Advantages and disadvantages of grounding the neutral

The advantages of grounding (earthing) the neutral are as follows

  1. Sensitive current protection schemes can be used to quickly identify an earth fault.
  2. The external surges and overvoltages caused by lightning or switching are discharged to the ground.  If the neutral is not grounded, these waves will get reflected and cause overvoltages in the system.
  3. The phase voltages are within limit and the value is the voltage between the phase to ground.
  4. Arcing grounds, which occur at the location of an earth fault are avoided.

The disadvantages of grounding the neutral are

  1. The system will trip even for a minor earth fault.  This affects the reliability of the power supply.
  2. The zero sequence currents which flow through the neutral can cause interference to telecommunication lines.