Comparison Between Indoor And Outdoor Substation, Merits And Demerits

March 5, 2021February 21, 2022 Shilpa Annigeri

Hello guys, welcome back to my blog. In this article, I will discuss the comparison between indoor and outdoor substations, what is an indoor substation, what is an outdoor substations, the advantages, and disadvantages of outdoor substations, etc.

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Comparison Between Indoor And Outdoor Substation

What is an Indoor substation?

In this type of substation, all the equipment is installed within the substation building. These substations are for the voltage up to 11 kV, but this can be erected for 30KV, to 66KV, whenever the surrounding atmosphere will be contaminated with the impurities like fumes, metal corroding gases, etc. Indoor substations can be classified as,

01. Integrally built-up substation: The apparatus will be installed on-site, and the cell structures will be made up of concrete or bricks.

02. Composite built-up substations: These substations are of the type in which, factory or workshops are built and these are assembled on-site within a substation switchgear room.

03. Unit type, factory-fabricated substations, and metal-clad: These switchboards are built inside the electrical workshops and they can be carried to the site of installations fully pre-assembled.

What is Outdoor substation?

These are the type of substations in which all the electrical equipment are placed in the open air. Outdoor substations can be divided as,

Pole mounted substations.
Foundation mounted substations.

01. Pole mounted substations: Pole mounted substations. These are erected to mount the distribution transformers which have a capacity of up to 250KV. These are cheap, smallest and simple too.

02. Foundation mounted substations: These types of substations will be built totally in the open air and all the equipment will be assembled into one unit.

Comparison between the indoor substation and outdoor substation

01. The cost required for the installation of indoor substations is very small. Whereas for outdoor substations, the installation cost is too high.

02. Regarding construction work for indoor substation it is a bit complicated. Because first we need to build a building, to place or to set up larger electrical equipment such as, Transformers, motors, generators, etc, and we need to make cutouts for power cables which bring power to the substations.

03. As we know all, indoor substations will have compact arrangements. Therefore, if any fault occurs in indoor substations, then it might be difficult to find the location of the fault. But in outdoor substations, the equipment will be placed apart and in different places too. So we can find the location of the fault easily.

04. Usually in indoor substations, the buildings will be constructed with respect to the size of the present transformer. But after some days, if you want to increase the rating of the substation then again you have to Demolish, or again, you need to make some civil works within the pre-built building in order to host a highly rated Transformer. But in outdoor substations equipment will be placed in the open air. Those can be replaced by just increasing the area of fencing.

05. Regarding safety, indoor substations are safer than outdoor substations because animals or unauthorized persons cannot enter the indoor substations. In opposite to this, outdoor substations are not much safe.

06. In indoor substations, the appearance of these substations looks good, because there will be no electrical equipment that is visible from outside. Whereas the outdoor substations’ appearance is not good.

07. Indoor substation requires high maintenance. It requires both specialized and time labor. So it will be too costly. But the maintenance of the outdoor substation will be too cheap.

Advantages of outdoor substation over indoor

All the equipment is placed in an open ear and a bit far. Therefore, fault location will be easier.
If we require the extension of the installation is possible and easy.
Very less few building materials are required.
The fault doesn’t affect too much.
The repairing work will be easy.

Disadvantages of outdoor substation over indoor

Space consumption is more.
Very long control cables are needed.
More protection devices are needed to be installed to protect against lightning surges.

This was about the Comparison Between Indoor And Outdoor Substation. I hope this article “Comparison Between Indoor And Outdoor Substation” may help you all a lot. Thank you for reading.

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Shilpa Annigeri: Ships annigeri

Department of Electrical and Electronics engineering, B.L.D.E.A's V.P.Dr.P.G.Halalatti college of engineering and technology Vijayapur.