Sel SEL-421 - POTT Scheme Logic (ECOMM:= POTT3) with Echo and Weak Infeed

R.1.99
Date Code 20111215 Reference Manual SEL-421 Relay
Protection Functions
Permissive Overreaching Transfer Tripping Scheme
Figure 1.65 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
M2P
APS Z2G Z3G
67G3
67Q3
XAG3
M3P
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