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1MRK 506 369-UEN B
8.12.3.9
Line distance protection REL670 2.2 IEC
Application manual
accidental event be given precaution, the phase-to-earth reach (RFPEZx) of all
instantaneous zones has to be set below the emergency load for the pole-open
situation. Again, this is only for the application where there is a risk that one
breaker pole would open without a preceding fault. If this never happens, for
example when there is no parallel circuit, there is no need to change any phase-to-
earth reach according to the pole-open scenario.
Other settings
IMinOpPEZx and IMinOpPPZx
The ability for a specific loop and zone to issue a start or a trip is inhibited if the
magnitude of the input current for this loop falls below the threshold value defined
by these settings. The output of a phase-to-earth loop Ln is blocked if ILn <
IminOpPE(Zx). In is the RMS value of the fundamental current in phase n.
The output of a phase-to-phase loop LmLn is blocked if ILmLn < IMinOpPP(Zx).
ILmLn is the RMS value of the vector difference between phase currents Lm and
Ln.
Both current limits IMinOpPEZx and IMinOpPPZx are automatically reduced to
75% of regular set values if the zone is set to operate in reverse direction, that is,
OperationDir is set to 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
This setting defines 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 figure182,
where the positive impedance corresponds to the direction out on the protected
line.
Section 8
Impedance protection
GUID-9D65B411-6FE2-433B-AE6C-C6DD716D1181 v7
355
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