phase to ground fault
figure 13.2 shows the traces associated with a phase to ground fault.
there are 1.5 circles of prefault normal load flow and two cycles of increased current during the fault.
when the local breaker opens there is a redistribution of fault current.
although the total fault current will be reduced, the contribution from either end may increase due to infeed (see example 4.6)
figure 13.2 shows this increase from the local end until the remote end opens when the fault is cleared
prior to the fault, there is no ground current.
actually, as discussed above, there may be some slight ground current trace due to unbalance
there are two cycles of ground fault current with both breakers closed, an increase when the local breaker opens and then zero when the remote end breaker opens.
Since the two ends of the line will not open or close simultaneously, by comparing the oscillograms from the two ends, the exact breaker sequence can be determined.
the first breaker to open will remove the fault current from that end of the line while the remote oscillogram will continue to show fault current.
the first breaker to close will result in an indicator of charging current until the other end closes and load current is restored.
since the phase current trace must accommodate the normal prefault load current while the ground current trace sees only the small prefault system unbalance, the two traces are calibrate differntly
phase to ground fault
figure 13.2 shows the traces associated with a phase to ground fault.
there are 1.5 circles of prefault normal load flow and two cycles of increased current during the fault.
when the local breaker opens there is a redistribution of fault current.
although the total fault current will be reduced, the contribution from either end may increase due to infeed (see example 4.6)
figure 13.2 shows this increase from the local end until the remote end opens when the fault is cleared
prior to the fault, there is no ground current.
actually, as discussed above, there may be some slight ground current trace due to unbalance
there are two cycles of ground fault current with both breakers closed, an increase when the local breaker opens and then zero when the remote end breaker opens.
Since the two ends of the line will not open or close simultaneously, by comparing the oscillograms from the two ends, the exact breaker sequence can be determined.
the first breaker to open will remove the fault current from that end of the line while the remote oscillogram will continue to show fault current.
the first breaker to close will result in an indicator of charging current until the other end closes and load current is restored.
since the phase current trace must accommodate the normal prefault load current while the ground current trace sees only the small prefault system unbalance, the two traces are calibrate differntly
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ระยะพื้นดินผิด
รูปที่ 13.2 แสดงร่องรอยที่เกี่ยวข้องกับเฟสของพื้นดิน .
มี 1.5 วงกลมของ prefault ปกติโหลดและการไหลสองรอบเพิ่มขึ้นในปัจจุบัน ในความผิด .
เมื่อเบรกเกอร์ท้องถิ่นเปิดมีการกระจายของความผิดในปัจจุบัน .
แม้ปัจจุบันความผิดทั้งหมดจะลดลง , บริจาค จากจบอาจเพิ่มขึ้นเนื่องจากการป้อนเข้า ( ดูตัวอย่างก่อน )
figure 13.2 shows this increase from the local end until the remote end opens when the fault is cleared
prior to the fault, there is no ground current.
actually, as discussed above, there may be some slight ground current trace due to unbalance
there are two cycles of ground fault current with both breakers closed,เพิ่มเมื่อเบรกเกอร์ท้องถิ่นเปิดแล้วศูนย์เมื่อเบรกเกอร์ สิ้นสุดระยะไกล .
ตั้งแต่ทั้งสองปลายของเส้นจะไม่เปิด หรือ ปิดพร้อมกัน โดยการเปรียบเทียบ oscillograms จากสองจบ ตามลําดับ เบรกเกอร์แน่นอน
สามารถระบุได้the first breaker to open will remove the fault current from that end of the line while the remote oscillogram will continue to show fault current.
the first breaker to close will result in an indicator of charging current until the other end closes and load current is restored.
since the phase current trace must accommodate the normal prefault load current while the ground current trace sees only the small prefault system unbalance, the two traces are calibrate differntly
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