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Controlled Zone
Z1B
7SA6 Manual
C53000-G1176-C156-2
For the first zone, Z1, an additional tilt α (Figure 6-29) can be set by means of the pa-
rameter in address 1307 Zone Reduction . This setting is required if short circuits
with a large fault resistance (e.g. overhead lines without earth/shield wire) are expect-
ed on lines with an infeed at both ends and load transfer in the direction of the line (ex-
port).
Different delay times can be set for single- and multiple-phase faults in the first zone:
T1-1phase (address 1305 ) and T1-multi-phase (address 1306 ). The first zone
is typically set to operate without additional time delay.
The corresponding parameters for the higher zones are:
R(Z2) (address 1312 ), X(Z2) (address 1313 ), RE(Z2) (address 1314 );
R(Z3) (address 1322 ), X(Z3) (address 1323 ), RE(Z3) (address 1324 );
R(Z4) (address 1332 ), X(Z4) (address 1333 ), RE(Z4) (address 1334 );
R(Z5) (address 1342 ), X(Z5)+ (address 1343 ) for forward direction, X (Z5)-
(address 1346 ) for reverse direction, RE(Z5) (address 1344 );
For the second zone it is also possible to set separate delay times for single- and multi-
phase faults. In general the delay times are set the same. If stability problems are ex-
pected during multiple-phase faults, a shorter time delay T2-multi-phase (address
1316 ) may be considered under the given circumstances while a higher setting for
T2-1phase (address 1315 ) for single-phase faults may be tolerated.
The zone timers for the remaining zones are set with the parameters T3 DELAY (ad-
dress 1325 ), T4 DELAY (address 1335 ) and T5 DELAY (address 1345 ).
If the device is provided with the capability to trip single-pole, single-pole tripping is
then possible in the zones Z1 and Z2. While single-pole tripping then usually applies
to single-phase faults in Z1(if the other conditions for single-pole tripping are satisfied),
this may also be selected for the second zone with address 1317A Trip 1pole Z2 .
Single pole tripping in zone 2 is only possible if this address is set to YES. The pre-
setting is NO .
Note:
For fast tripping (undelayed) in the forward direction the first zone Z1 should always
be used, as only the Z1 and Z1B are guaranteed to trip with the shortest operating
time of the device. The further zones should be used sequentially for grading in the
forward direction.
If fast tripping (undelayed) is required in the reverse direction, the zone Z3 should be
used for this purpose, as only this zone is guaranteed to trip with the shortest device
operating time for faults in the reverse direction. Zone Z3 is also recommended as re-
verse looking zone in teleprotection Blocking schemes.
The overreaching zone Z1B is a controlled zone. The normal zones Z1 to Z5 are not
influenced by Z1B. There is therefore no zone switching, but rather the overreaching
zone is activated or deactivated by the corresponding criteria. Z1B can also be select-
ed in address 1351 to be Op. mode Z1B = Forward , Reverse or Non-Direc-
tional . If this stage is not required, it is set to Inactive in address 1351 . The set-
ting options are similar to those of zone Z1: address 1352 R(Z1B) Ø-Ø , address
1353 X(Z1B) , address 1354 RE(Z1B) Ø-E . The delay times for single-phase and
multiple-phase faults can again be set separately: T1B-1phase (address 1355 ) and
T1B-multi-phase (address 1356 ).
Functions
6-63
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