1. ANSI/IEEE Standard C57.13.Requirements for Instrument Transformers 1993(R 2008).
2. ANSI/IEEE Standard C57.13.2.Conformance Test Procedures for Instrument Transformers 2005.
3. IEC 60044‐1.Instrument Transformers Part 1 (Current Transformers) 1997.
4. Relay performance considerations with low-ratio CTs and high-fault currents