Siemens siprotec 7SA6, Manual

Page: 305 / 876

Functions
6-115
7SA6 Manual
C53000-G1176-C156-2
−
Pilot Wire
Comparison
= Pilot wire comparison with control wires, as referred to in
Sub-section 6.6.1.10,
−
Reverse
Interlocking
= Reverse interlocking with control wires, as referred to in
Sub-section 6.6.1.11.
In address
2101 FCT Telep. Dis.
the application of a teleprotection scheme can
be switched
ON
or
OFF
.
If the teleprotection is applied to a line with three ends, the address
2102
must be set
to
Line Config.
=
Three terminals
, otherwise it remains at the setting
Two
Terminals
.
Digital
Transmission
The following modes are possible with digital transmission using the protection data
interface:
− PUTT
Permissive Underreach Transfer Trip with zone
(Z1B acceleration)
acceleration Z1B and
protection data interface,
as described in Subsection 6.6.1.1,
−
POTT
Permissive Overreach Transfer Trip (POTT), as
described in Section 6.6.1.4.
The desired mode is selected at address
2101 FCT Telep. Dis.
. Here, the use of
a signal transmission mode can also be switched
ON
or
OFF
. In that case, address
2102 Type of Line
is relevant and must have the same setting in all devices.
Teleprotection modes over protection interface are only active if the parameter
121
Teleprot. Dist.
has been set to
POTT over Protection Interface
in all
devices of the setup.
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 6-68 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-
plied end. In the case of the impedance pickup at least one of the distance stages must
be set to
Reverse
or
Non-Directional
. During a fault in the shaded area at the
left of Figure 6-68, 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 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!
To produce a blocking signal the blocking scheme additionally requires a fast reverse
stage. For this purpose, the third zone is to be applied without time delay (see also
“Note” on page 63 in Subsection 6.2.4.2).