2.2 Distance protection
89
7SA522 Manual
C53000-G1176-C155-3
5(=( (address ) for the R intersection applicable to phase-earth faults
and delay time settings.
For the first zone, Z1, an additional tilt α can be set by means of the parameter in
address =RQH5HGXFWLRQ. This setting is required if short circuits with a large
fault resistance (e.g. overhead lines without earth wire) are expected on lines with an
infeed at both ends and load transfer in the direction of the line (export).
Different delay times can be set for single- and multiple-phase faults in the first zone:
7SKDVH (address ) and 7PXOWLSKDVH (address ). The first zone
is typically set to operate without additional time delay.
For the remaining zones the following correspondingly applies:
;= (address ), 5= (address ), 5(=( (address );
;= (address ), 5= (address ), 5(=( (address );
;= (address ), 5= (address ), 5(=( (address );
;= (address) for forward direction, ;= (address ) for reverse di-
rection, 5= (address ), 5(=( (address ).
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 delay time can be considered for 7
PXOWLSKDVH (address ) while a higher setting for single phase faults may be
tolerated 7SKDVH (address ).
The zone timers for the remaining zones are set with the parameters 7'(/$< (ad-
dress ), 7'(/$< (address ) and 7'(/$< (address ).
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 usually applies to
single-phase faults in Z1 (if the remaining conditions for single-pole tripping are satis-
fied), this may also be selected for the second zone with address 7ULSSROH
=. Single pole tripping in zone 2 is only possible if this address is set to <(6. The
default setting is 12.
Note
For instantaneous 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 instantaneous tripping (undelayed) is required in the reverse direction, the zone Z3
should be used for this purpose, as only this zone is ensures instantaneous pickup
with the shortest device operating time for faults in the reverse direction. This setting
is also recommended in teleprotection %/2&.,1* schemes.
Controlled Zone
Z1B
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. At address 2S
PRGH=% = )RUZDUG, it can also be switched 5HYHUVH or 1RQ'LUHFWLRQDO. If
this stage is not required, it is set to ,QDFWLYH in address . The setting options
are similar to those of zone Z1: Address 5=%, address ;=%,
address 5(=%(. The delay times for single-phase and multiple-phase
faults can again be set separately: 7%SKDVH (address ) and 7%PXOWL
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