Date Code 20080110 Metering and Monitoring 5-5
SEL-387E Instruction Manual
=>>METER DIF <Enter>
XFMR 1 Date: MM/DD/YY Time: HH:MM:SS.SSS
STATION A
Operate Currents Restraint Currents
IOP1 IOP2 IOP3 IRT1 IRT2 IRT3
I (Mult. of Tap) 123.12 123.12 123.12 123.12 123.12 123.12
Second Harmonic Currents Fifth Harmonic Currents
I1F2 I2F2 I3F2 I1F5 I2F5 I3F5
I (Mult. of Tap) 123.12 123.12 123.12 123.12 123.12 123.12
=>>
The quantities I1F2/IOP1, I2F2/IOP2, I3F2/IOP3, and I1F5/IOP1, etc., form the basis for the
harmonic blocking feature. To determine if blocking should take place, these ratios of harmonic-
to-fundamental operating current (times 100%) are compared to the user-selected blocking
threshold settings PCT2 and PCT5.
Phasor Metering Function (METER SEC Command)
The phasor metering function is a useful tool for verifying proper phase rotation of input
currents, for checking CT connections and polarities, and for checking that “in” currents are
about 180
°
out-of-phase with “out” currents. With normal load currents on the transformer, the
correctness (or lack thereof) of all the input connections becomes apparent.
In response to the
METER SEC
(
MET SEC
) command, the separate phase currents, as well as
the positive-sequence, negative-sequence, and residual currents for each winding are shown in
secondary amperes and at a calculated phase angle. The relay uses the sample data to calculate
the RMS phasor magnitudes and instantaneous phase angles as a kind of “snapshot” of all the
phasor currents at an instant in time. If the command is typed as
MET SEC 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 SEC report is as follows:
=>>METER SEC <Enter>
XFMR 1 Date: MM/DD/YY Time: HH:MM:SS.SSS
STATION A
Phase Currents Sequence Currents
Wdg1 IAW1 IBW1 ICW1 3I1W1 3I2W1 IRW1
I (A,sec) 123.12 123.12 123.12 123.12 123.12 123.12
Angle (deg) ±123.12 ±123.12 ±123.12 ±123.12 ±123.12 ±123.12
Wdg2 IAW2 IBW2 ICW2 3I1W2 3I2W2 IRW2
I (A,sec) 123.12 123.12 123.12 123.12 123.12 123.12
Angle (deg) ±123.12 ±123.12 ±123.12 ±123.12 ±123.12 ±123.12
Wdg3 IAW3 IBW3 ICW3 3I1W3 3I2W3 IRW3
I (A,sec) 123.12 123.12 123.12 123.12 123.12 123.12
Angle (deg) ±123.12 ±123.12 ±123.12 ±123.12 ±123.12 ±123.12
Phase Voltages Sequence Voltages
WdgX VAWX VBWX VCWX 3V1WX 3V2WX VRWX
V (V,sec) 123.12 123.12 123.12 123.12 123.12 123.12
Angle (deg) ±123.12 ±123.12 ±123.12 ±123.12 ±123.12 ±123.12
=>>
The phase angles given are all referenced to voltage VAWX. That is, the full set of 24 calculated
phasors is rotated in a manner that brings VAWX to an angle of zero degrees. However, if the
magnitude of VAWX is less than 0.0975 • V
nom
(13 V for a 120 V relay), the angles are listed
according to the phasor calculation, without further adjustment.
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