8-12
Monitoring and Metering Functions
Date Code 20060731
SEL-300G Instruction Manual
Note:
When open-delta PTs are applied, (DELTA_Y = D), the relay displays three-phase
energy quantities only.
Via Front Panel
The information and reset functions available via the previously discussed serial port commands
MET E
and
MET RE
are also available via the front-panel METER pushbutton. See Figure 9.2
in
Section 9: Front-Panel Operation
.
Energy Metering Updating and Storage
The SEL-300G updates energy values approximately every two seconds.
The relay stores energy values to nonvolatile storage once per day (it overwrites the previous
stored value). Should the relay lose control power, it will restore the energy values saved by the
relay at 23:50 hours on the previous day.
Accumulated energy metering values in the relay function like those in an electromechanical
energy meter. When the energy meter reaches 999999 MWh or 999999 MVARh, it starts over at
zero.
Note:
If you are using Modbus
®
RTU Communications Protocol to retrieve energy metering
data from the SEL-300G, you are limited to a maximum of 65535 MWh or 65535
MVARh. The energy meter values do not reset automatically, but they can be reset, either
locally (front panel or serial port) or from a Modbus master location when they reach the
maximum value mentioned above.
M
AXIMUM
/M
INIMUM
M
ETERING
View or Reset Maximum/Minimum Metering Information
Via Serial Port
See
MET Command (Metering Data), MET M—Maximum/Minimum Metering
in
Section 10:
Serial Port Communications and Commands
. The
MET M
command displays
maximum/minimum metering for the following values:
I
A,B,C,N
Input currents (A primary)
I
G
Residual ground current (A primary; IG = 3I0 =
IA + IB + IC)
Currents
I
A87,B87,C87
87-Input currents (A primary, Models 0300G1,
and 0300G3)
V
A,B,C,N
Input voltages (kV primary, DELTA_Y = Y)
V
AB,BC,CA,N
Input voltages (kV primary, DELTA_Y = D)
V
s
Input voltage (kV primary, Models 0300G2 and
0300G3)
V
P3
, V
N3
Terminal (DELTA_Y = Y) and neutral third-
harmonic voltages (V secondary)
Voltages
V
N1
Neutral fundamental voltage (V secondary)
Summary of Contents for SEL-300G
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