In my last dispatch I have indicated the number of panels
required to be installed for HT connection .A picture of the same was also
attached. Numbers of panels are erected aligned on line. Incoming and outgoing
cables are laid through spreader room . These panels are erected by the side of
the service bay through an opening kept for this purpose only. Once these
panels are and aligned then pre-commissioning activity starts.
Opening has been kept at service bay side to lift panels as shown in the above picture.
Cable spreader room erection of cable trays under progress. This is below the Panel room
This is the panel room ..civil works under progress.
Following testing are being carried on HT panel after
erection.
a. Insulation resistance measurement of bus
bar (power ,control ),vcb
b.
Busbar,contact resistance measurement
c. High voltage test
– bus.
d. Primary injection test
- vts & cts.
e.
Protection, interlocks and metering circuits .
Following
instruments (calibrated) , systems ,
qualified testing personnel ( Accident
while testing is very common, this may be fatal at HT lines) etc are required
to be lined up.
5000v insulation tester (motorized)
; 3 phase 415 ac 50 hz system with
variac (3 ph and 1 ph)
Dc control supply (preferably from
permanent DC source; Hi pot ac/dc source
Measurement kit ; Current injection kit ; Micro
ohm meter; Milliseconds timer ; Multimeter ( 4 and half digit ) digital ; Ananlog
Multimeter ; Volt and Ampere meter for measurement; Tong tester; Number of long testing leads with end
connectors ; Supplier’s tools for the panel etc.
Safety precaution is paramount
before and after testing a few points are given below:-
The Engineer-In-Charge of the
testing team will inform each member of
his team as to the exact nature and extent of his contribution and
responsibilities towards the tests carried out.
Only nominated person will take part in the
tests.
All persons must acquaint
themselves with the use and location of fire
extinguishers and first aid posts.
Adequate lighting facilities will
be provided at all times.
Each test will be carried out under
the control of the test team leader.
A strict and safe method of
applying test leads shall be practiced.
Bare wires shall not be inserted into sockets.
A record of any alternation made
during the test such as shorts or disconnections, shall be made and annexed to
relevant test procedures .
Adequate number of poster
,signboard are placed strategic location for safety.
All procedures are recorded and
checked with the drawings . A single line diagram or conditions to energise the
particular panel and also for tripping may be made before testing .This will be
immense help. This is not a must condition but helps during testing as ready
reference.
CHECKLIST FOR THE FOLLOWING PANELS
ARE CHECKED
i. Incomer panels (1 & 2) ;ii. Outgoing
feeders; iii. Bus coupler; iv. Tie breaker
- All incoming and outgoing cables
to incomer panels are completed.
-Interlocks for closing and protection
for tripping are to be checked as per standard check list.
-11KV Bus Duct/Cable erection from
station switch gear to unit switch gear complete in all respects.
-The Tie Breakers at station
switchgear end of tie is tested and in withdrawn position with shutters locked.
All circuit breakers contained in
11KV unit switch gear in withdrawn position.
Clearance from Erection Department
for carrying out tests on 11KV unit switchgear
and 11KV Bus duct/cable from unit to station switchgear obtained.
-11KV station switchgear associated
with the energising of this unit switchgear is live.
-Safety Clearance notification
issued and effective for 11KV unit
switchgear and 11KV tie bus duct/cable.
-The associated DAS/Annunciation
scheme is complete, tested and in service.
-The control supplies are
available.
COMMISSIONING PROCEDURE :
-Check and test all the panels of
11 KV unit switch board and associated equipments as per their standard check
list. Record in a format for future use.
Check and test the unit switchgear
bus bars and the Tie bus duct/cable to the station switchgear as per their
standard check lists and record.
Check and test supply cables for
the DC control bus and the AC heater supplies as per their connection diagram
and record.
Continued to PART-III --PRE ENERGISING TESTING ,AND COMMISSIONING
