ABB RET670 - Page 129

X1
R
X
85%
1
3
5
2
6
4
50% RLdFw
ArgNegRes
0.5·RFFwPP
ArgLd
I
EC09000735-2-en.vsd
ArgDir
60°
)/( p
haseW
)/( phaseW
7
IEC09000735 V2 EN
Figure 55: Operating characteristic for phase selection function, forward
direction phase-to-phase faults
Table 22: Test points for phase-earth loop L3-E (Ohm/loop)
Test point Value Comments
1 X [X1+XN] XN=(X
0
-X
1
)/3
R 0
2 X 0
R RLdFw
3 X 0.85·[X1+XN] R≈0.491·(X1+XN)+RFFwPE
R 0.85·[X1+XN]·1/tan(60°)+RFFwPE
4 X 0.85·[X1+XN]
R -0.85·[X1+XN]·
tan (AngNegRes-90°)
5 X RFFwPE·tan (ArgLd)
R RFFwPE
6 X -0.5·RLdFw·tan (ArgDir)
R 0.5·RLdFw
The table showing test points for phase-to- earth loops is used together with figure
54.
1MRK 504 088-UEN C Section 13
Verifying settings by secondary injection
123
Installation and commissioning manual