Blocking Signal Received From The Residual Voltage Relay; Circuit-Breaker Failure Protection - ABB REX 521 Technical Reference Manual, Standard Configurations

REX 521
9.1.5.2.
9.1.5.3.
114
Protection Relay
Technical Reference Manual, Standard Configurations
selected in the Main menu\Configuration\Output Signals. In this
example, the over-current stage 3I>> is routed via Start 1 and then connected to the
power output 2, PO2. In this application example, the checksum for the Start 1 is 2.

Blocking signal received from the residual voltage relay

To release blocking, the start signals from a residual voltage relay can be connected
to the earth-fault stages in the outgoing feeder. There are two input blocking signals,
Blocking 1 and Blocking 2, which can have different functions depending on the
different protections.
The Blocking 1 input signal is connected to the BS1 input and the Blocking 2 input
signal is connected to the BS2 input of the earth-fault-stages Io>, Io>> and Io>>>.
The BS1 in this application example will stop the DT (Definite time) or the IDTM
(Inverse Definite Time) timer and the BS2 will block the trip signal. Please refer to
the CD-ROM Technical Descriptions of Functions (1MRS 750889-MCD) for more
information.
In this application example, the digital input DI9 is connected to the input signal
Blocking 1 and then routed to the BS1 input of the earth fault stage Io>. The
Blocking 1 signal can be found in Main menu\Configuration\Input
Signals\Blocking 1\ where the DI9 is selected. The checksum for the
switchgroup in Main menu\Configuration\Input SWGRP\
Blocking 1\ is 8 to block Io>.
Normally the Blocking 1 signal is set to release the Io> blocking when the residual
relay starts, and give the Io> protection a permission to start and further execute trip
after the set time delay has elapsed. For instance, this can be established by inverting
the digital input DI9 and use the start signal from the residual relay for permission.

Circuit-breaker failure protection

Every protection function in the standard configuration B01 provides a delayed trip
signal CBFP after the trip signal unless the fault has not disappeared during the set
CBFP time delay. In circuit-breaker failure protection, the CBFP output can be used
for operating an upstream circuit-breaker.
The settings for the breaker failure are set separately for each protection function.
For example, to set the CBFP time for the 3I>> go to
Main menu\Protection\3I>>\Control settings, where it is possible
to set the "CBFP time" from 100 ms to 1000 ms. The control parameter "Trip pulse"
sets the width of the trip output signal, but also of the CBFP output signal.
The CBFP signals from the protection functions are routed to the output signals via
the output switchgroups. These settings can be found in
Main menu\Configuration\Output SWGRP\CBFP. When the three-stage
overcurrent, the two-stage earth-fault, the unbalance and thermal overload
protection are selected the checksum for the CBFP is 223.
The CBFP signal is then connected to any of the output relays, via
Main menu\Configuration\Output Signals\. In this example, the
circuit-breaker failure signal is connected to the power output 1, PO1.
1MRS 751802-MUM