7.10
SEL-400 Series Relays Instruction Manual Date Code 20171006
Metering
Energy Metering
Demand Metering Updating and Storage
The relay updates demand and peak demand values once per second. The relay
also stores peak demand values and the date and time these occurred to nonvola-
tile storage once per day (it overwrites the previous stored value if it is exceeded).
Should the relay lose control power, it will restore the peak demand information
saved at 23:50 hours on the previous day.
Demand metering updating and peak recording is suspended during the time that
SEL
OGIC control equation FAULT asserts Relay Word bit DFAULT (Delayed
FAULT Suspend).
Energy Metering
Energy is the power consumed or developed in the electric power system mea-
sured over time. You can use accurate accounting of power system energy flow to
manage billing revenues, whether your system is a net energy producer or con-
sumer. Time-synchronized demand and energy measurements make demand and
energy metering information even more useful for power system status applica-
tions.
NOTE: Not all SEL-400 series relays
support energy metering.
The relay integrates energy imported and exported on a per-phase basis every
second. As in demand metering, the relay uses the longer-term accumulations of
rms or true real power for reliable energy data.
View or Reset Energy Metering Information
You can read the energy metering quantities by using a communications port,
QuickSet, or the relay front-panel LCD screen.
To reset the energy values, use the MET RE command from a communications
terminal, or use the RESET button in the QuickSet HMI > Meter and Control >
Energy window, or answer
Y and press ENT at the Energy Meter submenu reset
prompt on the front-panel LCD screen. You can also reset energy metering with
Global setting RST_ENE when EDRSTC (Data Reset Control) is Y.
Energy Metering Updating and Storage
The relay updates energy values once per second. The relay also stores energy
values to nonvolatile storage once every four hours, referenced from 23:50 hours
(it overwrites the previously stored value if it is exceeded). Should the relay lose
control power, it restores the energy values saved at the end of the last four-hour
period.
Synchrophasor Metering
The relay provides synchrophasor measurement with an angle reference accord-
ing to IEEE C37.118. The relay calculates the phasor measurement quantities 50
or 60 times per second, depending on the nominal system frequency contained in
Global setting NFREQ.
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