1. Residual current criteria
2. No quadrilateral impedance characteristic. The impedance reach outside the load area is
theoretically infinite. The practical reach, however, will be determined by the minimum
operating current limits.
3. Load encroachment characteristic is always active, but can be switched off by selecting a high
setting.
The DLECND output is non-directional. The directionality is determined by the distance zones
directional function. There are outputs from FDPSPDIS (21) that indicate whether a pickup is in
forward or reverse direction or non-directional, for example FWD_A, REV_A and NDIR_A.
These directional indications are based on the sector boundaries of the directional function and
the impedance setting of FDPSPDIS (21) function. Their operating characteristics are illustrated in
figure
82.
en05000668_ansi.vsd
R
X
R
X
R
X
Non-directional (ND) Forward (FWD) Reverse (REV)
60°
60°
60°
60°
ANSI05000668 V1 EN-US
Figure 82: Characteristics for non-directional, forward and reverse operation of Phase
selection with load encroachment, quadrilateral characteristic FDPSPDIS (21)
The setting of the load encroachment function may influence the total operating characteristic,
(for more information, refer to section "Load encroachment").
The input DIRCND contains binary coded information about the directional coming from the
directional function . It shall be connected to the STDIR output on ZDRDIR, directional measuring
block. This information is also transferred to the input DIRCND on the distance measuring zones,
that is, the ZMQPDIS, distance measuring block.
The code built up for the directionality is as follows:
STDIR= FWD_A*1+FWD_B*2+FWD_C*4+FWD_AB*8+
+FWD_BC*16+FWD_CA*32+REV_A*64+REV_B*128+REV_C*256+
+REV_AB*512+REV_BC*1024+REV_CA*2048
If the binary information is 1 then it will be considered that we have pickup in forward direction in
phase A. If the binary code is 3 then we have pickup in forward direction in phase A and B, binary
code 192 means pickup in reverse direction in phase L1 and L2A and B etc.
1MRK 502 066-UUS B Section 7
Impedance protection
201
Technical manual
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