66kV XLPE Cables
Manufacturing: The basic design features of 66 kV XLPE Cables‘s Lead Sheath Constructions conforms to IS:7098.
Conductor : The conductor consists of annealed copper wires compacted having a smooth circular shape for sizes upto 1000 mm2 cross-sectional area conforming to EC: 228 or IS: 8130-84.Note:
- In special cases, Aluminium Conductors are provided depending on specific need of the
- Beyond 1000mm2 Milliken Conductors (segmental) are recommended.
Conductor Screen : The conductor screen consists of a layer of smooth black extruded semi-conducting XLPE compound firmly bonded with the insulation. This eliminates electrical discharges at the interface between conductor and insulation.
Insulation: The insulation consists of super clean XLPE compound. The extrusion process is conducted in clinically clean environment. The insulation thickness conforms to IS: 7098(Part 3) or as per customer's specification.
Insulation Screen : The screen consists of smooth black semi-conducting XLPE compound firmly bonded with a smooth interface with the insulation. The conductor screen, insulation and insulation screen and extruded simultaneously in Dry-Cure Process.
Moisture Barrier : To make the cable longitudinally watertight a semi-conducting water blocking tape is applied over the core, to prevent water penetration in the cable. The tape is of non-woven material which has non-biodegradable characteristics.
Seamless Lead Sheath: Extruded Seamless Lead Alloy 'E' Sheath having high fatigue endurance limit is provided. This is the most popular metallic sheath used World-wide.
- Hermetically sealed - Corrosion resistant
- Mechanical protection
- Serves as an earthed metallic screen - To carry
earth fault current
- Low sheath losses and higher current rating
Copper Wire Screen
Copper Wires are applied over the Lead Sheath to carry the necessary earth fault current along with the Lead Sheath. This is particularly applicable where the requirement of earth fault current is high. This also helps in reducing the weight of the cable by avoiding excess lead thickness. A counter open helix copper tape is provided over the copper wires. Note: Semi-conducting tape(s) is generally provided between the Lead and Copper Wire Screen.
The Jacket material consists of Extruded Black PVC (ST2) or High Density Polyethylene (HOPE). A graphite coat is provided over the outer surface of the sheath.
We follow rigorous Test Procedures. The Tests are classified in five categories, namely,
- Product Sample Test - Our Cables for both type of construction, Lead Sheath have been Type Tested at Central Power Research Institute (CPRI), Bangalore.
- Type Test - at Works
- Routine Test - at Works
- Acceptance Test - at Works
- Installation Test - at Site
- Electrical Type Tests
- Test & Sequence
- Bending Test
- Partial Discharge Test
- Tan Delta. at Elevated temp
- Heat Cycle Voltage Test
- Impulse Voltage with stand test
- High Voltage (a.c.) Test
- High Voltage (a.c) special Test
- Water Penetration Test