Siemens siprotec 7SD5, Руководство пользователя

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2.7 Teleprotection for Distance Protection (optional)
203
7SD5 Manual
C53000-G1176-C169-1
At address
2101 FCT Telep. Dis.
the use of a teleprotection scheme can be
turned
ON
or
OFF
.
If the teleprotection has to be applied to a three terminal line the setting in address
2102
must be
Type of Line
=
Three terminals
, if not, the setting remains
Two
Terminals
.
The following modes are possible with digital transmission using the protection data
interface:
PUTT (Z1B)
Permissive Underreach Transfer Trip with Zone Accel-
eration Z1B (PUTT) via protection interface,
POTT
Permissive Overreach Transfer Trip (POTT),
Dir.Comp.Pickup
Directional comparison pickup,
The send and receive signals must in these cases be assigned to fast command chan-
nels of the protection data interface (DIGSI matrix).
Distance Protection
Prerequisites For all applications of teleprotection schemes (except PUTT), it must be ensured that
the fault detection of the distance protection in the reverse direction has a greater
reach than the overreaching zone of the opposite line end (refer to the shaded areas
in Figure 2-87 on the right hand side)! This is normally predefined for the U/
I /
ϕ
pickup
since the local voltage of a reverse fault is smaller than the voltage of the remote sup-
plying end. For impedance pickup at least one of the distance stages must be set to
Reverse
or
Non-Directional
. During a fault in the shaded area (in the left section
of the picture), this fault would be in zone Z1B of the protection at B as zone Z1B is
set incorrectly. The distance protection at A would not pick up and therefore the pro-
tection in B would interpret this as a fault with single end infeed from B (echo from A
or no block signal at A). This would result in a false trip!
The blocking scheme needs furthermore a fast reverse stage to generate the blocking
signal. Apply zone 3 with non-delayed setting to this end.
Figure 2-87 Distance protection setting with permissive overreach schemes
Time Settings The send signal prolongation
Send Prolong.
(address
2103
) must ensure that the
send signal reliably reaches the opposite line end, even if there is very fast tripping at
the sending line end and/or the signal transmission time is relatively long. In the case
of the permissive overreaching schemes
POTT
,
Dir.Comp.Pickup
and
UNBLOCKING
this signal prolongation time is only effective if the device has already
issued a trip command. This ensures the release of the other line ends even if the
short-circuit has been cleared very rapidly by the instantaneous zone Z1. In the case
of the blocking scheme
BLOCKING
the transmit signal is always prolonged by this
time. In this case it corresponds to a transient blocking following a reverse fault. This
setting is only possible via DIGSI
®
at Additional Settings .
In order to detect steady-state line faults such as open circuits, a monitoring time
Delay for alarm
is started when a fault is detected (address
2107
). Upon expira-
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