Trip-Circuit Supervision; Condition Monitoring Of The Breaker Wear; Disconnector And Earth-Switch Indication - ABB REX 521 Technical Reference Manual, Standard Configurations

1MRS 751802-MUM
9.1.5.4.
9.1.5.5.
9.1.5.6.
Protection Relay
Technical Reference Manual, Standard Configurations

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 is
provided after an adjustable delay time. The settings for the function can be found
in Main menu\Cond. monit.\TCS\.
To avoid unnecessary alarms, the 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\Configuration\Input SWGRP\TCS\. The default setting of
the parameter is "Not in use".
Another solution is to use an external resistor to prevent the TCS alarm. Please refer
to Technical Reference Manual, General (1MRS 751108-MUM) for more
information about the trip-circuit supervision.

Condition monitoring of the breaker wear

Calculating the electrical wear of the circuit breaker is based on the current in each
phase before opening. The breaker wear is calculated for each phase separately and
when the accumulated breaker-wear has reached the setting value, the function
block will issue an alarm signal.
When the circuit breaker is in the close state, the rising edge of the Open pulse will
trigger the function, which again ends when the circuit breaker enters from the
undefined state to the open state. The function finds the maximum current peak-
value in each phase and uses the obtained values as a reference when interpolating
the breaker wear for each phase by means of the 16-point setting table. The settings
for the breaker-wear function can be found in Main menu\Cond. monit.\CB
wear\.
The status indications "CB pos. open" and "CB pos. close" are automatically used
for the breaker-wear function. The open pulse for the HSPO1 also triggers the
function.
The alarm signal from the breaker wear function is routed via
Main menu\Configuration\Output SWGRP\Alarm 1\ or \Alarm 2\
to the output signal together with the other available alarm signals from the relay. If
the CB wear alarm alone is selected in Alarm 1, the checksum is 128.
The Alarm 1 signal is then connected to an output relay via
Main menu\Configuration\Output Signals\, and in this example, the
breaker wear alarm signal is connected to the signal output 1, SO1.

Disconnector and earth-switch indication

If the status indication signals are available from the disconnector or the earth-
switch, they can be connected to the digital inputs for indication sent as events to a
monitoring system or to include in the interlocking scheme for close-operation of the
breaker. These settings can be found in: Main menu\Configuration\Input
Signals\.
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