the start signal has been confirmed 3 times in succession as a special security
measure. The trip command will be issued by the IED after the trip decision is
made with the added delay time form the hardware and communication.
Figure
42 shows charging current compensation when the exact method is used
(CCCOpMode = U based). The charging current is subtracted from all three
phases.
TOTAL COMPENSATED CURRENT IN PHASE L1
37 A subtracted under
fault conditions
92 A subtracted from the fundamental
frequency differential current
37 A subtracted
92 A subtracted
fault
fault
fault
37 A subtracted
92 A subtracted
CCC starts
after 100 ms
TOTAL COMPENSATED CURRENT IN PHASE L2
TOTAL COMPENSATED CURRENT IN PHASE L3
Tim e in seconds
IEC15000466-1-en.vsd
IEC15000466 V1 EN-US
Figure 42: Charging current compensation using the exact method
Charging current compensation starts 100 ms after simulation start when the power
line was switched on to normal load. Under normal load conditions, approximately
92 A is subtracted, which results in all fundamental frequency differential currents
being close to zero. Under fault conditions with very low voltage at the fault and
decreased voltages at both ends, the charging current is smaller, and only 37 A is
subtracted from the differential currents.
Figure
43 shows charging current compensation when the approximate method is
used (CCCOpMode = IDiff reduction). The charging current is subtracted from all
three phases.
Section 4 1MRK 505 382-UEN B
Analog and binary signal transfer for line differential protection
52 Communication set-up 670/650 series 2.2
Application Guide
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