Potential Transformer module
The PT (potential or voltage transformer) module is external to
the circuit breaker on the NRX NF frame. It may be externally
mounted or internally mounted and wired in the NRX RF frame
circuit breaker to the line side circuit breaker terminals. It
provides the signals to measure the system voltage. These
input signals are used to measure voltage and calculate; power,
energy, and if selected, perform protection functions on voltage
and frequency. The PT module is a three-phase, three-wire
input and a four-wire output step-down transformer with a wye
to wye configuration.
The power and energy metering and protection functions are
calculated with the convention that power flow is from line to
load through the circuit breaker. This assumes the top side
conductor to be the line side. If the distribution system is
configured such that the bottom side is the incoming side, the
power values will indicate reverse power. This can be changed
via setpoint programming.
Trip Events
1. Observe any Trip LED flashing on trip unit.
2. Observe message on the display.
3. Step to the event submenu to observe the timestamp
of event and trip current data. This data, along with the
timestamp, will also be stored in the event log. The maximum
trip current value that can be displayed is 65535A.
4. After any trip condition, the trip unit should be reset by
pressing the Reset pushbutton
A reset pushbutton operation does the following after a trip:
• Clears the cause of trip flashing LED after a trip event
• Clears the Trip LED
• Clears display data
5. Reclose circuit breaker as desired.
See
Appendix D: Display, Indicators and Menus
for more
information on viewing trip events and screen information that
can be viewed after the event
Waveform capture - Trip
The following causes for a trip will perform a 10 cycle waveform
capture. The waveform information will contain 6 pre-event
cycles and 4 post-event cycles of data.
•
Long Delay
•
Short Delay
•
Instantaneous
•
Ground
•
Phase Loss
•
Current Unbalance
•
Over Voltage
•
Under Voltage
•
Voltage Unbalance
•
Reverse Power
•
Over Frequency
•
Under Frequency
•
Maintenance Mode
•
Neutral
19
EATON
www.eaton.com
Alarm Events
1. Alarm LED flashing on trip unit.
2. Observe message on the display.
3. Step to the event submenu to observe the timestamp of
event and data. This data, along with the timestamp, will also
be stored in the event log.
4. After any alarm condition, the trip unit should be reset by
pressing the Reset pushbutton
See
Appendix D: Display, Indicators and Menus
for more
information on viewing alarm events and screen information
that can be viewed after the event.
Alarms are tracked in real-time and a Reset pushbutton may
momentarily clear the alarm but the Alarm LED and alarm
message will reappear if the condition is still present.
The ESCape pushbutton activation will remove the alarm
message from the display and return to normal menu viewing
mode, but the Alarm LED will remain lit.
ote:
N
A way to clear an alarm if desired, after reviewing the alarm
and its associated data, is to enter the Program settings submenu and
change or turn off the associated alarm setpoint value.
Waveform capture - Alarms
The following alarms will perform a 6 cycle waveform capture:
•
Long Delay Pickup
•
Current Unbalance
•
Ground Fault
•
High Current Fault
•
High Load
•
Neutral Current
•
Phase Rotation
•
Over Voltage
•
Under Voltage
•
Voltage Unbalance
•
Over Frequency
•
Under Frequency
•
Low Power Factor
•
Reverse Power
•
kVA Demand
•
kW Demand
•
THD
Effective September 2013
Instructional Leaflet IL01301064E
Operating Manual for Series NRX
Digitrip Trip Units 1150 / 1150i
