2.1 General
55
7UT613/63x Manual
C53000-G1176-C160-2
Current comparison for common winding of an auto-transformer:
If during configuration of the functional scope in section 2.1.3 a pure current compar-
ison via each winding has been selected, then the example of figure 2-7 applies.
Besides the common winding terminals of the sides
S1
(full winding) and
S2
(tap) with
the assigned 3-phase measuring locations
M1
and
M2
, one more side
S3
is defined at
the starpoint terminals with the 3-phase measuring location
M3
. In this way, a current
comparison can be realised over each of the three transformer windings, i.e. each
phase with its 3 measuring locations.
Such current comparison is more sensitive to 1-phase earth faults in one of the trans-
formers than the normal differential protection. This has a certain importance consid-
ering that 1-phase earth faults are the most probable faults in such banks. By means
of the parameter setting at address
105
PROT. OBJECT
=
Autotransf.Autotr.
node
, the current comparison protection of the auto-transf. node is supported.
On the other hand, the compensation winding cannot and must not be included into
this protection even if it is accessible and equipped with current transformers. This ap-
plication variant is based on the current law in that all currents flowing in to a winding
must total to zero. In auto-transformers with stabilising winding, the stabilising winding
should be protected separately (e.g. with time overcurrent protection). During setting
of address
105
PROT. OBJECT
=
Autotransf.
, a stabilising winding can be includ-
ed.
The current transformer
X1
in figure 2-7 is not required. In order to realise an earth
overcurrent protection or a restricted earth fault protection in this arrangement, you
can feed the sum of the three currents measured at
M3
to an auxiliary 1-phase current
input of the device. An example of a connection, where a measuring location
M3
serves as 3-phase measuring location for the current comparison and where simulta-
neously the total current 3
I
0
of the transformer set is led to a 1-phase measuring loca-
tion
I
X1
of the device, is available in the annex.
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 ...