4. One and Half Breaker scheme
21 3
1,2,3--.>Breaker Red –open ,Green-close
5. CT are provided on
both side of Breaker
so that differential
and line protection
provided
If all breaker are closed power is
feed from both bus and goes
through line 3 and 4Two
Line protection is done by out board
CT of Line breaker
Differential protection is by
outboard CT of bus breaker
ONE AND HALF BREAKER SCHEME
Two line and feed from
single Breaker so called
breaker and half
7. If breaker 4 to be on maintenance
open isolator of breaker 4 now
feeder1 and 2 are feed from bus 1
If a fault on bus A it is isolate from
system and now feed by bus b