Protective Relay; Voltage Unbalance Relay; Current Unbalance Relay; Under Voltage Relay - GE EntelliGuard TU Installation, Operation And Maintenance Manual

EntelliGuard®TU Trip Unit
Section 1 – General Information

PROTECTIVE RELAY

The protection relay can be set to either cause a trip or
an alarm. If the PR Enable on the LCD is set to ON, a trip
will be generated, if set to NO an alarm will be generated.

Voltage Unbalance Relay

This function compares the highest or lowest phase
voltage with the average of all three phases and initiates
a trip if the difference exceeds the set point.
Table 9: Voltage Unbalance Settings
Item Option
Voltage unbalance Adjustable from 10% to 50%
pickup in increments of 1%.
Voltage unbalance Adjustable from 1 sec to
delay setting 15 sec in increments of 1 sec.
Setting this value to zero (0)
disables this function.

Current Unbalance Relay

This function compares the current in the highest or
lowest phase with the average of all three phases and
initiates a trip if the difference exceeds the set point.

Table 10: Current Unbalance Settings

Item Option
Current unbalance Adjustable from 10% to 50%
pickup in increments of 1%.
Current unbalance Adjustable from 1 sec to
delay setting 15 sec in increments of 1 sec.
Setting this value to zero (0)
disables this function.

Under Voltage Relay

This function measures the voltage in all phases and
initiates a trip if any phase voltage drops below the set
point.

Under Voltage Relay Zero-Volt Trip Enable

This function determines if the relay trips when all three-
phase voltages drop to zero volts. See Table 11.

Table 11: Under Voltage Settings

Item Option
Under voltage Adjustable from 50% to 90% in
pickup increments of 1%.
Under voltage Adjustable from 1 sec to 15 sec in
delay setting: increments of 1 sec. Setting this value
to zero (0) disables this function.
12
Courtesy of NationalSwitchgear.com

Over Voltage Relay

This function measures the voltage in all phases and
initiates a trip if any phase voltage exceeds the set point.
See Table 12.

Table 12: Over Voltage Settings

Item Option
Over voltage Adjustable from 110% to 150% in
pickup increments of 1%.
Over voltage Adjustable from 1 sec to 15 sec in
delay increments of 1 sec. Setting this value
to zero (0) disables this function.

Power-Reversal Relay

This function measures the direction of power flow
through the breaker and initiates a trip if a sufficient
magnitude of reverse power is detected.

Table 13: Power Reversal Settings

Item Option
Power Adjustable from 10 kW to 990 kW in
reversal increments of 10 kW.
pickup
Power Adjustable from 1 sec to 15 sec in
reversal delay increments of 1 sec. Setting this value
to zero (0) will disable this function.

Power Direction Setup

This function selects the normal power flow direction for
the breaker, either from line to load or from load to line.
This direction setup also affects the sign of the normal
power metering displays.

Potential Transformer Primary Voltage

Enter the primary voltage rating of the potential
transformer. The range of values is 120 V to 600 V, with
an increment of 1 V.
NOTICE
Incorrect set point will result in incorrect metering
values.

Potential Transformer Connection

Select the appropriate potential transformer connection,
either line-to-line (Ph-Ph) or line-to-neutral (Ph-N).
© 2008 General Electric All Rights Reserved
09/25/08