Power system MCQ #10

Power system MCQ 145 to 148:

145) A 3-phase 4-wire system is commonly used for

      (a) primary transmission

      (b) secondary distribution

      (c) primary distribution

      (d) secondary transmission

146) The rated voltage of a 3-phase system is given as

      (a) RMS line to line voltage

      (b) peak phase voltage

      (c) RMS phase voltage

      (d) peak line to line voltage

147) 66kV is suitable for transmission of power over _____ km

      (a) 30

      (b) 60

      (c) 120

      (d) 200

148) The volume of copper is required for an AC transmission line is inversely proportional to

      (a) E^2

      (b) E

      (c) 1/(E^2)

      (d) 1/E

ANSWER: | 145-b | 146-a | 147-b | 148-c |

149) RCC poles usually have the span of

      (a) 250-400 m

      (b) 80-150 m

      (c) 50-80 m

      (d) 25-50 m    

150) The material used for to manufacturing of ground wire is

      (a) aluminum

      (b) cast iron

      (c) galvanized steel

      (d) stainless steel

151) The effect of wind pressure is more predominant on

      (a) transmission lines

      (b) insulators

      (c) supporting towers

      (d) none of the above

152) Strain type insulators are used

      (a) at dead ends

      (b) on straight run

      (c) at intermediate anchor tower

      (d) at dead end or intermediate anchor tower

ANSWER: | 149-b | 150-c | 151-c | 152-d |

153) Which type of insulators are used on 132 kV transmission line?

      (a) shackle type

      (b) disc type

      (c) pin type

      (d) pin and shackle type

154) What do you mean by 100% string efficiency

      (a) zero potential across each disc

      (b) one of the insulator discs is shorted

      (c) equal potential across each disc

      (d) none of the above

155) The effect of corona is

      (a) increased inductance

      (b) increased reactance

      (c) increased energy loss

      (d) all of the above

156) Skin effect exist in

      (a) cable carrying dc current

      (b) DC transmission line only

      (c) AC transmission line only

      (d) both DC and AC transmission line

ANSWER: | 153-b | 154-c | 155-c | 156-c |