Operation & Maintenance Manual
19
COMMISSIONING
3. Trap the key in PE lock provided at BUS Copler panel and
move DS of BUS Coupler to Earth postion.
4. Earth BUS-B by making DS Riser and breaker of BUS coupler
ON.
3. PROOF OF EARTH
Feeder: Incomer & Outgoing Panels
Proof of Earth (POE)
1. In normal condition key will be trapped in POE lock located at
DS mechanism.
2. Key shall be available free only when DS in Earthed.
3. DS can not be operated from Earth position, till Key is inserted
in lock.
Sequence of operation to open cable compartment cover
person
1. After Earthing cable, take out key from POE lock located at
DS mechanism.
2. This POE key can be used to open power cable compartment.
3. Key will be trapped in lock provided for opening power cable
compartment cover till it is open.
4. Key will be available free only after closing cable
compartment with its cover.
4. CABLE ACCESS
The opening of cable access cover is not possible unless the
cable have been connected to EARTH .
Isolator operation is not possible if the cable access cover is
OPEN .
Padlocking Facility :-
1. Metering & DS mechanism compartment door handle.
2. VCB compartment door handle.
3. Aux./ front cable entry compartment door handle.
4. DS operating hole pad loack.
Visual Indications :-
1. ON & OFF status of VCB.
2. ON , OFF & EARTH status of Disconnector Switch.
3. Operation counter (5digit) on VCB front facia.
4. Spring Charged/Discharged indication ag on VCB front
facia.
5. SF6 Gas pressure monitoring device on VCB compartment
door facia for VCB & DS compartment tank.
6. SF6 Gas pressure monitoring device on Metering & DS
mechanism compartment door facia for busbar chamber
tank. This device is provided in any one panel of the
board as bus bar chamber tank is common.
Optional Interlock and Visual Indication :-
Following Optional interlocks can be provided :-
1. M.I.L. solenoid interlock is provided to prevent opening of
rear cable cover.
2. VCB is tripped electrically if SF6 Gas pressure falls below
the minimum permissible value i.e., 1.2 bars.
3. Semaphore indication is provided.
4. For any special key interlock please refer key interlock
arrangement provided by Design.
Figure 6.4.6 - Incomer & Outgoing Panels
Lock & Key Qty Details
POE: 2 Lock & 1 Key
Q1
DISCONNECTOR
SWITCH
1250A
Q0
VCB
1250A
EAR
TH
OFF
ON
POE
POE