Neutral Grounding:

Neutral grounding in electrical distribution systems helps avoid accidents to personnel and damage to property caused through:   fire in case of the lightning and a breakdown among secondary and primary windings of transformers or accidental contact of high-voltage wires and low- voltage wires. If a few point on the circuit is grounded (in this case neutral ground), the lightning striking the wires would be conducted into the ground and breakdown among the primary and secondary windings of a transformer would cause the primary transformer fuses to blow. Other advantage of neutral grounding is that it decrease the amount of insulation required for high-voltage transmission lines.