Protection Modes; Overview; Unblocking Mode - Siemens SWT 3000 Equipment Manual

Functional Description

2.7 Protection Modes

2.7 Protection Modes

Overview

2.7.1
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

2.7.2
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 ) is used.
unbl.
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
[dwprunbm-010711-01.tif, 1, en_US]
Figure 2-8
10 ms to 300 ms
50
Principle of the Unblocking Mode
10 ms to 300 ms
= 10 ms to 300 ms).
unbl.
Smart Communication, SWT 3000 Teleprotection, Equipment Manual
C53000-G6040-C605-1, Edition 03.2020