ON
OFF
Bus Zone 2 (BZ2)
blocking coil
Bus Zone 1 (BZ1)
16
5.2.4 Interlocking of various panel types
In case of remote control interlocking will perform accordingly.
5.2.4.1 Incomer and feeder panels
Important!
As per 5.2.2 interlocking
scheme may depart from
the above.
5.2.4.2 Bus section coupler
(consisting of bus section circuit-breaker and riser panel)
Usually a bus section coupler inter-
locking scheme applying a mixture
of mechanical (as per 5.2.3.1) and
electrical interlocks using blocking
coils is installed.
These blocking coils ensure safe
switchboard / bus section coupler
operation if bus zones have to be
separated, reconnected or earthed.
They are mounted at drive
mechanisme of:
•
Bus section panel:
- earthing switch
- disconnector switch
- circuit-breaker ON (close)
and OFF (trip)
•
Bus riser panel:
- earthing switch
- disconnector switch
•
Incomer and feeder panels
- disconnector switch
Fig. 5.4
Principle of electromechanical interlocking
bus section coupler
Switching device
position/
position/
position/
position/
position/
operation
operation
operation
operation
operation
Circuit-breaker
ON
ON
OFF
ON
OFF
Spring charging
–
–
–
–
discharged
3position switch:
Disconnector
ON
OFF
ON
OFF
OFF
Interlocking lever
blocked
blocked
free
blocked
free
Earthing switch
OFF
OFF
OFF
ON
OFF
Interlocking lever
blocked
blocked
blocked
free
free
Crank handle operation
–
–
–
–
blocked
– not relevant for interlocking