8-28
Breaker Monitor and Metering Functions
Date Code 20011205
SEL-311B Instruction Manual
View or Reset Demand Metering Information
Via Serial Port
See
MET Command (Metering Data)
, MET D—Demand Metering in
Section 10: Serial Port
Communications and Commands
. The
MET D
command displays demand and peak demand
metering for the following values:
Currents I
A,B,C
I
G
3I
2
Input currents (A primary)
Residual ground current (A primary; I
G
=3I
0
= I
A
+ I
B
+ I
C
)
Negative-sequence current (A primary)
Power MW
A,B,C
MVAR
A,B,C
MW
3P
MVAR
3P
Single-phase megawatts
Single-phase megavars
Three-phase megawatts
Three-phase megavars
The
MET RD
command resets the demand metering values. The
MET RP
command resets the
peak demand metering values.
Via Front Panel
The information and reset functions available via the previously discussed serial port commands
MET D
,
MET RD
, and
MET RP
are also available via the front-panel METER pushbutton.
See Figure 11.2 in
Section 11: Front-Panel Interface
.
Demand Metering Updating and Storage
The SEL-311B Relay updates demand values approximately every 2 seconds.
The relay stores peak demand values to nonvolatile 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 values saved by the relay at 23:50 hours on the previous day.
Demand metering updating and peak recording is momentarily suspended when SEL
OGIC
control
equation setting FAULT is asserted (= logical 1). See the explanation for the FAULT setting in
the following
Maximum/Minimum Metering
subsection.
E
NERGY
M
ETERING
View or Reset Energy Metering Information
Via Serial Port
See
MET Command (Metering Data)
, MET E—Energy Metering in
Section 10: Serial Port
Communications and Commands
. The
MET E
command displays accumulated single- and
three-phase megawatt and megavar hours. The
MET RE
command resets the accumulated
single- and three-phase megawatt and megavar hours.
Summary of Contents for SEL-311B
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