Transformer Maximum MVA Rating

What is the maximum and minimum MVA ratings of following transformers used in transmission and distribution of power-

1 .66KV/11KV transformers

2.132KV/11KV Transformer

  1. What is the criteria on which the manufacturers decides the MVA rating

asked 7/9/2013

2 Answers

The minimum transformer is 6.6 MVA and range can be as maximum as per the application keeping in view following factors a) Voltage drop, b) Distance, c) type of conductor and d) temperature.

answered 10/28/2013 Sathya Narayana JE E/M 46
Sathya Narayana JE E/M
Voltage grade wise Transformer rating depends on Supply company rules and regulations. Highest rating of Transformer in a particular voltage grade depends on % voltage drop allowed which depends on Amperage and distance/length of line.
For Example:
I need 500MVA at 50 Km then it may not be suitable through 11/0.4KVTransformer because of the higher voltage drop being huge current. This is the way to restrict highest rating of the transformer in a particular voltage grade.
Similarly for minimum rating.
answered 9/13/2013 Er. S K Pal 2
Er. S K Pal
  • Thanks for your reply.Can you guide
    1. What is the % voltage drop allowed for EHV systems considering maximum amperage and maximum distance allowed(thumb rule based )?
    2. Also is there a restriction on Maximum MVA rating for transformers for particular voltage grades like 31.5MVA in 66KV grade,100MVA in 220KV grade,315MVA in 400KV grade. There is manual on this subject by Dakshin Haryana Bijli Vitram Nigam Ltd,India which I can mail to you. - ram31 9/29/2013

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