HT Tranning

1. VOCTIONAL TRAINING REPORT ON
HT Jointing
Submitted By,
Name: SAYAN BASAK
B. P. Poddar Institute of Management and
Technology
University Roll: 11501620025
Date: 25/07/2022 – 30/07/2022

2. Certificate of Declaration:
This is to clarify that Mr. Sayan Basak, engineering trainee
(distribution) have successfully completed her training in LT mains
under my guidance as a part of the training program for engineering
trainee.
Date: .
Mr. Prasenjit Karmakar
Dy. Manager Mains
(HT Jointing)

3. Introduction
Kolkata, being one of the major hubs as far as India’s Industrial and Business
scenario is concerned; there is a steady increase in electricity demand in the
city. The scorching and sultry weather is also one of the key factors in this
regard. Every summer we see a rush ofapplications for new ACs leading to
heavy increase in load demand and hence system capacity.
Now, CESC has this responsibility of distributing power to the entire
population of 3 million in the metropolitan area of Kolkata and Howrah,
some portions of North & South 24 Parganas for which it has to maintain a
large distribution network. The distribution system is healthy and reliable
investments are made on an ongoing basis to maintain the network.
In addition to maintenance, CESC is constantly making efforts, inviting new
ideas to improve the existing network, starting from Distribution
Transformer up to the service end to meet various challenges faced by it on
daily basis.
Mainly distribution systems are of 2 types, they are-
• Primary Distribution system (33KV/11KV or 6KV)
• Secondary Distribution system (11KV or 6KV/400V)
Mains (Distribution) have two wings - LT and HT. The high-tension line has
an operating voltage of 33KV, so the operating voltage of this line will range
from 11Kv to 33KV and if it is above 33KV then it is called an extra high-
tension line. We can’t see many faults in high tension lines because it is not
directly connected to the load. The higher voltage transmission would need
larger structures with longer insulator chains. The high voltage transmission
is done by using several transformers, cascade arrangement of the
transformer is done.

4. Day Wise Report:
Day 1 Report:
On Monday 25/07/2022, I reported at around 9 am at Taratala office. Dy.
Manager sir Mr. Prasenjit Karmakar referred me to Mr. Shyamal Bauldas, with
him I went the site Horticultural Development Centre, Alipore, Kolkata.
Job Details: Under the supervision of Mr. Shyamal Bauldas, a link cable
connection was built between RMU and Transformer. RMU was linked to
300sqmm XLPE(AL). Two termination matching was already done between O/T
to RMU.
Cable Joint Type - Heat Shrinkable Termination.
Cable Voltage -11kV.
Number of Cores - Three Core (Aluminium).
Conductors - 300sqmm.
Cable Type – XLPE.
Type- Indoor Termination.
Ring Main Unit [RMU]: Ring Main Unit is a compact Gas Insulated Switchgear
cubicle equipped with SF6 Switch disconnector and SF6 circuit breakers. The
below figure shows the RMU with 3-Incomers and 1-Outgoing feeder to
distribution transformer.
Ring Main Units are the major part of Ring Main
Network. The power is distributed through these
RMUs for the end consumers. Ring Main Unit
distribution is costly compared to other
distribution networks, so this type of distribution
can find in urban cities where supply reliability is
major issue.
Ring main units are available in different voltage
ratings ranging from 11KV to 33KV. These units
allow the connection of transformers through
Under Ground cables and also provide protection
to the transformers.
SIEMENS 8DJH ST RMU

5. Day 2 Report:
On Tuesday 26/07/2022, I reported at around 9 am at Taratala office. Dy.
Manager sir Mr. Prasenjit Karmakar referred me to Ajay sir, with him I went the
site Badartala, Kolkata.
Job Details: Under the supervision of Mr. Ajay, heat shrink cable joints were
completed on 97 sqmm of PILC copper with 300 sqmm of XLPE cable.
Cable Joint Type – Heat Shrink.
Cable Voltage – 11kV.
Number of Cores – 3 Core.
Conductors – 97sqmm,300sqmm.
Cable Type – PILC, XLPE.
Heat Shrink Joint: Primarily, a heat shrink cable joint provides electrical
insulation, mechanical protection and stress control for high voltage power
cables – integral also to the cable joint design is the requirement to prevent
water ingress into the cables. Although initial risk assessments would include
consideration of electrical water damage, such as cable flood damage, the
requirement to deliver medium/high voltage power can necessitate cable
exposure to potential flooding, condensation and water immersion. A robust
cable joint is designed to withstand the deteriorative effects of water in both
indoor or outdoor environments.
O/T Side Opened RMU side joint was done along with
CT and Sensor

6. Prior to installing the outer shrink tube, the jointer should clean, de-grease and
abrade the outer cable sheath of the 11kV cable – to achieve an even wall
thickness the cable jointer should keep the
flame moving and avoid scorch or burn
damage to the heat shrink or cable.
The jointer will apply heat evenly to the
centre of the cable joint – once the heat
shrink tube is fully recovered (“shrunk”)
the joint should be smooth, wrinkle-free
and the heat activated sealant should be
visible at the tube ends in contact with the
cable sheath.
The tough and durable heat shrink
provides reinstatement of cable sheath or
jacket insulation and withstands trench
backfill prior to energisation of the HV
joint.
The 11kV joints are installed using normal procedures for heat shrink cable
joints with clear installation instructions confirming precise cable stripping
dimensions and marking measurements for sheath, semicon and insulation
removal – joints are installed using the standard cable jointing tools depending
upon cable construction.
Outer Shrink Tube Provided Outer Shrink Tube Filled with compound

7. Day 3 Report:
On Wednesday 27/07/2022, I reported at around 9 am at Taratala office. Dy.
Manager sir Mr. Prasenjit Karmakar referred me to Mr. Arun Ghosh, with him
I went the site Rabindra Sadan D/S, Kolkata.
Job Details: Single core Cu wire Screened, XLPE Insulated cable was used to
complete an indoor and outdoor earthing termination joint under the
supervision of Mr. Arun Ghosh sir.
Cable Joint Type - Heat Shrinkable Termination.
Cable Voltage -11kV.
Number of Cores - Single Core (Cu).
Conductors - 630sqmm.
Cable Type – XLPE.
Type- Indoor and Outdoor Termination.
Transformer Ratting- 33kV
HEAT SHRINKABLE TYPE: The term ‘Heat Shrinkable’ refers to extruded or
moulded – polymeric material which are cross linked to develop elastic memory
and supplied in an expanded or otherwise deformed size and shape. Subsequent
heating in an unconstrained state to a temperature above the shrink
temperature results in the materials recovering or shrinking to its original shape.
Stress control and stress grading wherever necessary in the termination and joint
shall be by means of semi conducting heat shrinkable tubing.
Environmental sealing between the heat shrinkable materials and cable surfaces
shall be achieved by using hot melted sealants or adhesives. Where such sealants
or adhesives are exposed to high electrical stress, they must be track resistant.
The adhesive or sealant used in the joint/terminations should not permit any
entry of moisture into the joint/termination.
The external covering of insulated cores for terminations shall be by means of
modified silicon heat shrinkable tubing’s, which have non-tracking and erosion
resistant properties. The purchaser reserves the right to insist on checking the
tracking resistance property of the non-tracking materials.
Cable Preparation and Installing for both Indoor and Outdoor Terminals:
• Align the cable and cut to the required length. Keep enough extra length
to set the core into the final position.

8. • Remove the outer sheath. Clean and degrease the end of the outer
sheath.
• Remove release paper from sealing mastic (red) and wrap it with small
overlap and slight tension around the end of outer sheath for 40-50mm.
• Cut the core off to the required length. Remove insulation screen 50mm
above the outer sheath cut. Clean the surface of insulation and remove
all traces of conductive material.
• Apply slight amount of silicon grease on the XLPE insulation.
• Insert the stress control tube (black) over the core.
• Insert non-tracking tube over the core keeping sealant coated end
downwards.
• Remove the release paper from the lug seal. Cut off the XLPE insulation
with the help of nylon string.
• Position the lug seal so that it covers lug and core equally.
• Install thimble with bolts. Two bolts are there, fasten bolt of one
conductor side alternating and steadily with tool until the head shears off.
• Indoor installation is completed. Only for outdoor termination creepage
extension sheds are provided.
Indoor Termination Outer Termination

9. Day 4 Report:
On Thursday 28/07/2022, I reported at around 9 am at Taratala office. Dy.
Manager sir Mr. Prasenjit Karmakar referred me to bidhan sir, with him I went
the site Shalimar Railway Station, Howrah.
Job Details: Under the supervision of bidhan sir, a link cable joint was built
between RMU and RMU module FBX-M-12kV. The link cable was an XLPE
300sqmm kind. A XLPE link cable both terminal was jointed with colour
matching.
Cable Joint Type - Heat Shrinkable Termination.
Cable Voltage -11kV.
Number of Cores - Three Core (Aluminium).
Conductors - 300sqmm.
Cable Type – XLPE.
Type- Indoor Termination.
RMU- Schneider Electric.
Heat Shrinkable Cable Termination: Heat shrink cable terminations can be
used for LV-MV-HV power cables present indoors and outdoors. Indoors, these
cable terminations connect to substation switchgear, transformers and
insulated cable boxes. Outdoors, they are used in overhead and underground
distribution lines.
Cable Preparation and Installing Terminals:
• Align the cable and cut to the required length. Keep enough extra length
to set the core into the final position.
• Remove the outer sheath. Clean and degrease
the end of the outer sheath.
• Tie tin plated copper wire and spread out the
armour wires. Wrap one or two layers of PVC
tape tightly around inner sheath. Insert
back=up ring and thereafter fold back the
armour wires over the support ring.
• Solder a small copper braid to the copper
screen of each core.
• Place the large copper braid over the armour.
Keep it in level with top of the armour.

10. • Place the Jubilee clamps and the screws of the worm drive clips in
diametrically opposite position and tighten thoroughly.
• Apply red mastic tape over the cable sheath and large copper braid. Over
this layer and wrap two more layers for embedding this braid. Also, wrap
black mastic for covering entire armour area.
• Pass the adhesive coated anti=tracking
breakout over the cores and pull it down in to
the cables as much as possible.
• Clean the surface of insulation and remove all
traces of conductive material. Clean the surface
of insulation and remove all traces of conductive
material.
• Apply slight amount of silicon grease on the
XLPE insulation.
• Insert the stress control tube (black) over the
core.
• Insert Heat Shrinkable anti-tracking tubings one over each core and push
down to over the fingers of the breakout.
• Cut off the XLPE insulation with the help of nylon
string.
• Crimps the lugs with the tool. Remove the sharp
edges from the crimped ferrule with the help of
aluminium oxide cloth. Clean the lugs with
cleaning solvent.
• Fill the gap between XLPE insulation and
terminal lug with red mastic. Also apply red
mastic on the crimped portion.
• Position the lug sealing tubing in such a way that
it equally covers the lug and core.
• Indoor Termination is now completed.
Termination was done

11. Day 5 Report:
On Friday 29/07/2022, I was absent for my passport police verification.
Day 6 Report:
On Tuesday 30/07/2022, I reported at around 9 am at Taratala office. Dy.
Manager sir Mr. Prasenjit Karmakar referred me to Arun sir, with him I went
the site near Ruby Hospital, Kolkata.
Job Details: Under the supervision of Mr. Arun Ghosh sir, heat shrinkable cable
joints were completed with two 300 sqmm XLPE cables.
Cable Joint Type - Heat Shrinkable Transition.
Cable Voltage -11kV.
Number of Cores - Three Core (Aluminium).
Conductors - 300sqmm.
Cable Type – XLPE.
Cable Preparation of jointing:
• Prepare the cables to remove outer sheath and armour as per the
dimension. Also, remove the inner sheath leaving 10mm from the armour
cut.
• Spread out and align the cores to be joined.
• Remove the insulation as per required.
Clean the cores on the long side and insert
one set of nested tube over each core and
push down up to the crotch.
• Similarly clean the cores on the short side
and insert two no’s of black sealing tubing’s
on each side of the joint.
• Crimp the connectors ferrules with a
suitable tool.
• Clean the cable insulation using cleaning
tissues and moping cloth. Remove the
release paper from the stress grading
mastic.

12. • Pull out the stress control tubes from the of the set of nested tubes and
position each centrally over the respective
conductor to overlap the semicon screen on
both sides.
• Pull out the insulation tubes from the nested
set of tubes. Position centrally over the
shrunk stress control tubes and shrink in
place starting at the centre and proceeding
towards the ends.
• Position black heat shrinkable tubing’s on
the stress control mastic- covering red
mastic and the combined set of tubing’s and
core equally.
• Starting at the copper tape screen on one side, wrap the tinned copper
wire mesh tightly around each core.
• Lift the armour wires. Insert one support ring under armour wires of each
cables. Take care not to dislodge the armour wires.
• Placed the tinned copper earth braids across the joint over the armour of
the both the cables. Wrap copper wire mesh on the armour and
thereafter tighten the braids with worm drive clips.
• Position the black insulating tubing on the armour portion in such a way
that it fully covers black mastic tape applied on the armour and shrink.
• Pour the compound slowly into the joint.

13. Conclusion:
I have completed my training in HT cell from Taratala site under Mr. Prasenjit
Karmakar from the period of 25/07/2022 to 30/07/2022.
Throughout the training period I learned about jointing of HT lines, types of
cable and joints etc.
The training was very an important as it helps to gain practical knowledge about
the subject which will helped me to gain practical knowledge and experience.