A system consists of an alternator having reactance of 0.5pu connected to an infinite bus through a series of reactance of 1 pu. The generator terminal voltage of IBB is 1 pu and that of 1.2 pu. The Steady state occurs at power angle of ________degree.

A system consists of an alternator having reactance of 0.5pu connected to an infinite bus through a series of reactance of 1 pu. The generator terminal voltage of IBB is 1 pu and that of 1.2 pu. The emf induced in the alternator will have the phase difference with respect to reference for the maximum power transfer is _______________

A

90

B

0

C

73.87

D

86.25

Each of the question below consists of a question and three statements number I, II and III given below it. You have to decide whether the data provided in the statement are sufficient to answer the question. If the bus is travelling from Surat to Ahmadabad and a car is travelling from Ahmadabad to Surat, then what is the distance between Surat and Ahmadabad? I. The speed of a car is 40% less than the speed of bus. Bus started at 9 am and car started at 10 am and they meet at 3 pm of the same day. II. After travelling for 1 hour, because of traffic average speed of bus is decreased by 20% and covers distance between Surat to Ahmadabad in 11 hours. Original speed of car is 20% less than original speed of bus and before crossing bus it covered 200 km if starts 1 hour later than bus. After crossing car, bus covers remaining distance in 5 hours. III. Speed of bus is 10 km/hr more than the speed of car and before crossing car ratio of distances covered bus and car in same time was 5 : 4. Time taken by car to cover the distance between Ahmadabad and Surat is 2 hours 15 minutes more than time taken by bus to cover the same distance.

A

The data in statement II alone is sufficient to answer the question, while the data in neither statement I nor III alone are sufficient to answer the question.

B

The data in either statement II or in Statement III alone is sufficient to answer the question, while the data in statement I alone is not sufficient to answer the question.

C

The data is only statement III alone or in Statement I and II together are sufficient to answer the question.

D

The data in all Statement I, II and III together are not sufficient to answer the question.

E

If the data in all the Statement I, II and III together are necessary to answer the question.

Transient stability of the generator is dependent on (a) generator reactance; lower reactance decreases peak power and increases initial rotor angle. (b) how heavily the generator is loaded. (c) generator inertia; higher the inertia, slower the rate of the change of angle. (d) generator output during fault Which of the above is incorrect?

A

a

B

b

C

c

D

None of the above

An alternator, with synchronous reactance of 0.8 pv is connected to an IBB at rated voltage. With its excitation emf adjusted to 1.3 pv, the alternator delivers an output of 0.5 pv. The load angle is __________

A

17.92

B

72.08

C

34.92

D

90

Shweta has connected a cell with a bulb. The bulb didn't glow. What could be the reasons? A. Bulb was connected by the positive terminal from both ends. B. One end of the bulb was connected with a positive terminal and another end was connected with a negative terminal. C. Bulb was connected by the negative terminal from both ends D. Bulb was fuse.

A

B, C

B

A,B and D

C

A,C

D

A, C, D

Before an alternator can be connected to an infinite bus, which of the following must be the same for the alternator and the infinite bus?

A

Only frequency

B

Voltage, frequency and phase sequence; and the phase difference between the alternator and infinite voltages must be zero

C

Only voltage

D

Only phase sequence

A 50 Hz synchronous generator is initially connected to a long lossless transmission line which is open circuited at the receiving end. With the field voltage held constant, the generator is disconnected from the transmission line. Which of the following may be said about the steady state terminal voltage and field current of the generator?

A

The magnitude of terminal voltage decreases, and the field current does not change.

B

The magnitude of terminal voltage increases, and the field current does not change.

C

The magnitude of terminal voltage increases, and the field current increases.

D

The magnitude of terminal voltage does not change and the field current decreases.

A three-phase cylindrical rotor synchronous generator has a synchronous reactance Xs and a negligible armature resistance. The magnitude of per phase terminal voltage is VA and the magnitude of per phase induced emf is EA. Considering the following two statements, P and Q, P: For any three-phase balanced leading load connected across the terminals of this synchronous generator, VA is always more than EA Q: For any three-phase balanced lagging load connected across the terminals of this synchronous generator, VA is always less than EA Which of the following options is correct?

A

P is false and Q is true

B

P is true and Q is false

C

P is false and Q is false

D

P is true and Q is true

(I) For constant power of an isolated alternator, V-curves can be obtained. (II) For constant power of an alternator connected to IBB, V-curves can be obtained

A

I is true, II is false

B

Both the statements are true

C

I is false while II is true

D

Both are false

(I)For constant power of an isolated alternator, V-curves can be obtained. (II)For constant power of an alternator connected to IBB, V-curves can be obtained.

A

I is true, II is false

B

Both the statements are true

C

I is false while II is true

D

Both are false

A system consists of an alternator having reactance of 0.5pu connected to an infinite bus through a series of reactance of 1 pu. The generator terminal voltage of IBB is 1 pu and that of 1.2 pu. The Steady state occurs at power angle of ________degree.

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