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8.30
SEL-351-5, -6, -7 Relay
Instruction Manual
Date Code 20070117
Breaker Monitor, Metering, and Load Profile Functions
Maximum/Minimum Metering
Maximum/Minimum Metering
View or Reset
Maximum/Minimum
Metering Information
Via Serial Port
See
MET M—Maximum/Minimum Metering on page 10.24
. The
MET M
command displays maximum/minimum metering for the following values:
The
MET RM
command resets the maximum/minimum metering values.
The power maximum and minimum values can be negative or positive,
indicating the range of power flow that has occurred since the last
MET RM
reset command. These functions simulate analog meter drag-hands, with the
maximum value representing the upper drag-hand and the minimum value
representing the lower drag-hand.
shows the values that the relay would record for various power flow
directions (either MW3P or MVAR3P).
Via Front Panel
The metering and reset functions available via serial port commands
MET M
and
MET RM
are also available via the front-panel
{METER}
pushbutton. See
Maximum/Minimum
Metering Update and
Storage
The maximum/minimum metering function is intended to reflect normal load
variations rather than fault conditions or outages. Therefore, the SEL-351
updates maximum/minimum values only if SEL
OGIC
control equation setting
FAULT is deasserted (= logical 0) and has been deasserted for at least
3600 cycles.
Currents I
A,B,C,N
Input currents (A primary)
I
G
Residual ground current (A primary; I
G
=
3I
0
)
Voltages V
A,B,C,
Input voltages (kV primary, wye-connected
voltage only)
V
AB,BC,CA
Input voltages (kV primary, delta-
connected voltage only)
V
S
Input voltage (kV primary)
Power MW
3P
Three-phase megawatts (primary)
MWAR
3P
Three-phase megavars (primary
Table 8.4
Operation of Maximum/Minimum Metering With Directional Power
Quantities
a
a
For simplicity, the date and time stamps are not shown here.
If Power Varies
Recorded MAX
Recorded MIN
From:
To:
9.7
16.2
16.2
9.7
–4.2
1.4
1.4
–4.2
–25.3
–17.4
–17.4
–25.3
–6.2
27.4
27.4
–6.2
NOTE:
Firmware releases R300–
R305, inclusive, treated the positive
and negative power values differently.
See
Appendix A: Firmware and Manual
for a list of previous firmware
releases.
Summary of Contents for SEL-351-5
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