5-258 F60 Feeder Protection System GE Multilin
5.7 CONTROL ELEMENTS 5 SETTINGS
5
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
MESSAGE
HI-Z ARCING
SENSITIVITY: 5
Range: 1 to 10 in steps of 1
MESSAGE
HI-Z ARCING DET SOE
RESET TIME: 0.0 s
Range: 0.0 to 6000.0 s in steps of 0.1
MESSAGE
HI-Z PHASE EVENT
COUNT: 30
Range: 10 to 250 in steps of 1
MESSAGE
HI-Z GROUND EVENT
COUNT: 30
Range: 10 to 500 in steps of 1
MESSAGE
HI-Z EVENT COUNT
TIME: 15 min
Range: 5 to 180 min. in steps of 1
MESSAGE
HI-Z OC PROTECTION
COORD TIMEOUT: 15 s
Range: 10 to 200 s in steps of 1
MESSAGE
HI-Z PHASE OC MIN
PICKUP: 1.50 pu
Range: 0.01 to 10.00 pu in steps of 0.01
MESSAGE
HI-Z NEUTRAL OC MIN
PICKUP: 1.00 pu
Range: 0.01 to 10.00 pu in steps of 0.01
MESSAGE
HI-Z PHASE RATE OF
CHANGE: 150 A/2cycle
Range: 1 to 999 A/2cycle in steps of 1
MESSAGE
HI-Z NEUTRAL RATE OF
CHANGE: 150 A/2cycle
Range: 1 to 999 A/2cycle in steps of 1
MESSAGE
HI-Z LOSS OF LOAD
THRESHOLD: 15%
Range: 5 to 100% in steps of 1
MESSAGE
HI-Z 3-PHASE EVENT
THRESHOLD: 25 A
Range: 1 to 1000 A in steps of 1
MESSAGE
HI-Z VOLTAGE SUPV
THRESHOLD: 5%
Range: 0 (off) to 100% in steps of 1
MESSAGE
HI-Z VOLTAGE SUPV
DELAY: 60 cycles
Range: 0 to 300 cycles in steps of 2
MESSAGE
HI-Z EVEN HARMONIC
RESTRAINT: 20%
Range: 0 to 100% in steps of 1
MESSAGE
HI-Z TARGET:
Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
HI-Z EVENTS:
Disabled
Range: Disabled, Enabled
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