ABB RED670 Handbuch Seite 204

Abschnitt 4
IED Anwendung
200
é
æ
+
Iph KN
ê
ç
è
ê
= ×
Z p Z 1
L
ê
ê
ë
EQUATION1379 V1 DE
Calculation for a 400 kV line, where we for simplicity have excluded the
resistance, gives with X1L=0.303 Ω/km, X0L=0.88 Ω/km, zone 1 reach is set to
90% of the line reactance p=71% i.e. the protection is underreaching with
approximately 20%.
The zero-sequence mutual coupling can reduce the reach of distance protection on
the protected circuit when the parallel line is in normal operation. The reduction of
the reach is most pronounced with no infeed in the line terminal closest to the fault.
This reach reduction is normally less than 15%. But when the reach is reduced at
one line end, it is proportionally increased at the opposite line end. So this 15%
reach reduction does not significantly affect the operation of a permissive under-
reach scheme.
Parallele Leitung außer Betrieb und geerdet
A
Z0m
Z<
DOCUMENT11520-IMG867 V1 DE
Abb. 89: Die parallele Leitung ist außer Betrieb und geerdet.
Wenn die parallele Leitung außer Betrieb und an beiden Enden der
Sammelschienenseite des Leitungs-Stromwandler geerdet ist, so dass Nullstrom
auf der parallelen Leitung fließen kann, entspricht der äquivalente Nullkreis der
parallelen Leitungen Abb. 89.
×
3 I p
0
× + ×
3 0 I KN
m
-
2 p
+ ×
Iph 3 I KN
0
B
Z<
en05000222.vsd
1MRK 505 186-UDE B
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ö
ú
÷
ø
ú
ú
ú
û
(Gleichung 103)
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