Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.96 POTT Scheme Logic (ECOMM:= POTT3) with Echo and Weak Infeed

5.132
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Functions
Permissive Overreaching Transfer Tripping Scheme
Figure 5.96 POTT Scheme Logic (ECOMM := POTT3) With Echo and Weak Infeed
ILOP
ELOP=Y1
SPOA
MAG3
XAG2
EBLKD=OFF
ETDPU=OFF
PTA
TPA
KEYA Z3RBA EKEYA
ECTTA
WFC
|Vab|
|Vbc|
|Vca|
27PPW
59NW
|3V0|
EWFC=Y,SP
Note: PTB, KEYB for B-Phase PTC, KEYC for C-phase
MAG2
Z2P
APS Z2G Z3G
67G3
67Q3
XAG3
Z3P
67QGSP=Y
Multi-Phase
Fault
3PO
67G3
67Q3
ETDPU
0
0
EBLKD
0
EDURD
0
2
CYC
0.5 CYC
Z3RBD
0.75 CYC
0