Gapped core current transformer characteristics and performance

The results of an IEEE working group's study of the gapped-core current transformer (CT) are presented. The characteristics and performance of CTs having small gaps are discussed. The effects of remanent flux in CT cores on CT performance and of small gaps to control remanence for improved transient performance of the CT are also discussed. Advantages and disadvantages of gapped-core CTs are enumerated. Proposed performance requirements for gapped-core CTs are presented, and a method of specifying gapped-core CTs to produce the required performance for protective relaying application of such CTs is proposed. A short description of terms is included.<>