Comparison of different current transformer modeling techniques for protection system studies

If current transformer (CT) characteristics are not properly selected for fault conditions, saturation will occur and relays can have delayed response or even fail to trip. To verify that CT saturation will not cause mis-coordination with other protection devices a study needs to be performed, which requires CT modeling. This paper compares different CT computer modeling techniques. Models of a 1200/5 A CT were developed using electromagnetic transient type programs. Simulation results were compared against laboratory tests.