Siemens siprotec 7SD5, Руководство пользователя, Страница: 146 / 698

2 Functions
146
7SD5 Manual
C53000-G1176-C169-1
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:
T1-1phase
(address
1605
) and
T1-multi-phase
(address
1606
). The first zone
is typically set to operate without additional time delay.
For the remaining zones the following correspondingly applies:
X(Z2)
(address
1613
),
R(Z2) Ø-Ø
(address
1612
),
RE(Z2) Ø-E
(address
1614
);
X(Z3)
(address
1623
),
R(Z3) Ø-Ø
(address
1622
),
RE(Z3) Ø-E
(address
1624
);
X(Z4)
(address
1633
),
R(Z4) Ø-Ø
(address
1632
),
RE(Z4) Ø-E
(address
1634
);
X(Z5)+
(address
1643
) for forward direction,
X(Z5)-
(address
1646
) for reverse di-
rection,
R(Z5) Ø-Ø
(address
1642
),
RE(Z5) Ø-E
(address
1644
).
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
T2-
multi-phase
(address
1616
) while a higher setting for single phase faults may be
tolerated
T2-1phase
(address
1615
).
The zone timers for the remaining zones are set with the parameters
T3 DELAY
(ad-
dress
1625
),
T4 DELAY
(address
1635
) and
T5 DELAY
(address
1645
).
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
1617 Trip 1pole
Z2
. Single pole tripping in zone 2 is only possible if this address is set to
YES
. The
default setting is
NO
.
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 ensures instantaneous pickup with
the shortest device operating time for faults in the reverse direction. This setting is also
recommended in teleprotection
BLOCKING
schemes.
Blocking of Zone Z1 If the main protection functions - differential protection and distance protection -
operate in parallel, the distance protection of Zone Z1 may pick up before the differen-
tial protection (e.g. in the case of close-up faults). If this is desired, the distance pro-
tection works as a „booster“ stage for fast tripping. If the fast tripping acts on one end
of the line only, accelerated tripping of zone Z1 is not desired (see also Section
2.5.1.4).
There are two ways of blocking Z1. If the device operates in differential protection
mode, zone Z1 can be blocked by setting a parameter (address
1533 Z1 blkd by
diff ). Another way of blocking the zone is to set a binary input (No. 3610 „>BLOCK
Z1-Trip“ ).
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