ABB REX 521 Technical Reference Manual, Standard Configurations Download

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1MRS751802-MUM

REX 521

143

Protection Relay

Technical Reference Manual, Standard Configurations

9.1.5.1.

Outgoing blocking signal to the incoming feeder

The start signals from any protection function can be routed to an output relay to
provide a blocking signal to the incoming feeder. The overcurrent stages 3I>> and
3I>>> have also a separate BSOUT signal for blocking purpose.

To use the start signal from a protection function the signal has to be routed via the

Main menu\Configuration\Output SWGRP\Start 1

\Start 2

. When the start signals have been routed, the output relay has to be

selected in the

Main menu\Configuration\Output Signals

. In this

example, the overcurrent 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.

9.1.5.2.

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. Refer to the CD-
ROM

Technical Descriptions of Functions

(see Section 1.5. Related documents) 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
voltage 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.

9.1.5.3.

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.