GE Multilin F60 Feeder Protection System 5-2135 SETTINGS 5.7 CONTROL ELEMENTS5Some faults in overhead distribution feeders are characterized by low fault current due to high ground resistance. If the faultcurrent is in the order of expected unbalance load or less, it cannot be reliably detected by overcurrent protection. Thesefaults 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-blownfault.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 onpole top insulators, but instead is in contact with earth or a grounded object• Arcing fault: any high impedance fault which exhibits arcingMESSAGE HI-Z ARCINGSENSITIVITY: 5Range: 1 to 10 in steps of 1MESSAGE HI-Z ARCING DET SOERESET TIME: 0.0 sRange: 0.0 to 6000.0 s in steps of 0.1MESSAGE HI-Z PHASE EVENTCOUNT: 30Range: 10 to 250 in steps of 1MESSAGE HI-Z GROUND EVENTCOUNT: 30Range: 10 to 500 in steps of 1MESSAGE HI-Z EVENT COUNTTIME: 15 minRange: 5 to 180 min. in steps of 1MESSAGE HI-Z OC PROTECTIONCOORD TIMEOUT: 15 sRange: 10 to 200 s in steps of 1MESSAGE HI-Z PHASE OC MINPICKUP: 1.50 puRange: 0.01 to 10.00 pu in steps of 0.01MESSAGE HI-Z NEUTRAL OC MINPICKUP: 1.00 puRange: 0.01 to 10.00 pu in steps of 0.01MESSAGE HI-Z PHASE RATE OFCHANGE: 150 A/2cycleRange: 1 to 999 A/2cycle in steps of 1MESSAGE HI-Z NEUTRAL RATE OFCHANGE: 150 A/2cycleRange: 1 to 999 A/2cycle in steps of 1MESSAGE HI-Z LOSS OF LOADTHRESHOLD: 15%Range: 5 to 100% in steps of 1MESSAGE HI-Z 3-PHASE EVENTTHRESHOLD: 25 ARange: 1 to 1000 A in steps of 1MESSAGE HI-Z VOLTAGE SUPVTHRESHOLD: 5%Range: 0 (off) to 100% in steps of 1MESSAGE HI-Z VOLTAGE SUPVDELAY: 60 cyclesRange: 0 to 300 cycles in steps of 2MESSAGE HI-Z EVEN HARMONICRESTRAINT: 20%Range: 0 to 100% in steps of 1MESSAGE HI-Z TARGET:Self-resetRange: Self-reset, Latched, DisabledMESSAGE HI-Z EVENTS:DisabledRange: Disabled, Enabled
