Transformers are devices that alter alternating voltage using the principle of electromagnetic induction, primarily consisting of primary and secondary coils, and an iron core (magnetic core). Their main functions include voltage transformation, current transformation, impedance transformation, isolation, and voltage stabilization (magnetic saturation transformers).

Transformers can be categorized by their applications into: distribution transformers, power transformers, fully sealed transformers, modular transformers, dry-type transformers, oil-immersed transformers, single-phase transformers, electric furnace transformers, rectifier transformers, reactors, anti-interference transformers, lightning protection transformers, cabinet transformers, test transformers, corner transformers, high-current transformers, excitation transformers, etc.

Transformers are fundamental equipment for power transmission and distribution, widely used in industries, agriculture, transportation, and urban communities. There are approximately 17 million transformers in operation in our country, with a total capacity of around 11 billion kilovolt-amperes. Transformer losses account for about 40% of the power losses in transmission and distribution, offering significant potential for energy savings.