2.2 Differential Protection
129
7UT613/63x Manual
C53000-G1176-C160-2
current of the 7UT613/63x) amounts to
I
N
= 0.1 A at nominal conditions, with correct
matching.
Figure 2-48
Winding arrangement of summation and matching transformers 4AM5120
Differential Current
Monitoring
Whereas a high sensitivity of the differential protection is normally required for trans-
formers, reactors, and rotating machines in order to detect even small fault currents,
high fault currents are expected in case of faults on a busbar so that a higher pickup
threshold (above rated current) is conceded here. This allows for a continuous moni-
toring of the differential currents on a low level. A small differential current in the range
of operational currents indicates a fault in the secondary circuit of the current trans-
formers.
When, during normal load conditions, a differential current is detected in the order of
the load current of a feeder, this indicates a missing secondary current, i.e. a fault in
the secondary current leads (short-circuit or open-circuit). This condition is annunciat-
ed with time delay. The differential protection is blocked at the same time.
Feeder Current
Guard
With busbars a release of the trip command can be set if a threshold is exceeded by
one of the incoming currents. The currents of each feeder are monitored for over-
shooting of a set value. Trip command is allowed only when at least one of these cur-
rents exceeds a certain (settable) threshold.
2.2.7
Setting Notes
General
Differential protection is only effective and available if this function was set during con-
figuration of the Functional Scope
DIFF. PROT.
=
Enabled
(address
112
) . If the
function is not required
Disabled
is to be set.
Additionally, the type of protected object must be decided during configuration (ad-
dress
105
PROT. OBJECT
). Only those parameters are offered which are reasonable
for the selected type of protected object; all remaining are suppressed.
The differential protection can be switched
1201
or
DIFF. PROT.
in address
ON
OFF
.
The option
Block relay
allows to operate the protection but the trip output relay is
blocked.
Summary of Contents for SIPROTEC 7UT613 series
Page 16: ...Contents 16 7UT613 63x Manual C53000 G1176 C160 2 Literature 631 Glossary 623 Index 633 ...
Page 30: ...1 Introduction 30 7UT613 63x Manual C53000 G1176 C160 2 ...
Page 506: ...A Appendix 506 7UT613 63x Manual C53000 G1176 C160 2 7UT633 D E ...
Page 508: ...A Appendix 508 7UT613 63x Manual C53000 G1176 C160 2 7UT633 P Q ...
Page 510: ...A Appendix 510 7UT613 63x Manual C53000 G1176 C160 2 7UT635 D E ...
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Page 515: ...A 2 Terminal Assignments 515 7UT613 63x Manual C53000 G1176 C160 2 7UT633 B ...
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Page 632: ...Literature 632 7UT613 63x Manual C53000 G1176 C160 2 ...