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.
6.2.3.3 Minimum operate currents
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.
6.3 Faulty phase identification with load enchroachment for
mho FMPSPDIS (21)
6.3.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Faulty phase identification with load
encroachment for mho
FMPSPDIS
S00346 V1 EN
-
6.3.2 Application
Faulty phase identification with load encroachment for mho (FMPSPDIS) function is
designed to accurately select the proper fault loop in the Distance protection function
(ZQMPDIS, 21) dependent on the fault type.
The heavy load transfer that is common in many transmission networks may in some cases
be in opposite to the wanted fault resistance coverage. Therefore, FMPSPDIS has an built-
in algorithm for load encroachment, which gives the possibility to enlarge the resistive
setting of both the Phase selection with load encroachment and the measuring zones Five
Section 6 1MRK 506 334-UUS A
Impedance protection
146
Application manual
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