Overhead Transmission Conductors: Corrosion & Protection Measures

Introduction

At present, overhead transmission conductors at home and abroad are mainly composed of steel-cored aluminum strands. As the core carrier of power transmission, they shoulder the key mission of transmitting electrical energy from the power source to the power load center, and occupy an irreplaceable important position in the entire transmission line system.

With the rapid development of China's economy and the acceleration of industrialization, the service environment of overhead transmission conductors has become increasingly complex and deteriorated. Under the influence of harsh natural environments such as wind load and freezing, the conductors are prone to swaying, which in turn causes fretting wear and fretting fatigue; at the same time, corrosive media such as moisture, chemical gases, dust and salts in the atmosphere will continuously act on the surface of the conductors, leading to corrosion of the conductors—characterized by brittle material, significant reduction in tensile strength, and ultimately triggering various transmission safety accidents.

The corrosion problem of overhead transmission conductors has become an important hidden danger threatening the long-term, safe and stable operation of the power grid, and also a key issue to be solved urgently in the power industry.

1. Corrosion Behavior and Hazards of Overhead Transmission Conductors

It is a common consensus in the domestic and foreign power industry that corrosion of the line itself is the main cause of strand breakage and failure of overhead transmission conductors. At present, the global power field attaches great importance to the corrosion management of transmission lines—organizations such as the Electric Power Research Institute of the United States and Canadian power technology research institutions have listed corrosion assessment, corrosion control and protection technologies of power grids as core research directions for power grid management; China is also continuously promoting research on corrosion assessment and protection technologies of transmission lines, and gradually improving the corrosion prevention and control system.

The impact of corrosion on overhead transmission conductors has obvious regional and time-sensitive characteristics: in strong corrosive environments such as coastal areas (high salt spray, high humidity) and heavy industrial pollution areas (high chemical gases, dust), the corrosion rate of conventional steel-cored aluminum strands accelerates significantly, and obvious rust usually appears after 4 to 8 years of service.

Conductor rust not only reduces its own mechanical and electrical conductivity, but also forms serious safety hazards, requiring timely replacement of conductors. This not only increases the cost of power operation and maintenance, but may also cause power outages due to conductor replacement, affecting industrial production and residents' lives.

Therefore, how to improve the corrosion resistance of overhead transmission conductors, extend the service life of steel-cored aluminum strands, and meet the service requirements of overhead transmission conductors in corrosive areas has become a key issue of common concern to cable manufacturing enterprises and power operation departments.

2. Core Protection Measures for Overhead Transmission Conductors

In response to the corrosion problem of overhead transmission conductors, a variety of mature protection technologies have been formed in the industry. The core purpose is to isolate the contact between corrosive media and the conductor surface, delay the corrosion process, and ensure the long-term stable service of the conductors. At present, the mainstream anti-corrosion measures are mainly divided into the following categories:

1. Coating Anti-Corrosion Grease

This is a simple and economical protection method. By coating special anti-corrosion grease on the surface of the conductor, a dense protective film is formed to isolate corrosive media such as moisture, salt spray and chemical gases in the atmosphere, and reduce the occurrence of corrosion reactions. This method is suitable for mild corrosive environments and requires regular maintenance and re-coating to ensure the protection effect.

2. Alloy Coating Protection

A layer of corrosion-resistant alloy (such as zinc, zinc-aluminum alloy, etc.) is plated on the surface of the steel-cored aluminum strand. Using the sacrificial anode protection principle of the alloy, the corrosion of the conductor matrix is slowed down. This protection method has a long-lasting protection effect, is suitable for mild to moderate corrosive environments, and is one of the widely used protection methods at present.

3. Aluminum-Clad Steel Technology

Conductors are made of aluminum-clad steel material. The steel is used as the core to ensure the mechanical strength of the conductor, and the outer aluminum layer plays a role in corrosion resistance protection while taking into account the electrical conductivity. Aluminum-clad steel conductors have excellent corrosion resistance and mechanical strength, are suitable for strong corrosive environments such as coastal areas and heavy industry, and can effectively extend the service life of conductors.

4. Application of New Materials and New Processes

With the development of materials science, new corrosion-resistant materials (such as anti-corrosion aluminum alloys, composite materials, etc.) have been gradually applied in the manufacture of overhead transmission conductors; at the same time, the conductor production process is optimized to improve the flatness and compactness of the conductor surface, reduce the adhesion of corrosive media, and further enhance the corrosion resistance of the conductor.

5. New Conductor Structure Design

By optimizing the conductor structure (such as increasing the thickness of the protective layer, designing a sealed structure, etc.), the contact area between corrosive media and the conductor core is reduced, and the overall corrosion resistance of the conductor is improved. The new structure conductor can not only effectively prevent corrosion, but also take into account the conductivity efficiency and mechanical stability, adapting to complex and harsh service environments.

3. Conclusion

As the core carrier of power transmission, the corrosion problem of overhead transmission conductors is directly related to the safe and stable operation of the power grid and the reliability of power supply. With the increasing complexity of the service environment, the safety hazards and economic losses caused by corrosion have become more prominent, and strengthening conductor corrosion protection has become an inevitable demand of the power industry.

At present, protection measures such as anti-corrosion grease coating, alloy coating and aluminum-clad steel have been widely applied. Combined with new materials, new processes and new structure designs, they can effectively improve the corrosion resistance of conductors and extend their service life. In the future, with the continuous innovation of corrosion protection technology, the long-term, safe and stable operation of overhead transmission conductors in various strong corrosive environments will be gradually realized, providing protection for the safety of the power grid.

Frequently Asked Questions (FAQ)

Q1: What is the main material of overhead transmission conductors?

At present, the mainstream material of overhead transmission conductors at home and abroad is steel-cored aluminum strand, which has both the mechanical strength of steel and the excellent electrical conductivity of aluminum, and is the core carrier of power transmission.

Q2: What is the service life of steel-cored aluminum strands in strong corrosive environments?

In strong corrosive environments such as coastal areas and heavy industrial pollution areas, conventional steel-cored aluminum strands usually show obvious rust after 4 to 8 years of service and need to be replaced in time to eliminate safety hazards.

Q3: What are the core protection measures for overhead transmission conductors?

The core protection measures mainly include: anti-corrosion grease coating, alloy coating, aluminum-clad steel technology, application of new materials and new processes, new conductor structure design, etc. The appropriate protection method can be selected according to the intensity of the corrosive environment.

Keyword Tags

overhead transmission conductors, steel-cored aluminum strands, conductor corrosion, conductor protection measures, aluminum-clad steel conductors, alloy coating protection, transmission line corrosion, power grid safety