Date Code 20171006 Instruction Manual SEL-400 Series Relays
Instruction Manual
SECTION 7
Metering
The relay provides extensive capabilities for metering important power system
parameters.
This section provides basic information about metering capabilities in typical
SEL-400 series relays. Not all SEL-400 series relays support every metering fea-
ture described in this section. See Section 7: Metering, Monitoring, and Reports
of the product-specific instruction manual for information on the specific meter-
ing capabilities of a specific relay.
SEL-400 series relays typically provide the following metering modes for measur-
ing power system operations:
➤ Instantaneous Metering on page 7.2
➤ Maximum/Minimum Metering on page 7.5
➤ Demand Metering on page 7.6
➤ Energy Metering on page 7.10
➤ Synchrophasor Metering on page 7.10
➤ Battery Metering on page 7.11
➤ RTD Metering on page 7.12
➤ Protection Math Variable Metering on page 7.12
➤ Automation Math Variable Metering on page 7.13
➤ MIRRORED BITS Remote Analog Metering on page 7.13
Monitor present power system operating conditions with instantaneous metering.
Maximum/Minimum metering displays the largest and smallest system devia-
tions since the last reset. Demand metering includes either thermal or rolling ana-
lyzes of the power system and peak demand metering. Energy metering displays
the megawatt-hours imported, megawatt-hours exported, and total megawatt-
hours. Time-synchronized metering displays the line voltage and current syn-
chrophasors.
The relay processes various sets of currents and voltages, depending on the spe-
cific relay.
Use the MET command to access the metering functions. Issuing the MET com-
mand with no options returns fundamental measurement quantities. The MET
command followed by a number, MET k, specifies the number of times the com-
mand will repeat (k can range from 1–32767). This is useful for troubleshooting
or investigating uncharacteristic power system conditions.
Table 7.1 lists some common MET command variants.
Table 7.1 MET Command (Sheet 1 of 2)
Name Description
MET Display fundamental line metering information
MET RMS Display rms line metering information
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