Machine-translated by Google. Questions are authored in English.
Top

Discussion

A metering core and a protection core are often provided on the same current transformer because

  • A.their requirements at fault current are opposite
  • B.one core alone could not carry the ampere-turns needed by both circuits
  • C.the two circuits must be electrically isolated from one another
  • D.the protection relay operates at a different frequency from the meter

Answer: A

Metering wants early saturation to protect the instruments and high accuracy at normal current; protection wants no saturation until far above rated current and accepts a looser ratio. No single core can do both, so two cores share one primary conductor.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.