Phase Loss (current based)
The phase loss trip function can be selected in the program
settings submenu. It is set to OFF initially as a factory
default. A time delay of 1 to 30 seconds can be selected. If
there exists a 75% difference between the maximum phase
and minimum phase currents and if maintained for the
selected time delay, the breaker will trip with a PHASE LOSS
TRIP message and red Trip LED illuminated. The function
does require auxiliary power to the Digitrip unit. To avoid
unnecessary operation of the function, the trip unit requires
that the circuit breaker must be carrying 55% of the Ir rating on
at least one phase before it will trip via phase loss.
Voltage, Frequency, Reverse Power
These functions, unlike the LSIG current protection functions,
require a reliable source of +24 Vdc auxiliary power to the trip
unit on the circuit breaker secondary contacts 21 and 22.
The voltage is sensed on all three phases. Any phase-to-phase
voltage exceeding the specified limit will activate the protection
function.
Voltage and frequency and reverse power tripping and/or
alarming can be set by entering the program settings submenu.
The functions can be mapped to Relay 1 and or Relay 2 for
desired output contact indication.
The voltage, frequency, and power functions each have a
master setting to enable or disable the related trip and alarm
settings.
The frequency trip or alarm functions have a valid frequency
range betwenn 45 Hz to 65 Hz.
ote:
N
Frequency is sensed on phase A voltage input. The frequency
trip, or alarm function will not be active if this voltage falls below 69 V
Line to Line.
Voltage, Frequency, Power - Trip
Voltage, frequency and power protection trip functions, if
enabled, are active whenever the circuit breaker is closed.
These trip functions are made inactive after a trip or when the
circuit breaker opens. After a tripping event enter the Events
log submenu and observe the event that initiated the trip.
Voltage, Frequency, Power - Alarms
Alarms are real-time and are active when the circuit breaker is
in either the Open or Closed state. The Alarm LED will light to
indicate any enabled alarm condition.
The setting range for under-frequency or over-frequency tripping
and alarming is 45.0 to 65.0 Hz for either a 50 or 60 Hz system.
Voltage unbalance is adjustable from 5-50% in steps of 1%. The
voltage unbalance value is calculated by multiplying the setting
as a decimal times the V maximum value. If the V Minimum
value is less than the voltage unbalanced value the alarm will
be activate.
The Phase Rotation alarm can be set to ABC or CBA or OFF
in the Alarm submenu under the Program settings submenu.
The phase rotation alarm can then be mapped to relay 1 or 2
if programmed for alarms. With this contact an application of
using an interposing relay with time delay can be employed to
provide time and contact arrangements to interface with the
circuit breaker’s closing circuit (spring release coil) to either
prevent closing or to open the circuit breaker (shunt trip coil)
based on the phase rotation.
Other System Settings
Time and Date
The trip unit has the present date displayed in DD Mmm YY
format. For example: 12 Mar 11 is the 12th day of March for
the year 2011. Time is displayed HH:MM:SS in 24 hour format
with hours from 0 to 23, minutes from 0 to 60, and seconds
from 0 to 59.
Frequency
This setting is to reflect the power system’s operating
frequency of 50 or 60 Hz.
Demand Window
A fixed or sliding window demand calculation can be chosen
for currents, kW demand, or kVA demand. The window has a
range from 5 to 60 minutes. There are separate widow settings
for current and power.
Power and Energy Parameters
Power has an approximate 1 second update rate and is shown
as forward or reverse power in kW units. The parameters kVA
and kvar are also updated in a similar time period. Demand kW
is presented as forward or reverse. Programming alarms (kW
or kVA) to exceed a threshold value will produce an alarm as
well as an event timestamp log.
Demand maximum kW, and demand maximum kVA are peak
values that have been encountered since the last reset of these
parameters. As a factory default, both kW and kVA demands
are set for a “fixed” 15-minute window. The update rate for the
calculation is 15-minutes. A “Sliding” window calculation is a
possible setting that will calculate a continuous new demand
value and updates the value if a new maximum is encountered
every 15 seconds or 1 minute depending upon the sliding
window size.
The trip unit will display kWh units of both forward and reverse
energy values. An additional energy parameter is kVAh. The
rollover energy value is 999,999,999 for both.
Sign Convention
The Digitrip trip unit is capable of four-quadrant metering and
has a setpoint that determines the sign convention used for
reactive power and power factor.
IEC Sign Convention
This setting uses the power engineering convention where
P = VI*. Where power is the complex product of volts times
the conjugate of current. The sign of the power factor follows
the mathematical definition of the PF = P / VA
IEEE Sign Convention
This setting uses the power engineering convention where
P = VI*. Where power is the complex product of volts times
the conjugate of current. The sign of the power factor is
positive if the signs of Watts and VARs are the same. A lagging
PF is positive. This sign convention should be used when using
a PROFIBUS communication module to be compatible with the
PROFIBUS circuit breaker profile.
26
EATON
www.eaton.com
Effective September 2013
Instructional Leaflet IL01301064E
Operating Manual for Series NRX
Digitrip Trip Units 1150 / 1150i
