The development of the power industry has promoted the production and application of transformers. The level and accuracy of transformers have also been greatly improved. There are more and more types of transformers, such as voltage and current composite transformers and DC current transformers. More and more. However, in the power industry, the transformers used must be consistent with the use of the power system, and transformers of the corresponding voltage levels and accuracy must be developed to meet the needs of the power system measurement, protection and control.
With the development of technology and the application of new materials, the types of transformers are more and more, and the performance is getting better and better. Among them, the core current transformers are adapted to electric power in various structures such as dry, oil immersed and gas insulated. The development needs of the construction. However, with the continuous increase of power transmission capacity, the continuous improvement of the voltage level of the power grid and the continuous improvement of the protection requirements, the general core-type current transformer structure has gradually exposed the weak points that are incompatible with it, and its inherent large volume and magnetic Many shortcomings such as saturation, ferromagnetic resonance, and small dynamic range cannot meet the needs of the new generation of power system automation and power digital network, so it is necessary to continuously promote the development of the industry.