12.8
SEL-351S Relay Instruction Manual Date Code 20080103
Standard Event Reports, Sag/Swell/Interruption Report, and SER
Standard 15/30-Cycle Event Reports
take advantage of the Compressed ASCII format. Use the EVE C command
or CEVENT command to display Compressed ASCII event reports. See the
CEVENT command discussion in Appendix E: Compressed ASCII
Commands for further information.
Filtered and
Unfiltered Event
Reports
The SEL-351S samples the basic power system measurands (ac voltage, ac
current, station battery, and optoisolated inputs) 16 times per power system
cycle. The relay filters the measurands to remove transient signals. The relay
operates on the filtered values and reports them in the event report.
To view the raw inputs to the relay, select the unfiltered event report (e.g.,
EVE R). Use the unfiltered event reports to observe:
➤ Power system harmonics on channels IA, IB, IC, IN, VA, VB, VC, VS
➤ Decaying dc offset during fault conditions on IA, IB, IC
➤ Optoisolated input contact bounce on channels IN101–IN106
➤ Transients on the station dc battery channel Vdc (power input
terminals Z25 and Z26)
The filters for ac current and voltage and station battery are fixed. You can
adjust the optoisolated input debounce via debounce settings (see Figure 7.1).
Raw event reports display one extra cycle of data at the beginning of the
report.
Unfiltered Event Reports With PTCONN = DELTA
When global setting PTCONN = DELTA, the raw event report voltage
columns reflect the signals applied to relay terminals VA-N, VB-N, VC-N, even
though the relay is configured for an open-delta PT connection (see
Figure 2.29). If the relay is properly wired, the value shown in column
VB
should be at or near 0 kV, because input terminal VB is tied to terminal N.
Column
VA should reflect power system voltage V
AB
, and column VC should
reflect power system voltage V
CB
(or –V
BC
).
Clearing Standard
Event Report Buffer
The HIS C command clears the event summaries and corresponding standard
event reports from nonvolatile memory. See Section 10: Serial Port
Communications and Commands for more information on the HIS (Event
Summaries/History) command.
Standard Event
Report Column
Definitions
Refer to the example event report in Figure 12.3 to view event report columns.
This example event report displays rows of information each 1/4 cycle and
was retrieved with the EVE command.
The columns contain ac current, ac voltage, station dc battery voltage,
frequency, output, input, and protection and control element information.
Current, Voltage, and Frequency Columns
Table 12.2 summarizes the event report current, voltage, and frequency
columns.
NOTE: Compressed ASCII Event
Reports contain all of the Relay Word
bits. Regular, uncompressed event
reports only contain a subset of the
Relay Word bits.
NOTE: Figure 12.3 is on multiple
pages.
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