Functions
2.5 Power System Data 1
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
58
Phase Rotation
Address 271 PHASE SEQ. is used to change the default phase sequence (L1 L2 L3 for clockwise rotation),
if your power system permanently has an anti-clockwise phase sequence (L1 L3 L2). A temporary reversal
of rotation is also possible using binary inputs (see Section 2.47).
Figure 2-10 Phase sequences
Operating Mode
The 272 SCHEME setting specifies whether the generator to be protected is operated in Unit transf. or in
Busbar mode. This specification is important for stator earth fault connection and for the inverse O/C time pro-
tection with undervoltage consideration, as different voltages are used here, depending on the corresponding
operating mode (see „Undervoltage Consideration“ in Section 2.10).
ATEX100
Parameter 274 ATEX100 allows compliance with PTB requirements (special requirements in Germany) for
thermal replicas. If this parameter is set to YES, all thermal replicas of the 7UM62 are stored on auxiliary power
supply failure. As soon as the supply voltage returns, the thermal replicas continue operating with the stored
values. If the parameter is set to NO, the calculated overtemperature values of all thermal replicas are reset to
zero on auxiliary power supply failure.
Command Duration
In address 280 the minimum trip command duration TMin TRIP CMD is set. This duration is valid for all pro-
tection functions which can issue a trip command.
Current-flow Monitoring
Address 281 BkrClosed I MIN corresponds to the threshold value of the integrated current flow monitoring
system. This parameter is used for the elapsed-time meter, the restart inhibit and the overload protection. If the
set threshold current is exceeded, the circuit breaker is considered closed and the power system is considered
to be in operation. In the case of overload protection, this criterion distinguishes between standstill and motion
of the machine to be protected.
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