ABB RELION RET670 - Page 257

R
X
60°
60°
1
2
3
5
6
6
6
6
7
7
8
8
4
IEC09000043_1_en.vsd
W( / loop)
W( / loop)
4
3 5
IEC09000043 V1 EN-US
Figure 117: Relation between distance protection phase selection (FDPSPDIS)
(21) and impedance zone (ZMQPDIS) (21) for phase-to-ground fault
φloop>60° (setting parameters in italic)
1 FDPSPDIS (phase selection)(21) (red line)
2 ZMQPDIS (Impedance protection zone)(21)
3
RFltRevPG
PHS
4 ( X1
PHS
+XN)/tan(60°)
5
RFltFwdPG
PHS
6 RFPG
ZM
7 X1
PHS
+XN
8 φloop
9
X1
ZM
+XN
1MRK 504 163-UUS A Section 8
Impedance protection
Transformer protection RET670 2.2 ANSI 251
Application manual