Time Stamp For Record Type Objects; Additional Fault Record Implementation Details - ABB RELION Series Communication Protocol Manual

Section 3
Vendor-specific implementation
3.6.3
3.6.4
24
The stored fault records are internally saved in indexes numbered 1...128. When the
controlling station writes a value 1...128 to the "Select record" object, the entire set of
fault record values belonging to that record is copied to the "Recorded" fault record
DNP3 AI values. Thereafter, the controlling station can read the fault record values.

Time stamp for record type objects

One disadvantage of the DNP3 protocol is that static data read does not include any
time stamps for the static values. It is impossible to know when the DNP3 data object
was updated to its value. Therefore, the time stamp of the record itself is re-coded into
a set of seven DNP3 analog input objects. The objects separately contain the year,
month, day, hour, minute, second, and millisecond values of the time stamp.

Additional fault record implementation details

The protection relay's native fault record application can be configured to make
captures at an operate situation only, or during start situations (not leading into
operate). The latter alternative most often causes more captures. The DNP3 protocol
has no part in the setup of the fault record application. The chosen fault record setup
is reflected to all readers of the fault record data, including HMI. If the values are
intended to be available for several readers, a fault record clear operation from any
reading source is not recommended. There are several alternatives for any remote
client, including DNP3, to access the captured fault record data.
Alternative 1, buffering on the DNP3 client side
The easiest alternative is that the client receives the time tagged fault record values as
events at the moment when they are captured in the protection relay. The client system
must then observe that all fault record values with identical event time tag belong to
the same capture. A new fault record capture can take place in the protection relay
right after the previous one. The new fault record values are again sent as events to the
client. The client system is responsible for buffering up these values, in case it is
necessary to later look at older captures.
Alternative 2, buffering on the DNP3 outstation side
If fault records' values not are sent as events to the client, the latest record capture
values can be read directly from the outstation DNP3 AI-area. In this case, also the
older captures are to be read out from the outstation than the latest one, the client must
perform a control action towards the server.
There are up to 128 fault records stored inside the protection relay. The records are
located chronologically in a circular buffer indexed from 1...128. If the client makes
a DNP3 AO-write with an index value (1...128) to the object
FLTRFRC1.SelRow.ctlVal, the values from that particular record are internally
copied into the FLTRFRC1 fault record values. Thereafter the DNP3 client can read
them using regular DNP3 AI reading.
1MRS758757 A
REC615 and RER615
Communication Protocol Manual