1321MRS 751802-MUMProtection RelayTechnical Reference Manual, Standard ConfigurationsREX 521timer and the BS2 will block the trip signal. Please refer to the CD-ROM TechnicalDescriptions of Functions (1MRS 750889-MCD) for more information about thedifferent protection function blocks.In this application example the digital input DI9 is connected to the input signalBlocking 1 and then routed to the BS1 input of the overcurrent stage 3I>>. TheBlocking 1 signal can be found in Main menu\Configuration\InputSignals\Blocking 1\ where DI9 is selected. The checksum for theswitchgroup in Main menu\Configuration\Input SWGRP\Blocking 1\ should be 2 to block the 3I>>.9.3.4.2. Circuit-breaker failure protectionAll of the protection functions in the standard configuration B01 provide a delayedtrip signal CBFP after the trip signal unless the fault has not disappeared during theset CBFP time delay. In the circuit-breaker failure protection, the CBFP output canbe used for operating an upstream circuit breaker.The settings for breaker failure are set separately for each protection function. Forexample, to set the CBFP time for 3I>>, go toMain menu\Protection\3I>>\Control setting, where it is possibleto 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 viathe output switchgroups. These settings can be found inMain menu\Configuration\Output SWGRP\CBFP. When the three-stageovercurrent and two-stage earth-fault protection are selected the checksum forCBFP will be 31.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.
