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

Discussion

The short-circuit current of a transformer with 5 per cent impedance is about

  • A.one twentieth of its rated current
  • B.equal to its rated current
  • C.twenty times its rated current
  • D.five times its rated current

Answer: C

The reciprocal of the per unit impedance gives the multiple, so a low impedance means a stiff supply and a large fault current. Switchgear has to be rated for that current, which is one reason impedance is not made smaller than it needs to be.

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

Post your comment

Please log in or register to post a comment.