Top 80+ Solved Power Quality and Management MCQ Questions Answer
Q. 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
Q. Earth wire on EHV overhead transmission line is provided to protect the lineagainst
a. lightning surge
b. switching surge
c. excessive fault voltages
d. corona effect
Q. 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
Q. 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
Q. 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
Q. 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
Q. 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
Q. 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
Q. 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
Q. Harmonics in transformer result in
a. increased core losses
b. increased 12R losses
c. magnetic interference with communication circuits
d. all of the above
Q. 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
Q. Most of the power quality problems are related to ______
a. Transmission Issue
b. Grounding Issue
c. Distribution Issue
d. all of the above
Q. Which of the following is not considered as good power quality voltage
a. Power Supply is more compared to demand
b. Constant sine wave
c. Constant Velocity
d. Constant RMS Value unchanged with time
Q. Lightening and Tree striking on a live conductor is an example________ PowerQuality issue.
a. Voltage Sag
b. Voltage Swell
c. Interruption
d. Surge
Q. Interruption is
a. complete loss of power
b. complete loss of voltage
c. complete loss of current
d. all the above