18/30 Kv Medium Voltage Overhead Covers Conductors Thick (CCT) - Cables

Enhanced Protection: The thick protective covering is not an afterthought but a core design element, addressing the primary failure modes of traditional overhead conductors—environmental corrosion, mechanical damage, and insulation breakdown.

Balanced Performance: The cable design achieves a harmonious balance between electrical conductivity, mechanical strength, and flexibility. This ensures efficient power transmission while enabling installation across long spans and challenging terrains.

Long-Term Reliability: Every component, from Conductor Material to insulation chemistry, is selected to maximize service life, withstanding the rigors of outdoor exposure and varying operating conditions.

High-Strength Aluminum Alloy (AA 6201-T81): This alloy is a preferred choice for most applications, offering an exceptional combination of properties:

Electrical Conductivity: 52% IACS (International Annealed Copper Standard), ensuring efficient current flow with minimal losses.

Tensile Strength: Minimum 310MPa, providing the mechanical robustness required for overhead installation.

Weight Advantage: Approximately 30% lighter than Copper Conductors of equivalent capacity, reducing load on supporting structures.

Corrosion Resistance: Naturally forming a protective oxide layer, enhanced by additional surface treatments.

Aluminum-Clad Steel (ACS): For applications requiring superior tensile strength, such as long spans exceeding 100 meters, ACS conductors are utilized:

Composite Structure: A high-strength steel core (providing 70-80% of tensile strength) coated with a layer of high-purity aluminum (1350 series).

Strength: Tensile strength ranging from 800-1000MPa, enabling spans up to 150 meters without intermediate supports.

Conductivity: 55% IACS, ensuring good electrical performance despite the steel core.

Cross-Linked Polyethylene (XLPE):

Manufacturing Process: Formed by cross-linking polyethylene molecules using either peroxide or radiation, creating a three-dimensional molecular structure that enhances thermal and mechanical properties.

Key Properties:

Dielectric strength: >25kV/mm, ensuring reliable insulation at 18/30 Kv.

Operating temperature: -40°C to +90°C continuously, with short-term overload capability up to 130°C.

Water absorption: <0.01% by weight, preventing moisture-induced degradation.

UV resistance: Enhanced with 2-3% carbon black to prevent photo-oxidation.

Ethylene Propylene Rubber (EPR):

Manufacturing Process: Synthetic rubber produced by copolymerizing ethylene and propylene, offering superior flexibility and aging resistance.

Key Properties:

Dielectric strength: >20kV/mm, providing reliable insulation for medium-voltage applications.

Operating temperature: -50°C to +105°C continuously, making it suitable for extreme climates.

Flexibility: Superior to XLPE, with a minimum bending radius of 8 times the cable diameter.

Chemical Resistance: Excellent resistance to oils, ozone, and environmental pollutants.

Uniform thickness with a tolerance of ±0.2mm across the cable length.

Complete adhesion to the conductor surface, eliminating air gaps that could cause partial discharges.

Smooth outer finish to minimize wind resistance and prevent moisture trapping.

Semiconductive Layer: A thin (0.5mm) layer between the conductor and main insulation, made of carbon-loaded polymer, which ensures uniform electric field distribution and prevents partial discharges.

Flame-Retardant Additives: Incorporated into the protective covering for installations in high-risk areas, meeting IEC 60332-1 flame spread requirements.

Water-Blocking Tape: Applied between the conductor and insulation in extremely humid environments, swelling upon contact with water to prevent longitudinal moisture migration.

Color Coding: UV-stable color pigments (red, blue, yellow) for phase identification, aiding in installation and maintenance.

Power Frequency Withstand Test: 36kV (twice the rated phase-to-ground voltage) applied for 10 minutes without breakdown, simulating overvoltage conditions.

Impulse Withstand Test: 95kV (1.2/50μs waveform) applied 10 times in both positive and negative polarities, verifying protection against lightning strikes and switching transients.

Partial Discharge Test: Measured at 1.73 times the rated phase-to-ground voltage (31.14kV), with partial discharge levels <10pC, indicating high-quality insulation with no internal defects.

Insulation Resistance: Exceeds 1000MΩ·km when measured with a 5kV megohmmeter, ensuring minimal leakage current.

90% of rated value at 40°C ambient temperature

85% for installation in enclosed ducts

80% when multiple cables are bundled with spacing <100mm

Low conductor resistance, with AC resistance at 50Hz typically 5-8% higher than DC resistance due to skin effect

Low dielectric loss, with dissipation factor (tan δ) <0.001 at 20°C

Efficient heat dissipation enabled by the protective covering's thermal conductivity (0.3 W/m·K for XLPE)

Ultimate Tensile Strength:

AA 6201 conductors: 310-345MPa

ACS conductors: 800-1000MPa

Maximum Operating Tension: 40% of ultimate tensile strength to ensure long-term reliability

Breaking Load:

50mm² AA 6201: 15kN

120mm² AA 6201: 35kN

240mm² AA 6201: 70kN

120mm² ACS: 85kN

AA 6201 conductors: up to 100 meters

ACS conductors: up to 150 meters

Minimum Bending Radius:

During installation: 10 times the cable outer diameter (typically 60-80mm)

During operation: 15 times the cable outer diameter

Elongation at Break:

Conductor: 3-5%

Protective covering: >200% for XLPE, >300% for EPR

Temperature Range:

XLPE insulation: -40°C to +90°C (continuous), -50°C to +130°C (short-term)

EPR insulation: -50°C to +105°C (continuous), -60°C to +150°C (short-term)

UV Resistance: After 2000 hours of UVB-313 exposure (equivalent to 20 years of outdoor service), the protective covering retains >80% of its original tensile strength.

Water Resistance: Insulation resistance remains >1000MΩ·km after 1000 hours of immersion in water at 90°C.

Ozone Resistance: Unaffected by ozone concentrations up to 200ppm, ensuring performance in industrial areas.

Salt Spray Resistance: Passes 5000 hours of salt spray testing per ASTM B117 with <5% corrosion, making them suitable for coastal areas.

Chemical Resistance: Resistant to:

5% sulfuric acid and 10% hydrochloric acid (1000 hours exposure)

10% sodium hydroxide and 10% ammonia solutions (1000 hours exposure)

Petroleum products, lubricating oils, and most industrial solvents

Pollution Resistance: Smooth insulation surface minimizes dust accumulation, reducing tracking and erosion risks in polluted environments.

Thermal Aging: Exposure to 100°C (XLPE) or 135°C (EPR) for 10,000 hours results in <20% loss in insulation tensile strength.

Weathering: Combined UV, temperature cycling, and moisture exposure for 5000 hours shows minimal degradation.

Fatigue Resistance: Withstands 100,000 cycles of tension variation (30-70% of maximum operating tension) without failure.

Urban Distribution: Connecting substations to commercial districts and residential complexes, where their insulated design enhances safety in populated areas. They are often installed along roadways and in urban canyons, withstanding pollution and vibration.

Suburban Networks: Used in residential areas with longer spans between poles, reducing the need for frequent maintenance while ensuring reliable power delivery.

Long Span Installations: Crossing valleys, rivers, and remote areas with spans up to 150 meters (using ACS conductors), reducing the number of poles required and lowering installation costs.

Harsh Environment Performance: Withstanding extreme temperatures, high humidity, and agricultural chemicals, ensuring reliable power in farming communities.

Low Maintenance Requirements: Ideal for areas with limited access to maintenance crews, with projected maintenance intervals of 5-7 years versus 1-2 years for bare conductors.

Industrial Zones: Powering factories, refineries, and manufacturing facilities, where chemical resistance and flame-retardant options provide additional safety.

Wind Farms: Connecting wind turbines to collection substations, withstanding vibrational stress and variable weather conditions.

Solar Parks: Transmitting power from solar arrays to grid connection points, withstanding high temperatures and UV exposure.