MCQ on Power System Earthing

1. What is the primary goal of earthing in electrical systems?
(a). Enhancing system efficiency
(b). Facilitating the venting of electrical energy for safety
(c). Increasing voltage surges
(d). Minimizing equipment maintenance

Answer
           B

2. What is the foremost objective of earthing related to personnel safety?
(a). Lightning protection
(b). Surge arresters
(c). Protection versus electric shocks
(d). Equipment maintenance

Answer
           C

3. What does earthing provide a designated venting path for, offering protection versus lightning and voltage surges?
(a). Grounded neutral systems
(b). Surge arresters
(c). Electrical connections
(d). Earthing leads

Answer
           B

4. What does earthing establish for systems utilizing grounded neutral configurations?
(a). Personnel safety
(b). Ground connections
(c). Equipment maintenance
(d). Venting paths

Answer
           B

5. In the context of power system earthing, why is having multiple grounds and connections often considered desirable?
(a). To increase system efficiency
(b). To enhance ground protection
(c). To reduce earthing leads
(d). To minimize equipment maintenance

Answer
           B

6. What does Neutral Earthing involve in power systems?
(a). Connecting the neutral points to high-resistance earth
(b). Connecting the neutral points to low-resistance earth
(c). Disconnecting the neutral points from earth
(d). Utilizing ungrounded neutral configurations

Answer
           B

7. What is Equipment Earthing primarily focused on in power systems?
(a). Grounding neutral systems
(b). Earthing metallic conductors
(c). Earthing non-current delivering parts
(d). Establishing venting paths

Answer
           C

8. What does Resistance-To-Earth or Earth Resistance signify in power system earthing?
(a). Resistance between metallic conductors
(b). Resistance of soil between the electrode and zero potential point
(c). Resistance of the earth electrode to lightning
(d). Resistance of equipment frames

Answer
           B

9. What is the term for the current prodigal by the earth electrode into the ground?
(a). Earth lead current
(b). Ground current
(c). Earthing current
(d). Metallic current

Answer
           C


10. What does Step Potential denote in power systems?
(a). Potential difference within a grounding grid
(b). Potential difference between feet during earth fault current
(c). Potential difference between fingers touching a faulted structure
(d). Potential difference between equipment frames

Answer
           B

11. What does Touch Potential refer to in power systems?
(a). Potential difference within a mesh of the grounding grid
(b). Potential difference between equipment frames
(c). Potential difference between fingers touching a faulted structure and feet on the substation floor
(d). Potential difference between metallic conductors

Answer
           C

12. What is the term for the maximum touch potential within a mesh of the grounding grid?
(a). Mesh current
(b). Grid potential
(c). Transferred potential
(d). Mesh potential

Answer
           D

13. When is Transferred Potential observed in power systems?
(a). During equipment maintenance
(b). During lightning strikes
(c). When potential is transferred into or out of the substation
(d). During earth fault current

Answer
           C

14. At what current level do individuals start to finger a tingling sensation upon contact with an electrified object through intact skin?
(a). 20-100 mA
(b). 1 mA
(c). 9 mA (for men) / 6 mA (for women)
(d). 6 A and above

Answer
           B

15. What is the current level at which individuals can release their grip on a conductor?
(a). 20-100 mA
(b). 1 mA
(c). 9 mA (for men) / 6 mA (for women)
(d). 6 A and above

Answer
           C

16. What type of wrecking involves currents in the range of 20-100 mA, causing pain and potential physical injury?
(a). Ventricular Fibrillation
(b). Hold-On-Type Accident
(c). Threshold of Perception
(d). Let Go Current

Answer
           B

17. At what current level is there a risk of ventricular fibrillation, a serious cardiac emergency?
(a). 20-100 mA
(b). 1 mA
(c). 9 mA (for men) / 6 mA (for women)
(d). 6 A and above

Answer
           A

18. What do upper currents (6 A and above) pose a danger of in terms of the human body?
(a). Temporary respiratory paralysis and serious burns
(b). Ventricular fibrillation
(c). Threshold of Perception
(d). Hold-On-Type Accident

Answer
           A

19. Why is understanding the effects of electric currents on the human soul crucial for designing earthing systems?
(a). To increase system efficiency
(b). To enhance ground protection
(c). To prioritize safety in electrical installations
(d). To reduce earthing leads

Answer
           C

20. What does a robust earthing system need to withstand without causing hazardous voltage increases or urgent shutdowns?
(a). High-resistance earth
(b). Unwont conditions
(c). Low-resistance earth
(d). Metallic conductors

Answer
           B

21. What is imperative for a well-designed earthing system in power systems?
(a). Multiple grounds and connections
(b). Low-resistance earth
(c). High-resistance earth
(d). Unfluctuating turnout

Answer
           A

22. What type of earthing involves connecting the neutral points of 3-phase windings to low-resistance earth?
(a). Equipment Earthing
(b). Neutral Earthing
(c). Grounding Neutral Systems
(d). Earth Electrode

Answer
           B

23. What is primarily focused on earthing non-current delivering parts in power systems?
(a). Grounding Neutral Systems
(b). Equipment Earthing
(c). Earth Electrode
(d). Earthing Lead

Answer
           B

24. What is the term for the resistance offered by the earth electrode to the spritz of current into the ground?
(a). Resistance-To-Earth
(b). Earth Resistance
(c). Ground Resistance
(d). Soil Resistance

Answer
           B

25. What does the earthing lead connect to in power systems?
(a). Metallic conductors
(b). Grounding mats
(c). Earth wire or other workings to be earthed
(d). Earth electrode

Answer
           C

26. What is the term for the potential difference between the fingers of a raised hand touching a faulted structure and the feet of the person standing on the substation floor?
(a). Step Potential
(b). Touch Potential
(c). Mesh Potential
(d). Transferred Potential

Answer
           B