1. The main function of a transmission system is to:
(A) Transfer electrical power from generation to load centers
(B) Generate electricity
(C) Store electrical energy
(D) Convert DC to AC
2. High voltage is used in transmission to:
(A) Increase resistive losses
(B) Increase current
(C) Reduce voltage drop
(D) Reduce transmission losses
3. The typical voltage levels for high voltage transmission lines are:
(A) 1 kV, 5 kV
(B) 12 V, 24 V
(C) 110 kV, 220 kV, 400 kV
(D) 1 MV, 10 MV
4. Transmission lines are usually made of:
(A) Aluminum or aluminum alloy
(B) Copper only
(C) Steel
(D) Iron
5. Corona loss occurs due to:
(A) Ionization of air around high voltage conductors
(B) Resistive heating
(C) Transformer leakage
(D) Mechanical vibration
6. The main purpose of a substation is to:
(A) Store energy
(B) Generate electricity
(C) Step up or step down voltage and distribute power
(D) Convert DC to AC
7. A typical transmission system consists of:
(A) Generators, transmission lines, transformers, and load
(B) Generators only
(C) Transformers only
(D) Load only
8. The main advantage of three-phase transmission over single-phase is:
(A) More efficient and balanced power
(B) Cheaper
(C) Less complex
(D) Requires less conductor
9. The characteristic impedance of a transmission line depends on:
(A) Voltage only
(B) Resistance only
(C) Line inductance and capacitance
(D) Load
10. The main cause of voltage drop in transmission lines is:
(A) Transformer losses
(B) Line resistance and reactance
(C) Generator efficiency
(D) Load factor
11. A busbar in a substation is used for:
(A) Connecting multiple circuits
(B) Generating power
(C) Reducing voltage
(D) Measuring current
12. A protective relay operates to:
(A) Detect faults and initiate circuit breaker action
(B) Increase voltage
(C) Step up current
(D) Convert DC to AC
13. The main purpose of a circuit breaker is:
(A) Reduce line losses
(B) Step up voltage
(C) Convert DC to AC
(D) Interrupt fault current
14. Overcurrent protection is provided by:
(A) Fuses and overcurrent relays
(B) Transformers
(C) Circuit breakers only
(D) Transmission lines
15. The main types of faults in power systems are:
(A) Only short circuits
(B) Line-to-line, line-to-ground, three-phase
(C) Only open circuits
(D) Only voltage fluctuations
16. Earth fault occurs when:
(A) A live conductor touches the ground
(B) Two conductors touch each other
(C) Load is disconnected
(D) Transformer overloads
17. Distance protection relays operate based on:
(A) Current only
(B) Voltage only
(C) Impedance measurement
(D) Frequency
18. The main function of a lightning arrester is to:
(A) Protect equipment from high voltage surges
(B) Protect from overload
(C) Increase voltage
(D) Reduce frequency
19. Distribution lines operate at:
(A) Medium and low voltages (11 kV, 415 V)
(B) High voltage only
(C) DC voltage only
(D) Extra high voltage only
20. Primary distribution lines are:
(A) DC lines only
(B) Low voltage lines
(C) Underground only
(D) High voltage lines supplying transformers
21. Secondary distribution lines supply:
(A) Consumers at low voltage
(B) Substations only
(C) Generators
(D) Transformers only
22. The main advantage of underground distribution is:
(A) Low installation cost
(B) Reduced maintenance and improved aesthetics
(C) Easy expansion
(D) Less insulation required
23. The main disadvantage of underground distribution is:
(A) High installation cost
(B) Low reliability
(C) Low safety
(D) High losses
24. Protective devices for distribution systems include:
(A) Transmission lines
(B) Transformers only
(C) Fuses, relays, and circuit breakers
(D) Capacitors
25. The type of relay that operates instantly during fault is:
(A) Instantaneous overcurrent relay
(B) Electromagnetic relay
(C) Thermal relay
(D) Differential relay
26. The difference between protective relay and circuit breaker is:
(A) Circuit breaker detects fault
(B) Relay interrupts fault
(C) Relay detects fault, circuit breaker interrupts fault
(D) Both are same
27. The line-to-line voltage in a 3-phase, 415 V system is:
(A) 415 V
(B) 240 V
(C) 110 V
(D) 400 V
28. The line-to-neutral voltage in the same system is:
(A) 400 V
(B) 415 V
(C) 110 V
(D) 240 V
29. Short-circuit current depends on:
(A) System voltage and impedance
(B) Load
(C) Transformer rating only
(D) Frequency only
30. Power system stability refers to:
(A) Maintaining current
(B) Maintaining voltage
(C) Ability to remain in synchronism after disturbance
(D) Reducing losses
31. A neutral earthing resistor is used to:
(A) Limit fault current
(B) Increase voltage
(C) Reduce transformer losses
(D) Control power factor
32. A star-delta transformer connection helps in:
(A) Step up power
(B) Increasing voltage
(C) Reducing starting current for motors
(D) Improving efficiency
33. Protective relays are classified as:
(A) Overcurrent, differential, distance, and earth fault relays
(B) Fuses only
(C) Transformers only
(D) Circuit breakers only
34. Transmission line losses are mainly due to:
(A) Resistance and corona
(B) Load only
(C) Voltage fluctuation
(D) Frequency only
35. A bus zone protection scheme protects:
(A) Generator only
(B) Transformer only
(C) Transmission line only
(D) Entire busbar against faults
36. Protective coordination ensures:
(A) Fault isolation with minimum interruption
(B) Maximum power generation
(C) Voltage regulation
(D) Load balancing
37. A ring main distribution system is preferred because:
(A) Low maintenance only
(B) Cheap to install
(C) Improved reliability and continuity of supply
(D) Less conductor required
38. The main disadvantage of overcurrent protection alone is:
(A) Cannot detect faults in parallel feeders
(B) High cost
(C) Low reliability
(D) Requires frequent testing
39. The operating time of a protective relay is usually:
(A) Minutes
(B) Hours
(C) A few milliseconds to seconds
(D) Days
40. Feeder protection is provided by:
(A) Overcurrent relays
(B) Differential relays
(C) Distance relays
(D) Fuses only
41. A ring main unit (RMU) is used in:
(A) Generators only
(B) Transmission only
(C) Medium voltage distribution systems
(D) Low voltage only
42. The advantage of differential protection is:
(A) High sensitivity and selectivity
(B) Cheap
(C) Easy to install
(D) Reduces voltage only
43. Lightning arresters are usually connected:
(A) Across transformers
(B) Between phase and ground
(C) Across generators
(D) Between conductors only
44. Distribution transformers usually operate at:
(A) 11/0.415 kV
(B) 220/11 kV
(C) 132/11 kV
(D) 400/230 kV
45. The main purpose of a neutral in distribution systems is:
(A) Reduce line losses
(B) Increase voltage
(C) Provide return path and maintain voltage
(D) Protect transformer
46. Surge arresters protect equipment against:
(A) Overvoltage and lightning strikes
(B) Overcurrent only
(C) Low voltage
(D) Harmonics
47. The main advantage of overhead distribution lines is:
(A) Less losses
(B) Reduced maintenance
(C) High aesthetics
(D) Low installation cost
48. Protective devices should operate:
(A) Selectively and quickly
(B) Slowly
(C) Randomly
(D) At zero voltage only
49. The main function of a potential transformer is to:
(A) Reduce losses
(B) Step up voltage
(C) Supply power
(D) Step down voltage for metering and relays
50. Transmission line insulation must withstand:
(A) Line voltage and overvoltages
(B) Load only
(C) Short circuit current
(D) Frequency changes only