7 Electrical Components used in power sub station │Electronicsinfos



Electrical substations Play a Key Role in controlling, Measuring, and Secure Electrical Components of the distribution grid and transmission systems. It gives the facility between generating station, transmission system and load points. In the power system, we need to change the electrical parameters like AC - to DC Conversion, the power factor improvements, change the frequency as per needs, control and safety of electrical equipment.

 There are different types of generating stations does not care whether they are hydro-electrical, Steam or nuclear. Mainly Electrical substations contain incoming and outgoing circuits that are connected with a common bus bar. In a substation, each component is in a sequence order so we can easily operate this by hand in normal mode and shut down automatically in a short circuit mode. 

Many Components are used in Electrical substations. Each Component Plays The Important Role in the substation transformer and is used to step up and step down the voltage in the transmission lines to one that is suitable for the distribution grid. Instrument  Transformer-like C.T and P.T used to Measure the Electrical Quantity. Insulators are played an important role because they provide insulation between the conductor. Relay is Used to Detect the Fault and generate the signal. 

They are also equipped with circuit breakers to protect the distribution system and can be used to control the flow of current in different directions. we used a Bus bar to distribute electricity in different feeders. lightning Arrester is used to protect the overall system from lightning .there are different types of Lightning Arresters. An isolator is used to isolate the Electrical part.

  1. Electrical transformers
  2. Instrument transformers
  3. Insulators
  4. Relays
  5. Bus bars
  6. Circuit Breakers
  7. Lightning Arrester

Electrical transformers 

The primary motivation behind the power transformer is to move forward the transmission voltage at the aged unit and step down the transmission voltage at the circulation unit. By and large for rating up to 10MVA (Mega-volt-Amperes) oil inundated, normally cooled and 3-stage transformers are utilized. Essentially, for more than 10MVA (Mega-volt-Amperes), air-impact-cooled transformers are utilized.

Types of transformers

  1. step-up transformer
  2. step down transformer

Step-up Transformer

A Step-Up Transformer is a type of transformer in which the primary voltages are lower than its primary voltage. A Step-Up Transformer, therefore "steps up" the voltage supplied .step up transformer means the voltage level of this type of transformer on the secondary side is greater than the primary side and the current is vice versa.

step up transformer

Step down Transformer: 

 A Step-Down Transformer is a Non-power distribution transformer in which the secondary voltage is lower than its primary voltage. A Step-down Transformer, therefore "steps down" the voltage supplied .step down transformer means the voltage level of this type of transformer on the secondary side is lower than the primary side and the current is vice versa.

                                step down transformer
To read More About Transformers 

Instrument transformers

The primary reason for an instrument transformer is to diminish high current as well as voltages for solid and practical worth. These qualities can be determined with traditional gadgets. The scope of voltage and current are 110 V, and 1A (or) 5A. These transformers are arranged into two sorts specifically a voltage transformer and a current transformer.

There are two main types of Instrument Transformer

  1. Current Transformer
  1. Potential Transformer

Current Transformer

A current transformer is a gadget used to deliver a rotating current in its auxiliary, which is relative to the AC current in its essence. The incited auxiliary current is then appropriate for estimating instruments or handling electronic gear, which commonly needs a separation between the essential and optional circuits.


The ratings of secondary current are 5 A or  1A  for measurements.
The Primary Current is up to 49000A.

potential transformer:

A Potential transformer is a type of instrument transformer which is widely used for safety and measurements purpose. the secondary voltage rating is 120v and the primary voltage rating is 24kv i.e. they have many turns on the primary side while the auxiliary has not had many turns. where the number of turns is greater the voltage is also greater just like the primary side and another side is a lower number of turns so the voltage is also low.


The rating of the Secondary voltage is 120 volts.
The primary ratings are up to 24,000 volts.


An Electrical insulator is one in which electric current does not flow freely. there are different types of electrical insulators used in power substations. there are many types of insulators like high as tension insulators, low-tension insulators, substation insulators, and special types of insulators. insulators are made from different insulating materials just as porcelain, mica, plastics, paper, wood etc. Insulators are also manufactured in different shapes and sizes.


Relay plays an important role in electrical substations .its used to protect the system. relay is an electrically operated device. there are two contacts of relays one is normally open(NO) contact and the other is normally close(NC).there are different sizes and shapes of relays.


Types of Relays:

  1. Electromagnetic Relays.
  2. Electronic Relays.
  3. Electromechanical Relays
  4. Reed Relays
  5. Time Delay Relays
  6. High-Voltage Relays
  7. Small Signal Relays

Bus bars

A busbar is a metallic bar used for local high-current power distribution. they are used in typically inside switchgear and panel boards. There are many types of busbar schemes used in substations.

Bus bars


There are different sizes of busbars.
  • 40x4mm
  • 40x5mm
  • 60x8mm 
  • 50x6mm 
  • 80x8mm 


Circuit Breakers

A circuit breaker is a device which is work in normal and abnormal conditions To secure the electrical system. A circuit breaker is used to make and break the electrical system. There are different sizes, shapes and ratings of Circuit breakers. the circuit breaker categories as Indoor circuit breaker and outdoor circuit breaker w.r.t services.

Types of Circuit Breakers W.r.t construction:

  1. High voltage circuit breaker(HV)
  2. Medium voltage circuit breaker(MV)
  3. Low voltage circuit breaker(LV)

Lightning Arrester

A lightning arrester is a component that protects from the damaging effects of lightning. there are different types of lightning arrestersThey are used in towers, transmission poles, buildings and substations.

lightning arrester

Types of Lightning Arrester

  • Horn Gap Arresters
  • Valve-Type Arresters
  • Pellet-Type Arresters

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