ABB Relion 650 Series Technical Manual page 84

Section 5
Impedance protection
1
IEC09000309 V1 EN-US
Figure 34: Characteristic for phase-to-phase measuring
RFPP
1 0.5 ·
2 Z1
LineAng
3
The fault loop reach with respect to each fault type may also be presented as in figure 35. Note in
particular the difference in definition regarding the (fault) resistive reach for phase-to-phase
faults and three-phase faults.
VC
ANSI09000242 V1 EN-US
Figure 35: Fault loop model
The Z1 in figure
fault location. The settings
is 1-5 depending on selected zone) are the eventual fault resistances in the faulty place.
Regarding the illustration of three-phase fault in figure 35, there is of course fault current flowing
also in the third phase during a three-phase fault. The illustration merely reflects the loop
measurement, which is made phase-to-phase.
The zone can be set to operate in Offset, Forward or Reverse direction through the setting
DirModex (where x is 1-5 depending on selected zone). The result from respective set value is
illustrated in figure 36. The impedance reach is symmetric, in the sense that it conforms for
forward and reverse direction. Therefore, all reach settings apply to both directions.
78
( W /phase)
X
1 1
2
3
R
1 1
1
IEC09000309_1_en.vsd
35 represents the positive sequence impedance from the measuring point to the
RFPEx (where x is 1-5 depending on selected zone) and RFPPx (where x
© Copyright 2011 ABB Power Grids. All rights reserved
( W /phase)
1MRK 506 326-UUS B
Line distance protection REL650
Technical manual