technical of TWISTED LINK FOR ADSS
1. Ultimate Tensile Strength (UTS)
1. Aluminum-clad or galvanized steel wire UTS:
I. ≥1250 MPa (minimum, as per ASTM A475 or IEC 1008)
2. Twisted link assemblies are rated for specific ADSS cable designs and must exceed the RTS (Rated Tensile Strength) of the associated cable:
I. Typically supports: 5–15 kN, depending on span length and cable diameter
2. Working Load / Safe Working Load (SWL)
1. SWL is defined as 40–50% of the ultimate strength:
I. Typical SWL range: 2–7.5 kN
2. Must support:
I. Long-term self-weight of cable
II. Wind load and ice accretion
III. Occasional tension from maintenance or movement
3. Conductor Diameter Compatibility
1. Available for ADSS cables ranging from 8 mm to 25 mm
2. Twisted link inner diameter and pitch are matched to:
I. Specific cable OD
II. Minimum bending radius compliance
3. Prevents cable flattening, abrasion, or overstress during installation and operation
4. Slip Strength:
1. Helical shape and friction grip prevent axial movement of the cable
2. Typical minimum slip strength: ≥90% of cable RTS, e.g.:
I. For a 10 kN cable, slip resistance ≥ 9 kN
4. Enhanced by:
I. Conformity of wire pitch to cable structure
II. Tight grip without mechanical crushing
5. Temperature Withstanding Capacity:
1. Operating range: –40°C to +85°C
2. Short-term peak: up to 120°C (during extreme solar heating or electrical field stress)
3. No mechanical deformation or coating degradation within this range
6. Corrosion Resistance:
1. Aluminum-clad steel or galvanized steel is inherently corrosion-resistant
2. Galvanization thickness: ≥ 80 μm (per IS 2629 / ASTM A153)
3. Optional: UV-stable polymer coating for added protection in high-UV zones
7. Impact & Fatigue Strength:
1. Designed to absorb:
I. Aeolian vibrations
II. Galloping from wind
III. Line sway due to storms or seismic activity
2. Fatigue tested for >10⁵ cycles without slippage or failure
3. No conductor fretting or strand damage observed in trials
8. Mechanical Endurance:
1. Life expectancy: >30 years in standard conditions
2. Retains mechanical strength and grip over years of thermal and mechanical cycling
3. No relaxation or creep observed in lab simulations and field trials
9. Design Safety Factors:
1. Safety factor: ≥2.5 to 3.0 (based on UTS vs SWL)
2. Tested at 150% of RTS without permanent deformation
3. Designed to fail progressively (wire-by-wire) in extreme cases, without catastrophic snapback
Top 5 Quality Assurance
1. Mechanical Type Testing (IEC 60794-1-2 / IEEE 1222)
a. Tensile strength test of entire assembly
b. Slip load test (cable movement resistance)
c. Fatigue and vibration endurance test
d. Load-to-failure testing at room and elevated temperatures
2. Material Compliance & Coating Thickness
a. Raw material verified for:
I. Wire tensile strength (≥1250 MPa for high-carbon steel)
II. Galvanization/Aluminum-cladding thickness via DFT meter
b. Supplier batch traceability and certifications (ASTM A641 / A475)
3. Dimensional & Visual Inspection
a. Length, twist pitch, wire count, and end angle checked per drawing
b. Visual check for:
I. Uniform spiral geometry
II. Cracks, burrs, surface rust, improper twists
4. Environmental & Corrosion Testing
a. Salt spray test (ASTM B117): ≥500–1000 hours
b. Optional tests:
I. UV exposure chamber
II. Humidity and thermal cycling test
c. No surface degradation, delamination, or strength loss allowed
5. Marking, Traceability & Documentation
a. Every bundle/lot tagged with:
I. Cable diameter compatibility
II. Batch number and material code
b. Supplied with:
I. Routine Test Certificates
II. GTP (Guaranteed Technical Particulars)
III. ISO 9001/14001 certifications
IV. Third-party lab test reports if required (ERDA, CPRI)