ABB REG650 Technical Manual page 99

1MRK 502 034-UEN -
Technical Manual
TRIPRESL1
TRIPRESL2
TRIPRESL3
TRIPUNREL1
TRIPUNREL2
TRIPUNREL3
TRNSSENS
TRNSUNR
IEC05000278 V1 EN
Figure 41: Transformer differential protection internal grouping of tripping
signals
IEC05000279-TIFF V1 EN
Figure 42: Transformer differential protection internal grouping of logical signals
Logic in figures 39, 40,
1. The three fundamental frequency differential currents are applied in a phase-
wise manner to two limits. The first limit is the operate-restrain characteristic,
while the other is the high-set unrestrained limit. If the first limit is exceeded, a
start signal START is set. If the unrestrained limit is exceeded, an immediate
unrestrained trip TRIPUNRE and common trip TRIP are issued.
2. If a start signal is issued in a phase, then the harmonic-, and the waveform
block signals are checked. Only a start signal, which is free of all of its
respective block signals, can result in a trip command. If the cross-block logic
scheme is applied, then only if all phases with set start signal are free of their
OR
OR
41 and 42 can be summarized as follows:
Section 5
Differential protection
TRIPRES
TRIPUNRE
TRIP
OR
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