A transformer is a device that utilizes the principle of electromagnetic induction to alter alternating current (AC) voltage; its primary components are the primary coil, the secondary coil, and the iron core (magnetic core). Its main functions include voltage transformation, current transformation, impedance transformation, electrical isolation, and voltage regulation (in the case of magnetic saturation transformers), among others.
Based on their intended application, transformers can be categorized into: distribution transformers, power transformers, fully sealed transformers, combined transformers, dry-type transformers, oil-immersed transformers, single-phase transformers, electric furnace transformers, rectifier transformers, reactors, anti-interference transformers, lightning-protection transformers, box-type substations, test transformers, angle transformers, high-current transformers, excitation transformers, and more.
Transformers serve as fundamental equipment in power transmission and distribution systems and are widely utilized across various sectors, including industry, agriculture, transportation, and urban communities. Currently, there are approximately 17 million transformers in operation across China's power grid, with a combined capacity of approximately 11 billion kilovolt-amperes (kVA). Transformer losses account for roughly 40% of total power losses within transmission and distribution networks, thereby presenting significant potential for energy conservation. To accelerate the promotion and adoption of high-efficiency, energy-saving transformers-and to enhance the efficiency of energy resource utilization while fostering green, low-carbon, and high-quality development-the Ministry of Industry and Information Technology, the State Administration for Market Regulation, and the National Energy Administration jointly formulated the *Transformer Energy Efficiency Improvement Plan (2021–2023)* in January 2021. By 2025, the total export value of China's transformers is projected to reach 64.6 billion RMB, representing an increase of nearly 36% compared to 2024. Furthermore, by 2025, the total output value of China's transformer industry is expected to exceed 300 billion RMB, with its production volume accounting for over 50% of the global total.
