A2 Metering; Metering Conventions - GE Feeder Management Relay 750 Instruction Manual

6.3 A2 METERING

6.3A2 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 volt-
age signals are present.
I
2
I
3
SOURCE
6
6-8
Courtesy of NationalSwitchgear.com
ONE LINE DIAGRAM
I
1
I
4
POSITIVE
DIRECTION
RELAY
PER IEEE DEFINITIONS
PHASOR DIAGRAM
(POSITIVE ROTATION)
S2
S1
- Watt + Watt
- Var
- Var
PF=Lag
PF=Lead
I
I
1
2
4
I I
S4
S3 3 4
+ Watt
- Watt
+ Var + Var
PF=Lag
PF=Lead
= Angle By Which Voltage Leads Current
4
Figure 6–3: POWER QUANTITY RELATIONSHIPS
750/760 Feeder Management Relay
POWER PLANE DIAGRAMS
-P
LOAD
-P
^
I 2
S2=E
^
I 3
S3=E
-P
Bus Voltage E
-P
6 ACTUAL VALUES

6.3.1 METERING CONVENTIONS

+Q
P1
+P
Q1
^
I 1
S1=E
-Q
+Q
P2
+P
Q2
-Q
+Q
Q3
P3
+P
-Q
+Q
^
I 4
S4=E
Q4
4
P4 +P
-Q
818773AC.CDR
GE Multilin