Energization Inhibit; Energization Sensing - GE 745 TRANSFORMER MANAGEMENT RELAY Instruction Manual

5.6 S4 ELEMENTS
The energization inhibit feature may also be put in service during sympathetic inrush. The onset of sympathetic
inrush is detected via a close command to the parallel transformer switching device connected to a logic input,
assigned to the PARALL XFMR BRKR CLS setpoint. The energization inhibit settings are put in service when the
contact closes. Upon the removal of the signal, the energization inhibit duration timer is initiated and the set-
tings are removed from service when the time delay elapses.
In a "breaker-and-a-half scheme", where current can be present in the CTs without being present in the trans-
former winding, it may be necessary to use the Parallel transformer Breaker Close contact to initiate Energiza-
tion Inhibit.
S ENERGIZATN INHIBIT
S [ENTER] for more

ENERGIZATION INHIBIT

FUNCTION: Enabled
ENERGIZATION INHIBIT
PARAMETERS: 2nd
HARMONIC AVERAGING:
Enabled
5
ENERGIZATION INHIBIT
LEVEL: 20.0% ƒο
ENERGIZATION INHIBIT
DURATION: 0.10 s
d) ENERGIZATION SENSING
This section contains the settings for the Energization Sensing element. Energization sensing allows for the
measurement of de-energization by current and voltage.
S ENERGIZATION SENSING
S [ENTER] for more

ENERGIZATION SENSING

BY CURRENT: Enabled
MINIMUM ENERGIZATION
CURRENT: 0.10 x CT
5-50
This message indicates the start of the ENERGIZATION INHIBIT section. To
continue with these setpoints press
next section.
Range: Disabled / Enabled
Range: 2nd / 2nd + 5th
Select 2nd to compare the 2
LEVEL. Select 2nd+5th to use the RMS sum of the 2
Range: Disabled / Enabled
Select Enabled to use the three-phase average of the harmonic current
against the harmonic inhibit setting.
Range: 0.1 to 65.0 (steps of 0.1)
Enter the level of harmonic current (2
differential element is inhibited from operating. This setting will often need to
be set significantly lower than the HARMONIC INHIBIT LEVEL, especially when
used with the Parallel Xfmr BkrCls logic input function for sympathetic inrush.
Range: 0.05 to 600.00 (steps of 0.01)
Enter the time delay from the moment of energization (or the end of the
parallel breaker close command) before the energization inhibit feature is
removed from service.
This message indicates the start of the ENERGIZATION SENSING section. To
continue with these setpoints press
next section.
Range: Disabled / Enabled
Select Enabled to detect de-energization by the level of all currents dropping
below the minimum energization current.
Range: 0.10 to 0.50 (steps of 0.01)
Enter the level of current below which the transformer is considered de-
energized (energization sensing by current enabled), and above which the
transformer is considered energized (any energization sensing enabled).
745 Transformer Management Relay
, or press
E N TE R
M E SSA G E
nd
harmonic current against HARMONIC INHIBIT
nd
and 5
nd nd th
or 2 + 5 ) above which the percent
, or press
E N TE R
M E SSA G E
GE Power Management
5 SETPOINTS
to go to the
th
harmonics.
to go to the