210
1MRS751802-MUM
Protection Relay
Technical Reference Manual, Standard Configurations
REX 521
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. The CBFP signal is
then connected to any of the output relays via
Main menu\Configuration\Output Signals\, and in this example the
circuit-breaker failure signal is connected to the power output 1, PO1.
11.2.5.4. Trip-circuit supervision
The trip-circuit supervision is available for the HSPO1 relay. If the resistance of the
trip circuit exceeds a certain limit, for instance due to a bad contact or oxidation, the
supervision function will be activated and a trip-circuit supervision alarm signal will
be provided after an adjustable delay time. The settings for the function can be found
in Main menu\Cond. monit.\TCS1\.
To avoid unnecessary alarms, trip-circuit supervision can be blocked by the BS
signal, which disables the supervision output when the circuit breaker is open. The
BS signal is configured to be operated by the “CB pos. open” status from the selected
digital input. The BS signal can be connected via the switchgroup in
Main menu\Input SWGRP\TCS1\. The default setting of the parameter is
“Not in use”.
Another solution is to use an external resistor to prevent the TCS1 alarm. Refer to
REX 521 Technical Reference Manual, General
(see Section 1.5. Related
documents) for more information about the trip-circuit supervision.
11.3. Bus sectionalizer, High H03
11.3.1. Features
This application example describes a bus sectionalizer of a single busbar including:
• Overcurrent protection
• Synchro-check and
• Voltage-check function
The network can be compensated, isolated, resistance or solidly earthed. Three-
phase current measurement is established with a set of current transformers. Phase-
to-phase voltage measurements are established with voltage transformers in both
sections of the busbar.
The High H03 variant of REX 521 is selected to be used in this application because
of the synchro-check and voltage-check functionality. This selection makes it
possible to extend the automatic supervision functionality in the substation. The
synchro-check function does not allow closing of the bus sectionalizer if the
operation criteria are not fulfilled.
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