Power System(Transmission & Distribution)-05:

102)   A single phase AC distributor supplies two single phase loads as shown. What is the voltage drop from A to C?

a. 4.5 V
b. 30 V
c. 31.5 V
d. 20 V

103)   An industrial consumer has a load pattern of 2000 kW, 0.8 lag for 12 hours and 1000 kW UPF for 12 hours. What is its load factor?

a. 10.5
b. 0.75
c. 0.6
d. 2.0

104)   Where are the strain type of insulators used?

a. Low voltage overhead lines
b. Dead ends
c. Change in direction of the transmission lines
d. Both (b) and (c)

105)   Strain and Shackle type insulators are provided on which type of plane?

a. Vertical plane
b. Horizontal plane
c. On the surface
d. All of these

106)   Which insulator is also called as spool type of insulators?

a. Pin type
b. Shackle type
c. Suspension type
d. Stay insulators

107)   Assembly of which type of insulators are used as strain type of insulators?

a. Pin type
b. Shackle type
c. Suspension type
d. None of these

108)   Which type of insulators is mainly used for low voltage overhead lines?

a. Pin type
b. Shackle type
c. Suspension type
d. None of these

109)   The stay type of insulators is insulated at a height of not less than _________ m.

a. 5
b. 6
c. 3
d. 4

110)   Post type insulators are generally used in lines operating

a. Above 100 kV
b. Below 33 kV
c. At any voltage level
d. None of these

111)   Which type of insulators is used in guy wires?

a. Stay insulators
b. Shackle insulators
c. Pin type
d. Strain type

112)   Assertion (A): Glazing on ceramic insulators is done to make it smooth and non – absorbent.
Reason (R): Moisture from atmosphere collects on the surface causing electrical breakdown.

a. Both A and R are true and R is the correct explanation of A
b. Both A and R are true and R is not the explanation of A
c. A is true but R is false
d. A is false but R is true

113)   The types of suspension insulators are

a. Hewlett type
b. Inter linking type
c. Cemented cap type
d. All of these

114)   Each disc in a suspension type of insulators is designed for what voltage?

a. 33 kV
b. 22 kV
c. 11 kV
d. 66 kV

115)   Where is the suspension type of insulators mainly used?

a. RCC poles
b. Wooden poles
c. Steel poles
d. Steel towers

116)   The voltage across the various discs of a string of suspension insulators having identical discs is different due to

a. Surface leakage currents
b. Series capacitance
c. Shunt capacitance to ground
d. Series and shunt capacitance

117)   On what factor does the string efficiency of a string of suspension insulators is dependent?

a. Size of the insulator
b. Number of discs in the string
c. Size of tower
d. None of these

118)   The maximum voltage of the disc type insulators is at

a. Same at all points
b. Near the tower or starting of the insulator
c. Near to the conductors
d. None of these

119)   The string efficiency of a high voltage line is around ______.

a. 100 %
b. 80 %
c. 40 %
d. 10 %

120)   What is the voltage across the second unit from the top in case of a suspension type insulator?

a. V₂ = V₁ (3 + 4K)
b. V₂ = V₁ (1 + K)
c. V₂ = V₁ (1 + K²)
d. None of these

 

121)   Voltage across the string is ___________ times the line voltage.

a. √3
b. √2
c. 1 / √3
d. 1 / √2

122)   In a test by Murray loop for ground fault on 500 m of cable having a resistance of 1.6 Ω / km, the faulty cable is looped with the sound cable of some length and area of cross section. If the ratio of the other two arms of the testing network at balance is 3:1, what is the distance of fault from the testing end of cables?

a. 100 m
b. 200 m
c. 250 m
d. 300 m

123)   A 3 phase over head transmission line is supported by three discs of suspension insulators. The potentials across the first and second insulator are 8 and 11 kV respectively. What is the line voltage and string efficiency?

a. 0.654 and 63.5%
b. 0.375 and 68.3 %
c. 0.527 and 56.34 %
d. 0.287 and 65.258 %

124)   What is the purpose of guard ring?

a. Reduce the earth capacitance of the lowest unit.  
b. Increase the earth capacitance of the lowest unit.
c. Reduce the transmission line losses.
d. None of these.

125)   Assertion (A): The string efficiency can be improved by using long cross arms.
Reason (R): Use of long cross arms reduces the ratio of capacity to earth to capacity per insulator thereby increasing the string efficiency.

a. Both A and R are true and R is the correct explanation of A
b. Both A and R are true and R is not the explanation of A
c. A is true but R is false
d. A is false but R is true

126)   Which shielding is called the static shielding of the string?

a. Using the guard rings
b. Grading the insulators
c. Increasing the length of cross arms
d. None of these

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