Arc Horn are used in High Voltage Transmission Line Why?

Why Arcing Horns are used in Insulator:

Arcing horns are used to protect the transmission conductors, insulators, transformers bushings and other transmission equipments from lightning high voltages, transient voltages and surge voltages. Arc horns are working under the principle of arcing.

arc horn in insulators
arc horn in insulators during lightning over voltages

Arc horns are consisting of two small conductors which are placed in transmission lines and Earth point typically two end of the protecting equipments (insulator). You can see in the figure. In that figure the arc horns in two end of the insulator. The distance

Arc Horns in Transmission Line
Arc Horns in Transmisformer Bushing

Yellow color mark is the flow of current

Working Principle of Arc horns:

In High voltage transmission system, insulator provides the physical separation between the conductors with some distances. Here the air around the insulator become ionized due to the electrical field caused by high voltages. The spark gap between the horn conductors are maintained to avoid the arc Under Normal condition. During lightning condition, the voltage in the transmission conductors are increased. Hence this high voltage ionizes further the air surrounding insulator. Due to this ionization process, further free electron starts flows in the form of sparks through the air and it forms a flashover. By the way, the high voltages are suppressed.

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