HomeElectricalSubstationWhat is the Substation - The Main Purpose of an Electrical Substation

What is the Substation – The Main Purpose of an Electrical Substation

An electrical substation is a part of the Electrical generation, transmission, and distribution system. We can turn voltage from high to low or low to high and do various important works with the help of a substation. 

The substation is situated between powerplant and customers. Where various electrical devices and numbers of feeders are used for transforming Electricity into voltage with different values, with the help of a transformer. Also, power factor, frequency, and AC turn into DC with the help of a substation. Today we will discuss what is the main purpose of an Electrical substation?

Things we should keep in mind while designing Electrical substations

  • First, we have to select a suitable place.
  • Ensure the security- Proper maintenance, changing defective devices, regular inspection and examining by standard, security from fire-related accidents and other matters should be considered.
  • It has to be easily manageable, and maintained and should be of minimum cost.

Types of substation 

We can divide substations into different types. Here we will show the types based on two factors:

  • Service
  • Structural characteristics 


It is mainly based on voltage level up down, improving power factor, turning AC power into DC power, etc. 

  • Transformer substation: For controlling up down of voltage.
  • Switching substation: For switching the line. 
  • Power factor correction substation: For improving power factor.
  • Converting substation: For turning AC into DC.
  • Industrial substation: For supplying power in different industries. 
  • Frequency substation.

Structural Characteristics 

  • Indoor substation: If the devices and equipment used in the substation are placed in a shade or building, then it is an indoor substation. Its voltage is a maximum of 11 kV.
  • Outdoor substation: If the devices and equipment are placed in an open place, then it is an outdoor substation. They are mainly higher than 66 kV.
  • Underground substation: This type of substation is situated in the underground of populated places.
  • Paul mounted substation: It is a type of outdoor substation which is situated between the H-pole and 4 poles.

The above-mentioned substation can be divided into different types :

  • Step-up substation
  • Primary substation
  • Secondary substation
  • Distribution substation

The view of substation element:

Generating Station>>Substation>>Distribution

 Electrical substation
  1. Primary power lines side
  2. Secondary power lines side.

Primary Power lines side

  1. Primary power lines
  2. Ground wire
  3. Overhead lines
  4. Lightning arrester
  5. Disconnect switch
  6. Circuit breaker
  7. Current transformer
  8. Transformer for measurement of electric voltage
  9. Main transformer
  10. Control building
  11. Security fence
  12. Secondary Power line

The components we need for a substation

Incoming Circuit:
  • Lightning Arrestor.
  • Overhead earth wire.
  • Isolator
  • Fuses
  • Earthling Switch etc
  • Incoming Lines (Underground & Overhead)
High Voltage Switchgear Panel: (HT)
  • Bus bars
  • Isolators
  • Circuit breaker
  • C.T
  • P.T
  • Metering system
  • Indicating instruments
  • Various protective relays
Low Voltage Switchgear Panel: (LT)
  • Bus bars
  • Isolators
  • Fuses
  • Magnetic contractors
  • Air-break switch
  • Various types of no-fuse breaker
  • Metering system
  • Indicating instruments
  • Various protective relays etc
  • PFI capacitors
Some other common components:
  • Transformer
  • The battery bank and charging system
  • Outgoing line
  • Emergency power supply system
  • Also, some other components are needed based on the types of substations.

That was all for today’s article what is the main purpose of an electrical substation?

Hope now it is clear for you to understand what is the main purpose of an electrical substation?

If you have any questions on what is the main purpose of an electrical substation, feel free to ask in the comment section.

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Md. Nazmul Islam
Md. Nazmul Islam
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