ABB Relion 670 series - Page 283

7.7.6.1 Phase-to-ground fault
GUID-37AF6C9C-852E-48D9-A307-A23F2BF6884A v1
Index PHS in images and equations reference settings for Phase selection,
quadrilateral characteristic with settable angle (FRPSPDIS, 21).
( , )
( , )
PHSn
VA B C
IA B C
Z =
EQUATION1554 V1 EN-US (Equation 74)
where:
n corresponds to the particular phase (n=1, 2 or 3)
The characteristic for FRPSPDIS (21) function at phase-to-ground fault is according to figure 134.
The characteristic has a settable angle for the resistive boundary in the first quadrant of 70°.
The resistance RN and reactance XN are the impedance in the ground-return path defined
according to equation
77 and equation 78.
0 1
3
R PE R PE
RN
-
=
EQUATION-2125 V1 EN-US (Equation 75)
0 1
3
R R
RN
-
=
EQUATION1256 V1 EN-US (Equation 75)
0 1
3
X X
XN
-
=
EQUATION1257 V1 EN-US (Equation 76)
1MRK 502 066-UUS B Section 7
Impedance protection
277
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