A large power plant generates electricity at 12.0 kV. Its old transformer once c

Question

A large power plant generates electricity at 12.0 kV. Its old transformer once converted the voltage to 425 kV. The secondary of this transformer is being replaced so that its output can be 525 kV for more efficient cross-country transmission on upgraded transmission lines.

(a) What is the ratio of turns in the new secondary to turns in the old secondary?

(b) What is the ratio of new current output to old output (at 425 kV) for the same power?

(c) If the upgraded transmission lines have the same resistance, what is the ratio of new line power loss to old?

Explanation / Answer

(a) The ratio of turns in the new secondary to turns in the old secondary which is given as :

Nn,s / No,s = Vn,s / Vo,s

Nn,s / No,s = (525 kV) / (425 kV)

Nn,s / No,s = 1.23

(b) The ratio of new current output to old output (at 425 kV) for the same power which is given as :

Inew / Iold = Vold / Vnew

Inew / Iold = (425 kV) / (525 kV)

Inew / Iold = 0.809

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.