SMC (Sheet Molding Compound) is a sheet-like composite material made with unsaturated polyester resin as the matrix, glass fiber as the reinforcement, and additions of fillers, initiators, mold release agents, and other auxiliaries. It possesses excellent electrical insulation properties, mechanical strength, corrosion resistance, heat resistance, and moldability, and has been widely and importantly applied in the power industry, providing reliable assurance for the safe and stable operation of power equipment.
Ⅰ. Applications in Transmission and Transformation Equipment
1.1 Insulators
SMC insulators are key insulating components in transmission and transformation lines, used to support conductors and ensure insulation between conductors and towers. Compared with traditional ceramic insulators, SMC insulators have notable advantages: first, they have high mechanical strength, excellent bending and impact resistance, can withstand significant wind, ice loads, and conductor tension, reducing the risk of accidents caused by mechanical damage; second, they show strong weather resistance, maintaining stable performance in harsh conditions such as high and low temperatures, humidity, and UV exposure, with a service life of over 20 years without cracking or aging issues; moreover, they are lightweight, only about 1/3 to 1/2 the weight of ceramic insulators, greatly reducing the load on towers and lowering installation and transportation costs. Currently, SMC insulators are widely used in transmission lines of 110kV, 220kV, 500kV, and above, especially showing excellent performance in coastal and chemically aggressive areas.
1.2 Cable Branch Box Enclosures
Cable branch boxes are important equipment in distribution systems for cable branching and connections. Their enclosures need to provide good insulation, sealing, corrosion resistance, and mechanical protection. Enclosures made from SMC materials have high insulation resistance, effectively preventing electrical leakage accidents; they feature good sealing, using specialized sealing structures to achieve an IP67 protection level, resisting intrusion from rain, dust, etc.; they are highly corrosion-resistant, able to withstand acidic, alkaline, and salt spray environments, suitable for outdoor and underground use; in addition, they can be molded with high precision, allowing complex shapes according to design requirements, aesthetically pleasing with smooth surfaces, and easy to clean and maintain. SMC cable branch box enclosures have been widely applied in urban distribution network upgrades and rural power grid construction.
2. Applications in New Energy Power Equipment
2.1 Wind Turbine Blades
In wind power generation equipment, wind turbine blades are the core components that convert wind energy into mechanical energy, and their performance directly affects the power generation efficiency and reliability of wind turbines. SMC materials, with their high strength, lightweight, and fatigue resistance, have become one of the ideal materials for wind turbine blades. By optimizing the glass fiber content and laying method, SMC wind turbine blades can achieve high specific strength and stiffness, effectively reducing blade weight while ensuring structural stability, lowering the rotational inertia of the rotor, and improving power generation efficiency. In addition, SMC materials have good fatigue resistance, allowing them to withstand long-term alternating loads and extend the service life of blades. Currently, SMC wind turbine blades are mainly used in small and medium-sized wind turbines, and with continuous advancements in material technology, their application in large-scale wind turbines is gradually expanding.
2.2 Photovoltaic Module Frames
Photovoltaic module frames are used to secure and protect solar panels, requiring good mechanical strength, corrosion resistance, and insulation. Compared to traditional aluminum alloy frames, SMC photovoltaic module frames have several advantages: first, they are lower in cost, with relatively stable raw material prices, and a simple manufacturing process, which can reduce the production cost of solar modules; second, they offer stronger corrosion resistance, making them less prone to rust in harsh outdoor environments and extending their service life; third, they have excellent insulating properties, effectively preventing eddy current losses that may occur with aluminum frames, thereby improving the power generation efficiency of the photovoltaic system. Additionally, SMC frames are lightweight and easy to install, reducing the load on photovoltaic supports. Currently, SMC photovoltaic module frames have begun to be increasingly used in distributed photovoltaic power stations and small-scale solar systems.
3. Applications in Power Control Equipment
3.1 Switchgear Cabinets
Switchgear is essential equipment in power systems for controlling, protecting, and distributing electricity. Its cabinet requires good electrical insulation, flame retardancy, mechanical strength, and protective performance. SMC switchgear cabinets are made using molding processes, featuring compact structures and high strength, capable of effectively bearing the weight of internal electrical components and the electrodynamic forces generated by short-circuit currents. They exhibit excellent flame retardancy with high oxygen indexes, making them difficult to ignite and effectively preventing fire expansion. Their good electrical insulation helps avoid safety hazards caused by electrified cabinet surfaces, while their strong corrosion and weather resistance make them suitable for various indoor and outdoor environments. SMC switchgear cabinets are widely used in substations, power plants, and industrial distribution systems.
3.2 Instrument Panel Housings
The instrument panel housings in power control centers need good insulation, sealing, and aesthetics to protect the internal precision instruments and electronic components. SMC instrument panel housings have smooth and even surfaces, uniform color, and attractive appearance. They offer excellent insulation, helping to prevent electromagnetic interference and leakage accidents. Their strong sealing prevents dust, moisture, and other contaminants from entering the housing, ensuring the proper operation of instruments. Additionally, SMC housings are easy to mold and can be custom-manufactured to fit instruments of various sizes and shapes, meeting different design requirements. Currently, SMC instrument panel housings are used in power dispatch centers, substation control rooms, and other similar places.
4. Summary of the Advantages of SMC Composites in the Power Industry
- Excellent electrical insulation performance: SMC materials have high volume resistivity, low dielectric loss tangent, and high breakdown voltage, which can meet the strict insulation requirements of power equipment and effectively ensure the safe operation of power systems.
- Good mechanical performance: They possess high tensile strength, flexural strength, and impact strength, allowing them to withstand various mechanical loads, resist damage, and extend the service life of equipment.
- Outstanding corrosion resistance: They exhibit good resistance to various corrosive media, including acids, alkalis, salts, and oils, making them suitable for harsh environments and reducing equipment maintenance costs.
- Excellent moldability: They can be molded into various complex shapes using compression molding processes, with high production efficiency, precise dimensional accuracy, and good consistency, facilitating large-scale production.
- Lightweight characteristics: Compared with traditional materials such as metal and ceramics, SMC materials have low density and light weight, reducing the weight of equipment and the cost of installation and transportation, and alleviating the load on supporting structures like poles and brackets.
5. Outlook on Development Trends
With the continuous development of the power industry, performance requirements for power equipment are becoming increasingly stringent, and the application prospects of SMC composites in the power industry are very promising. In the future, SMC materials will develop towards high performance, multifunctionality, and intelligence: First, material modification technologies will be used to enhance heat resistance, aging resistance, and mechanical strength to meet the demands of higher voltage levels and harsher environments. Second, SMC composites with functions such as conductivity, thermal conductivity, and electromagnetic shielding will be developed to expand their applications in power equipment. Third, advanced forming technologies, such as 3D printing, will be combined to enable rapid customized production of SMC products, improving production efficiency and product added value. It is believed that in the near future, SMC composites will play a more important role in the power industry and make greater contributions to the development of the power sector.
