GE 889 - Page 318

4–188 889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
PROTECTION CHAPTER 4: SETPOINTS
Figure 4-66: Ground Directional Voltage-polarized Characteristics
Path: Setpoints > Protection > Group 1(6) > Current > Ground Directional OC 1(X)
FUNCTION
Range: Disabled, Enabled
Default: Disabled
POLARIZING MODE
Range: Voltage, Current, Dual
Default: Voltage
NOTE
NOTE:
It is not recommended to use this function in the case of 50:0.025A CT input. If this is
applied consider Isg phasor metering errors in magnitude and angle in the settings.
This setting selects the polarizing mode for the directional unit.
•If Voltage polarizing mode is selected, the element uses the zero-sequence voltage
angle for polarization. The user can select either the zero-sequence voltage V_0,
calculated from the phase voltages, or the zero-sequence voltage supplied externally
as the auxiliary voltage V_X.
827805X1.CDR
VAG
(reference)
VBG
VCG
-Ig line
Ig line
ECA line
-ECA line
LA
LA
LA
LA
ECA
FWD LA
line
FWD Operating
Region
REV Operating
Region
FWD LA
line
REV LA
line
REV LA
line
-3V_0 line
3V_0 line