5-50
745 Transformer Management Relay
GE Power Management
5.6 S4 ELEMENTS
5 SETPOINTS
5
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.
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.
y
ENERGIZATN INHIBIT
y
[ENTER] for more
This message indicates the start of the
ENERGIZATION INHIBIT
section. To
continue with these setpoints press
, or press
to go to the
next section.
ENERGIZATION INHIBIT
FUNCTION: Enabled
Range: Disabled / Enabled
ENERGIZATION INHIBIT
PARAMETERS: 2nd
Range: 2nd / 2nd + 5th
Select
2nd
to compare the 2
nd
harmonic current against
HARMONIC INHIBIT
LEVEL
. Select
2nd+5th
to use the RMS sum of the 2
nd
and 5
th
harmonics.
HARMONIC AVERAGING:
Enabled
Range: Disabled / Enabled
Select
Enabled
to use the three-phase average of the harmonic current
against the harmonic inhibit setting.
ENERGIZATION INHIBIT
LEVEL: 20.0%
ƒο
Range: 0.1 to 65.0 (steps of 0.1)
Enter the level of harmonic current (2
nd
or 2
nd
+ 5
th
) above which the percent
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.
ENERGIZATION INHIBIT
DURATION: 0.10 s
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.
y
ENERGIZATION SENSING
y
[ENTER] for more
This message indicates the start of the
ENERGIZATION SENSING
section. To
continue with these setpoints press
, or press
to go to the
next section.
ENERGIZATION SENSING
BY CURRENT: Enabled
Range: Disabled / Enabled
Select
Enabled
to detect de-energization by the level of all currents dropping
below the minimum energization current.
MINIMUM ENERGIZATION
CURRENT: 0.10 x CT
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).
E N TE R
M E SSA G E
E N T E R
M E SSA G E
Summary of Contents for 745 TRANSFORMER MANAGEMENT RELAY
Page 30: ...2 8 745 Transformer Management Relay GE Power Management 2 3 SECURITY 2 GETTING STARTED 2 ...
Page 210: ...7 36 745 Transformer Management Relay GE Power Management 7 2 BLOCK DIAGRAMS 7 SCHEME LOGIC 7 ...
Page 322: ...9 12 745 Transformer Management Relay GE Power Management 9 3 USING 745PC 9 745 PC SOFTWARE 9 ...
Page 396: ...A 4 745 Transformer Management Relay GE Power Management A 1 FIGURES AND TABLES APPENDIXA A ...
Page 400: ...C 2 745 Transformer Management Relay GE Power Management C 1 WARRANTY INFORMATION APPENDIXC C ...
Page 406: ...vi 745 Transformer Management Relay GE Power Management ...
Page 407: ...GE Power Management 745 Transformer Management Relay NOTES ...