12.28
SEL-351A Relay Instruction Manual Date Code 20080213
Standard Event Reports and SER
Example Standard 15-Cycle Event Report
Figure 12.5 Derivation of Event Report Current Values and RMS Current
Values From Sampled Current Waveform
In Figure 12.5, note that any two rows of current data from the event report in
Figure 12.3, 1/4 cycle apart, can be used to calculate rms current values.
Event Report Column
1474
–2320
–1479
2317
2317
–1479
–2320
1474
IA
1
2
2
2
Multiply by
1
Multiply by
2317
–2320
–1479
1474
–2091
-3281
2085
3277
t
IA
1/4 cyc.
IA
peak
= 3887 A
peak
3887 A
peak
= 2749 A
RMS
(1474)
2
+ (–2320)
2
(–2320)
2
+ (–1479)
2
(–1479)
2
+ (2317)
2
= 2749
= 2751
= 2749
Courtesy of NationalSwitchgear.com