5-4
Metering and Monitoring
Date Code 20020129
SEL-387E Instruction Manual
primary amperes. If the command is typed as
MET P m
, where m is any number from 1 to
32767, the report will be repeated m times in succession. In this mode subsequent reports are not
generated until the previous report has been completely sent. The format for the METER P
report is as follows:
=>>METER P<ENTER>
XFMR 1 Date: MM/DD/YY Time: HH:MM:SS.SSS
STATION A
Peak Dem I (A, pri) Date: Time:
Wdg 1 IAW1 12345 MM/DD/YY HH:MM:SS.SSS
IBW1 12345 MM/DD/YY HH:MM:SS.SSS
ICW1 12345 MM/DD/YY HH:MM:SS.SSS
3I2W1 12345 MM/DD/YY HH:MM:SS.SSS
IRW1 12345 MM/DD/YY HH:MM:SS.SSS
Wdg 2 IAW2 12345 MM/DD/YY HH:MM:SS.SSS
IBW2 12345 MM/DD/YY HH:MM:SS.SSS
ICW2 12345 MM/DD/YY HH:MM:SS.SSS
3I2W2 12345 MM/DD/YY HH:MM:SS.SSS
IRW2 12345 MM/DD/YY HH:MM:SS.SSS
Wdg 3 IAW3 12345 MM/DD/YY HH:MM:SS.SSS
IBW3 12345 MM/DD/YY HH:MM:SS.SSS
ICW3 12345 MM/DD/YY HH:MM:SS.SSS
3I2W3 12345 MM/DD/YY HH:MM:SS.SSS
IRW3 12345 MM/DD/YY HH:MM:SS.SSS
LAST PEAK DEMAND RESET FOR Wdg1: MM/DD/YY HH:MM:SS.SSS
Wdg2: MM/DD/YY HH:MM:SS.SSS
Wdg3: MM/DD/YY HH:MM:SS.SSS
=>>
The report for METER P contains the last reset times for the peak demand registers for each
winding.
Differential Metering Function (METER DIF Command)
This metering function is performed on an element basis, not on a winding basis, because of the
nature of the function. The relay has three differential elements, one per phase, denoted 87-1,
87-2, and 87-3. The “A-phase” currents for each winding are compensated for CT and
transformer winding connections, divided by the tap value for each winding, and then entered
into the calculations as dimensionless “multiples of tap.” These values are then summed in 87-1
on a phasor basis for determining operating current (IOPk) and on a scalar magnitude basis for
the restraint current (IRTk) calculation (k = 1, 2, 3). The B-phase and C-phase values find their
ways to 87-2 and 87-3, respectively.
In response to the
METER DIF
(
MET DIF
) command, the fundamental frequency operate and
restraint currents for each differential element are displayed in multiples of tap. The second- and
fifth-harmonic currents in each element are also shown in multiples of tap. These are calculated
in the same way as the operate currents, using the harmonic current from each winding in a
phasor addition. If the command is typed as
MET DIF m
, where m is any number from 1 to
32767, the report will be repeated m times in succession. In this mode subsequent reports are not
generated until the previous report has been completely sent. The format for the METER DIF
report is as follows:
