GE Multilin
745 Transformer Management Relay
5-33
5 SETPOINTS
5.4 S2 SYSTEM SETUP
5
The 745 also calculates the total harmonic distortion of the phase current input signals. The band of frequencies over which
this calculation is made can be changed to be more selective than the default 2
nd
to 21
st
harmonics.
•
HARMONIC DERATING FUNCTION
: Enter "Enabled" to enable the harmonic derating factor calculations.
•
THD MINIMUM/MAXIMUM HARMONIC NUMBER
Enter the minimum/maximum harmonic number of the frequency
band over which total harmonic distortion is calculated.
5.4.6 FLEXCURVES™
PATH: SETPOINTS
ÖØ
S2 SYSTEM SETUP
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FLEXCURVES
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FLEXCURVE A(C)
Three programmed custom FlexCurves™ can be stored in the 745 as FlexCurve™ A, FlexCurve™ B, and FlexCurve™ C.
This allows the user to save special curves for specific applications and then select them as required for time overcurrent
element curves. The custom FlexCurve™ has setpoints for entering the times-to-trip at various levels of pickup. The levels
are as follows: 1.03, 1.05, 1.1 to 6.0
×
PU in steps of 0.1, and 6.5 to 20.0
×
PU in steps of 0.5.
•
CURVE TRIP TIME AT n
×
PU
: Enter the trip time for n = 1.03. 1.05,..., 20.0
×
PU for FlexCurve™ A(C). The messages
that follow sequentially correspond to the trip times for the various pickup levels as indicated above.
5.4.7 VOLTAGE INPUT
PATH: SETPOINTS
ÖØ
S2 SYSTEM SETUP
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VOLTAGE INPUT
The 745 provides a voltage input for the purposes of energization detection (for the Energization Inhibit feature of the per-
cent differential element), overexcitation protection (the Volts-per-Hertz 1 and 2 functions), and frequency protection (the
Underfrequency, Frequency Decay, and Overfrequency functions). Note that the frequency elements will use the Winding 1
Phase A current input if voltage is not available.
•
VOLTAGE INPUT PARAMETER
: Enter the winding and phase of the voltage connected to the voltage input.
•
NOMINAL VT SECONDARY VOLTAGE
: Enter the nominal secondary voltage (in volts) of the voltage transformer.
•
VT RATIO
: Enter the ratio of the voltage transformer.
FLEXCURVE A
[ENTER] for more
CURVE A TRIP TIME AT
1.03 x PU:
0 ms
Range: 0 to 65000 ms in steps of 1
CURVE TRIP TIME AT
1.05 x pu:
0 ms
Range: 0 to 65000 ms in steps of 1
↓
CURVE TRIP TIME AT
20.0 x pu:
0 ms
Range: 0 to 65000 ms in steps of 1
VOLTAGE INPUT
[ENTER] for more
VOLTAGE SENSING:
Disabled
Range: Enabled, Disabled
VOLTAGE INPUT
PARAMETER: W1 Van
Range: W1, W2, W3;
Van, Vbn, Vcn, Vab, Vbc, Vca
NOMINAL VT SECONDARY
VOLTAGE: 120.0 V
Range: 60.0 to 120.0 in steps of 0.1
VT RATIO:
1000:1
Range: 1 to 5000:1 in steps of 1
ENTER
ESCAPE
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