A2 Metering - GE 750 Instruction Manual

A2 METERING

6.3.1 Metering
Conventions
6 - 10
6.3 A2 Metering
The relay measures all RMS currents and voltages, frequency, and an auxiliary analog
input. Other values like average and neutral current, average line and phase voltage,
symmetrical components, frequency decay rate, synchrocheck delta, power factor, power
(real, reactive, apparent), energy (real, reactive), running and maximum demands (current,
real power, reactive power, apparent power), and analog input rate of change are derived.
All quantities are recalculated every power system cycle and perform protection and
monitoring functions. Displayed metered quantities are updated approximately three (3)
times a second for readability. All phasors and symmetrical components are referenced to
the A-N voltage phasor for wye-connected VTs; to the A-B voltage phasor for delta-
connected VTs; or to the phase A current phasor when no voltage signals are present.
ONE LINE DIAGRAM
I
2
I
3
SOURCE
PER IEEE DEFINITIONS
PHASOR DIAGRAM
(POSITIVE ROTATION)
S2
- Watt
- Var
PF=Lag
I
2
I
S3 3
- Watt
+ Var
PF=Lead
= Angle By Which Voltage Leads Current
4
FIGURE 6–3: Power Quantity Relationships
I
1
I
4
POSITIVE
DIRECTION
LOAD
RELAY
S2=E
S3=E
S1
+ Watt
- Var
PF=Lead
I
1
Bus Voltage E
4
I
4 S4
+ Watt
+ Var
PF=Lag
750 FEEDER MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 6: ACTUAL VALUES
POWER PLANE DIAGRAMS
+Q
P1
-P +P
Q1
^
I 1
S1=E
-Q
+Q
P2
-P +P
Q2
^
I 2
-Q
+Q
^
I 3
Q3
P3
-P +P
-Q
+Q
^
I 4
S4=E
Q4
4
-P P4 +P
-Q
818773AC.CDR