GE 745 TRANSFORMER MANAGEMENT RELAY User Manual

GE Power Management 745 Transformer Management Relay 5-51
5 SETPOINTS 5.6 S4 ELEMENTS
5
e) 5TH HARMONIC INHIBIT
This section contains the settings of the 5
th
harmonic inhibit feature of the percent differential element, which
allows inhibiting the percent differential during intentional overexcitation of the system. This feature inhibits the
percent differential element in a particular phase if the 5
th
harmonic of the same phase exceeds the harmonic
inhibit level setting. With harmonic averaging enabled, all three phases are inhibited if the three-phase average
of the 5
th
harmonic exceeds the level setting.
ENERGIZATION SENSING
BY VOLTAGE: Disabled
Range: Disabled / Enabled
Select
Enabled
to detect de-energization by the level of the voltage dropping
below the minimum energization voltage. This setpoint is displayed only if
voltage sensing is enabled under
S2 SYSTEM SETUP/VOLTAGE INPUT
.
MINIMUM ENERGIZATION
VOLTAGE: 0.85 X VT
Range: 0.50 to 0.99 (steps of 0.01)
Enter the voltage level below which the transformer is considered de-
energized (when
ENERGIZATION SENSING BY VOLTAGE
is
Enabled
). Displayed
only if
S2 SYSTEM SETUP/VOLTAGE INPUT/VOLTAGE SENSING
is
Enabled
.
BREAKERS ARE OPEN
SIGNAL: Disabled
Range: Disabled / Logc Inpt 1 (2-16)
Select any logic input which, when asserted, will indicate to the 745 that the
transformer is de-energized. The selected logic input should be connected to
the auxiliary contacts of the transformer breaker or disconnect switch.
PARALL XFMR BRKR CLS
SIGNAL: Disabled
Range: Disabled / Logc Inpt 1 (2-16)
Select any logic input which, when asserted, will indicate to the 745 the
onset of sympathetic inrush. The selected logic input should be connected to
the close command going to the parallel transformer switching device.
y 5th HARM INHIBIT
y
[ENTER] for more
This message indicates the start of the
5TH HARMONIC INHIBIT
section. To
continue with these setpoints press , or press to go to the
next section.
5th HARMONIC INHIBIT
FUNCTION: Disabled
Range: Disabled / Enabled
HARMONIC AVERAGING:
Disabled
Range: Disabled / Enabled
Select ‘Enabled’ to use the three-phase average of the 5th harmonic current
against the harmonic inhibit setting.
5th HARMONIC INHIBIT
LEVEL: 10.0%
ƒο
Range: 0.1 to 65.0 (steps of 0.1)
Enter the level of 5th harmonic current above which the percent differential
element will be inhibited from operating.
ENTER
MESSAGE

GE 745 TRANSFORMER MANAGEMENT RELAY Specifications

General

Brand	GE
Model	745 TRANSFORMER MANAGEMENT RELAY
Category	Relays
Language	English