9.2
SEL-751A Relay Instruction Manual Date Code 20100129
Analyzing Events
Event Reporting
Compressed Event
Reports
The SEL-751A provides Compressed ASCII event reports to facilitate event
report storage and display. SEL communications processors and the
ACSELERATOR
®
Analytic Assistant SEL-5601 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.
For accurate event report analysis, use the Compressed Event report with raw
(unfiltered) data (CEV R command). The regular ASCII Event report is useful
for a quick check. See Table C.2 for further information.
Compressed ASCII Event Reports contain all of the Relay Word bits.
Additionally, the SEL-751A Compressed Event (CEV command) report
includes four analog channels for the % arc-flash sensor light values that are
not available in the regular ASCII Event (EVE command) report.
Sequential Events
Recorder (SER)
The SER report captures digital element state changes over time. 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 information is stored when state changes occur.
SER report data are useful in commissioning tests and during operation for
system monitoring and control.
Event Reporting
Length
The SEL-751A 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. Changing the PRE setting has no effect on the stored reports.
Refer to the SET R command in SET Command (Change Settings) on
page 7.36 and Report Settings (SET R Command) on page SET.55.
Triggering
The SEL-751A triggers (generates) an event report when any of the following
occur:
➤ Relay Word bit TRIP asserts
➤ Programmable SELOGIC
®
control equation setting ER asserts
(in Report settings)
➤ TRI (Trigger Event Reports) serial port command executes
Relay Word Bit TR
Refer to Figure 4.29. If Relay Word bit TR asserts to logical 1, an event report
is automatically generated. Thus, any Relay Word bit that causes a trip does
not have to be entered in SEL
OGIC control equation setting ER.
Programmable SELOGIC Control Equation Setting ER
The programmable SELOGIC control equation event report trigger setting ER
is set to trigger event reports for conditions other than trip conditions (see
SET R in SET Command (Change Settings) on page 7.36). When setting ER
IMPORTANT: Changing the LER
setting will clear all events in
memory. Be sure to save critical
event data prior to changing the LER
setting.
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