NEA Electrical Level 3/4/5 – Set 1
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NEA Electrical Level 3/4/5 – Set 1 - sample questions with answers
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1. Which of the following voltages is not used in Nepal's transmission system?
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Answer: 430 KV
430 KV is not a transmission voltage used in the Nepal power grid.
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2. Which property must the air used in an Air Circuit Breaker possess?
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Answer: Must be free from moisture
The air used in an air circuit breaker must be free from moisture to ensure effective arc extinction.
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3. Into which elements does SF6 gas decompose during arc extinction?
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Answer: SF4 and SF2
During arc extinction, SF6 gas decomposes into SF4 and SF2.
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4. Where is the surge tank located in a hydroelectric power station?
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Answer: Near the turbine
In a hydroelectric power station, the surge tank is located near the turbine.
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5. Which turbine is suitable for low head and high discharge conditions?
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Answer: Reaction turbine
Reaction turbines are suitable for low head and high discharge conditions.
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6. Which type of turbine is used in areas with high head and low discharge conditions?
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Answer: Impulse turbine
Impulse turbines are suitable for high head and low discharge conditions.
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7. Under which conditions is a Pelton turbine most suitable for use?
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Answer: High head and low discharge
Pelton turbines are suitable for high head and low discharge conditions.
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8. Under which category of turbines does the Kaplan turbine fall?
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Answer: Reaction turbine
The Kaplan turbine is a type of reaction turbine.
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9. Which equipment is used in substations to improve the power factor?
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Answer: Synchronous condenser
Synchronous condensers are used in substations to improve the power factor.
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10. Which turbine is suitable for hydro power plants with a high head?
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Answer: Pelton turbine
Pelton turbines are suitable for high head hydro power plants.
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11. Which turbine is generally used in hydro power plants with medium head and medium discharge?
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Answer: Francis turbine
Francis turbines are suitable for medium head and medium discharge hydro power plants.
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12. Which of the following is NOT considered when selecting ACSR conductors for overhead transmission lines?
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Answer: Ambient temperature
The selection of ACSR conductors for overhead transmission lines depends on the permissible voltage drop, the power to be carried, and the length of the transmission line.
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13. If five lamps of equal resistance are connected in series with a 125 V DC supply, what is the voltage drop across each lamp?
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Answer: 25 V
Since the lamps have equal resistance and are in series, the total voltage is divided equally (125V / 5 = 25V).
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14. Which starter is suitable for a 3-phase induction motor with a capacity of 20 HP?
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Answer: Star-Delta starter
A Star-Delta starter is required for a 3-phase induction motor of 20 HP capacity.
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15. Which type of power plant is NOT operated by the Nepal Electricity Authority (NEA)?
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Answer: Wind power plant
The Nepal Electricity Authority operates hydroelectric plants, grid-connected solar power projects, and has historically maintained thermal backup plants. However, the NEA does not operate any commercial wind power plants under its direct generation portfolio. Small-scale wind energy projects in Nepal have largely been implemented through pilot schemes by the Alternative Energy Promotion Centre rather than utility-scale NEA operations.
This chapter has 74 questions. Practise them all with timing, answers and explanations.