Brief History of Transformers and the Emerging Trends
K.R.M. Nair · 2021
The theory of electromagnetic induction was discovered in the 1830s. The first transformer was made in the Ganz factory in Hungary in 1878. GE (USA) made the first oil-filled transformer in 1892. The progress in the past century was very fast. High-grade wrought iron was used in the early stages for core. By 1906, hot-rolled silicon steel of 7 w/kg at 1.5 T was introduced. The anisotropic property of silicon steel was established in 1920, and the “Goss” structure was invented in 1934. The w/kg at 1.5 T came down to 1.5 in 1939. Hi-B grade with 1.2 w/kg at 1.7 T was produced in 1968, and in 1980, the domain-refined CRGO was introduced. Iron-based amorphous metal for transformer application was developed by 1978, and the transformer with 60%–70% reduced no-load losses came into the market. Copper and aluminium are the most commonly used conducting materials. In order to reduce the load losses (resistance losses), high-performance materials are being developed. Superconducting material and carbon nanotubes give advantages of reduced losses. In place of the conventional core design of three-phase transformer using coplanar core, the symmetrical core construction (3D core) offers magnetic symmetry and reduced core loss. The conventional transformer is a static link in the power system and is not capable of meeting the emerging requirements of the “smart grid”. The solid-state transformer (SST) is designed with power electronics for converting and inverting the power and stepping down the voltage at medium frequency. The output is then converted and inverted to the desired low-voltage level at commercial frequency. Artificial intelligence (AI) is finding increasing usage in design optimization, and stochastic methods, artificial neural networks, genetic algorithm, etc., are increasingly used. Additive manufacturing (3D printing) method is finding application in transformer production.