GE F60 Instruction Manual page 353

5 SETTINGS
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
Some faults in overhead distribution feeders are characterized by low fault current due to high ground resistance. If the fault
current is in the order of expected unbalance load or less, it cannot be reliably detected by overcurrent protection. These
faults are classified as high-impedance (Hi-Z) faults. Since a Hi-Z fault is not accompanied by excessive current, it is gener-
ally not dangerous to the electrical installation except for some damage to the overhead conductor at the fault location.
However, an undetected Hi-Z fault is a risk to people and property as well as having a potential to evolve into a full-blown
fault.
The following event types are associated with Hi-Z faults. It is assumed that for all cases that ground is involved.
• High impedance fault: a fault with fault impedance sufficiently high such that it is not detected by overcurrent protection
• High impedance, downed conductor fault: a high impedance fault for which the primary conductor is no longer intact on
pole top insulators, but instead is in contact with earth or a grounded object
• Arcing fault: any high impedance fault which exhibits arcing
GE Multilin
HI-Z ARCING
SENSITIVITY: 5
HI-Z ARCING DET SOE
RESET TIME: 0.0 s
HI-Z PHASE EVENT
COUNT: 30
HI-Z GROUND EVENT
COUNT: 30
HI-Z EVENT COUNT
TIME: 15 min
HI-Z OC PROTECTION
COORD TIMEOUT: 15 s
HI-Z PHASE OC MIN
PICKUP: 1.50 pu
HI-Z NEUTRAL OC MIN
PICKUP: 1.00 pu
HI-Z PHASE RATE OF
CHANGE: 150 A/2cycle
HI-Z NEUTRAL RATE OF
CHANGE: 150 A/2cycle
HI-Z LOSS OF LOAD
THRESHOLD: 15%
HI-Z 3-PHASE EVENT
THRESHOLD: 25 A
HI-Z VOLTAGE SUPV
THRESHOLD: 5%
HI-Z VOLTAGE SUPV
DELAY: 60 cycles
HI-Z EVEN HARMONIC
RESTRAINT: 20%
HI-Z TARGET:
Self-reset
HI-Z EVENTS:
Disabled
F60 Feeder Protection System
5.7 CONTROL ELEMENTS
Range: 1 to 10 in steps of 1
Range: 0.0 to 6000.0 s in steps of 0.1
Range: 10 to 250 in steps of 1
Range: 10 to 500 in steps of 1
Range: 5 to 180 min. in steps of 1
Range: 10 to 200 s in steps of 1
Range: 0.01 to 10.00 pu in steps of 0.01
Range: 0.01 to 10.00 pu in steps of 0.01
Range: 1 to 999 A/2cycle in steps of 1
Range: 1 to 999 A/2cycle in steps of 1
Range: 5 to 100% in steps of 1
Range: 1 to 1000 A in steps of 1
Range: 0 (off) to 100% in steps of 1
Range: 0 to 300 cycles in steps of 2
Range: 0 to 100% in steps of 1
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
5
5-213