4-2 Event Reporting Date Code 970103
SEL-251, -2, -3 Instruction Manual
The summary event report includes:
• Relay terminal identifier
• Date and time
• Event type
• Fault location
• Reclosing relay shot
• FAULT TYPE front panel targets
• Currents (phase, 3 x negative-sequence, and residual) measured near the middle of the
fault or when the event report was triggered if no fault occurred.
The following shows an example summary event report.
Example 21.6 kV distribution feeder Date: 04/01/93 Time: 01:36:50.070
Event : AG T Location: 2.43 Shot: 0 Targets: INSTAQN
Currents (A pri), ABCQN: 2798 213 211 2741 2742
=>
See HISTORY in Section 3: Communications for more information. The relay clears the event
report and history buffer for the following conditions:
• Loss of control power
• Entry of new setting via SET or SET G command
• COPY command execution
LONG EVENT REPORT
The long event report contains 44 quarter-cycles of prefault, fault, and post fault voltage and
current information. For each quarter-cycle of information, the relay also records the states of all
fault measuring elements, outputs, and inputs. The report also includes settings active during the
event. This information is useful in reviewing fault inception and duration, relay element
response, fault evolution, and breaker reaction time.
The last twelve event records are stored in volatile memory. You can review the stored summary
reports quickly with the HISTORY command; use the EVENT command to display the long
form of each event report.
INTERPRETING VOLTAGE AND CURRENT DATA
The relay determines voltage and current data in the event report using the following steps. The
process uses secondary quantities presented to the rear panel of the relay.
1. Two-pole, low pass filters with cutoff frequencies of approximately 85 Hz filter input analog
signals.
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