Substations and Voltage Levels — MCQs – EE

1. A substation is used for:
(A) Generating electrical energy
(B) Transforming voltage levels and switching circuits
(C) Measuring current only
(D) Power factor correction only

2. The main function of a substation is to:
(A) Convert AC to DC
(B) Change voltage levels for transmission and distribution
(C) Increase frequency
(D) Generate reactive power

3. A distribution substation generally operates at voltages up to:
(A) 400 kV
(B) 220 kV
(C) 66 kV
(D) 33 kV and below

4. A transmission substation is primarily used for:
(A) Power factor correction
(B) Stepping up or down voltage for long-distance transmission
(C) Energy metering
(D) Consumer billing

5. Which of the following is not a type of substation?
(A) Step-up substation
(B) Step-down substation
(C) Distribution substation
(D) Transmission generator

6. A step-up substation is located near:
(A) The load center
(B) The generating station
(C) The consumer premises
(D) The city distribution area

7. A step-down substation is located near:
(A) Generating station
(B) Load center
(C) Transmission tower
(D) Grid interconnection point

8. The voltage level for an EHV transmission system is usually above:
(A) 11 kV
(B) 33 kV
(C) 132 kV
(D) 400 V

9. The primary distribution voltage generally ranges from:
(A) 230 V to 400 V
(B) 3.3 kV to 11 kV
(C) 33 kV to 132 kV
(D) 132 kV to 400 kV

10. The secondary distribution voltage generally ranges from:
(A) 11 kV to 33 kV
(B) 400 V to 230 V
(C) 132 kV to 400 kV
(D) 3.3 kV to 6.6 kV

11. Which type of substation uses both circuit breakers and isolators?
(A) Indoor substation
(B) Outdoor substation
(C) Pole-mounted substation
(D) All of the above

12. The equipment used to connect or disconnect a part of a substation for maintenance is:
(A) Circuit breaker
(B) Isolator
(C) Transformer
(D) Lightning arrester

13. Busbars in a substation are used to:
(A) Step up voltage
(B) Collect electrical energy from incoming feeders
(C) Measure current
(D) Provide earthing

14. Which of the following substations occupies the least space?
(A) Outdoor substation
(B) Indoor substation
(C) Underground substation
(D) Gas-insulated substation

15. A gas-insulated substation (GIS) uses which gas for insulation?
(A) Hydrogen
(B) Nitrogen
(C) SF₆ (sulfur hexafluoride)
(D) Carbon dioxide

16. The main advantage of an SF₆ gas-insulated substation is:
(A) High losses
(B) Compactness and high reliability
(C) Requires frequent maintenance
(D) Inexpensive to construct

17. Which substation is most suitable for urban and space-limited areas?
(A) Outdoor substation
(B) Gas-insulated substation
(C) Rural substation
(D) Pole-mounted substation

18. The main disadvantage of a gas-insulated substation is:
(A) Large space requirement
(B) High cost
(C) Low reliability
(D) High losses

19. The voltage level between two substations is generally referred to as:
(A) Transmission voltage
(B) Sub-transmission voltage
(C) Distribution voltage
(D) Utilization voltage

20. A pole-mounted substation is generally used for:
(A) 132 kV system
(B) 11 kV or below system
(C) 220 kV system
(D) 400 kV system

21. The equipment used for stepping up or stepping down voltage is:
(A) Transformer
(B) Circuit breaker
(C) Isolator
(D) Relay

22. The purpose of a lightning arrester in a substation is to:
(A) Increase power factor
(B) Protect equipment from surges
(C) Regulate voltage
(D) Control frequency

23. The control room in a substation houses:
(A) Transformers
(B) Control panels and protection relays
(C) Circuit breakers
(D) Transmission lines

24. Earthing in substations is provided to:
(A) Increase resistance
(B) Protect personnel and equipment from electric shocks
(C) Increase voltage
(D) Reduce losses

25. The switching station is a type of substation that:
(A) Has no transformers
(B) Has only transformers
(C) Converts AC to DC
(D) Distributes to domestic consumers

26. The busbar arrangement used for maximum flexibility and reliability is:
(A) Single bus system
(B) Double bus system
(C) Ring bus system
(D) Mesh bus system

27. A grid substation connects:
(A) Consumers to distribution network
(B) Two or more generating stations or transmission lines
(C) Low-voltage feeders
(D) Underground cables

28. The normal utilization voltage for domestic consumers is:
(A) 230 V single-phase or 400 V three-phase
(B) 11 kV
(C) 132 kV
(D) 66 kV

29. The substation which connects the transmission system to the distribution system is called:
(A) Step-up substation
(B) Step-down substation
(C) Switching substation
(D) Generating substation

30. The highest transmission voltage level used in India is approximately:
(A) 132 kV
(B) 220 kV
(C) 400 kV
(D) 765 kV