Flexcurves; Voltage Input - GE Multilin 745 Instruction Manual

745
Transformer Management Relay

FlexCurves™

! FLEXCURVE A

Voltage Input

! VOLTAGE INPUT
5–34
information that is often only available from the transformer manufacturer's test
report, including the three-phase resistance of each winding and the load loss at
rated load. The harmonic derating factor will only be valid if this information has
been entered correctly.
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
• 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.
PATH: SETPOINTS S2 SYSTEM SETUP
!"
[!] FLEXCURVE A DELAY AT
1.03 x PU:
FLEXCURVE A DELAY AT
MESSAGE
1.05 x pu:
FLEXCURVE A DELAY AT
MESSAGE
20.0 x pu:
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
• FLEXCURVE A DELAY AT n
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.
PATH: SETPOINTS S2 SYSTEM SETUP
!"
[!] VOLTAGE SENSING:
Disabled
VOLTAGE INPUT
MESSAGE
PARAMETER: W1 Van
NOMINAL VT SECONDARY
MESSAGE
VOLTAGE: 120.0 V
VT RATIO:
MESSAGE
1000:1
The 745 provides a voltage input for the purposes of energization detection (for the
Energization Inhibit feature of the percent 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.
http://www.GEindustrial.com/multilin
nd st
to 21 harmonics.
FLEXCURVES FLEXCURVE A(C)
!" !
Range: 0 to 65000 ms in steps of 1
0 ms
Range: 0 to 65000 ms in steps of 1
0 ms
↓
Range: 0 to 65000 ms in steps of 1
0 ms
PU in steps of 0.5.
×
PU: Enter the trip time for n = 1.03. 1.05,...,
×
VOLTAGE INPUT
!"
Range: Enabled, Disabled
Range: W1, W2, W3;
Range: 60.0 to 120.0 in steps of 0.1
Range: 1 to 5000:1 in steps of 1
S2 System Setup
Van, Vbn, Vcn, Vab, Vbc, Vca
GE Multilin