Sensitive Ground - GE 750 Instruction Manual

750/760
Feeder Management Relay

Sensitive Ground

SENSITIVE GND
CURRENT
5–52
caused by system unbalanced voltages or VT ratio errors. For well-balanced
systems and 1% accuracy VTs, this setpoint can be as low as 2% of VT nominal
voltage. For systems with high-resistance grounding or floating neutrals, this
setpoint can be as high as 20%. The default value of "0.05 x VT" is appropriate
for most solidly grounded systems.
FIGURE 5–17: Ground Directional Overcurrent Logic
a) Main Menu
PATH: SETPOINTS S5 PROTECTION
[ ]
MESSAGE
MESSAGE
MESSAGE
Two sensitive ground overcurrent elements and a restricted earth fault element are
provided. One time overcurrent element and one instantaneous element. Sensitive
ground overcurrent elements can be controlled by the sensitive ground directional
element allowing operation for faults in the permitted direction only. Also, the
elements can be blocked individually or as a group by logic inputs.
http://www.GEmultilin.com
SENSITIVE GND CURRENT
SENSITIVE GND [ ]
See page 5–53.
TIME OVERCURRENT
SENSITIVE GND [ ]
See page 5–54.
INST OVERCURRENT
SENSITIVE GND [ ]
See page 5–55.
DIRECTIONAL
RESTRICTED [ ]
See page 5–56.
EARTH FAULT
S5 Protection
GE Multilin