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What is the difference between Power Transformers and Distribution Transformers?

 Those transformers installed at the ending or receiving end of long high voltage transmission lines are the power transformers. The distribution transformers (generally pole mounted) are those installed in the location of the city to provide utilization voltage at the consumer terminals.
  •  Power transformers are used in transmission network of higher voltages for step-up and step down application (400 kV, 200 kV, 110 kV, 66 kV, 33kV) and are generally rated above 200MVA.
  • Distribution transformers are used for lower voltage distribution networks as a means to end user connectivity. (11kV, 6.6 kV, 3.3 kV, 440V, 230V) and are generally rated less than 200 MVA.
  • A power transformer usually has one primary and one secondary, and one input and output. A distribution transformer may have one primary and one divided or “Tapped” secondary, or two or more secondaries.
  • Power transformers generally operate at nearly full – load. However, a distribution transformer operates at light loads during major parts of the day.
  • The performance of the power transformers is generally judged from commercial efficiency whereas the performance of a distribution transformer is judged from all – day – efficiency.
  • The rating of a high transformer is many times greater than that of distribution transformer.
  • In Power Transformer the flux density is higher than the distribution transformer.
  • Power transformer’s primary winding always connected in star and secondary winding in delta while in distribution transformer primary winding connected in delta and secondary in star.
  • In The Sub station end of the transmission line, The Power Transformer Connection is Star-Delta.( For the purpose of Step down the Voltage Level)
  • In the star up of the  Transmission line (H-T), The Connection of the power Transformer is Delta – Star (For the purpose of Step Up the Voltage Level) But in case of Distribution Transformer, But Generally it is used in there-phase Step down distribution transformer( Delta – Star).

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difference between Power Transformers and Distribution Transformers

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  1. power transformer are not always connected in star primary side, pls correct it…

  2. the first two lines say that power and distribution transformers have same ratings but down its written that power transformer has greater ratings as compared to distribution.

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  4. Distribution transformers rated upto 750kVA.<br />Power transformer mostly use delta star connection

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  6. manishkumar v. bhoot

    Its very nice general knowledge for us which is provided by this side

  7. i really appreciated this interesting website i think this is not only for current generation but, for the next……

  8. The power rating cut off stated above is not a standard,you could have power transformer at a 132kv sub station rated 30,45,60mva .yes as low as that, also distribution transformers can be as low as 15mva.even the winding arrangement is not general cos a power transformer could have a tertiary winding 11kv in addition to the secondary which means the star delta rule is not applied here.

  9. Very nice general knowledge

  10. guys help us to add on my professional in electricity

  11. Eng Hankumba Miyanda

    on the last two statements,i would love you to shed more light on it, because what i know is for a step up tx- we have star delta and step down is the other way round because you want to have a neutral for distribution purposes.

  12. That’s good to know that distribution transformers are used for lower voltage distribution networks as a means to end user connectivity. I guess it doesn’t need as much voltage when it’s not traveling as far. After moving to the city and seeing transformers all over the place, I was wondering what the difference was.

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