Why Is Amorphous Alloy Thinner Than Silicon Steel Sheets?
An amorphous alloy transformeris a new type of energy-efficient transformer that uses a core made from amorphous alloy strip material as its transformer core. Amorphous alloy core transformers offer significant energy-saving and environmental benefits. Compared to S13 transformers, the no-load loss of amorphous alloy transformers is reduced by 57%. Compared to S11 transformers, the no-load loss is reduced by 64%, and compared to S9 transformers, the no-load loss is reduced by 72%.
During the forming process, amorphous alloy undergoes rapid cooling and develops stress when the core is wound. The amorphous alloy core material is highly sensitive to mechanical stress, as both tensile and bending stresses can affect its magnetic properties. To achieve favorable loss characteristics, the amorphous alloy core must undergo annealing under specific magnetic field conditions after forming. However, the annealing process is complex and requires high precision. Since the core loss of amorphous alloy increases with pressure, careful consideration must be given to the structural design of the transformer body during annealing, along with appropriate and effective measures. After annealing, amorphous alloy core material becomes extremely brittle and prone to producing debris, necessitating specific process measures during production. The thickness of amorphous alloy core laminations is extremely thin, only 0.025mm, less than one-tenth of the thickness of commonly used silicon steel sheets. The stacking factor of amorphous alloy cores is relatively low, at only 0.86. The saturation magnetic flux density of amorphous alloy is also low (approximately 1.5T), so the rated magnetic flux density of amorphous alloy cores (1.3–1.4T) is lower than that of cold-rolled silicon steel sheets (1.6–1.7T). As a result, product design is constrained by the material properties.
Performance of Amorphous Alloy Transformers
The iron-based amorphous alloy material used in amorphous alloy cores lacks a crystalline structure, resulting in low magnetizing power and high resistivity, which significantly reduces eddy current losses. Consequently, the no-load loss and no-load current of transformers using amorphous alloy cores are exceptionally low. The no-load loss of amorphous alloy core transformers is only about 35% of that of S11-type distribution transformers, making them particularly suitable for areas with fluctuating electricity loads, such as rural regions, towns, schools, and street lighting. However, some believe that the no-load loss of amorphous alloy core transformers may increase over time. This concern is unnecessary because the Curie temperature of amorphous alloy is approximately 415°C, and its crystallization temperature is 550°C. These temperatures are sufficiently high for processes such as amorphous strip processing, post-forming core annealing, normal operating temperatures, and short-circuit thermal stability, so concerns about crystallization are unfounded in practice.
Economic Performance and Social Benefits
Due to the very low no-load loss of amorphous alloy core transformers, they offer significant energy-saving effects and can effectively reduce transformer-related losses in power grid line losses. Under current market conditions, a comparative economic analysis of SH15-type three-phase oil-immersed amorphous alloy core distribution transformers and S9-type three-phase oil-immersed distribution transformers shows that the investment payback period for amorphous alloy core distribution transformers is just over three years, after which users can enjoy long-term benefits. China’s annual demand for transformers is approximately 100 million kVA. If amorphous alloy core transformers were adopted entirely, annual electricity savings could exceed 20 billion kWh, resulting in nearly 10 billion yuan in reduced energy consumption costs. Additionally, this would bring significant environmental benefits by reducing emissions of CO₂ and SO₂ into the atmosphere and minimizing non-recyclable waste. From a long-term perspective, promoting amorphous alloy core transformers can save substantial energy for the country while achieving notable environmental benefits, making them worthy of widespread adoption.