Protection Modes
Overview
The SWT 3000 system has the following different protection operating modes:
•
Protection operating mode 1 (double system protection) for the analog and digital interface.
The commands can be transmitted coded or uncoded with the application permissive or direct tripping
(selectable).
•
Protection operating mode 2 (single phase protection) for the analog and digital interface.
The commands can be transmitted coded or uncoded with the application permissive or direct tripping
(selectable).
•
Protection operating mode 3 (4 commands with priority) for the analog and digital interface.
The commands are transmitted uncoded with the application permissive or direct tripping (selectable).
•
Protection operating mode 3a (4 independent commands, 4iC) for the transmission of 4 independent
commands.
The commands are always transmitted coded with the application permissive or direct tripping (select-
able).
•
Protection operating mode 3b (2 plus 2).
This mode offers the transmission of mode 1 twice. 2 commands are transmitted in the fast permissive
underreach transfer trip, the other 2 are transmitted in the direct trip application and using the CT
feature.
•
Protection operating mode 4 (only one command active) for analog and digital interfaces.
The commands can be transmitted coded or uncoded with the application permissive or direct tripping
(selectable).
•
Protection operating mode 5A (3 independent commands) for analog and digital interfaces.
The commands are transmitted uncoded with the application permissive or direct tripping (selectable).
•
Protection operating mode 5D (16 independent commands) only for operation with digital interfaces.
Unblocking Mode
The unblocking mode is a release procedure. Short circuits on overhead lines can cause a disturbance of PLC
links. In this case, in order to warrant the release of the permissive protection device, the unblocking impulse
(t
unbl.
) is used.
If the signal to be transmitted does not reach the other line end, the receiver recognizes a fault and emits the
unblocking impulse. The reason for the unreached signal is because a short circuit on the line causes excessive
attenuation or reflection of the signal. The unblocking impulse is connected to the unblocking logic of the
protection relay. For Mode 1 and 2, the unblocking impulse is carried out via the interface module IFC-P/D
command output 4. For other Modes, it is carried out via alarm module RX alarm output. If there is a fault, the
unblocking logic of the protection device ensures the release (for t
unbl.
= 10 ms to 300 ms).
[dwprunbm-010711-01.tif, 1, en_US]
Figure 2-8
Principle of the Unblocking Mode
10 ms to 300 ms
10 ms to 300 ms
2.7
2.7.1
2.7.2
Functional Description
2.7 Protection Modes
50
Smart Communication, SWT 3000 Teleprotection, Equipment Manual
C53000-G6040-C605-1, Edition 03.2020
