POWER SYSTEM MCQ_61(VOLTAGE CONTROL_05)


Q.61 The excitation control method of voltage control is used ___
    A. only for short transmission line
    B. only for long transmission line
    C. only for medium transmission line
    D. any of the above
Ans.: A

Q.62 Tapped changing transformer method of voltage control is used in
    A. short transmission line
    B. long transmission line
    C. medium transmission line
    D. none of the above
Ans.: B

Q.63 Tapped changing in transformer means___
    A. changing the voltage ratio
    B. changing the ratio of transformation
    C. changing current ratio
    D. all of the above
Ans.: B

Q.64 In tapped changing method of voltage control the number of turns on primary side is decrease then ___
    A. emf per turn is increases
    B. increases in secondary output voltage
    C. decrease emf per turns and secondary output voltage
    D. Both a and B
Ans.: D

Q.65 Tap changing is always on____
    A. high voltage winding side
    B. low voltage winding side
    C. at intermediate between low and high voltage
    D. on high voltage transmission line
Ans.: A

Q.66 If the tapping at which the turns included are more than that of principal tapping is called___
    A. negative tapping
    B. positive tapping
    C. zero taping
    D. depend on voltage of load side
Ans.: B

Q.67 The tapping is placed ______
    A. on the primary side
    B. on the secondary side
    C. either primary or secondary
    D. neither primary nor secondary
Ans.: C

Q.68 In transformer installed at end of a transmission line, the tapping is provided on the
    A. secondary side
    B. primary side
    C. at the center of the core
    D. none of the above
Ans.: B

Q.69 the transformer installed at generating station, the tapping is provided on the
    A. secondary side
    B. primary side
    C. at the center of the core
    D. any of the above
Ans.: A

Q.70 Why tapping are usually provided on the HV voltage winding?
    A. It is difficult to tap on LV winding, since it is placed next to the core
    B. HV winding is placed outside the LV winding so it is easily accessible
    C. large number of the turns on the HV, so fine and smoother control of output voltage is obtained
    D. all of the above
Ans.: D

Q.71 Tap changing in transformer may be done
    A. Only on load tap changing
    B. only Off load tap changing
    C. Either On load or Off load
    D. neither of above
Ans.: C

Q.72 Why mechanical lock is provided in tap changing transformer?
    A. for preventing inadvertent operation
    B. to prevent unauthorized operation of the off load changer
    C. to prevent unnecessary operation of protecting device used for transformer protection
    D. all of the above
Ans.: D

Q.73 Which of the following one is cheapest method of changing the turn ratio of a transformer?
    A. Off load tap changing
    B. On load tap changing
    C. manual changing the number of turns
    D. none the above
Ans.: A

Q.74 Which of the following voltage control method is employed while the transformer is delivering load?
    A. Off load tap changing method
    B. On load tap changing method
    C. Excitation control method
    D. static device voltage control method
Ans.: B

Q.75 A tapping at which the number of turns included is less than at the principal tapping is known as__
    A. negative tapping
    B. zero tapping
    C. positive taping
    D. none of the above
Ans.: A

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