Key Strategies for Reliable Power Cable Systems

The stable operation of power systems relies on safe and reliable electrical cables. However, improper cable selection, non-standard installation, and inadequate maintenance can all create safety hazards, potentially leading to power system failures or even accidents. How can we ensure cable safety? This comprehensive guide provides essential strategies for cable selection, installation, and maintenance to safeguard power system stability.

Cable selection is the critical first step in ensuring power system safety and reliability. The process requires careful consideration of operating environment, load characteristics, and safety requirements. Key factors include:

• Voltage Rating: Select cables with voltage ratings matching or exceeding the system's maximum operating voltage to prevent insulation breakdown. Common ratings include low voltage (below 300V), medium voltage (3kV-35kV), and high voltage (110kV-500kV).
• Current Capacity: Choose cables with current-carrying capacity exceeding maximum system current to prevent overheating. Capacity depends on conductor material, cross-section, insulation, and installation method.

• Temperature: Select cables rated for environmental extremes. High temperatures accelerate insulation aging while low temperatures cause brittleness.
• Humidity: Moisture-resistant cables are essential for damp environments to prevent insulation degradation.
• Chemical Exposure: Corrosive environments require cables with polyethylene, PVC, or fluoroplastic insulation.
• Hazardous Areas: Flame-retardant or fire-resistant cables are mandatory for explosive atmospheres.
• Mechanical Stress: High-strength cables are needed for applications with physical strain.

Common cable categories include:

• Power Cables: For energy transmission (copper/aluminum conductors, XLPE/PVC insulation)
• Control Cables: For signal transmission (shielded, armored, or high-temperature variants)
• Communication Cables: Including fiber optic, coaxial, and twisted pair
• Specialty Cables: Designed for unique requirements (oil-resistant, marine, etc.)

• Copper: Superior conductivity and durability but higher cost
• Aluminum: Lighter and more economical but with lower current capacity

• PVC: Cost-effective with good insulation but limited temperature range
• XLPE: Excellent for high-voltage applications with superior thermal resistance
• Rubber: Flexible and cold-resistant but vulnerable to oils and chemicals

Proper installation prevents cable damage and reduces safety risks. Critical considerations:

• Direct Burial: Requires armored cables with corrosion protection
• Conduit Installation: Provides mechanical protection using appropriate conduit materials
• Cable Tray: Facilitates maintenance and routing flexibility
• Tunnel Installation: Offers maximum protection with proper ventilation

Maintain minimum bending radii (typically 10× diameter for power cables, 6× for control cables) to prevent insulation damage.

Avoid excessive pulling force (70N/mm² for copper, 40N/mm² for aluminum).

Use proper cable clamps spaced according to standards.

Ground metal sheaths and shields with dedicated conductors meeting resistance requirements.

Regular maintenance identifies potential issues before failures occur:

• Visual checks for damage or deterioration
• Insulation resistance testing
• Connection point examinations
• Grounding system verification

• Dielectric withstand tests to assess insulation integrity
• Leakage current measurements to detect insulation degradation

• Surface cleaning to maintain thermal performance
• Moisture prevention measures
• Corrosion protection
• Timely replacement of aged cables

Use silicone or fluoroplastic-insulated cables with reduced current ratings and enhanced cooling.

Select cold-resistant materials (nitrile rubber, polyurethane) with proper heating and mechanical protection.

Employ moisture-proof cables with sealed connections and drainage systems.

Use corrosion-resistant materials with protective coatings and adequate ventilation.

Mandatory flame-retardant cables with physical separation from combustibles and fire detection systems.

• Prioritizing cost over performance
• Inaccurate current capacity calculations
• Exceeding minimum bending radii
• Improper joint construction
• Inadequate grounding practices

As the circulatory system of power networks, cables require meticulous attention from selection through maintenance. Implementing these professional practices ensures electrical safety and system reliability, forming the foundation for stable power infrastructure.