Insights from the First-Year Operation of the World’s First 110kV Amorphous Alloy 3D Wound Core Oil-Immersed Power Transformer with Ultra Grade-1 Energy Efficiency

Against the backdrop of China’s advancement in energy green transition, transformers are shouldering the green mission of the power equipment sector. The Implementation Plan for High-Quality Development of Energy-Saving Equipment (2026-2028) explicitly supports the promotion and application of large-capacity high-efficiency amorphous alloy 3D Wound Core transformers. Behind this policy orientation lies the strong alignment between the energy-saving advantages of such transformers and the demands of the new-type power system dominated by new energy sources. Therefore, these transformers undertake not only conventional energy-saving tasks but also a greater mission of delivering systematic support for energy green transition from the equipment side in the construction of the new-type power system.

The world’s first 110kV amorphous alloy 3D wound core oil-immersed power transformer with Ultra Grade-1 energy efficiency, developed under the leadership of Guangdong Power Grid with Haihong Electric as the principal R&D entity, stands as a landmark practice in implementing this policy deployment. Now marking its first anniversary of commissioning, one-year field operation data has fully verified that the combination of amorphous alloy energy-saving material and 3D Wound Core energy-saving structure can unlock enormous energy-saving potential. It provides a real-world engineering sample for large-capacity amorphous-alloy-based equipment to be deployed in high-voltage-level power grids, and explores a new path for green equipment reform for China’s energy transition and new-type power system development.

Transformers are core energy-conversion equipment in power grids. Losses generated during power transformation constitute a key component of overall grid line losses. To build a new-type power system and deliver the Dual-Carbon Goals, we need to continuously scale up new-energy power supply such as wind and photovoltaic power. Meanwhile, energy-saving potential shall be tapped from the equipment side to cut persistent losses in power transmission and transformation links.

As an advanced magnetic material, amorphous alloy can drastically reduce no-load loss compared with conventional silicon steel. Nevertheless, long-standing bottlenecks including material brittleness, difficulties in forming large-capacity cores and complex core suspension have restricted its application scope. Amorphous alloy transformers were mostly confined to small-capacity scenarios within power distribution networks of 35 kV and below, and could hardly enter the 110-kV main power grid. Consequently, the inherent energy-saving strengths of new materials were not fully exploited. The advent of 3D Wound Core technology offers a viable solution to bring out the full performance of amorphous alloy materials.

Since commissioning, the energy-saving performance of the 110kV amorphous alloy 3D wound core oil-immersed power transformer with Ultra Grade-1 energy efficiency has been quantitatively validated. During the operation period from October-1-2025 to May-31-2026, its losses dropped by approximately 68% compared with the original Grade-3 energy-efficiency laminated silicon-steel core main transformer at the same substation in the previous cycle. Under equivalent load conditions, its losses decreased by 42 % versus the in-service Grade-2 energy-efficiency laminated silicon-steel core main transformer within the same substation.

After one-year full-condition practical operation on the grid, the equipment has maintained stable and efficient routine operation with reliable performance. It also successfully withstood the extreme stress of short-circuit current impact caused by an external-area fault, and remained stable after the incident.

Field monitoring data demonstrates outstanding overall performance: stable transformer temperature rise without local overheating, together with low operating noise and favorable acoustic indicators. Such excellent temperature-rise and noise performance stems from the synergistic effect of amorphous alloy material and 3D Wound Core structure. Adopting a continuous winding process, the 3D Wound Core features gap-free cores, coherent magnetic circuits, lower magnetic resistance and reduced magnetic leakage. Its core structure and manufacturing process effectively suppress vibration induced by magnetostriction. This represents more than mere compliance with short-term performance metrics; it lays a solid foundation for long-term safe equipment operation. The uniform temperature field mitigates failure risks triggered by overheating, better meeting the round-the-clock operation requirements of the main power grid.

Many main transformers stay energized in standby mode for long periods, consuming continuous electric energy via no-load losses. Promoting large-capacity high-efficiency amorphous alloy 3D Wound Core transformers can reduce no-load losses at source, achieve steady power conservation and substantially cut carbon emissions. With large-scale new-energy integration, power grids keep expanding and the installed base of power transformation equipment continues to grow. Centered on the technical approach combining new materials and 3D Wound Core, carbon-reduction benefits brought by improved equipment energy efficiency will keep accumulating and magnifying with large-scale deployment. This 110-kV main transformer demonstration has proven the engineering feasibility of high-voltage large-capacity amorphous 3D Wound Core transformers. It delivers measured data support for grid equipment selection and expands the options for energy-saving equipment in main power grids.

The industrialization of new amorphous alloy materials and mature full-chain manufacturing processes for high-voltage 3D Wound Core are domestic independent innovation achievements. Breakthroughs have been realized in the integration of materials, structures, processes and equipment, expanding the application boundary of amorphous alloy materials in power transmission and transformation. This technical route boasts great extensibility. Continuous innovation and iteration of 3D Wound Core technology will enable product application toward larger capacities and higher voltage levels, steadily unlocking the energy-saving dividends of new materials and structures.

Issued by the Ministry of Industry and Information Technology, the Implementation Plan for High-Quality Development of Energy-Saving Equipment (2026-2028) explicitly supports the promotion of large-capacity high-efficiency amorphous alloy 3D Wound Core transformers, constituting authoritative state-level recognition of the green value of this technology. At the press conference for the plan, Luo Junjie, Vice President of China Machinery Industry Federation, stated that China had successfully developed the world’s first 110-kV energy-saving amorphous alloy 3D Wound Core oil-immersed power transformer with energy-efficiency indicators far exceeding the Grade-1 standard. He also encouraged large-scale application of equipment including high-efficiency silicon-steel 3D Wound Core transformers, large-capacity high-efficiency amorphous alloy 3D Wound Core transformers, large-capacity solid-state transformers and flexible DC transformers.

Within the whole power transmission and transformation industry, 110-kV equipment serves as core facilities for transmission networks. This engineering practice breaks the long-term limitation that amorphous alloy 3D Wound Core transformers were only applied in distribution networks, and renews industry perceptions of high-voltage-level transformers adopting new soft magnetic materials. Previously, widespread industry concerns centered on formidable process challenges for amorphous alloy materials under large-capacity high-voltage scenarios and uncertainties over long-term equipment reliability. Real-world operation results of this project have effectively dispelled such doubts, laying a solid basis for subsequent engineering approval, grid-access test and large-scale promotion of more 110-kV and even higher-voltage large-capacity amorphous 3D Wound Core transformers.

Green transformation starts with equipment upgrades. The demonstration of the world’s first 110kV amorphous alloy 3D wound core oil-immersed power transformer with Ultra Grade-1 energy efficiency represents the synergy of national policy guidance, technological innovation of amorphous alloy 3D Wound Core and on-site grid practice. More than just an energy-saving transformer, it epitomizes the extension of China’s original soft-magnetic-material and 3D Wound Core technologies toward high-end main-grid power equipment. As demonstration effects gradually expand, this highly extensible technical route is expected to be adopted in more new-build and renovation projects, continuously curbing grid losses, facilitating new-type power system construction and contributing robust power-equipment strength to national green and low-carbon development.

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