The polarizing voltage is available as long as the positive-sequence voltage exceeds 5% of the set
base voltage
VBase
, thus the directional element can use it for all unsymmetrical faults including
close-in faults.
For close-in three-phase faults, the V1AM memory voltage, based on the same positive sequence
voltage, ensures correct directional discrimination.
The memory voltage is used for 100ms or until the positive sequence voltage is restored. After
100ms, the following occurs:
• If the current is still above the set value of the minimum operating current the condition seals
in.
• If the fault has caused tripping, the trip continues.
• If the fault was detected in the reverse direction, the measuring element in the reverse
direction remains in operation.
• If the current decreases below the minimum operate value, no directional indications will be
given until the positive sequence voltage exceeds 10% of its rated value.
The Directional impedance element for mho characteristic (ZDMRDIR ,21D) function has the
following output signals:
The STDIRCND output provides an integer signal that depends on the evaluation and is derived
from a binary coded signal as follows:
bit 11
(2048)
bit 10
(1024)
bit 9
(512)
bit 8
(256)
bit 7
(128)
bit 6
(64)
REV_CA1=1 REV_BC=1 REV_AB=1 REV_C=1 REV_B=1 REV_A=1
bit 5
(32)
bit 4
(16)
bit 3
(8)
bit 2
(4)
bit 1
(2)
bit 0
(1)
FWD_CA=1 FWD_BC=1 FWD_AB=1 FWD_C=1 FWD_B=1 FWD_A=1
The PUFW output is a logical signal with value 1 or 0. It is made up as an OR-function of all the
forward starting conditions, that is, FWD_A, FWD_B, FWD_C, FWD_AB, FWD_BC and RWD_CA. The
PUREV output is similar to the PUFW output, the only difference being that it is made up as an OR-
function of all the reverse starting conditions, that is, REV_A, REV_B, REV_C. REV_AB, REV_BC and
REV_CA.
7.5 Faulty phase identification with load encroachment
FMPSPDIS (21)
SEMOD153819-1 v5
7.5.1 Identification
SEMOD155879-2 v3
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-US
21
Section 7 1MRK 502 066-UUS B
Impedance protection
240
Technical manual
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