GE 850 - Page 335

CHAPTER 6: PROTECTION SETPOINTS CURRENT ELEMENTS
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 6–67
Figure 6-26: Negative Sequence Directional Characteristic
The forward-looking function is designed to be more secure compared to the reverse-
looking function, and should therefore be used for the tripping direction. The reverse-
looking function is designed to be faster compared to the forward-looking function and
should be used for the blocking direction. This allows better protection coordination. The
above bias should be taken into account when using the Negative Sequence Directional
Overcurrent element to directionalize other protection elements.
Path: Setpoints > Protection > Group 1(6) > Current > Negative Sequence Dir OC 1(X)
FUNCTION
Range: Disabled, Enabled
Default: Disabled
SIGNAL INPUT
Range: dependant upon the order code
Default: CT Bank 1 -J1
This setting provides a selection for the CT Bank input.
FAST PATH:
The “Current Input” setting is omitted for 850 which is defaulted to CT Bank 1-J1.
827806A2.CDR
VAG (reference)
VCG
VBG
-I_2 line
I_2 line
ECA line
-ECA line
LA
LA
LA
LA ECA
FWD Operating
Region
REV Operating
Region
FWD
LA
FWD
LA
REV
LA
REV
LA
V_2 line
-V_2 line