2 Functions
130
7UT613/63x Manual
C53000-G1176-C160-2
Note
When delivered from factory, the differential protection is switched OFF. The reason
is that the protection must not be in operation unless at least the connection group (of
a transformer) and the matching factors have been set before. Without proper set-
tings, the device may show unexpected reactions (incl. tripping)!
Starpoint Condi-
tioning
If there is a current transformer in the starpoint connection of an earthed transformer
winding, i. e. between starpoint and earth electrode, the starpoint current may be
taken into consideration for calculations of the differential protection. The earth-fault
sensitivity is thus ensured.
If a starpoint is earthed but the earth current is not available, the zero sequence
current is eliminated automatically in order to avoid a faulty reaction by the differential
protection in case of an external earth fault; the following parameters are then omitted.
Equally, the parameters are not available for sides of the protected object that are not
earthed. The device has been informed about the earthing conditions during setting of
the object properties (section „General Power System Data“ under margin heading
„Object Data with Transformers“, addresses
313
,
323
,
333
,
343
and/or
353
and
section „Topology of the Protected Object“ under margin heading Assignment of
Further „1-phase Measuring Locations“).
The conclusion is: If the starpoint of a side of the protected power transformer is
earthed and the starpoint current is fed to the device (via a further 1-phase current
input) you can, nevertheless, leave the default setting for inclusion of the earth current
unchanged in address
1211
DIFFw.IE1-MEAS
for side 1 on „Yes“.
This parameter can only be altered with DIGSI under
Additional Settings
. The same
considerations apply to any other or additional earthed sides:
•
1212
DIFFw.IE2-MEAS
for side 2 if earthed,
•
1213
DIFFw.IE3-MEAS
for side 3 if earthed,
•
1214
DIFFw.IE4-MEAS
for side 4 if earthed,
•
1215
DIFFw.IE5-MEAS
for side 5 if earthed.
During setting
YES
the corresponding earth current will be considered by the differen-
tial protection.
In auto-transformers the earth current flowing in the winding can be considered even
if a complete three-phase CT set has been installed as illustrated in figure 2-6, where
instead of measuring location Z3 also the three phase currents can be connected to a
three-phase measuring input of the device. The device then calculates the sum of the
three currents and uses it as earth current. Set address
1216
DIFFw.IE3phMEAS
to
YES
. It is required to assign the respective three-phase measuring location to one side
and to declare it as earth winding (the side of the auto-connected winding facing the
earth electrode). This parameter can only be altered in DIGSI at
Display Additional
Settings
.
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 ...
Page 512: ...A Appendix 512 7UT613 63x Manual C53000 G1176 C160 2 7UT635 P Q ...
Page 515: ...A 2 Terminal Assignments 515 7UT613 63x Manual C53000 G1176 C160 2 7UT633 B ...
Page 517: ...A 2 Terminal Assignments 517 7UT613 63x Manual C53000 G1176 C160 2 7UT633 N ...
Page 519: ...A 2 Terminal Assignments 519 7UT613 63x Manual C53000 G1176 C160 2 7UT635 B ...
Page 521: ...A 2 Terminal Assignments 521 7UT613 63x Manual C53000 G1176 C160 2 7UT635 N ...
Page 622: ...A Appendix 622 7UT613 63x Manual C53000 G1176 C160 2 ...
Page 632: ...Literature 632 7UT613 63x Manual C53000 G1176 C160 2 ...