Presented at Sterlite office

1. USE OF HELICAL TERMINATIONS FOR HPC & AAAC
1
SUPREME & CO. PVT. LTD.
P-200, BENARAS ROAD, HOWRAH -711108, WEST BENGAL, INDIA
Phone : +91-033-26516701-05
Fax : +91-033-26516706
Email : sales@supreme.in & info@supreme.in
Website : www.supreme.in

2. CONCEPT OF HELICAL DEAD END
 For the past 40 years, Helical Dead-ends are used to terminate conductor.
 The typical device is designed to hold 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) are single layer.
 Helical terminations for ADSS, OPGW and high temperature conductor can consist of a two
layer design.
 The structural reinforcing rod layer is similar to an armor rod layer and increases the contact
length of the dead-end.
2 # Ref: Over Head Lines – CIGRE Green Book, Chapter 9.11.6.1

3. 3
 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 that
the diameter of the conductor.
 This results in compressive force being applied to the conductor along the contact length
of the product.
 Typical single layer helical terminations will develop minimum of 90% RTS on
homogeneous AAAC (or AASC) and single layer ACSR.
 The helical termination only contacts the outside layer of the conductor so it must pass
the compressive load into the inner layer of the conductor.
CONCEPT OF HELICAL DEAD END
# Ref: Over Head Lines – CIGRE Green Book, Chapter 9.11.6.1

4. 4
 In case of multi-layer ACSR, the helical dead-end cannot pass enough holding strength onto the
core to develop 90% TRS of the conductor. In these cases, specially two layer helical terminations
may increase the holding strength above the 95% TRS level.
 Conductor construction may also affect the holding strength of helical terminations trapezoidal
wire construction can also affect holding strength of the helical termination if bridging of the wire
occurs and does not allow the compressive load to pass onto the core wires.
 There is low stress concentration since the compressive load is applied over a long contact length.
 The relatively low weight concentration does not result in forcing nodal points at the ends of the
termination and reduces the bending strain during cable motion such as Aeolian vibration.
N.B: Supreme has specially design interweaving double helix with differing orientation at thimble to
prevent twisting
CONCEPT OF HELICAL DEAD END
# Ref: Over Head Lines – CIGRE Green Book, Chapter 9.11.6.1

5. 5
HIGH PERFORMANCE CONDUCTOR

6. HPC DEFINITION AND APPLICATION
 The introduction of novel conductor materials and constructions such as those used
in high temperature, low-sag conductor (HTLS) systems, presents an urgent need
for transmission line designers to be certain that they will perform as expected over
the long life of the line in which they are installed.
 High temperature conductors are understood to be those conductors designed and
intended for maximum operating temperatures in excess of 250°C.
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7. KEY DIFFERENCE HIGH PERFORMANCE
CONDUCTORS (HPC)
The difference between a conventional conductor and a
conductor dedicated to High Performance applications is the
capability of the conductor to have a higher current carrying
capacity for the same cable section as well as low sag at high
temperature.
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8. SPECIFIC QUALIFICATION TYPE TEST
REQUIREMENTS
8
Used to validate the Helically Formed Dead End

9. 9

10. SPECIFIC QUALIFICATION TYPE TEST
REQUIREMENTS
10

11. MECHANICAL CREEP AT HIGH
TEMPERATURE TEST ON ALUMINIUM
OXIDE/POLYMER MATRIX CORE CONDUCTOR

12. TESTING ARRANGEMENT

13. TESTING ARRANGEMENT

14. TESTING ARRANGEMENT

15. Applied Tension 30 kN APPLIED TENSION 40kN
APPLIED TENSION 50kN APPLIED TENSION 60kN

16. APPLIED CURRENT
800 AMPS
APPLIED CURRENT
900 AMPS
APPLIED CURRENT
1000 AMPS

17. START TIME 9:15AM
DATE 02.01.14
END TIME 10:00AM
DATE 04.01.14
CONDUCTOR TEMP. MEASUREMENT POINT- CH-4

18. DEAD END JOINT –A TEMP. MEASUREMENT POINT CH-1,CH-2
& CH-3
START TIME
9:15AM
DATE 02.01.14
END TIME
10:00AM
DATE 04.01.14

19. DEAD END JOINT –B TEMP. MEASUREMENT POINT
CH-5, CH-7 & CH-8
START TIME
9:15AM
DATE 02.01.14
END TIME
10:00AM
DATE 04.01.14

20. 85.2
108.5 117
127.7
135.5
142.7
149.2
158.1
158.6 158.9 159.2
26.3 28.8 30.0 31.4 32.3 33.2
34.0 34.9 35.6 36.4
36.9
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
0 5 10 15 20 25 30 35 40 45 50 55
TEMP°C
TIME IN HOURS
Aluminium Oxide/Polymer Matrix core HPC
RESULT

21. PROPOSED SPLICE METHOD

22. ALUMINIUM OXIDE/POLYMER MATRIX CORE HPC
FEASIBILITY TEST OF THE MECHANICAL AND THERMAL
EFFECTS ON HELICALLY FORMED DEAD END GRIP
INSTALLED ON ALUMINIUM OXIDE FIBRE CORE HPC.
 A 50Hrs high temperature current cycle test at 160°C above ambient
temperature was carried out on HPC conductor using helically formed
dead end grip for fiber/polymer matrix core, Dead End sleeve and Jumper
terminal.
 The typical device is designed to hold the mechanical load of the conductor
and is not designed to transfer electrical loads.

23. TEST STANDARDS MODIFICATIONS PASS/FAIL CRITERIA
Thermal Profile None Pass current to heat conductor
and hardware to maximum
(emergency) operating
temperature. Measure
temperatures on hardware.
Temperature in hardware below
specified maximum use
temperature of materials used in
hardware.
Current Cycling ANSI C119.4-
section 6-modified,
ANSI C119.7
(draft), IEC 61284
SECTION 13-
modified
Each Cycle to conductor
emergency temperature rating,
plus a further 100 cycles to
(emergency +60° C)
Show resistance and temperature
stability per standard
Tensile Strength ANSI C119.4 -
section 7.3.4,IEC
61284 section
11.6.1
None. Measure slipping or
failure load. This is typically a
partial tension connector ( low
Strength)
Meets partial-tension strength
rating of the hardware.
TEST MATRIX (TERMINAL CONNECTORS)

24. TEST STANDARDS MODIFICATIONS PASS/FAIL CRITERIA
Dead-end, Joint
Strengths
ANSI C119-section
7.3.4, IEC 61284-
section 11.5.1
None, but option to use epoxy as one
of terminations. Only test dead-end
designs that are also an electrical
junction.
Exceeds 95% RBS of conductor
Current Cycling ANSI C119.4-section
6-modifed, ANSI C119.7
(draft), IEC
61284-section 13-
Modified
Each cycle to conductor emergency
temperature rating, plus a further 100
cycles to (emergency + 60°C)
Show resistance and temperature stability
per standard
Sustained Load
(Room Temperature)
ANSI C119.4-section
7.3.3
None but option to use epoxy as one
of terminations
No slippage. Exceeds 95% RBS of
conductor after sustained load test
Sustained Load
(High Temperature)
ANSI C119.4 -
section 7.3.3- modify
to higher Temperature
As ANSI C119.4, but with 15%RBS at
conductor emergency temperature
No slippage. Exceeds 95% RBS of
conductor after sustained load
Thermal Profile None Pass current to heat conductor and
hardware to maximum (emergency)
operating temperature. Measure
temperatures on hardware.
Temperature in hardware below specified
maximum use temperature of materials
used in hardware. Attachment point (to
insulator) temperature less than maximum
specified for the insulator
Corona IEEE 539/656 None Corona extinction voltage and maximum
RIV shall meet required specification
TEST MATRIX (DEAD-END/MID-SPAN JOINTS)

25. TEST STANDARDS MODIFICATIONS PASS/FAIL CRITERIA
Aeolian
Vibration
IEEE 1138-
annex B,
IEC 60794-1-2
None No broken or damaged strands. Optional
tensile test-exceeds 95% RBS
Ice
Galloping
IEEE 1138-
annex C
8% RBS No broken or damaged strands. Optional
tensile test-exceed 95% RBS
Turning
Angle
none Hold a minimum of >40% BS (or
maximum heavy load design value)
through suspension with 30° turning
Angle
No broken or damaged strands. Optional
tensile test-exceeds 95% RBS
Unbalanc
ed Load
IEC 61284 Measure load to get slip of conductor
in suspension
Meet slip load specification and no
damage to conductor. Optional tensile
test-exceeds 95% RBS
Thermal
Profile
None Pass current to heat conductor and
hardware to maximum emergency)
operating temperature. Measure
temperatures on hardware
Temperature in hardware below specified
maximum use temperature of materials
used in hardware. Attachment point (to
insulator) temperature less than
maximum specified for the insulator
TEST MATRIX (SUSPENSION CLAMPS)

26. Test Standards Modifications Pass/Fail Criteria
Dampers
Damper
Efficiency
IEEE 664,IEC
61897-
section 7.11
None Demonstrate damping efficiency
exceeds minimum specification
across the frequency range.
Spacers
Short Circuit
bundle
collapse test
None Apply Short circuit pulses to force
conductor bundles to collapse Choose
current and time interval to meet utility
specification. Adjust tension to permit
collapse condition
No conductor and spacer damage
after short circuit collapse
Thermal
Profile
None Pass current to heat conductor and
hardware to maximum operating
temperature. Measure temperatures on
hardware
Temperature in hardware below
specified maximum use
temperature of materials used in
hardware.
Corona
Testing
IEEE539/656,
IEC
None Corona extinction voltage and
maximum RIV shall meet required
specification
TEST MATRIX (VIBRATION DAMPERS/ SPACER DAMPER)

27. 27
SINGLE LAYER HELICAL TERMINATION
FOR AAAC & AL59

28. ADVANTAGES OF HELICALLY FORMED
TERMINATION FOR AAAC AND AL59 CONDUCTOR
Single Layer Helically grip dead end is also desirable in place of compression dead end due to following
advantages:-
1. No special compression tools or machine require at site
2. No need to use Jumper connection
3. No risk of human error
4. Significant reduction in error cost
5. Around 2% cost deduction over compression dead end fitting
6. There is low stress concentration since the compressive load is applied over a long contact length.
In addition, the relatively low weight concentration does not result in forcing nodal points at the ends
of the termination. This reduces the bending strain during cable motion such as Aeolian vibration.28

29. 29
VALIDATION OF HELICALLY FORMED
TERMINATION FOR AAAC AND AL59 CONDUCTOR

30. TEST ON AAAC CONDUCTOR WITH HELICALLY
FORMED DEAD END GRIP

31. TEST ON AAAC CONDUCTOR WITH
HELICALLY FORMED DEAD END GRIP
AAAC 525 Sq mm Conductor
UTS 95% = 139kN withstood

32. THANK YOU
SUPREME & CO. PVT. LTD.
P-200, BENARAS ROAD, HOWRAH -711108, WEST BENGAL, INDIA
Phone : +91-033-26516701 TO 05
Fax : +91-033-26516706
Email : sales@supreme.in & info@supreme.in
Website : www.supreme.in
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