996
Power Circuit Breakers Type DSII and
SPB with OPTIM Trip Units
Electronic Trip Units
A peak demand exceeded alarm is available
with OPTIM 1050. For ensuring a minimum
degree of power quality, acceptable total harmonic distortion levels can be set with OPTIM 1050 and an alarming feature can be
initiated should these levels be exceeded.
● Programmable high load phase and neutral alarm, adjustable between 50 and 100
percent of Ir (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 without tripping the breaker (LSIA units).
● Incom close contact for remote closing of
breaker via IMPACC.
System Diagnostics
Systems Monitoring
Whenever a circuit breaker trips it is imperative that the cause of trip be determined
quickly, the faulty conditions rectified, and
the breaker put back into service. Digitrip OPTIM electronic trip units incorporate a complete package of systems diagnostics to meet
this challenge.
Digitrip RMS and Digitrip OPTIM electronic
trip units offer a complete menu of monitoring capability to include current, power and
energy, power factor, power quality harmonics, and other related parameters with a high
level of accuracy.
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.
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 preset 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, instantaneous or ground fault.
A long-life lithium battery is included to provide power to the LED is following a breaker
trip and simultaneous loss of control power
to the power/relay module. The battery is located in the rating plug and can be easily replaced 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,
6VA➀) brought into the breaker’s secondary
contacts to operate the communications circuitry and reason for trip LED indicators. Secondly, it acts to provide signal relay contact
closures when conditions apply that warrant
advance warning alerts to potential problems
or actual trip conditions.
Current Monitoring - OPTIM 750 and 1050
Digitrip OPTIM 750 and 1050 trip units are capable 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
rating➁.
Power and Energy Monitoring - OPTIM 1050
For the trip unit to calculate true power and
energy values, a Potential Transformer Module 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).
Harmonics Monitoring
Digitrip OPTIM 1050 trip units are capable of
monitoring values of current harmonics. Percentage 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 system 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, protection, and control communications system
is the most highly reliable, cost effective communications system available. Digitrip OPTIM
750 and 1050 electronic trip units include a capability to communicate within an IMPACC
System. IMPACC system communications are
done over a shielded twisted pair communications 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:
●
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●
●
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 values➂
Power Factor➂
Line to line voltage➂
Power quality current harmonic values➂
Waveform capture➂
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.
Digitrip 1050 trip units have the additional
capability of monitoring line to line voltage as
well as system power factor.
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, auxiliary CTs and the OPTIM trip unit. When current is
less than 2% of sensor ratings, no current
reading is available.
➂ OPTIM 1050 only
March 1996
215
F
Power Circuit Breakers Type DSII and
SPB with OPTIM Trip Units
Electronic Trip Units
Programming and Monitoring
Digitrip OPTIMizer
Hand-Held Programmer
The OPTIMizer plugs into the front of
the trip unit and is powered by a nine
volt battery. The Digitrip OPTIMizer
hand held programmer accesses, displays, and configures information
from OPTIM Trip Units.
Breaker Interface Module
Panel Mounted User Interface
The Breaker Interface Module can be
mounted directly on the assembly or
at a remote location and can be used
to access, configure, and display information from OPTIM Trip Units.
Stand Alone
Digitrip OPTIM 750 and 1050 electronic trip
units are programmable by the use of a Hand
held programmer called a Digitrip OPTIMizer. The Digitrip OPTIMizer accesses, displays
and configures trip settings and information.
The portable programmer plugs into the
front of the trip unit and is powered by a nine
volt battery. A telephone type cord stretches
up to eight feet away from the breaker.
Sub-Network
Digitrip OPTIM 750 and 1050 electronic
trip units can also be connected as part of a
sub-network system to a panel mounted user
interface device called a Breaker Interface
Module (BIM). A Breaker Interface Module
accesses, configures, and displays OPTIM
trip unit information and for Digitrip RMS 810
and 910 trip units and Energy Sentinels. The
BIM communicates with up to 50 devices.
The BIM, like the AEMII, is normally mounted
on the front of an electrical assembly.
Field Bus System
Digitrip OPTIM 750 and 1050 electronic trip
units can be connected into a field bus system which is called IMPACC. All control,
monitoring and configuration of the trip units
can be carried out from a central personal
computer. See page 641 of this catalog for
more information on IMPACC.
Field Testing
IMPACC Communications
Programming and Other Capabilities from a
Personal Computer
All OPTIM programming, configuration, advance warning, diagnostic,
monitoring, and control capabilities
can be accessed from a central personal computer using IMPACC Series III
software.
Other software packages are available,
including a Trip Curve Package that displays, configures, and coordinates
time-current protection curves for OPTIM Trip Units and other devices that
can be included on an IMPACC System.
Custom Billing Software, a stand alone
application specific software package,
provides the capabilities to determine
energy usage data by individual departments or tenants in a facility...and then
creates “electric bills” based on this data.
System maintenance is an extremely important part of any distribution system and the
capability to test electronic trip units is an essential requirement.
Digitrip OPTIM 750 and 1050 electronic trip
units have an integral test capability and do
not require a special external test set. Both
phase and ground, trip and no trip, testing
can be carried out with the breaker in the
connected cell position using an OPTIMizer,
a BIM or IMPACC.
An Auxiliary Power Module can be provided
for bench testing Digitrip OPTIM 750 and
1050 electronic trip units, or when the
breaker is disconnected from the cell. The
Auxiliary Power Module operates from a
120 Vac supply and provides control power
to test the trip unit.
Typical Specifications
Waveform and harmonic display software is capable of performing a waveform capture of phase currents A, B, C
as well as neutral or ground. In addition, total harmonic distortion (THD)
and individual harmonic contents can
be displayed.
216
March 1996
Power Circuit Breakers Type DSII and
SPB with OPTIM Trip Units
Typical Specifications
Table 1
Digitrip
Optimizer
Breaker
Interface
Module
IMPACC
Network
Initial System Setup
Select Breaker Addresses
X
Select System Frequency (50/60) Hz
X
X
X
Set System Baud Rate
X
X
X
Set System Password
X
X
X
X
X
X
Configure the System
Change Address
Change Time-Current Setpoints
X
X
X
Select Protection Options
X
X
X
Select Alarm Levels
X
X
X
Breaker Information
X
X
X
Time-Current Setpoints
X
X
X
Metered Values
X
X
X
Trip Event Information
X
X
X
Display Information
Test Trip Unit Performance
Phase and Ground
X
X
X
Trip/No Trip
X
X
X
Set Addresses for Group Energy Monitoring
X
X
Group Energy Readings
X
X
Remote Indication/Alarming
X
X
Breaker Status LED Indication
X
Expanded Energy Monitoring
Local and Remote Indications
Expanded Communications
Communicates with:
OPTIM Trip Units:
X
X
X
Digitrip 810 & 910 Trip Units
X
X
IQ Energy Sentinel
X
X
Up to 50 Devices
X
X
Up to 1000 Devices
X
Expanded Capabilities
Wave Form Analysis
X
Custom Billing Software
X
Trip Curve Software
X
Type DSII or SPB Circuit Breakers with Digitrip OPTIM 750 and 1050 Electronic Trip
Units.
Cutler-Hammer/Westinghouse power breakers with microprocessor-based RMS sensing
trip units. Provide circuit breakers that are
U.L. listed for application at 100% of their continuous ampere rating in their intended enclosure.
Note to Specifier — For trip units with the
functions of Digitrip OPTIM 750 for SPB or
DSII circuit breakers, insert the following:
Provide Cutler-Hammer/Westinghouse Digitrip OPTIM trip units for SPB or DS circuit
breakers with the following features.
Interchangeable rating plugs shall establish
the continuous trip ratings of each circuit
breaker. Rating plugs shall be fixed type as indicated. Rating plugs shall be unique to a
given breaker frame, and interlocked such
that a breaker cannot be closed and latched
with the rating plug removed.
System coordination shall be provided by the
following microprocessor-based programmable time-current curve shaping adjustments. The short time pickup adjustment
shall be dependent on the long time pickup
setting.
● Programmable long time pickup
● Programmable long time delay with selectable I2t and I4t curve shaping
● Programmable short time pickup
● Programmable short time delay with selectable flat or I2t curve shaping and zone
selective interlocking
● Programmable instantaneous pickup trip
or alarm
● Programmable ground fault pickup
● Programmable ground fault delay with selectable flat or I2t curve shaping and zone
selective interlocking
The microprocessor-based trip unit shall have
a powered/unpowered selectable thermal
memory to provide protection against cumulative overheating should a number
of overload conditions occur in quick
succession.
Provide zone interlocking for the short time
delay and ground fault delay trip functions for
improved system coordination. The zone interlocking system shall restrain the tripping of
an upstream circuit breaker and allow the circuit breaker closest to the fault to trip with no
intentional time delay. In the event that the
downstream breaker does not trip, the
upstream breaker shall trip after the
pre-set time delay.
When the instantaneous adjustment is not
provided, a user selectable discriminator cir-
March 1996
217
F
Power Circuit Breakers Type DSII and
SPB with OPTIM Trip Units
Typical Specifications
cuit shall be included to prevent the breaker
being closed and latched onto a faulted
circuit.
The trip unit shall have an information system
that utilizes battery backed-up LED's to indicate mode of trip following an automatic trip
operation. The indication of the mode of trip
shall be retained after an automatic trip. A trip
reset button shall be provided to turn off the
LED indication after an automatic trip. A test
pushbutton shall energize an LED to indicate
battery status.
Circuit breakers shall be provided with a
power/relay module to supply control power.
Internal relays shall provide contacts for
remote indication of the mode of trip (long
delay, short circuit, ground fault) and high load.
A red LED shall be provided on the face of the
trip unit and pre-set to flash on and off when
an adjustable high load level is exceeded.
A time delay shall be provided to avoid
nuisance alarms.
The microprocessor-based trip units shall be
capable of monitoring the following data:
● Instantaneous value of phase, neutral and
ground current
● Minimum and maximum current values
● Average demand current
● System diagnostic information such as
alarms and cause of trip
● Approximate level of fault current that
initiated an automatic trip operation
The monitored data shall be displayed by a
hand-held programmer, a breaker interface
module or a remote computer.
The trip unit shall be capable of two-way communication via a network twisted pair for remote monitoring and control. The trip unit
shall be provided with a programmable address. Transmittable parameters shall include
protection settings, individual phase, neutral
and ground current, minimum and maximum
currents, average demand current breaker
status (open/closed/tripped), trip events and
mode of trip; information on external trip net-
218
work commands, data or program memory
test failure, missing or defective rating plug,
test push-button operation, or communication failure. The breaker shall be capable of
responding to open and close commands via
the communication network. Where indicated, provide electrical operators which respond to a close command via the
communication network.
The trip unit shall contain test capability. Testing shall be carried out by using a hand-held
programmer, a breaker interface module or a
remote computer to select the values of test
current within a range of available settings.
The basic protection functions shall not be
affected during test operations. The breaker
may be tested in either the “Trip” or “No trip”
test mode. Provide an optional auxiliary
power module to allow the breaker trip unit to
be bench tested with a 120 volt external
power source.
A hand held programming unit shall be provided to set/change the network communication breaker address for each device, set the
system baud rate, distribution frequency,
display breaker information and display
monitored values. In addition, provide password protection for programming timecurrent set points and to perform functional
testing of phase and ground trip characteristics. The programmer shall be self powered
by an internal battery. Provide one hand-held
programming unit when other means of
programming the circuit breakers are not
provided.
Provide a local area network connecting each
circuit breaker trip unit to a breaker interface
module (BIM). The BIM shall be capable of
changing the network communication
breaker address for each device, setting the
system baud rate and distribution frequency,
displaying breaker information and displaying monitored values. In addition, provide
password protection for programming time
current set points, and to perform functional
testing of phase and ground trip characteristics. The BIM shall have help message
capabilities and shall communicate information for up to fifty devices including Digitrip
OPTIM, 810, and 910 trip units and energy
sentinels. Provide a 30-volt DC power supply
for the BIM which is to be mounted within the
assembly. Provide a product operated network interface (PONI) for the BIM to communicate via the IMPACC network to a remote
computer.
Provide Cutler-Hammer/Westinghouse
Digitrip OPTIM 750 Trip Units
Note to Specifier — For trip units with the
additional functions of the Digitrip OPTIM
1050 for SPB or DSII circuit breakers, insert
the following:
The microprocessor-based trip units shall be
capable of monitoring the following data:
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Peak demand (Megawatts)
Present demand (Megawatts)
Reverse power flow
Energy consumption (Megawatt-hours)
Reverse energy consumption
Power Factor
Percentage harmonic content
Total harmonic distortion (THD)
The monitored data shall be displayed by a
hand-held programming unit, a breaker interface module or a remote computer.
Circuit Breakers shall be provided with a
potential transformer module, suitable for
operation up to 600 volts. The primary of the
potential transformer module shall be connected internally to the load side of the circuit
breaker through a dielectric disconnect plug.
The trip unit shall be capable of two-way
communication via a network twisted pair for
remote monitoring and control. Transmittable parameters shall include the addition of
power and energy values, line-to-line voltage,
power factor, total harmonic distortion,
harmonic content and waveform capture, via
the IMPACC communication network .
Provide Cutler-Hammer/ Westinghouse
Digitrip OPTIM 1050 Trip Units.
March 1996