Sel 411L - Figure 3.148 DCB Logic Diagram; Permissive Overreaching Transfer Tripping Scheme

P.3.224
SEL-411L Relay Protection Manual Date Code 20151029
Protection Functions
Permissive Overreaching Transfer Tripping Scheme
Figure 3.148 DCB Logic Diagram
Permissive Overreaching Transfer Tripping Scheme
Use MIRRORED BITS
®
communications to implement a permissive
overreaching transfer tripping (POTT) scheme efficiently and economically.
M
IRRORED BITS communications technology improves security and improves
the overall operating speed. If the communications channel is reliable and
noise-free (as with fiber-optic channels), then POTT provides both security
and reliability. You can also implement a POTT scheme with other
conventional communications channels such as leased telephone lines and
microwave. The DCUB trip scheme is a better choice if the communications
channel is less than perfect, but communications channel failures are unlikely
to occur during external faults.
2
CYC
0
21SD
0
0
1/4
CYC
67SD
0
0
BTXD
Z3XPU
Z3XD
—
+
—
+
—
+
Relay
Word
Bits
Relay
Word
Bits
BT
DSTRT
67G2
67Q2
Z2G
Z2P
50G3
50Q3
67G3
67Q3
Z3G
Z3P
Z3P
Relay
Word
Bits
Z3XT
DSTRT
NSTRT
Z2PGS
67QG2S
STOP
BTX
VPOLV
ICAL
IBCL
IABL
0.1 • I
nom
SEL
OGIC
Setting