ABB RELION RET670, Applications Manual

Page: 452 / 1016

The output of a phase-to-phase loop mn is blocked if Imn < IMinOpPPZx . Imn is the
RMS value of the vector difference between phase currents m and n.
Both current limits IMinOpPGZx and IMinOpPPZx are automatically reduced to 75%
of regular set values if the zone is set to operate in reverse direction, that is,
OperationDir = Reverse .
OpModePPZx and OpModePEZx
These settings, two per zone (x=1,2..5&RV), with options {Off, Quadrilateral, Mho,
Offset}, are used to set the operation and characteristic for phase-to-earth and phase-to-
phase faults, respectively.
For example, in one zone it is possible to choose Mho characteristic for the three Ph-Ph
measuring loops and Quadrilateral characteristic for the three Ph-E measuring loops.
DirModeZx
These settings define the operating direction for Zones Z3, Z4 and Z5 (the
directionality of zones Z1, Z2 and ZRV is fixed). The options are
Non-directional ,
Forward or Reverse . The result from respective set value is illustrated in figure 226
below, where positive impedance corresponds to the direction out on the protected line.
IEC05000182-2-en.vsdx
R
X
R
X
R
X
Non-directional Forward Reverse
IEC05000182 V2 EN-US
Figure 226: Directional operating modes of the distance measuring zones 3 to 5
tPPZx , tPGZx , TimerModeZx , ZoneLinkPU and TimerLinksZx
Refer to chapter Simplified logic schemes in Technical Manual for the application of
these settings.
Section 8
1MRK 504 163-UUS A
Impedance protection
446 Transformer protection RET670 2.2 ANSI
Application manual