high which limits the zero sequence current on the parallel line to very low values. In
practice, the equivalent zero sequence impedance circuit for faults at the remote bus
bar can be simplified to the circuit shown in figure
The line zero sequence mutual impedance does not influence the measurement of the
distance protection in a faulty circuit.
A
B
C
IEC09000255_1_en.vsd
I
0
I
0
Z
0m
Z
0
-
Z
0m
Z
0m
Z
0
-
IEC09000255 V1 EN-US
Figure 159:
Equivalent zero sequence impedance circuit for a double-circuit line
with one circuit disconnected and not grounded.
8.9.2.7
Tapped line application
GUID-1230B60C-8C3C-4405-8209-E089CAF07847 v1
C
A
B
BC
ANSI05000224-2-en.vsd
ANSI05000224 V2 EN-US
Figure 160:
Example of tapped line with Auto transformer.
This application gives rise to similar problem that was highlighted in section
, that is increased measured impedance due to fault current
1MRK 504 163-UUS A
Section 8
Impedance protection
Transformer protection RET670 2.2 ANSI
335
Application manual
Содержание RELION RET670
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