= ×
2
min
0.8
exp max
RLdFwd
P
V
where:
P
exp max is the maximum exporting active power
V
min is the minimum voltage for which the Pexp max occurs
0.8 is a security factor to ensure that the setting of
RLdFwd
can be lesser than the calculated
minimal resistive load.
The resistive boundary RLdRev for load encroachment characteristic in reverse
direction can be calculated in the same way as RLdFwd, but use maximum importing
power that might occur instead of maximum exporting power and the relevant
Vmin
voltage for this condition.
8.2.3.3 Minimum operate currents
M13142-334 v5
FDPSPDIS
(21) has two current setting parameters which blocks the respective phase-
to-ground loop and phase-to-phase loop if the RMS value of the phase current (ILn)
and phase difference current (ILmILn) is below the settable threshold.
The threshold to activate the phase selector for phase-to-ground (IMinPUPG) is set to
securely detect a single phase-to-ground fault at the furthest reach of the phase
selection. It is recommended to set IMinPUPP to double value of IMinPUPG.
The threshold for opening the measuring loop for phase-to-ground fault
(3I0Enable_PG) is set securely detect single line-to-ground fault at remote end on the
protected line. It is recommended to set 3I0BLK_PP to double value of 3I0Enable_PG.
Section 8 1MRK 504 163-UUS A
Impedance protection
256 Transformer protection RET670 2.2 ANSI
Application manual
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