Design Lead Team
Mr.H.K.Agarwal ,C.E.O
Mr . A. K. Pal , Sr. General Manager
Mr. T. C. Roy , Manager
Mr. R.S.Dutta ,Sr.Drafts man
Mr. Ashim Bhowmick ,Sr.Engineer
Supreme & Co. Pvt. Ltd.
 M/s
Sterlite Grid Limited faced a problem in
400kV D/C Quad Transmission Line
Bongaigon to Siliguri.
 Un-Compressed zone of Compression type
dead end sleeve are elongated in line.
 One of the supplier incorrectly supplied EC
Grade Dead End Sleeve instead of Al.Alloy
Sleeve.
 Conductor Used In Line :AAAC 525 Sq.mm
 Overall Diameter : 29.79 mm
 Minimum UTS : 146.03 kN
1.
Due to the lower Tensile strength rating of EC Aluminium
sleeve, it cant perform that designated mechanical function of
dead ending conductors.
2. While the EC sleeve is unsuitable as mechanical component, it
will still function perfectly as an electrical component by
adequately transmitting current to the jumper.
3. The solution lies in the physical separation of dead
end assembly parts into discreet mechanical and electrical
components.
4. While the sleeve already installed and this will continue to
function as electrical component, we overlay a mechanical
component on the existing installation which will allow the line
to be tensioned with appropriate factor of safety.
QUOTE :9.11.6.1. HELICAL TERMINATIONS
FOR CONDUCTORS (GREEN BOOK 9-50)
Helical dead-ends are used to terminate
conductors. They have been used successfully for
the past 40 years.
 The typical device is designed to hold the
mechanical load of the conductor and is not
designed to transfer electrical loads.
 Most helical terminations for smaller ACSR and
conductors of homogeneous construction (such as
AAAC or AASC.
 The structural reinforcing rod layer is similar to
an armour rod layer and increases the contact
length of the dead end.





The second layer is a helical termination that is
wrapped over the structural reinforcing layer.
The helical termination is designed such that the bore of
the helical wrap is smaller than the diameter of the
conductor. This results in compressive force being
applied to the conductor along the contact length of the
product.
The helical termination only contacts the out side layer
of the conductor.So it must pass the compressive load
into the inner layer of the conductor.
In case of multi-layer ACSR,the helical dead end cannot
pass enough holding strength onto the core to develop
90% RTS of the conductor. In these cases, specially
designed two layer helical termination may increase the
holding strength above the 95% RTS level.
DRAWING
BRIEF TECHNICAL PARAMETERS:
As suggested in above drawing, we shall use
aluminium alloy re-inforcing rods
helically wound on conductor so that such
re-inforced conductor would be nearly equal to
sleeve outer diameter of compressed portion of
dead end.
 Add one more layer high strength
aluminium clad steel looped and helically wound
dead-end covering the entire length spanning the
sleeve and re-inforced portion of conductor.
 We shall install additional corona-ring of smaller
dia of 200 to shield the extended portion.

GUARANTEED TECHNICAL PARTICULAR
1.
Maker’s Name & Address
: Supreme & Co. Pvt. Ltd. P-200 Benaras
Road Howrah 711108
2.
Drawing No.
: 19003/P (Part -14/1) Date: 19.09.2014
3.
Protective Helix Material
: High Strength Al.Alloy type 6061
4.
No of rods per set
: 13
5.
Diameter of rod
: 7.87mm
6.
Length of rod
: 2080mm
7.
Dead End Grip Materials
: Al.Clad Steel wire
8.
No of rods per set
: 8
9.
Diameter of rod
: 3 mm
10.
Length of Rod
: 2750 mm
11.
Glue & Grit
: Used
12.
Grading Ring
: Extruded Aluminium tube as per IS 733 or
IS 1285 or Al.Casting IS 617 Gr 4600
13.
Packing
: In Wooden Crate
EXPERIMENTAL TYPE (DESIGN) TEST :


EXPERIMENT NO.: 1 (With Out Steel Sleeve)
ON A PIECE OF AAAC 525 SQ. MM. CONDUCTOR ONE
SIDE COMPRESSED WITH M/S. SUPREME MAKE
COMPRESSION DEAD END CLAMP & THE OTHER SIDE
WERE COMPRESSED WITH M/S. STERLITE PROVIDED
DEAD END CLAMP WITHOUT STEEL SLEEVE.
Mechanical Failing Load Test:
 (i) A tensile load of 139KN (i.e 95% UTS of
Conductor) was applied and hold for 5mins.

Result : No Slip observed
 (ii) Load increased up to 161 KN (i.e 110% UTS of
Conductor ) and hold for 5mins.

Result : Conductor Strand broken down

EXPERIMENT NO.: 2 (WITH STEEL SLEEVE)

ON A PIECE OF AAAC 525 SQ. MM. CONDUCTOR ONE
SIDE COMPRESSED WITH M/S. SUPREME MAKE
COMPRESSION DEAD END CLAMP & THE OTHER
SIDE WERE COMPRESSED WITH M/S. STERLITE
PROVIDED DEAD END CLAMP WITH STEEL SLEEVE.
Mechanical Failing Load Test:
 (i) A tensile load of 139KN (i.e 95% UTS of
Conductor) was applied and hold for 5mins.

Result : No Slip observed
 (ii) Load increased up to 159 KN

Result : M/s Sterlite provided Dead End Clamp
Broken down from Un- compressed zone.

FITMENT TEST AT LINE:
Protective Helix on
Conductor
Helically formed Dead
End Grip