Advantages and disadvantages of three phase transformer

A three-phase transformer is used as a step up and step down for Ac voltage in various stages of a power system. Here this post gives the advantages and disadvantages of 3 phases transformed to better understand this topic.

Advantages of three phase transformer:

  • It is lighter and smaller.
  • High efficiency.
  • It occupies less floor space for equal rating.
  • It requires a few bushing. 
  • Less transformer oil is used.
  • Less external wiring.
  • Less material for the same three-phase power ad voltage rating
  • Low cost compared with three units of single-phase transformer.
  • Transportation is easy and also the transportation cost is less.
  • Bus bar structure and switcher installation for a single three-phase unit are simpler.
  • Being prewired and ready to install these can be easier to install. 
  • To provide the same KVA the core material required is very less compared to a bank of three single-phase transformer.
  • Only three-terminal is required to be brought out in the case of a three-phase transformer.
  • It requires 1/3 as much iron for the magnetic circuit as compared to a bank of three 1 phase transformer.

Disadvantages of three-phase transformer:

  • If the failure of only one phase puts the entire transformer out of service.
  • Great cost study unit.
  • Additional cost and inconvenience of repair, so cost is more.
  • To restore the service, the spare unit cost is more compared with one single phase transformer.
  • When some of the case these are self-cooled, so the capacity of the transformer is reduced.
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