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4 FRONT PANEL OPERATION
d) DIFFERENTIAL BLOCKED
The DIFFERENTIAL BLOCKED indicator is on when the restrained differential protection feature is enabled
but is being blocked from operating by any of the harmonic restraint features.
The indicator is on if the following condition is met:
S4 ELEMENTS / DIFFERENTIAL / HARMONIC RESTRAINT is blocking any phase (see scheme logic)
•
e) LOCAL
The LOCAL indicator is on when the 745 is in local mode, i.e. the front panel RESET key is operational.
f) MESSAGE
The MESSAGE indicator is on when any element has picked up, operated, or is now in a latched state waiting
to be reset. With this indicator on, the front panel display is sequentially displaying information about each ele-
ment that has detected an abnormal condition.
a) TRANSFORMER DE-ENERGIZED
The TRANSFORMER DE-ENERGIZED indicator is on when the energization inhibit
feature has detected that the transformer is de-energized.
The indicator is on if the S4 ELEMENTS/DIFFERENTIAL/ENERGIZATN INHIBIT feature is
detecting the transformer as de-energized
b) TRANSFORMER OVERLOAD
The TRANSFORMER OVERLOAD indicator is on when S4 ELEMENTS/XFORMER
OVERLOAD has operated.
c) LOAD-LIMIT REDUCED
The LOAD-LIMIT REDUCED indicator is on when the adaptive harmonic factor cor-
rection feature is detecting enough harmonic content to reduce the load rating of the
transformer. The indicator is on if S2 SYSTEM SETUP/HARMONIC DERATING/HARMONIC
DERATING ESTIMATION is Enabled and the harmonic derating function is below 0.96.
d) SETPOINT GROUP 1
The SETPOINT GROUP 1 indicator is on when the active setpoint group is 1. This indicator flashes when this
setpoint group is being edited.
e) SETPOINT GROUP 2
The SETPOINT GROUP 2 indicator is on when the active setpoint group is 2. This indicator flashes when this
setpoint group is being edited.
f) SETPOINT GROUP 3
The SETPOINT GROUP 3 indicator is on when the active setpoint group is 3. This indicator flashes when this
setpoint group is being edited.
g) SETPOINT GROUP 4
The SETPOINT GROUP 4 indicator is on when the active setpoint group is 4. This indicator flashes when this
setpoint group is being edited.
GE Power Management
4.2 DISPLAY, INDICATORS, AND FRONT PORT
745 Transformer Management Relay
4.2.4 SYSTEM STATUS INDICATORS
4
4-3
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