A power station consists of two synchronous generators A and B of rating 250 MVA and 500 MVA with inertia 1.6 p.u. and 1 p.u. respectively on their own base MVA ratings. The equivalent : P.U inertia for the system on 100 MVA common base will be

1.  2.6

2.  0.615

3.  1.625

4.   9.0

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4
Correct Answer :

9.0


Explanation :
No Explanation available for this question

An alternator having induced end of 1.6 p.u. is connected to an infinite bus of 1.0 p.u. If the bus has reactance of 0.6 p.u. and alternator has reactance of 0.2 p.u., the maximum power that can be transferred is given by

1.  8 p.u.

2.  2. p.u.

3.  2.67 p.u.

4.  5.0 P.u.

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4
Correct Answer :

2. p.u.


Explanation :
No Explanation available for this question

The per unit impedance of a circuit element 0.15. If the base kV and base MVN A are halved then the new value of the per unit impedance of the circuit element will he

1.  0.075

2.  0.15

3.  0.30

4.  0.600

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4
Correct Answer :

0.30


Explanation :
No Explanation available for this question

The velocity of travelling wave through a cable at relative permittivity 9 is

1.  9 x 108 metre/sec

2.  3 x108 metre/sec

3.  108 metre/sec

4.   2 x108 metre/sec

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4
Correct Answer :

108 metre/sec


Explanation :
No Explanation available for this question

A 66 kV system has string insulator having five discs and the earth to disc capacitance ratio at 0.10. The string efficiency will be

1.  89%

2.  75%

3.  67%

4.  55%

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4
Correct Answer :

67\%


Explanation :
No Explanation available for this question

A voltage of 1000 kV is applied to an overhead line with its receiving end open. If the surge impedance of the line is 500 ohm, then the total surge power in the line is

1.  2000 MW

2.  500 MW

3.  2 MW

4.   0.5 MW

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4
Correct Answer :

2000 MW


Explanation :
No Explanation available for this question

The main criterion for selection of the size of a distribution for a radial distribution system is

1.  voltage drop

2.  corona loss

3.  temperature rise

4.   capital cost

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4
Correct Answer :

voltage drop


Explanation :
No Explanation available for this question

If an induction machine is run at above synchronous speed, it acts as

1.  a synchronous motor

2.  an indcution generator

3.  an inductor motor

4.  none of these

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4
Correct Answer :

an indcution generator


Explanation :
No Explanation available for this question

The low voltage winding of a 400/230. V, 1-phase, 50 Hz transformer is to be connected to a 25 Hz, the supply voltage should be

1.  230 V

2.  460 V

3.  115 V

4.  65 V

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4
Correct Answer :

115 V


Explanation :
No Explanation available for this question

Three phase transformers which cannot be connected in parallel are

1.  YY with ΔΔ

2.  Y Δ with Δ Y

3.  YY with YΔ

4.  none of these

View Answer  
4
Correct Answer :

YY with YΔ


Explanation :
No Explanation available for this question
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