Design of Novel Structure Current Transformer with Shielding Coils for Overcoming the Saturation of Core

摘要

The core saturation of current transformers is one of the key obstructions in the development of high-reliable protective approaches and devices of power systems. A novel structure current transformer with shielding coils is presented and analyzed in this paper. The coils are enwound outside the secondary winding, and a couple of coils are connected in opposed-polarity. With the coils the magnetic flux linkage linking both the primary and the secondary windings of the transformer is not changed, but the magnetic field in the core produced by sideward-phase current can be decreased greatly, so that the core saturation can be avoided.