5.6
SEL-787 Relay Instruction Manual Date Code 20150130
Metering and Monitoring
Metering
Energy Metering
The SEL-787 with the voltage option includes energy metering. Use this form
of metering to quantify real and reactive energy supplied by the transformer. Refer
to Figure 5.1 for the definitions of positive real power, negative real power, positive
reactive power, and negative reactive power. Below are the energy meter values:
➤ MWhP—Positive real 3-phase energy
➤ MWhN—Negative real 3-phase energy
➤ MVARhP—Positive reactive 3-phase energy
➤ MVARhN—Negative reactive 3-phase energy
➤ Last date and time energy meter quantities were reset
Figure 5.5 shows the device response to the METER E command.
To reset energy meter values, issue the MET RE command as shown in
Figure 5.6.
Energy metering values are stored to nonvolatile memory four times per day
and within one minute of the energy metering values being reset.
Maximum and
Minimum Metering
Maximum and minimum metering allows you to determine maximum and
minimum operating quantities such as currents, voltages, power, analog input
quantities, RTD quantities and frequency. Table 5.5 lists the max/min
metering quantities.
=>MET E <Enter>
SEL-787 Date: 02/23/2009 Time: 13:48:27
TRNSFRMR RELAY Time Source: Internal
Energy
Positive MWH (MWh) 5.300
Negative MWH (MWh) 0.000
Positive MVARH (MVArh) 0.000
Negative MVARH (MVArh) 0.411
LAST RESET = 02/20/2009 10:55:52
=>
Figure 5.5 METER E Command Report
=>>MET RE <Enter>
Reset Metering Quantities (Y,N)? Y <Enter>
Reset Complete
=>>
Figure 5.6 METER RE Command Report
NOTE: Energy values roll over after
99,999.999 MVAh and reset to 0.
Table 5.5 Maximum/Minimum Meter Values (Sheet 1 of 2)
Relay Option Max/Min Meter Values
Base Model Maximum and minimum line currents IAW1,
IBW1, ICW1, IAW2, IBW2, ICW2 (A primary)
Maximum and minimum IG (residual ground fault
current) magnitude (A primary)
With Neutral Current Option (REF) Maximum and minimum neutral current IN
magnitudes (A primary)
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