Answer:
Explanation:
a ) The transformer steps up the voltage from 12000 V to 335000 V . Voltage in primary is 12000 V and in the secondary it is 335000 V in old transformer
If n₁ be no of turns in primary coil and n₂ be no of turns in secondary coils
the formula is
n₂ / n₁ = voltage in secondry / voltage in primary
n₂ / n₁ = 335000 / 12000
ratio of turns in old transformer
= 27.9
ratio of turns in new transformer
n₃ / n₁ = 750 / 12 ( n₃ is no of turns in the secondary of new transformer )
= 62.5
T he ratio of turns in the new secondary compared with the old secondary
n₃ / n₂ = 62.5 / 27.9
= 2.24
b ) Current in secondary / current in primary
= turns in primary / turns in secondary
current output ratio of old
= Current in secondary / current in primary
= n₁ / n₂
= 12 / 335
= .03582
current output ratio of new
= Current in secondary / current in primary
= n₁ / n₃
= 12 / 750
= .016
The ratio of new current output to old output (at 335 kV) for the same power
= .016 / .03582
= .4466
c ) power loss in new
= (current in secondary )² x resistance of secondary
=( .016 x current in primary )² x R
= 2.56 X 10⁻⁴ X ( current in primary )² x R
power loss in old
= (current in secondary )² x resistance of secondary
=( .03582 x current in primary )² x R
= 12.83 X 10⁻⁴ X ( current in primary )² x R
ratio of new line power loss to old
= 2.56 / 12.83
= .199
