We previously observed the working of the Lightning arrester. In this post, you’ll learn the 6 different types of lightning arresters.
List of Contents
Expulsion type lightning arrester
Expulsion type arrester is an economically available inexpensive arrester that is used for lower voltages (<33kV). It consists of a fiber tube and two gaps.
In case of a fault, the heat of arc vaporizes a portion of the fiber tube and produces the gas. In extreme conditions, the gas leaves through the tube and carries ionized air around the arc. The deionizing causes the arc to go dead at the current zero.
Horn gap arrester
The horn gap construction involves two horn-shaped rods that are separated by an air gap. The horns are installed in a configuration like this:
i.e the distance between their bottom is lowest and the distance increases as we move towards the top.
These horns are actually mounted on porcelain insulators.
Under normal conditions the gap is open.
One the fault occurs the arc initiates at the bottom point. The magnetic effect across the arc causes it to move upwards.
In the beginning: \_/
After some time: \-/
Once the point \^/ reaches the arc is difficult to be maintained. As a result of this arc extinguishes.
Such arresters contain multiple gaps that consist of series of metallic cylinders that are separated at small intervals forming the gaps.
Rod gap arrester
The rod gap involves two rods which are bent at the right angle with a gap in between them. One of the rods connects with the earth while the other one joins the line.
Under normal condition the gap is non-conducting, In case of the surge the gap becomes conductive and causes the current to flow to the earth.
Valve type lightning arrester
These are HV arresters which are used for systems at or above 220 kV.
Let’s understand the physical construction: