ABB REX 521 Technical Reference Manual, Standard Configurations

Also see for REX 521: Operator's manual Technical Reference Manual, General Technical Reference Manual, General Operating guide Technical Reference Manual, Standard Configurations

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ABB REX 521 Technical Reference Manual, Standard Configurations Manual pdf 144 page image

1441MRS751802-MUMProtection RelayTechnical Reference Manual, Standard ConfigurationsREX 521The CBFP signals from the protection functions are routed to the output signals viathe output switchgroups. These settings can be found inMain menu\Configuration\Output SWGRP\CBFP. When the three-stageovercurrent, the two-stage earth fault, the unbalance and thermal overload protectionare selected the checksum for the CBFP is 223.The CBFP signal is then connected to any of the output relays, viaMain menu\Configuration\Output Signals\. In this example, thecircuit-breaker failure signal is connected to the power output 1, PO1.9.1.5.4. Trip-circuit supervisionThe trip-circuit supervision is available for the HSPO1 relay. If the resistance of thetrip circuit exceeds a certain limit, for instance due to a bad contact or oxidation, thesupervision function will be activated and a trip-circuit supervision alarm signal isprovided after an adjustable delay time. The settings for the function can be foundin Main menu\Cond. monit.\TCS1\.To avoid unnecessary alarms, the trip-circuit supervision can be blocked by the BSsignal, which disables the supervision output when the circuit breaker is open. TheBS signal is configured to be operated by the “CB pos. open” status from the selecteddigital input. The BS signal can be connected via the switchgroup inMain menu\Configuration\Input SWGRP\TCS1\. The default setting ofthe parameter is ”Not in use”.Another solution is to use an external resistor to prevent the TCS1 alarm. Refer toTechnical Reference Manual, General (see Section 1.5. Related documents) formore information about the trip-circuit supervision.9.1.5.5. Condition monitoring of the breaker wearCalculating the electrical wear of the circuit breaker is based on the current in eachphase before opening. The breaker wear is calculated for each phase separately andwhen the accumulated breaker-wear has reached the setting value, the functionblock will issue an alarm signal.When the circuit breaker is in the close state, the rising edge of the Open pulse willtrigger the function, which again ends when the circuit breaker enters from theundefined 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 interpolatingthe breaker wear for each phase by means of the 16-point setting table. The settingsfor the breaker-wear function can be found in Main menu\Cond. monit.\CBwear\.The status indications “CB pos. open” and “CB pos. close” are automatically usedfor the breaker-wear function. The open pulse for the HSPO1 also triggers thefunction.The alarm signal from the breaker wear function is routed viaMain menu\Configuration\Output SWGRP\Alarm 1\ or \Alarm2\ 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.