A. delta-delta
B. star-star
C. delta-star
D. star-delta
Answer: C. delta-star
Explanation:
A current transformer is an instrument transformer in which the secondary current is substantially proportional to primary current and differs in phase from it by ideally zero degree.
In case of a star-delta transformer, the currents on the two sides differ in phase by 30°. This is compensated by connecting current transformers in delta on the star side and in star on the delta side of the transformer.
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