The Seminar on Green Energy Saving High Load Transformer Successfully Held in Shanghai

The '2025 Green Energy-Saving High-Load Transformer: Design Challenges, Innovative Solutions, and Future Trends' seminar, co-hosted by the International Copper Association and Changtai Group, was successfully held at Shanghai Jinjiang Hotel. The event, held on December 12,2025, focused on cutting-edge developments in transformer technology.

The conference, organized by the International Copper Association, brought together experts from power supply bureaus, industry associations, renowned universities, design institutes, and related enterprises. Discussions focused on several key aspects, including the policy background of green and low-carbon initiatives, the technical feasibility of green (high overload) transformers, their application scenarios and socio-economic benefits, as well as the establishment of relevant standards.

1. Policy Context

The State Council's "Action Plan for Green and Low-Carbon Development of Manufacturing Industry (2025-2027)" emphasizes accelerating green technological innovation and promoting advanced green technologies. The March 2023 Government Work Report introduced a carbon footprint management system, while the State Grid's Green Procurement Mechanism (2023) explicitly defines equipment selection criteria for green, low-carbon, and eco-friendly concepts. These policies present unprecedented opportunities and challenges for green transformer development. As the primary insulation material for open-type dry-type transformers, polyimide polymer composite materials demonstrate exceptional performance: high/low-temperature resistance, corrosion resistance, salt spray resistance, radiation resistance, excellent flame retardancy, and high insulation ratings (above H-class). This material exemplifies green and low-carbon principles. Rather than encouraging prolonged overload operation, it enhances transformer design to withstand short-term, cyclical, or emergency load surges, enabling users to select more cost-effective capacities during initial investment. This approach reduces equipment procurement costs for users while minimizing redundant grid investments and improving overall resource utilization efficiency.

2. The technical feasibility of green (high overload) transformer

In order to achieve safe and reliable high overload capacity, the technical breakthrough is mainly made from three paths, and the products with their own characteristics are derived.
Path 1: Transformer Core Structure Optimization. Replacing flat laminated cores with three-dimensional wound cores, this design significantly reduces no-load losses through optimized magnetic circuitry and lighter core weight, achieving substantial energy savings.
Path 2: Insulation Material Innovation. Open-type dry-type transformers now utilize polyimide polymer composites instead of traditional epoxy resin insulation. The material's high-temperature resistance and disc-shaped coil configuration dramatically enhance overload capacity, enabling year-round operation at 130% overload without fan activation. Furthermore, silicone rubber cast dry-type transformers employing advanced elastic materials like silicone rubber as primary insulation demonstrate superior short-term overload tolerance and long-term operational safety, thanks to their exceptional heat resistance, flame retardancy, and eco-friendly recyclability.
Path 3: Innovation in Transformer Oil. Transformers using natural esters (vegetable oils) as alternatives to traditional mineral oils can operate safely at higher temperature rises due to their higher ignition points and better compatibility with insulating materials, thereby extending the allowable overload duration.

3. Application Scenarios and Socioeconomic Benefits

The seminar thoroughly examined the application potential of green (high-load) transformers across multiple sectors.
Industrial Sector: Take power supply systems in steel plants as an example. When one transformer fails, another must urgently take over the entire load.
Municipal Sector: Water treatment plants and sewage facilities often experience short-term peak loads during motor self-starting, rainy season full-load operation, or single-power supply scenarios.
Shipbuilding and Large-Scale Shore Power Sector: Both shipbuilding and large shore power facilities frequently encounter load fluctuations and capacity matching challenges. These scenarios all require transformers with short-term overload capacity.
Civil Building Sector: Many commercial buildings currently operate with low transformer load rates, resulting in "overkill" situations. During retrofitting, adopting green (high-load) transformers enables capacity expansion without enlarging distribution rooms or replacing busbars, effectively addressing load surges or extreme weather-induced power spikes.
Under the two-part tariff system for industrial and commercial electricity, the economic benefits are substantial. Using the common demand reduction capacity calculation method, assuming a 2500kVA reduction at the 35kV voltage level, the monthly electricity cost savings would reach 36,500 yuan.

4. Establishment of Relevant Standards

It is understood that the technical standard "High Overload Capacity Transformer" formulated by China's power industry was first implemented on January 10,2018, and updated on January 6, 2021. This standard specifies core indicators such as short-circuit withstand capability, overload performance, and temperature rise limits for three-phase oil-immersed transformers with capacities ranging from 10kV to 500kVA, filling the gap in domestic technical standards. In 2023, the Gansu Electrical Engineering Society issued the supplementary group standard T/GES 001-2024, further detailing product definitions, testing methods, and transportation and storage requirements, which was officially implemented on October 26,2023. Neither of the above two standards clearly defines the high-load conditions for dry-type or oil-immersed transformers at higher voltage levels or transformers using new insulating media, leading to ambiguous performance definitions for market products and a lack of standard basis for design and selection, which has become a major bottleneck constraining the standardized development of the industry. Experts at the meeting unanimously agreed that it is urgent to incorporate high overload characteristics into a broader scope of green transformer standards, requiring joint efforts from all parties to establish relevant group or industry standards, and to establish national standards when conditions are ripe, thereby removing obstacles to design and selection.

5. Conclusion

This seminar advocates for a paradigm shift in conventional practices. Amid widespread energy waste caused by oversized transformer capacity designs and inadequate load factors, it calls for adopting green, low-carbon, and eco-friendly principles alongside high overload concepts. Industry associations should spearhead collaborative standard-setting efforts, initiating pilot programs in industrial parks, commercial buildings, and renewable energy plants. Regular technical exchanges will enhance industry awareness, while deepening industry-academia-research collaboration drives technological innovation and upgrades.
When standards, technology, market and policy form a joint force, this technology innovation hidden in the substation will release huge economic and social benefits, and inject green energy into high-quality development.