Alstom MiCOM P846, Technical Manual

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P846/EN MR/D Measurements and Recording
(MR) 8-4
MiCOM P846
MR
For extraction from a remote source via communications, refer to the SCADA
Communications chapter (P846/EN SC), where the procedure is fully explained.
1.2.1 Types of event
An event may be a change of state of a control input or output relay, an alarm condition,
setting change etc. The following sections show the various items that constitute an event:
1.2.1.1 Change of state of opto-isolated inputs
If one or more of the opto (logic) inputs has changed state since the last time that the
protection algorithm ran, the new status is logged as an event. When this event is selected
to be viewed on the LCD, three applicable cells will become visible as shown below:
Time & date of event
“LOGIC INPUTS #”
“Event Value 0101010101010101”
Where # = 1 or 2 depending upon which group of 32 opto inputs is selected. In the case of
P846 relay, however, the value will always be “1” as it is impossible to have more than 32
opto inputs.
The Event Value is an 8 or 24-bit word showing the status of the opto inputs, where the least
significant bit (extreme right) corresponds to opto input 1 etc. The same information is
present if the event is extracted and viewed via PC.
1.2.1.2 Change of state of one or more output relay contacts
If one or more of the output relay contacts have changed state since the last time that the
protection algorithm ran, then the new status is logged as an event. When this event is
selected to be viewed on the LCD, three applicable cells will become visible as shown below:
Time & date of event
“OUTPUT CONTACTS #”
“Event Value 010101010101010101010”
Where # = 1 or 2 depending upon which group of 32 output relays is selected. In the case of
P846 relay, however, the value will always be “1” as it is impossible to have more than 32
output relays.
The Event Value is a 8 or 32-bit word showing the status of the output contacts, where the
least significant bit (extreme right) corresponds to output contact 1 etc. The same
information is present if the event is extracted and viewed via PC.
1.2.1.3 Relay alarm conditions
Any alarm conditions generated by the relays will also be logged as individual events. The
following table shows examples of some of the alarm conditions and how they appear in the
event list: