GE Industrial Solutions Spectra RMS Molded Case - Manual (Page 21)

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GEH-702 Users Manual
Table 17. ZSI Settings
ZSI (ST/GF) enabled ZSI (ST/GF/INST) enabled
OFF OFF
GF only GF only
GF, ST GF, ST
ST only ST only
ST, INST
ST, GF, INST
Neutral Protection Pickup (Optional)
This set point is used to provide overcurrent protection
on the system neutral. Overcurrent protection on
the system neutral is directly proportional to the
parameters previously established for both the Long
Time and Short Time pickup settings. The available
settings for this parameter are OFF, 50%, 100% and 150%.
This optional set point requires a neutral CT connection
and the appropriate equipment interfaces.
Protective Relays (Optional)
Voltage Unbalance Relay Pickup – this relay compares
the highest and lowest true RMS phase voltage with
the average of all phase voltages and initiates a trip or
alarm is the difference exceeds the set point pickup and
delay values. The available range of voltage unbalance
set point values is 10% to 50% in increments of 1%.
Voltage Unbalance Relay Delay – this setting enables a
time delay from the point of pickup to the initiation of
a trip signal. The available range of time delay settings
is 1 to 15 seconds in increments of 1 second. Choosing
OFF disables the relay.
Current Unbalance Relay Pickup – this relay compares
the highest and lowest true RMS phase current with
the average of all phase currents and initiates a trip or
alarm is the difference exceeds the set point pickup and
delay values. The available range of current unbalance
set point values is 10% to 50% in increments of 1%.
Current Unbalance Relay Delay – this setting enables a
time delay from the point of pickup to the initiation of
a trip signal. The available range of time delay settings
is 1 to 15 seconds in increments of 1 second. Choosing
OFF disables the relay.
Under Voltage Relay Pickup – this relay measures the
true RMS phase voltage in all phases and initiates a trip
or alarm if any phase voltage drops below the set point
and delay values. The available range of under voltage
set point values is 50% to 90% of the nominal voltage
in increments of 1%.
Under Voltage Relay Delay – this setting enables a time
delay from the point of pickup to the initiation of a trip
signal. The available range of time delay settings is 1
to 15 seconds in increments of 1 second. Choosing OFF
disables the relay.
Over Voltage Relay Pickup – this relay measures the
true RMS phase voltage in all phases and initiates a trip
or alarm if any phase voltage exceeds the set point and
delay values. The available range of over voltage set
point values is 110% to 150% of the nominal voltage in
increments of 1%.
Over Voltage Relay Delay – this setting enables a time
delay from the point of pickup to the initiation of a trip
signal. The available range of time delay settings is 1
to 15 seconds in increments of 1 second. Choosing OFF
disables the relay.
Power Reversal Relay Pickup – this relay measures
the direction of power flow through the breaker and
initiates a trip or alarm if a sufficient magnitude of
reverse power is detected. The available range of
power reversal set point values is 10 to 990 kW in
increments of 10 kW.
Power Reversal Relay Delay – this setting enables a
time delay from the point of pickup to the initiation of
a trip signal. The available range of time delay settings
is 1 to 15 seconds in increments of 1 second. Choosing
OFF disables the relay.
Load Alarm – this relay is also referred to as the load
shedding relay. The purpose of this relay is to signal
that the breaker is approaching a percentage of the trip
unit’s established ampere rating “C” (long time setting x
rating plug value). There are two set points associated
with this relay; Load Alarm ON and Load Alarm OFF.
The Load Alarm OFF setting is interdependent on the
Load Alarm ON setting.
The range of available settings for Load Alarm ON is
0.55 to 1.00 in increments of 0.05. This value multiplied
by the ampere rating “C” establishes the current that
the Load Alarm relay changes state.