Start Inputs; Unblocking - ABB ETL600 Instruction Manual

ABB Switzerland Ltd
Alarm is given and the command output is set inactive should the
command duration exceed a predefined value (if monitoring is
enabled: 5 seconds per default, programmable via HMI600 in the
range of 1 to 60 seconds).
Note:
3.6.8.7.

Start Inputs

A start criterion from the protection relay may be used to prepare the
TPE channel for transmission of protection signals by switching off
Tx&Rx speech in the corresponding APLC channel in advance.
In case the TPE operates in the DPLC channel, MOD600 is not
switched off by the start signal.
In case there is no speech in the TPE channel, the disconnectable
data channels in the TPE channel are not switched off by the start
signal.
One start signal per TPE can be configured on the input(s) of the
teleprotection interface type G4AI. The interruption of speech is limited
to 1 second, beginning with the first start input being activated. Should
no command be injected, alarm is given after the maximum
programmed Tx trip duration alarm pick-up time and will stay as long
as the start input is active.
3.6.8.8.

Unblocking

An „unblocking" command used in directional comparison or in
permissive tripping schemes with overreaching first zone can be
allocated to one or more outputs on the teleprotection interface
module. Note that „unblocking" commands are not transmitted from the
remote end, but automatically produced by certain types of line faults
(PLC channels).
At time when neither tripping nor guard signals are being received, or
when the total signal level in the 2 kHz band is lower than the
configured unblocking threshold (range from –20 dB to –10 dB; default
–14 dB from nominal level), an unblocking pulse of a predefined
duration is generated which can be signaled by one or more outputs
on the relay interface type G4AI.
The internal signal evaluation time to detect the unblocking condition is
typical less than 20 ms. It is possible to define an additional delay via
HMI600 in the range of 0 to 100 ms (default 20 ms).
The unblocking pulse duration is set to 200 ms per default but can be
varied in the range of 50 to 500 ms.
The unblocking threshold is valid for both, the signal level in the
speech band as well as the signal level in the guard channel (i.e. the
3-80
1KHW001489-EN
If commands of long duration are to be transferred,
certain rules regarding the setting of the pick-up
times for the link and user alarms have to be
observed (please refer to Chapter 5 for details).
November 2005
ETL600
Structure and Function