1. Which of the following ACSR conductors is not made for high voltage power transmission?
A Moose
B Rabbit
C Zebra
D Snowbird
Answer: D Snowbird
2. What is the purpose of shunt reactors in high voltage substation?
A To avoid overvoltage problem
B To avoid undervoltage problem
C To avoid excessive fault current
D none of these
Answer: C To avoid excessive fault current
3. What is black start?
A Reduction in emissions of carbon dioxide or greenhouse gases made
B Use of a heat engine or a power station to simultaneously generate both electricity and useful heat.
C The amount of time that it is able to produce electricity over a certain period, divided by the amount of the time in the period.
D The process of restoring a power station to operation without relying on the extemal electric power transmission network.
Answer: D The process of restoring a power station to operation without relying on the extemal electric power transmission network.
4. For a 100 km line Surge Impedance is 350 ohm. If the length of the same line is doubled, the surge impedance will be
A equal to 350
B more than 350
C less than 3502
D may be greater or less than 350
Answer: A equal to 350 Ohm
5. The criterion for selection of size of conductor of a feeder is
A Temperature rise
B corona loss
C voltage drop
D radio interference
Answer: C voltage drop
5. Diversity factor multiplied by maximum demand is equal to
A average demand
B sum of consumers maximum demand
C installed capacity
D generated power
Answer: B sum of consumers maximum demand
6. With the help of SVC, it is possible to
A control voltage magnitue only
B maintain unity PF only
C control both voltage magnitude and unity PF
D control either voltage magnitude or unity PF
Answer: A control voltage magnitue only
7. ACSR conductors having 7 steel strands surrounded by 25 aluminium conductors will be specified as
A 7/25
B 7/32
C 25/7
D 25/32
Answer: C 25/7
8. If the insulation resistance of a cable of length 10 km is 1 Mohm, its insulation resistance for 50 km will be ...ΜΩ
A 0.2
B 1
C 5
D 50
Answer: A 0.2
Insulation resistance of a cable is inversly proportional to its length.
For 10 km cable the insulation resistance is 1M ohm.
Now for 50 km cable, the insulation resistance is:
10*103*1*106 / 50*10% = 0.2*106
= 0.2 MOhm
9. Change in real power affects more on ----- and change in reactive power affects more on .....if the power system is large and intereconnected
A voltage magnitude, frequency
B frequency, voltage magnitude
C frequency, frequency
D voltage magnitude, voltage magnitude
Answer: B frequency, voltage magnitude
10. The reason behind low voltage in power system can be
A inductive reactive power demand
B capacitive reactive power demand
C transmission line resistance
D generator resistance
Answer: A inductive reactive power demand
11. Most efficient plants are used as
A Base load plants
B Reverse plants.
C Peak load plants
D Both base and peak load plants.
Answer: A Base load plants
12. The voltage drop is the main consideration while designing a
A Radial system
B Feeder
C Service mains
D Distributor
Answer: D Distributor
13. Grounding is generally done at
A Supply end
B Receiving end
С Middle of the line
D At all places
Answer: A Supply end
14. Sheats are provided in the cables for
A Providing strength to conductors.
B Preventing moisture from entering the cable.
C Providing insulation.
D Reducing the capacitance
Answer: B Preventing moisture from entering the cable.
15. The travelling waves due to lighting are reduced considerably
A By the use of suspension insulators
B By the use of shackle insulators
C By the use of earth wires running above the transmission line and earthed at every tower
D By the use of earth wires running below the transmission line and earthed at every tower
Answer: C By the use of earth wires running above the transmission line and earthed at every tower.
16. The main reason for low power factor of the supply system is due to the use of
A Induction motor
B Resistive load
C Synchronous motor
D Capacitive load
Answer: A Induction motor
17. The efficiency of a transmission line
A Increases with the decrease in the load p.F.
B Decreases with the increase in the load p.f.
C Increase with the increases in the load p.F.
D Decreases with the decreases in the load p.F.
Answer: C Increase with the increases in the load p.F.
18. What type of insulator will be used if the direction of the transmission line is changed?
A Pin type
B Strain type
C Suspension type
D Shakle type
Answer: B Strain type
19. The sag of the transmission line is least affected by
A Ice deposited on the conductor
B Self weight of the conductor
C Temperature of surrounding air
D current through the conductor
Answer: D current through the conductor
20. In order to improve the voltage profile of the line, compensation is resorted by providing
A Capacitors at the receiving end.
B Resistors at the receiving end.
C Reactors at the receiving end.
D Transformers at the receiving end.
Answer: A Capacitors at the receiving end.
21. A string efficiency of 100% implies that
A Shunt capacitance is 1 uF.
B One of the insulator disc is shorted.
C Potantial across each disc is same.
D Potential across each disc is different.
Answer: C Potantial across each disc is same.
22. AC power is transmitted at high voltage
A To safeguard against pilferage.
B To reduce the cost of generation.
C To make the system stable.
D To make the system reliable.
Answer: B To reduce the cost of generation.
23. The type of distribution system which is least reliable is
A Radial system
B Tree system
C Interconnected system
D All of the above.
Answer: A Radial system
24. Which of the following is not a function of the state Load Dispatch Center?
A Ensure quality power at rated voltage and frequency
B Economical scheduling and dispatching of power produced by independent power projects.
C Formulating efficient tariff structures.
D Immediate restoration of power system after disturbance
Answer: C Formulating efficient tariff structures.
25. Conductors are bundled to
A Reduce the reactance.
B Increase radio interference,
C Increase the reactance.
D Reduce radio interference.
Answer: A Reduce the reactance.
26. If a fixed amount of power is to be transmitted over a given length with a certain power loss, it can be said that the volume of the conductor material required is
A Proportional to the voltage
B Proportional to the square of the voltage
C Inversely proportional to the square of the voltage and load PF
D Inversely proportional to the square of the voltage
Answer: C Inversely proportional to the square of the voltage and load PF
27. When the power is to be transmitted over a distance of 500 km, the transmission voltage should be in the range
A 33 kV - 66 kV
B 66 KV - 110 kV
C 110 kV - 150 kV
D 150 kV- 220 kV
Answer: D 150 kV- 220 kV
28. Underground cable system for 11 kV can work upto a length of
A 100 miles
B 50 miles
C 25 miles
D 400 miles
Answer: A 100 miles
29. IF ACSR conductor has a specification of 48/7, which of the following statements is correct for the conductor.
A The conductor has 48 strands
B The conductor has 55 strands
C The conductor has 48 aluminum and 7 steel strands
D The conductor has 48 steel and 7 aluminum strands
Answer: C The conductor has 48 aluminum and 7 steel strands
30. The criterion for the most economical distribution of load among various units of a plant is that
A The incremental fuel costs of all the units of the plant should be the same
B The incremental fuel costs of all the units of the plant should be different
C The penalties factors of all the units of the plants should be the same
D The penalties factors of all the units of the plants should be different
Answer: A The incremental fuel costs of all the units of the plant should be the same
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