9.2
SEL-749M Relay Instruction Manual Date Code 20080918
Analyzing Events
Event Reporting
➤ Event summary, including the front-panel target states at the
time of tripping and fault type
➤ Group, logic, global, and report settings (that were in service
when the event was recorded)
Compressed ASCII Event Reports, Event Summaries, and History
The SEL-749M provides Compressed ASCII event reports to facilitate event
report storage and display. SEL communications processors and the SEL-5601
Analytic Assistant software take advantage of the Compressed ASCII format.
Use the CHIS command to display Compressed ASCII event history
information. Use the CSUM command to display Compressed ASCII event
summary information. Use the CEVENT command to display Compressed
ASCII event reports. See the CEVENT Command (Compressed Event Report)
on page U.7.13 and SEL Compressed ASCII Commands on page C.1 for
further information.
Compressed ASCII Event Reports contain all of the Relay Word bits.
Sequential Events
Recorder (SER)
The SER report captures detailed digital element state changes over a long
time period. Settings allow up to 96 Relay Word bits to be monitored, in
addition to the automatically generated triggers for relay power-up, settings
changes, and active setting group changes. State changes are time-tagged to
the nearest millisecond.
SER report data are useful in commissioning tests and during operation for
system monitoring and control.
SER information is stored when state changes occur.
Event Reporting
Length
The SEL-749M provides selectable event report length (LER) and prefault
length (PRE). Event report length is either 15 or 64 cycles. Prefault length is
1–10 cycles for LER = 15 and 1–59 cycles for LER = 64. Prefault length is the
first part of the total event report length and precedes the event report
triggering point.
See the SET R command in Table 7.41 and Report Settings (SET R
Command) on page SET.16 of the SEL-749M Settings Sheets for instructions
on setting the LER and PRE settings.
Changing the PRE setting has no effect on the stored reports.
Triggering
The SEL-749M triggers (generates) an event report when any of the following
occur:
➤ Relay Word bit TRIP asserts
➤ Programmable SELOGIC
®
control equation setting ER asserts
to logical 1 (in Report settings)
➤ TRI (Trigger Event Reports) serial port command executed
NOTE: Changing the LER setting will
clear all events in memory. Be sure to
save critical event data prior to
changing the LER setting.
Courtesy of NationalSwitchgear.com
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