Home Electrical Why stones are used in Substation instead of Sand or Grass?

Why stones are used in Substation instead of Sand or Grass?


Why stones are used in Substation instead of Sand or Grass? Ever thought, why stones are used in substation instead of sand or grass? The reason is simple. But, can’t be explained easily.

substation stones
Substation Stones

What comes to mind when we hear about substations? Transformer, circuit breaker, lightning arrester, etc devices come to our mind. Besides all these, there is also the use of a very important substance for the benefits of the substation. You are feeling curious right now, aren’t you? So, let’s not drag it more and discuss it. That important substance is stone. Now, you might be even more amazed. It is natural. You might be wondering, how a stone can be a protector? Now, how it acts as a protector is discussed below.

Protection from Reptiles

A Chameleon

There are many reptiles like lizards, rats, chameleons, snakes, etc which find it very difficult to pass through the stones. As they are reptiles, they move only over grounds. So the stones act as the resistance in this case.

Protection from Rainwater

Rainwater in a bucket
Rainwater in a Bucket

Acid rainwater is a conductor of electricity. As a result, the stones act as an obstacle to protect direct contact of the substation from the rainwater. Thus, by increasing the resistance, the flow of electricity is reduced.

Prevention of fire from Pyranol Oil

Why stones are used in Substation instead of Sand or Grass?
Substation Fire

The transformers that are present in a substation are usually having a very high power rating. These transformer’s range is from little MVA to more hundreds of MVA. When there is an overload then the transformer becomes heated. Just as the old people use oil to cool down their heads, the transformers also use pyranol oil in order to cool down. Again, for the purpose of insulation, it is also necessary. While changing the oil, some of it falls on the ground. This oil can occur a fire accident in substations. As a result, stones are used so that the oil can’t stretch out much distance. 

Protection from Step and Touch Potential

For the people who work at a substation, it is a very familiar term to them. These two potential is quite harmful to any human. It can even kill them. People who aren’t not known to these technical terms, most often face accidents in the substation. The people who work there can easily tell how dangerous it is. When there is a fault in the substation or even if there is a spark or something, some ignorant people cause such accidents. This should not happen at all.

In a situation like this, even if you are 10 meters away from the area of the accident, you still might have a death risk. Because due to substation grounding or earthing fault or leakage, there creates a huge electromagnetic field. In such a situation, an area of range 10 meters might be electrocuted. So, if you are in this range, then your two legs might act as an electrode/conductor. And, step potential is the voltage difference between the two legs. Now, if you touch the faulty device in that position, then the voltage will arise between your hand and leg there. This is touch potential. Not only in a substation but also if there is a fault in a nearby electrical tower, there also you can be at a risk.

Which might not be at a death level always.

What’s the solution for this?

If you are at that range, then the only way to save yourself is bunny jump technique.

What is Bunny Jump?

Why stones are used in Substation instead of Sand or Grass?
Jumping Bunny

Simply, it means to jump like rabbits or bunnies. By jumping like a bunny you have to cross the death range, so that, your legs and hands can not come in contact with the electricity easily. Otherwise, touch and step potential can be the reason for your death.

Grass can’t grow in stones

Because of the stones, the area remains moisture-free. As a result, no grass or weeds can’t grow there.

To absorb the heat from the radiator of the transformer

Why stones are used in Substation instead of Sand or Grass?
Heat Flow from a Radiator

Stone can absorb heat easily. As a result, the stones absorb the heat coming out from the transformers. This prevents the occurrence of any unexpected situation.

To increase the tower footing resistance 

Why stones are used in Substation instead of Sand or Grass?
Transmission Towers

By using stones, the resistance between the feet of the towers and the ground increases. As a result, electricity won’t be able to flow in ample which prevents unwanted incidents.

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