Short Answer:

Earthing is very important in transmission and distribution systems because it helps protect both humans and electrical equipment from dangerous faults. By connecting non-current-carrying metal parts to the earth, any leakage or fault current is safely carried away, preventing electric shocks and fire hazards.

In power systems, earthing also helps maintain voltage stability, ensures proper operation of protective devices like fuses and circuit breakers, and protects against lightning and surge voltages. It creates a common reference point and keeps the system safe and reliable under all conditions.

Detailed Explanation:

Importance of Earthing in Transmission and Distribution

Earthing plays a vital role in the safety and performance of electrical systems, especially in high-voltage transmission lines and low-voltage distribution networks. It is the process of connecting electrical parts to the earth using a low-resistance path. This ensures that any leakage or fault current is diverted safely into the ground, minimizing risks and damage.

In large-scale power systems, earthing is essential for preventing electrical hazards, maintaining system stability, and protecting both equipment and people. Without proper earthing, a small fault can become dangerous, leading to fires, outages, or even life-threatening accidents.

Functions and Benefits of Earthing

Protection from Electric Shock

The most important purpose of earthing is to protect humans from electric shock.
When the metal body of electrical equipment accidentally comes into contact with a live wire, the earthing path allows the current to flow directly to the ground.
This prevents the current from passing through a person, thereby saving lives.

Fault Current Clearance

Earthing ensures that fault currents (such as those from short circuits or insulation failure) have a safe path to flow to the ground.
This flow activates protective devices like circuit breakers and fuses, which quickly disconnect the faulty part of the system.
Without proper earthing, these devices may not operate correctly, allowing the fault to persist and cause further damage.

Voltage Stabilization

Earthing provides a common reference point for the entire system, helping maintain balanced voltage levels.
In a three-phase system, for example, earthing the neutral point ensures that phase voltages remain stable and equal.
It reduces the risk of overvoltage in one part of the system due to faults or imbalances in other areas.

Lightning and Surge Protection

Earthing plays a key role in discharging high voltages caused by lightning strikes or power surges.
Lightning arresters are connected to the earth to redirect these voltages away from sensitive equipment and structures.
This protects transformers, insulators, and other critical components from damage.

Minimizing Fire Risk

Fault currents, if not properly earthed, can cause sparks or overheating, leading to electrical fires.
Earthing reduces this risk by allowing immediate dissipation of the fault current into the ground.

Improving Equipment Life

Equipment like transformers, breakers, and switchgear are protected from stress caused by unexpected voltages or faults.
Proper earthing prevents insulation breakdown and reduces wear and tear, thus increasing system reliability and equipment lifespan.

Earthing in Transmission Systems

In high-voltage transmission systems, substation earthing grids are used to ensure that all metal parts, towers, and equipment have a solid connection to the earth.
Transmission towers are earthed to protect them from lightning strikes and ensure safe operation even during severe faults.

Earthing in Distribution Systems

In low-voltage systems, earthing ensures that household and commercial electrical devices remain safe to touch.
It helps in maintaining the correct functioning of protective devices like miniature circuit breakers (MCBs) and residual current devices (RCDs).

Conclusion

Earthing is extremely important in both transmission and distribution systems. It protects human life from electric shock, ensures quick removal of fault currents, maintains voltage stability, prevents equipment damage, and reduces the chances of fire or system failure. Without proper earthing, electrical systems can become dangerous and unreliable. That’s why all electrical installations must follow standard earthing practices to ensure complete safety and performance.