1. Expecting the complete internal architecture of current transformer rated at EHV level.
2. Site tests & Lab tests conducted on current transformer
Too many types to generalize.
https://library.e.abb.com/public/e2462bd7f816437ac1256f9a007629cf/ITTechInfoAppGuide.pdf
Dear Sir,
You can find qualified informations about these topics in the book Stanley E. Zocholl - Analyzing and Applying Current Transformers – publisher: Schweitzer Engineering Laboratories, Inc., 2004 (and many other sources). Some producers gives also informations in theirs leaflets about magneto-optic current transformers (MOCTs) based on Faraday effect.
Regarding the tests, the dedicated international standards are: “IEC 61869-1 Instrument transformers – Part 1: General requirements” and “IEC 61869-2 Instrument transformers – Part 2: Additional requirements for current transformers”.
complete internal architecture depends on the type of CT for Eg: Protection, metering, Transient Performing etc or Optical types. Generally Site tests on a inductive type CT will be Secondary winding resistance test, Polarity tests, Ratio Test, VI Characteristics, Burden Measurement, IR Tests and Primary injection tests. For CT Testing you can employ Omicron CT analyser which is easier to use or use conventional methods which may be little time consuming.