SOLUTION

The process of connecting the neutral point of a supply system on the non-current carrying parts of electrical apparatus to the general mass of earth in such a manner that at all times an immediate discharge of electrical energy takes place without danger is called earthing.

In an earthed neutral system, the neutral is earthed either directly or through resistance or reactance depending on the requirement. Thus the system neutral can be grounded effectively or non-effectively. In an effectively grounded system, the neutral is grounded directly and hence it is called solid grounding.

The main advantages of neutral earthing are:

1. The magnitude of transient voltage is small in this system.
2. The static charges which are induced are grounded immediately and are thus prevented from causing any disturbance.
3. As the neutral point is not shifted in this system, thus the voltages of healthy phases remain nearly constant.
4. This system is more reliable, provides safety to personnel and equipment with reduced operational and maintenance costs than the ungrounded system.