The book outlines general methods for calculating current transformers; their main structures are described and analyzed - both domestic and foreign. Structural elements of current transformers are considered and specific methods of their calculation are given. Some information is given about magnetic materials used for the manufacture of current transformers. The book is designed for engineering and technical personnel involved in the design and production of high-voltage equipment, as well as for employees of power systems; in addition, it can be useful for students of technical schools and technical schools specializing in the field of high-voltage equipment and high-voltage technology.