GE 750 Instruction Manual page 136

750/760
Feeder Management Relay
PHASE
DIRECTIONAL
5–40
FIGURE 5–8: Phase IOC Logic
d) Phase Directional Overcurrent
PATH: SETPOINTS S5 PROTECTION
[ ] PHASE DIRECTIONAL
FUNCTION: Disabled
PHASE DIRECTIONAL
MESSAGE
RELAYS (3-7): -----
PHASE DIRECTIONAL
MESSAGE
MTA: 30° Lead
MIN POLARIZING
MESSAGE
VOLTAGE: 0.05 x VT
BLK OC WHEN VOLT MEM
MESSAGE
EXPIRES: Disabled
Directional overcurrent relaying is necessary for the protection of multiple source
feeders, when it is essential to discriminate between faults in different directions. It
would be impossible to obtain correct relay selectivity through the use of a non-
directional overcurrent relay in such cases. Fault directional control (ANSI device
67) is incorporated into the relay for all phase, neutral, sensitive ground, and
negative sequence overcurrent elements. If directional control is selected, it will
determine whether current flow in each phase is in the forward or reverse direction,
as determined by the connection of the phase source CTs, selected MTA angle,
voltage and current phasors. Each overcurrent element can be individually
programmed to operate for flow only in specific directions. For increased security, all
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PHASE CURRENT PHASE DIRECTIONAL
Range: Disabled,
Alarm, Control
Range: Any combination of 3 to 7
Auxiliary relays
Range: 0 to 359° in steps of 1
Range: 0.00 to 1.25 x VT in steps of
0.01
Range: Disabled, Enabled
S5 Protection
Alarm, Latched
GE Multilin