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
 
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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