ABB Relion 670 series, Technical Reference Manual

Page: 337 / 1232

6.10.2.2 Phase-to-phase fault
For a phase-to-phase fault, the measured impedance by FRPSPDIS (21) is according to
equation
29 .
2
Vm Vn
ZPHS
In
-
=
- ×
EQUATION1813-ANSI V1 EN
(Equation 69)
Vm is the leading phase voltage, Vn the lagging phase voltage and In the phase current
in the lagging phase n.
The operation characteristic is shown in figure 103 .
IEC09000634-1-en.vsd
X1
R (ohm/phase)
X (ohm/phase)
0.5·RFFwPP
R1PP
R1PP
X1
0.5·RFFwPP
0.5·FRvPP
0.5·RFRvPP
0.5·RFRvPP
0.5·RFFwPP
IEC09000634 V1 EN
Figure 171: The operation characteristic for FRPSPDIS (21) at phase-to-phase
fault (directional lines are drawn as "line-dot-dot-line")
1MRK505222-UUS C
Section 6
Impedance protection
331
Technical reference manual