The transient saturation of current transformer and its application calculation

The transient saturation of protective CT and its application are discussed in this paper. The transient saturation of CT has great influence on the performance of the protection. To ensure the relaying protections operating correctly under transient saturation, the types and parameters of CTs should be selected properly and a way to decrease the effect of CT saturation on the protection can be taken if necessary. Some calculation cases of CTs for large generator-transformer set protections are given in this paper.