U.4.46
SEL-421/SEL-421-1 Relay User’s Guide Date Code 20020501
Basic Relay Operations
Reading Oscillograms, Event Reports, and SER
Viewing Event
Report Data
Examine relay event reports to inspect the operating quantities the SEL-421
Relay used at each triggered event. Unlike the raw data samples/second high-
resolution oscillography files, these reports contain the filtered samples/cycle
data the relay uses to make protection decisions. Event reports are useful for
determining why the relay operated for a particular set of power system
conditions. For more information on event reports, see Event Report on
page A.3.12 in the Applications Handbook.
Retrieving Event Report Data Files: Terminal
The relay recorded the event triggered in Triggering an Event on page 4.39.
The procedure in the following steps shows you how to retrieve the event
report data files for this event. Perform the steps listed in Triggering an Event
on page 4.39 before executing the instructions in this example. For this
procedure, you must use a terminal program capable of Ymodem protocol file
transfer.
Step 1. Prepare to monitor the relay at Access Level 1. Using a
communications terminal, type ACC<Enter>. Type the Access
Level 1 password and press <Enter>. You will see the =>
action prompt.
Step 2. View the events file directory. Type FILE DIR EVENTS
<Enter>. The relay lists file names for recently recorded
events in a manner similar to that shown in Figure 4.36 on
page 4.43. In the figure, the relay shows two event report files:
E4_10001.TXT and E8_10001.TXT, and two Compressed
ASCII event report files: C4_10001.TXT and C8_10001.TXT.
Step 3. Prepare the relay to download the 8-samples/cycle event report.
Type FILE READ EVENTS C8_10001.TXT<Enter> to
transfer the Compressed ASCII event report file to your
computer.
Step 4. Download the file. Perform the steps necessary for your
terminal emulation program to receive a file. Typically, these
are the file transfer steps:
➢ Specify the destination file location in your computer
file storage system and file name.
➢ Select the transfer type as Y-Modem (if not already
enabled).
➢ Click on Receive.
➢ You will usually see a confirmation message when the
file transfer is complete.
Step 5. When this file has transferred successfully, use the SEL-5601
Analytic Assistant to play back the event report oscillograms of
the 8-samples/cycle event report file you just transferred.
Use the ASCII command CEVENT to retrieve event report files in
Compressed ASCII format. See SEL Compressed ASCII Commands on
page R.5.6 in the Reference Manual and CEVENT on page R.8.5 in the
Reference Manual for more information.
Viewing SER Records
The relay SER records relay operating changes and relay element states. In
response to an element change of state, the SER logs the element, the element
state, and a time stamp. Program the relay elements that the relay stores in the
SER records, thus capturing significant system events such as an input/output
change of state, element pickup/dropout, recloser state changes, etc. The
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