protection zone and this way influence the operation of the phase-to-phase and phase-to-ground
zone measuring elements, residual current and the load encroachment characteristic.
Figure 93 presents schematically the composition of non-directional phase selective signals
NDIR_A (B or C). Internal signals ZMn and ZMmn (m and n change between A, B and C according to
the phase) represent the fulfilled operating criteria for each separate loop measuring element,
that is, within the impedance characteristic. These signals are released if the setting
OperationZ<
is set to
Enabled
. Similarly, another group of internal signals
ILm
and
ILn
represent the fulfilled
phase current measurement criteria, which are released by setting the
OperationI>
parameter to
Enabled
.
ANSI00000545-5-en.vsd
AND
AND
AND
IRELPG
AND
AND
AND
IRELPP
INDIR_A
INDIR_B
INDIR_C
OR
OR
OR
OR
INDIR_CA
INDIR_BC
INDIR_AB
PHSEL_G
PHSEL_A
PHSEL_B
PHSEL_C
OR
PHSEL_PP
15 ms
0
15 ms
0
15 ms
0
15 ms
0
15 ms
0
LDEblockA
LDEblockB
LDEblockC
LDEblockAB
LDEblockBC
LDEblockCA
I_A
ZMA
OR
I_A & I_B
ZMAB
OR
I_B
ZMB
OR
I_C
ZMC
OR
I_B & I_C
ZMBC
OR
I_C & I_A
ZMCA
OR
ANSI00000545 V5 EN-US
Figure 93: Composition on non-directional phase selection signals
Composition of the directional (forward and reverse) phase selective signals is presented
schematically in figure 95 and figure 94. The directional criteria appears as a condition for the
correct phase selection in order to secure a high phase selectivity for simultaneous and evolving
faults on lines within the complex network configurations. Internal signals DFWn and DFWnm
present the corresponding directional signals for measuring loops with phases Ln and Lm.
Designation FW (figure
95) represents the forward direction as well as the designation RV
(figure
94) represents the reverse direction. All directional signals are derived within the
corresponding digital signal processor.
Figure
94 presents additionally a composition of a PHSELZ output signal, which is created on the
basis of the continuation of the impedance measuring conditions and the load encroachment
characteristic. This signal can be configured to PHSEL functional input signals of the distance
protection zone and this way influence the operation of the phase-to-phase and phase-to-ground
zone measuring elements and their phase related pickup and tripping signals.
1MRK 502 066-UUS B Section 7
Impedance protection
211
Technical manual
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