GE 745 Instruction Manual page 148

S4 ELEMENTS
5.6.3.3 Harmonic inhibit

HARMONIC
INHIBIT
5–52
PATH: SETPOINTS S4 ELEMENTS


[ ] HARMONIC INHIBIT
FUNCTION: Enabled
HARMONIC INHIBIT
MESSAGE
PARAMETERS: 2nd
HARMONIC AVERAGING:
MESSAGE
Disabled
HARMONIC INHIBIT
MESSAGE
LEVEL: 20.0% f0
This menu contains the percent differential harmonic inhibit settings. This is the percent
differential element in a particular phase if the 2
the
HARMONIC INHIBIT LEVEL
"2nd + 5th", the RMS sum of the 2
the level setting. With harmonic averaging enabled, all three phases are inhibited if the 3-
phase average of the harmonics exceeds the level setting.
The 2nd and 5th harmonics are calculated based on W1 three-phase currents. When
HARMONIC AVERAGING
harmonics per-phase for all three W1 phases, and calculates average harmonic value. This
value is compared against the level set under
is set to "Disabled", the extracted 2nd, or 2nd+5th harmonics are compared against the
level per each phase individually.
HARMONIC INHIBIT
• HARMONIC INHIBIT PARAMETERS: Select "2nd" to compare only the 2
current against the
nd th
of the 2 and 5
current alone will exceed 20% during energization and the "2nd" value is sufficient to
inhibit the differential element for inrush current.
• HARMONIC AVERAGING: Select "Enabled" to use the three-phase average of the
harmonic current against the harmonic inhibit setting. For most applications, enabling
harmonic averaging is not recommended.
• HARMONIC INHIBIT LEVEL: Enter the level of harmonic current (2
which the percent differential element will be inhibited from operating. For most
applications, this level should be set to "20%".
DIFFERENTIAL

nd
setpoint. With harmonic inhibit parameters set to
nd th
and 5 harmonic components is compared against
is set to Enabled, the relay extracts the 2nd, or the 2nd+5th
HARMONIC INHIBIT
HARMONIC INHIBIT LEVEL
harmonic components. For most transformers, the 2
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
HARMONIC INHIBIT

Range: Enabled, Disabled
Range: 2nd, 2nd + 5th
Range: Enabled, Disabled
Range: 0.1 to 65.0% f
0
harmonic of the same phase exceeds
. If
HARMONIC AVERAGING
nd
. Select "2nd + 5th" to use the RMS sum
nd
nd
or 2
in steps of 0.1
harmonic
harmonic
nd th
+5 ) above