ABB Relion 670 series - Page 336

IEC09000633-1-en.vsd
RFFwPE
X1+XN
R (Ohm/loop)
X (ohm/loop)
RFRvPE
RFRvPE
RFFwPE
R1PE+RN
RFRvPE
R1PE+RN
X1+XN
RFFwPE
IEC09000633 V1 EN
Figure 170: Characteristic of FRPSPDIS (21) for phase to fault (directional lines
are drawn as "line-dot-dot-line")
Besides this, the 3I
0
residual current must fulfil the conditions according to equation 27
and equation 28.
03 I 0.5 IMinOpPE× ³ ×
EQUATION2108 V1 EN
(Equation 67)
0
0
3 _
3 max
100
I Enable PG
I Iph× ³ ×
EQUATION1812-ANSI V1 EN (Equation 68)
where:
IMinOpPE is the minimum operation current for forward zones
3I
0
Enable_PG is the setting for the minimum residual current needed to enable operation in the phase-to-
ground fault loops (in %).
Iphmax is the maximum phase current in any of three phases.
Section 6 1MRK505222-UUS C
Impedance protection
330
Technical reference manual