An Overview of Polypropylene Insulated Power Cables and Their Standardization in China

Introduction

Polypropylene (PP) insulated power cables have gained significant attention due to their excellent electrical properties, environmental friendliness, and recyclability. As China promotes sustainable energy solutions and carbon neutrality, PP cables are emerging as a key component in the power industry. This article provides an overview of PP insulated power cables, their advantages, current standardization progress, and future development directions.

Why Polypropylene Insulated Power Cables?

Power cables are critical for stable electricity transmission. Traditionally, cross-linked polyethylene (XLPE) has been the dominant insulation material due to its high electrical and thermal performance. However, XLPE cables cannot be recycled, leading to environmental concerns. Polypropylene, as a thermoplastic material, offers a sustainable alternative with the following benefits:

• High Electrical Insulation: PP exhibits strong resistance to electrical breakdown, making it suitable for high-voltage applications.
• Environmental Sustainability: Unlike XLPE, PP cables can be recycled, reducing industrial waste and contributing to circular economy goals.
• Thermal Stability and Processing Efficiency: PP has a high operating temperature and can be processed without chemical cross-linking, simplifying manufacturing and lowering carbon emissions.
• Resistance to Water Treeing: PP naturally resists water treeing, a phenomenon that degrades cable insulation over time.

Development and Standardization of PP Power Cables in China

The development of PP insulated power cables in China has been progressing steadily, following international trends. Countries like Italy, South Korea, Japan, and Switzerland have already implemented PP cable technologies in medium- and high-voltage applications.

China’s research on PP power cables began in 2014, led by institutions such as Tsinghua University, Shanghai Jiao Tong University, Tianjin University, and Harbin Institute of Technology. These efforts have been complemented by major power grid research centers and industrial companies like China Petroleum & Chemical Corporation (Sinopec) and China National Nuclear Corporation (CNNC).

To ensure the safe and efficient application of PP cables, China has developed industry standards. Key standardization efforts include:

1. Material Standards: Guidelines for polypropylene-based insulation and semi-conductive shielding materials, specifying mechanical, electrical, and aging performance.
2. Cable Standards: Regulations for medium-voltage (6–35 kV) thermoplastic PP cables, including test methods, operating temperature limits, and electrical loss criteria.

Key Technical Considerations

PP materials require modifications to enhance their mechanical properties while maintaining electrical performance. Current research focuses on:

• Toughening Modification: PP is inherently brittle and requires modification through blending with elastomers or copolymerization with ethylene.
• Electrical Performance Enhancement: Methods such as grafting modification and nano-doping are being explored to improve insulation resistance and dielectric strength.
• Thermal Performance Optimization: Standards specify different working temperatures, with materials designed for 90°C and 105°C operation to ensure long-term reliability.

Chinese industry standards specify test requirements for dielectric loss (tan δ), volume resistivity, tensile strength, elongation at break, and thermal aging resistance. Additionally, safety considerations such as flame retardancy, low smoke emission, and recyclability are being incorporated into future cable designs.

Future Outlook

The future of PP insulated power cables in China is promising. Key development trends include:

• Expansion to High Voltage Applications: Research is progressing toward using PP insulation in 110 kV and above power transmission systems.
• Standard Refinement: As testing methodologies improve, standards will continue to evolve to ensure consistent performance across different operating conditions.
• Integration with Smart Grid Technologies: PP cables could play a role in smart power grids, offering high efficiency and adaptability to renewable energy sources.
• Sustainable Manufacturing and Recycling: The industry is actively developing recycling processes to maximize material reuse and reduce waste.

Conclusion

Polypropylene insulated power cables represent the future of eco-friendly and high-performance electrical transmission in China. With strong industry support, ongoing research, and advancing standards, PP cables are poised to replace traditional insulation materials, providing a more sustainable, efficient, and cost-effective solution for modern power networks.

By staying at the forefront of these developments, manufacturers and power grid operators can ensure they meet the increasing demands for sustainability, efficiency, and reliability in China’s evolving energy landscape.