ABB REL650 series Technical Manual page 139

1MRK 506 335-UUS A
Technical manual
RFItRevPG
RFItRevPG
60 deg
RFItRevPG
Kr·(X1+XN)
ANSI06000396 V1 EN
Figure 53: Characteristic of FDPSPDIS (21) for phase-to-ground fault (setting
parameters in italic), ohm/loop domain (directional lines are drawn as
"line-dot-dot-line")
Besides this, the 3I residual current must fulfil the conditions according to equation
0
and equation 29.
× ³ ×
3 I 0.5 IMinPUPG
0
EQUATION2108-ANSI V1 EN
3 I Enable PG _
× ³ ×
3 I Iph
0
0
100
EQUATION1812-ANSI V1 EN
where:
IMinPUPG
is the minimum operation current for forward zones
3I Enable_PG is the setting for the minimum residual current needed to enable operation in the phase-to-
0
ground fault loops (in %).
Iphmax is the maximum phase current in any of three phases.
X (ohm/loop)
Kr·(X1+XN)
RFItFwdPG
X1+XN
60 deg
RFItFwdPG
R (Ohm/loop)
X1+XN
Kr
RFItFwdPG
max
Impedance protection
1
=
tan(60 deg)
en06000396_ansi.vsd
Section 6
28
(Equation 28)
(Equation 29)
133