3-12
Communications
Date Code 970103
SEL-251, -2, -3 Instruction Manual
METER n
METER displays
present
values of the following:
IA :
A-phase current (primary amps)
B :
B-phase current (primary amps)
C :
C-phase current (primary amps)
R :
Ground/residual current (primary amps)
3I2 :
3 x negative-sequence current (primary amps)
P :
Three-phase real power (MW)
Q :
Three-phase reactive power (MVAR)
VA :
A-phase voltage (primary volts)
VB :
B-phase voltage (primary volts)
VC :
C-phase voltage (primary volts)
3V0 :
3 x zero-sequence voltage (primary volts)
AB :
AB phase-to-phase voltage (primary volts)
BC :
BC phase-to-phase voltage (primary volts)
CA :
CA phase-to-phase voltage (primary volts)
3V2 :
3 x negative-sequence voltage (primary volts)
=>METER <ENTER>
METER <ENTER>
Example 21.6 kV distribution feeder Date: 04/01/93 Time: 09:12:49
MET IA=356 B=364 C=361 R=6
3I2=5 P=12.910 Q=1.130
VA=12021 VB=12015 VC=12043 3V0=20
AB=20827 BC=20839 CA=20836 3V2=17
=>
P is positive when three-phase real power flows out from the bus and into the line. If P is
negative, three-phase real power flows in the opposite direction. Q is positive when three-phase
reactive power flows from the bus and into the line (net load on the line has a lagging power
factor). If Q is negative, three-phase reactive power flows in the opposite direction (net load on
the line has a leading power factor). If Q = 0, no net reactive power is flowing past the relay (net
load on the line has a unity power factor).
The optional parameter n selects the number of times the relay displays meter data. To display a
series of eight meter readings, type
METER 8 <ENTER>
.