The development and innovation in green transformer technology are reflected in various products, including three-dimensional (3D) wound core transformers, open-ventilated dry transformers, amorphous alloy 3D wound core open-ventilated transformers, natural ester (vegetable-based insulating oil) oil-immersed transformers, and silicone rubber insulated dry transformers. These technologies and products, with their unique design and material advantages, are driving the transformer industry toward a more environmentally friendly, efficient, and safe future.
Three-Dimensional Wound Core Transformers
Three-dimensional wound core transformers represent a breakthrough in traditional planar transformer core design, using a continuous winding method to create a core whose cross-section is approximately semi-circular, which, when assembled, forms an equilateral triangular 3D structure. This design achieves balanced three-phase operation, strong short-circuit resistance, uniform temperature distribution, and significantly reduced losses and noise. Compared to traditional designs, the no-load loss of 3D wound core transformers is reduced by about 30%, and the core weight is reduced by approximately 25%, making it an environmentally superior option that meets national standards for promoting green and efficient energy equipment. Currently, China is at the forefront of global production technology for 3D wound core transformers. Domestic enterprises have successfully applied 3D wound core technology to amorphous alloy transformers and 110kV power transformer projects. The series of silicon steel 3D wound core products now covers voltage levels up to and including 110kV and capacities up to 80,000kVA. As national policies on carbon peaking and carbon neutrality deepen, 3D wound core transformers, known for their safety, reliability, environmental friendliness, energy efficiency, and low noise, align perfectly with the green transformation needs of the power grid. Looking forward, 3D wound core technology is expected to advance toward higher voltage levels, greater energy efficiency, more environmentally friendly designs, and smarter operations.
Open-Ventilated Dry Transformers
Open-ventilated dry transformers utilize advanced moisture-resistant and fire-resistant insulation materials, such as aramid paper and specialized insulating varnishes, providing superior moisture resistance and high fire safety performance. This transformer technology is suitable for extreme environments, effectively reducing partial discharge levels, enhancing overload capacity, and offering a high insulation heat resistance rating. The innovative insulation structure not only ensures the long-term stable operation of the transformer but also significantly improves its safety and environmental friendliness. Currently, this technology is widely applied in various sectors such as power grids, buildings, renewable energy, electric vehicle charging stations, data centers, rail transit, and various industrial plants. Notable applications include the Hong Kong-Zhuhai-Macao Bridge, the "Ice Cube" at the 2022 Beijing Winter Olympics, Shenzhen Xiaotangshan Hospital, Guangzhou Metro, Baiyun Airport, and the Guangdong Rural Credit Cooperative Data Center. As the power industry's quality requirements rise, load demands on the user side increase, and digital power distribution technology matures, the future of open-ventilated dry transformer technology will evolve toward higher voltage levels, larger capacities, and smarter operations.
Amorphous Alloy 3D Wound Core Open Ventilated Transformers
By combining the advantages of amorphous alloy materials with 3D wound core technology, amorphous alloy 3D wound core open-ventilated transformers excel in reducing energy consumption, enhancing short-circuit resistance, and ensuring long-term stability. In 2011, amorphous alloy ribbons were applied to 3D wound core structures, overcoming technical bottlenecks, and production and sales began in 2012. This technology effectively addresses issues seen in traditional amorphous transformers, such as high noise levels, poor short-circuit resistance and unstable long-term performance. Given the superior properties and straightforward processing of amorphous alloy ribbons, this is a critical direction for new material development globally. China is the largest consumer of amorphous ribbons, accounting for over 50% of the global market, with domestically produced amorphous ribbons holding over 80% of the market share. Amorphous alloy 3D wound core open ventilated dry transformers are primarily used in rail transit traction rectifier power supply systems and cover voltage levels up to and including 35kV with capacities up to 3300kVA. As national policies on carbon peaking and carbon neutrality deepen, these transformers, with their superior low-loss and other green characteristics, fully meet the requirements for energy conservation and emission reduction. The future development of this technology will trend towards higher voltage levels, larger capacities, and smarter designs.
Natural Ester (Vegetable-Based Insulating Oil) Oil-Immersed Transformers
Natural ester oil-immersed transformers use vegetable-based insulating oil, which is highly environmentally friendly, biodegradable, non-toxic, and safe. Compared to traditional mineral oil, natural ester oil has a higher flash and fire point, significantly enhancing the transformer's safety performance. Additionally, natural ester oil excels in improving transformer overload capacity and extending insulation life, contributing to the construction of green grids. Currently, more than 3 million natural ester (vegetable-based insulating oil) transformers are operating safely and stably worldwide, primarily in the Americas, Europe, and parts of Asia. In China, natural ester (vegetable-based insulating oil) transformers have been integrated into most provincial power grids and are operating stably. By 2020, this technology was included in the State Grid's standard procurement technical agreement. The highest voltage level for transformers in operation in the State Grid system is 110kV, while the Southern Power Grid has deployed 220kV transformers and initiated a 500kV natural ester (vegetable-based insulating oil) transformer project. Beyond the power grid system, the number of users in the renewable energy and industrial sectors utilizing these transformers is also growing significantly, with a notable project being the 110kV transformer in the Chongqing Metro. Manufacturers of natural ester and vegetable-based insulating oil, transformer producers, power grids, and industrial users have all accumulated significant technical experience in applying these transformers. As the market develops, related application research is increasing and deepening. So far, natural ester (vegetable-based insulating oil) has been proven safe for use in all types of transformers up to and including 500kV, with mature theoretical foundations for design, production, operation, and maintenance. In 2020, the electric power industry published a series of group standards for "Natural Ester Insulating Oil Power Transformers" under T/CEC291.1-6.
Silicone Rubber Insulated Dry Transformers
Silicone rubber insulated dry transformers use high-performance silicone rubber as the insulating material, providing excellent temperature resistance, moisture resistance, and fire protection. The use of silicone rubber improves the transformer's safety and environmental adaptability, with notable advantages in reducing partial discharge and noise. This technology makes transformers more suitable for stable operation in harsh environments, while also facilitating transformer recycling and reuse. Silicone rubber can operate at temperatures ranging from -60℃ to 250℃, with a lifespan of at least 30 years under such conditions, without cracking even under strong vibrations or drastic temperature changes. Silicone rubber's hydrophobic and hydrophobic migration properties prevent the formation of water films in high-humidity and polluted environments, helping to prevent surface breakdown under high voltage. Transformer-grade high-performance silicone rubber is unaffected by ultraviolet light, opening up a broad application space for silicone rubber transformers. Based on high-quality insulation materials and reliable insulation technology, silicone rubber insulated transformers can minimize air insulation distances and shorten magnetic paths to reduce no-load losses. Silicone rubber encapsulated dry transformers meet the new first-level energy efficiency requirements of GB20052-2020 and have even developed cost-effective ultra-first-level energy efficiency dry transformers using electrical steel strips, with no-load losses 15% lower than the first-level energy efficiency standard and load losses 10% lower. They can also be customized to design energy-saving indices based on user load characteristics, achieving the best cost-performance ratio for dry transformers.
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