Why We Use Stone in Outdoor Electrical Substation?

Ok, you don’t need to be an Electrical Engineer to ask yourself that, Why They Use Stone in Outdoor Electrical Substation? But if you are an Electrical Engineer then you may need to answer this type of question to anyone.

I got one question like this from my top management that, Why We Will Use 2-2.5 inch size Stone and Why Not 0.5-1 inch Stone? In this post, I will discuss “Why We Use Stone in Outdoor Electrical Substation?

Explanation – Why We Use Stone in Outdoor Electrical Substation?

First of all, we use stone in our electrical substation for reducing the Ground Potential Rise (GPR) and in electrical engineering, it also called Earth Potential Rise (EPR) and it occurs when a large current flows to earth through earth grid impedance.

Stone increase resistance of soil, for this reason, step potential, and the touch potential limit decrease. When people are working in substations stone reduces the possibility of electric shock during work.

Related: Why Strong Magnetic and Electric Field Effect Come From Electrical Substation

Generally when we design an electrical substation that time step potential and touch potential is one of our first party. Because there is no compromise with safety. If there is any small glitch then the percentage of electrical shock will increase and we really don’t want that to happen with us.

Step Potential and Touch Potential
Step Potential and Touch Potential

Step Potential: The amount of potential present between a two or four-legged animal is called step potential. If there is imbalance potential on substation areas and if we stand that place then between our two legs we will have a potential difference and this is the real step potential.

Touch Potential: When a person stands on the ground and touch a machine then the potential between his hand and leg called touch potential.

Related: Advantage and Disadvantage of Outdoor Electrical Substation

Now there are some others and different benefit that we can get by using stone in an electrical substation.

  1. By using stone in substation grass and weed does not grow, so it remains nice and clean for perfect visual observation from outside.
  2. Stone reduce the potential movement of wild animals like snakes, frogs, rats etc. For this reason, it decreases the risk of short circuits when the substation is operational.
  3. Rainwater can drop fast so that it does make any mud inside the substation.
  4. If there is any oil fall from power transformers or circuit breakers then oil does not stay there if substation ground is covered by stone. But it also creates some problem. If you can’t see any oil under the transformer when there is an oil leakage then you may think everything is alright. So check the transformer oil reserve tank indicator during the physical inspection.
  5. If we compare with concrete casting using stone in the substation is cheap and remain clean.
  6. Stone can carry much higher capacity weight.

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