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Equipment in a 132 KV substation

The equipment required for a transformer substation depends upon the type of substation, service requirement and the degree of protection desired. 132KV substation has the following major equipment.

132 kV substation training for students
132 kV substation training for students


When a number of lines operating at the same voltage have to be directly connected electrically, busbar are used, it is made up of copper or aluminum bars (generally of rectangular X-Section) and operate at constant voltage.

The bus is a line in which the incoming feeders come into and get into the instruments for further step up or step down. The first bus is used for putting the incoming feeders in LA single line.

There may be double line in the bus so that if any fault occurs in the one, the other can still have the current and the supply will not stop. The two lines in the bus are separated by a little distance by a conductor having a connector between them.

This is so that one can work at a time and the other works only if the first is having any fault.

Transmission line disconnect switch
Transmission line disconnect switch (photo by Efrem Oshinsky @ Flickr)


The insulator serves two purpose. They support the conductor (or busbar) and confine the current to the conductor. The most commonly used material for the manufactures of insulators is porcelain.

There are several type of insulator (i.e. pine type, suspension type etc.) and their use in substation will depend upon the service requirement.

Post insulators are used for the busbars. A post insulator consists of a porcelain body, cast iron cap and flanged cast iron base. The whole cap is threaded so that busbars can be directly bolted to the cap. When the line is subjected to a greater tension, strain insulators are used.

When tension in line is exceedingly high, two or more strings are used in parallel.

Isolating Switches

In a power substation, it is always desired to disconnect a part of the system for general maintenance and some repairs. This is accomplished by an isolating switch or isolator.

An isolator is originally a knife switch and is design to often open a circuit under no load. Isolator switch operates only when the line is which they are connected to carry no load.

For example, consider that the isolator is connected on both sides of a cut breaker, if the isolators are to be opened, the circuit breaker must be opened first. If an isolator is opened carelessly, when carrying high current the resulting arc easily causes flashover to earth.

This may batter the supporting insulators and may even cause a fatal accident to the operator, particularly in the high voltage circuit.

The operating principle is manual plus one of the following:

  1. Electrical Motor Mechanism
  2. Pneumatic Mechanism

Isolators cannot be opened unless the Circuit Breakers are opened. Circuit Breakers cannot be closed until isolators are closed.

ABB - High voltage dead-tank circuit breaker 362 kV, max. 63 kA 362PMI
ABB – High voltage dead-tank circuit breaker

Circuit breakers

A circuit breaker is an equipment, which can open or close a circuit under normal as well as fault condition. These circuit breaker breaks for a fault which can damage other instrument in the station.

It is so designed that it can be operated manually (or by remote control) under normal conditions and automatically under fault condition. A circuit breaker consists of fixed and moving contacts, which are touching each other under normal condition i.e. when breaker is closed.

Whenever a fault occurs trip coil gets energized, the moving contacts are pulled by some mechanism and therefore the circuit is opened or circuit breaks.

When circuit breaks an arc is stack between contacts, the production of arc not only interrupts the current but generates enormous amount of heat which may cause damage to the system or the breaker itself.

Therefore the main problem in a circuit breaker is to extinguish the arc within the shortest possible time so that the heat generated by it may not reach a dangerous value.

Title:132 KV substation basic training for students – Rahul Saha (JIS School of Polytechnic)
Size:1.50 MB
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132 KV substation basic training for students
132 KV substation basic training for students

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  1. Sivanand.PA
    Jul 19, 2022

    It will be better to understand about substations

  2. Poloko Mokgopanyane
    Jun 14, 2021

    I’m currently undergoing a learnership program in Electrical engineering.
    I’m in need of a host employer to assist with my training. Please help, willing to volunteer.

  3. Thando
    Sep 16, 2019

    Thanks for the helpful in information
    If I may ask, why is the transformer, circuit breaker, CT and isolators connected in series with the line and VT in parallel?
    Thank You

    • Joe Chinda
      Mar 08, 2021

      Circuit breakers are connected in series with the load in order to disconnect the power in the event there was a fault. When it is connected in parallel it means that when the circuit breakers are tripped power supply will still flow .

      CT are connected in series because of current has to be same
      VT is connected in parallel to maintain the voltage.

      • Soodha Tharun
        Sep 28, 2021

        I want to train at 132/133 substation Dharmavaram

  4. Kabelo
    Jul 04, 2019

    Very interesting, where can I do this training?

  5. Zolani Ndadane
    Jun 27, 2019

    I don’t have comments but I need training for Hv over head lines (Towers)

  6. Ravindra Wali
    Dec 20, 2018

    Thank u so much,good job
    And very easily understand

  7. Paul Aronsohn
    Dec 20, 2018

    I am very impressed that your engineering training includes an experience like this. As an electrical engineer I did not get this type of experience during my college education.
    I would like to suggest including diagrams in your report. At minimum a single line diagram of the system would be very useful. Otherwise a very thorough report.
    Good luck in your education and career.

  8. Sicelo
    Dec 20, 2018

    Thanks that was very informative this will help me as an Electrical Technician in Training. My company generates 11kv and step it up to 132kv.

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