1MAC309294-MB F Section 5
Control functions
RER620 301
Technical Manual
• The circuit breaker is closed manually during an autoreclose sequence and the manual
close mode is FALSE.
Protection coordination controller
The PROT_CRD output is used for controlling the protection functions. In several
applications, such as fuse-saving applications involving down-stream fuses, tripping and
initiation of shot 1 should be fast (instantaneous or short-time delayed). The tripping and
initiation of shots 2, 3 and definite tripping time should be delayed.
In this example, two overcurrent elements 51P and 50P-2 are used. 50P-2 is given an
instantaneous characteristic and 51P is given a time delay.
The PROT_CRD output is activated, if the SHOT_PTR value is higher than the value
defined with the Protection crd limit setting and all initialization signals have been reset.
The PROT_CRD output is reset under the following conditions:
• If the cut-out time elapses
• If the reclaim time elapses and the AR function is ready for a new sequence
• If the AR function is in lockout or disabled, that is, if the value of the Protection crd
mode setting is “AR inoperative” or “AR inop, CB man”.
The PROT_CRD output can also be controlled with the Protection crd mode setting. The
setting has the following modes:
• “no condition”: the PROT_CRD output is controlled only with the Protection crd limit
setting
• “AR inoperative”: the PROT_CRD output is active, if the AR function is disabled or
in the lockout state, or if the INHIBIT_RECL input is active
• “CB close manual”: the PROT_CRD output is active for the reclaim time if the circuit
breaker has been manually closed, that is, the AR function has not issued a close
command
• “AR inop, CB man”: both the modes “AR inoperative” and “CB close manual” are
effective
• “always”: the PROT_CRD output is constantly active
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