Alstom MiCOM P846, Technical Manual

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P846/EN OP/D Operation
(OP) 5-20
MiCOM P846
OP
For a manual reclosure there is a CB Healthy check if required. This facility accepts an input
to one of the relays opto-isolators to indicate that the breaker is capable of closing (circuit
breaker energy for example). A user settable time delay is included "CB Healthy Time" for
manual closure with this check. If the CB does not indicate a healthy condition in this time
period following a close command then the relay will lockout and alarm.
The
CB CONTROL (0700) > CB Control by
setting selects the type of circuit breaker control
used in the logic.
If the CB fails to respond to the control command (indicated by no change in the state of CB
Status inputs) a "CB Failed to Trip" or "CB Failed to Close" alarm is generated after the
relevant trip or close pulses have expired. These alarms can be viewed on the relay LCD
display, remotely via the relay communications, or can be assigned to operate output
contacts using the relay’s programmable scheme logic (PSL).
The CB Control logic is illustrated in Figure 14.