Sel SEL-787 - Figure 5.8 METER RM Command Response; Figure 5.9 MET MV Command Report; Table 5.6 RMS Meter Values

5.8
SEL-787 Relay Instruction Manual Date Code 20150130
Metering and Monitoring
Metering
To reset maximum/minimum meter values, issue the MET RM command as
shown in Figure 5.8. The max/min meter values can be reset from the serial
port, the front panel, or assertion of the RSTMXMN relay element. The date
and time of the reset are preserved and shown in the max/min meter report.
All maximum and minimum metering values are stored to nonvolatile
memory four times per day and within one minute of the maximum and
minimum metering values being reset.
Math Variable
Metering
The SEL-787 includes 32 math variables. When you receive your SEL-787,
no math variables are enabled. To use math variables, enable the number of
math variables (between 1 and 32) you require, using the EMV setting in the
Logic setting category. Figure 5.9 shows the device response to the METER
MV M(ath) V(ariable) command with 8 of the 32 math variables enabled.
RMS Metering
The SEL-787 includes root mean squared (rms) metering. Use rms metering
to measure the entire signal (including harmonics). You can measure the rms
quantities shown in Table 5.6.
RMS quantities contain the total signal, including harmonics. This differs
from the fundamental meter (METER command) in that the fundamental
meter quantities only contain the fundamental frequency (60 Hz for a 60-Hz
system). Figure 5.10 shows the METER RMS command report.
=>>MET RM <Enter>
Reset Metering Quantities (Y,N)? Y <Enter>
Reset Complete
=>>
Figure 5.8 METER RM Command Response
=>>MET MV <Enter>
SEL-787 Date: 03/11/2008 Time: 12:32:10
TRNSFRMR RELAY Time Source: Internal
MV01 1.00
MV02 -32767.00
MV03 -1.00
MV04 0.00
MV05 1000.59
MV06 -1000.61
MV07 2411.01
MV08 2410.99
=>>
Figure 5.9 MET MV Command Report
Table 5.6 RMS Meter Values
Relay Option RMS Meter Values
Base Model RMS current IAW1, IBW1, ICW1, IAW2, IBW2, and ICW2
magnitudes (A primary)
With Neutral Current
(IN) Option
RMS current IN magnitude (A primary)
With Voltage Option VAB, VBC, VCA or VAN, VBN, VCN, and VG magnitudes
(V primary)