A. Elimination of arcing Grounds
B. Low maintenance and operating costs over isolated neautral systems.
C. Simplified Design of earth fault protection
D. Dichrging Of Overvoltages Due to lighting to earth
E. All of the Above
B. Low maintenance and operating costs over isolated neautral systems.
C. Simplified Design of earth fault protection
D. Dichrging Of Overvoltages Due to lighting to earth
E. All of the Above
Answer: E. All of the Above
Explanation:
What is Neutral Grounding or Earthing?
The process of connecting neutral point of 3-phase system to earth (i.e. soil) either directly or through some circuit element (e.g. resistance, reactance etc.) is called neutral grounding.
Neutral grounding provides protection to personal and equipment. It is because during earth fault, the current path is completed through the earthed neutral and the protective devices (e.g. a fuse etc.) operate to isolate the faulty conductor from the rest of the system.
ADVANTAGES OF NEUTRAL GROUNDING
- Voltages of the healthy phases do not exceed line to ground voltages i.e. they remain nearly constant.
- The high voltages due to arcing grounds are eliminated.
- The protective relays can be used to provide protection against earth faults. In case earth fault occurs on any line, the protective relay will operate to isolate the faulty line.
- The over-voltages due to lightning are discharged to earth.
- It provides greater safety to personnel and equipment.
- It provides improved service reliability.
- Operating and maintenance expenditures are reduced.
Note: It is interesting to mention here that ungrounded neutral has the following advantages:
- In case of earth fault on one line, the two healthy phases will continue to supply load for a short period.
- Interference with communication lines is reduced because of the absence of zero sequence currents.