Date Code 20010719 701 Motor Protection Relay
SELOGIC
®
Control Equations & Relay Logic
Selected Relay Logic Diagrams
B.35
Figure B.13 Overcurrent Element Logic.
Current
Magnitude
Calculations
50P1T
50P1P
|IP|
+
IG
50N1T
50N1P
50N2T
|IN|
IN
IC
IB
IA
Relay
Word
Bits
Negative-
Sequence
Current
Calculation
PHROT
3I2
|I
P
|
(Maximum Phase Current Magnitude)
|I
N
|
(Neutral Current Magnitude)
|I
G
|
(Residual Current Magnitude)
|3I2|
(Negative-Sequence Current Magnitude)
Settings
50P1D
0
0
50P2T
50P2P
0
50N2P
0
50G1T
50G1P
50G2T
50G2P
|IG|
0
0
50P2D
50N1D
50N2D
50G1D
50G2D