ABB RED650 Technical Manual page 129

1MRK 505 394-UEN A
Line differential protection RED650 2.2 IEC
Technical manual
R1Zx+RNZx
RFPEZx
X1Zx+XNZx
RFPEZx
RFPEZx
R1Zx+RNZx
IEC11000415 V2 EN-US
Figure 45: ZMFPDIS Characteristic for phase-to-earth measuring, ohm/loop
domain
The faulty loop in relation to the fault type can be presented as in figure 46. The
main intention with this illustration is to make clear how the fault resistive reach
should be interpreted and set. Note in particular that the setting RFPPZx always
represents the total fault resistance of the loop, regardless the fact that the fault
resistance (arc) may be divided into parts like for three-phase or phase-to-phase
faults. The R1Zx + jX1Zx represent the positive sequence impedance from the
measuring point to the fault location.
X (Ohm/loop)
RFPEZx
XNZx
RNZx
φ φ
N N
R
RFPEZx
X1Zx+XNZx
RFPEZx
Section 7
Impedance protection
X0Zx-X1Zx
=
3
R0Zx-R1Zx
=
3
(Ohm/loop)
IEC11000415-2-en.vsdx
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