PQM ( Power Quality and Management ) GTU MCQ ( Electrical Engineering SEM 8 MCQ)

PQM ( Power Quality and Management ) GTU MCQ ( Electrical Engineering SEM 8 MCQ)

Power Quality and Management GTU SEM 8 MCQ: Electrical Engineering

Here we mentioned most preferable MCQs which is more helpful in your GTU exam as well as other competitive Exams.

Power Quality and Management GTU MCQ SEM 8 Electrical Engineering

1. Non-sinusoidal waveforms are made of

A. different sinusoidal waveforms

B. fundamental and even harmonics

C. fundamental and odd harmonics

D. even and odd harmonics only

2. The positive and negative halves of a complex wave are symmetrical when

A. it contains even harmonics

B. phase difference between even harmonics and fundamentals is 0 or it

C. it contains odd harmonics

D. phase difference between even harmonics and fundamental is either n/2 or 3n/2

3. The rms value of the complex voltage given by v = 161i sin cot + 12 Ari sin Rot is

A. 20 Ari

B.20

C.28

D.192

4. In a 3-phase system,the harmonic has negative phase sequence of RBY.

A.9

B.13

C.5

D.15

5. Two complex waves will have the same wave-shape if

A. they contain the same harmonics

B. ratio of corresponding harmonics to their respective fundamentals is the same

C. harmonics are similarly spaced with respect to their fundamental

D. they have all of the above

6. The trigonometric Fourier series for a complex wave will contain positive cosine terms only when

A. it contains even harmonics

B. its two half-cycles are symmetrical

C. its value is zero at 0= n/2, 3n/2 etc.

D. its value is zero at 0= n, 2n etc.

7. Tansient disturbance is produced in a circuit whenever

A. it is suddenly connected or discon nected from the supply

B. it is shorted

C. its applied voltage is changed suddenly

D. all of the above

8. There are no transients in pure resistive circuits because they

A. offer high resistance

B. obey Ohm's law

C. have no stored energy

D. are linear circuits

9. Transient current in electrical circuits are associated with

A. inductors

B. capacitors

C. resistors

D. both (a) and (b)

10. The transients which are produced due to sudden but energetic changes from one

steady state of a circuit to another are called transients.

A. initiation

B. transition

C. relaxation

D. subsidence

11. In an R-L circuit connected to an alternating sinusoidal voltage, size of transient current primarily depends on

A. the instant in the voltage cycle at which circuit is closed

B. the peak value of the steady-state current

C. the circuit impedance

D. the voltage frequency

12. Double-energy transients are produced in circuits consisting of

A. two or more resistors

B. resistance and inductance

C. resistance and capacitance

D. resistance, inductance and capacitance

13. The transient current in a loss-free L-C circuit when excited from an ac source is a/an sine wave.

A. over-damped

B. undamped

C. under-damped

D. critically damped

14. Transient current in an R-L-C circuit is oscillatory when

A. R =0

B. R> 2f-17

C. R <2

D. R =2

15. For measuring positive, negative and zero sequence voltages in a system, the 

reference is taken as :

A. Neutral of the system only

B. Ground only

C. For zero sequence neutral and for positive and negative the ground

D. None of the above

16. The most economic load on an underground cable is :

A. Greater than its surge loading

B. Less thart the surge loading

C. Equal to the surge loading

D. None of the above is necessary

17. In case of a 3-phase short circuit is a system, the power fed into the system is :

A. Mostly reactive

B. Mostly active

C. Active and reactive both equal

D. Reactive only

18. If cc is the angle of voltage wave at which an R-L circuit is switched in and 0 is the impedance angle of the R-L circuit, there will be no transient when the circuit is switched in, if:

A. a = 0

B. = 90 �

C. a = 90 + 0

D. None of the above

19. An RLC series circuit remains predominantly inductive :

A. At resonance frequency

B. Below resonance frequency

C. Above resonance frequency

D. At the lower half power frequency

20. A generator is connected to a synchronous motor. From stability point of view it is preferable to have :

A. Generator neutral reactance grounded and motor neutral resistance grounded

B. Generator and motor neutrals resistance grounded

C. Generator and motor neutrals reactance grounded

D. Generator neutral resistance and motor neutral reactace grounded

21. The positive sequency component of voltage at the point of fault is zero when it is a :

A. 3-phase fault

B. L-L fault

C. L-L-G fault

D. L-G fault

22. Tick out the correct statement :

A. The negative and zero sequence voltages are maximum at the fault point and decreases

towards the neutral

B. The negative and zero sequence voltages are minimum at the fault point and increase

towards the neutral

C. The negative sequence is maximum and zero sequence minimum at the fault point and

decrease and increase respectively towards the neutral.

D. None of the above

23. The order of the lightning discharge current is 

A. 10,000 amp

B. 100 amp

C. 1 amp

D. 1 microampere

24. The magnetising-inrush-current in a transformer is rich in :

A. 3rd harmonics

B. 5th harmonics

C. 7th harmonics

D. 2nd harmonics

25. The in-rush current of a transformer at no load is maximum if the supply voltage is switched on 

A. At zero voltage value

B. At peak voltage value

C. At V/2 value

D. At ,6 /2V value

26. Pure inductive circuit takes power (reactive) from the a.c. line when

A. both applied voltage and current rise

B. both applied voltage and current decrease

C. applied voltage decreases but current increases

D. (a) and (b)

27. With 100% series compensation of lines

A. the circuit is series resonant at power frequency

B. low transient voltage

C. high transient current

D. (a) and (b)

28. In a pure LC parallel circuit under resonance condition, current drawn from the supply mains is

 

A. very large

B. V ,FTE

C. V /11-j

D.Zero

29. A lightning arrestor connected between the line and earth in a power system

A. protects the terminal equipment against travelling surges

B. protects the transmission line against lightning stroke

C. suppresses high frequency oscillations in the line

D. reflects back the travelling wave approaching it

30. Lightning arresters are used in power systems to protect electrical equipments against

 

A. direct strokes of lightning

B. power frequency overvoltages

C. overvoltages due to indirect lightning stroke

D. overcurrents due to lightning stroke

31. Consider the following statements : The transient stability of the power system under unbalanced fault conditions can be effectively improved by 1. Excitation control  2. phase-shifting transformer 3. single-pole switching of circuit breakers 4. increasing the turbine input. Of these statements 

A. 1 and 2 are correct

B. 2 and 3 are correct

C. 3 and 4 are correct

D. 1 and 3 are correct

32. One current transformer (CT) is mounted over a 3-phase 3-core cable with its sheath and armour removed from the portion covered by the CT. An ammeter placed in the CT secondary would measure 

A. the positive sequence current

B. the negative sequence current

C. the zero sequence current

D. three times the zero sequence

33. Earth wire on EHV overhead transmission line is provided to protect the line against 

A. lightning surge

B. switching surge

C. excessive fault voltages

D. corona effect

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

A. 9 x 108 m/s

B. 3 x 108 m/s

C. 108 m/s

D. 2 x 108 ms

35. A wave-trap is used at the termination of a HVAC overhead line to a station switchyard to 

A. prevent the transformer magnetising harritonics from reaching the overhead line

B. damp the incoming surge waves from the overhead lines

C. attenuate sub-harmonic oscillations

D. provide for carrier communication

36. Shunt compensation in an EHV line is used to improve

A. stability and fault level

B. fault level and voltage profile

C. voltage profile and stability

D. stability, fault level and voltage profile

37. The principal information obtained from load flow studies in a power system are 1. magnitude and phase angle of the voltage at each bus. 2. reactive and real power flows in each of lines. 3. total power loss in the network. 4. Transient stability limit of the system Select the correct answer from the codes given below : 

A. I and 2

B. 3 and 4

C. 1,2 and 3

D. 2 and 4

38. While rising and while falling, if a wave is symmetrical, it contains

A. even harmonics in addition to fundamental

B. odd harmonics in addition to fundamental

C.(b) both odd and even harmonics in addition to fundamental

D. none of the above

39. While rising and falling if a wave is not symmetrical, it contains

A. even harmonics in addition to fundamental

B. odd harmonics in addition to fundamental

C. both odd and even harmonics in additions to fundamental

D. none of the above

40. The main reason for generation of harmonics in a transformer could be

A. fluctuating load

B. poor insulation

C. mechanical vibrations

D. saturation of core

41. Harmonics in transformer result in

A. increased core losses

B. increased 12R losses

C. magnetic interference with communication circuits

D. all of the above

42. Which fractional pitch will eliminate the seventh harmonic from the voltage waveform of an alternator? 

A. 6/7

B. 7/8

C. 5/6

D. None of the above

Answer of the all above MCQs is mentioned in below table: