Technical Guide P92x/EN CT/E11
Courier Database
MiCOM P921-P922-P923 Page 79/118
NOTE : The control commands are generally materialized by the change
of the cell value. They dispose the same inherent security. No
response is allowed for the global orders to avoid any conflict in
the bus. For this type of order, a double transmission is used by
the relay for the verification of the message. The relay transmits
then a confirmation indicating that the control order or the
change of setting is accepted. If this is not the case, the relay
sends an error message.
2.4.11 Remote Change of setting
When using the serial port, the relay responds to the orders of setting changes only if
the SD0 Link =1 is selected.
· The selection of the SD0 Link =1 blocks all the remote changes of settings with
the exception of the SC logical Links and the password capture.
· When the SD0 Link =0 is selected, the remote setting changes are protected by
the password.
To make a remote changes of settings, a password is needed to be captured
(remotely), and then the SD and SD0 function Links have to be set equal to 1.
2.5 Events Extraction (MiCOM P922 and P923 only)
Events can be extracted either manually or automatically. For automatic extraction all
events are extracted in sequential order using the standard Courier mechanism, this
includes Faults. The manual approach allows the user to select events and faults
randomly from the stored records.
2.5.1 Automatic Event Extraction
This method is intended for continuous extraction of events and fault information as it
is produced via the rear port.
When a new event information is created, the event bit is set within the status byte.
This indicates to the Master device that an event information is available. The oldest
(and not extracted ) event can be extracted from the relay using the Send Event
Command. The relay will respond with the event data, which will be either a Courier
Type 0 or Type 3 event. The latest type is used for the fault records.
Once an event is extracted from the relay, the Accept Event can be used to confirm
that this event has been successfully extracted. If all the events are extracted, then the
event bit will reset. If there are more events to be extracted, the next one can be
accessed using the Send Event Command as before.
2.5.2 Events Types
Events will be created by the relay under the following circumstances:
· Change of state of output contact
· Change of state of opto input
· Protection element operation
· Alarm condition
· Setting change
· Fault record ( Type 3 Courier Event )
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