Calculation of KVA or MVA capacity of single phase and three phase transformer - Electrical C & V

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# Calculation of KVA or MVA capacity of single phase and three phase transformer

KVA-kilo volt ampere or MVA- mega volt ampere is the main rating of a transformer. Most power transformers are rated for KVA and MVA. To calculate KVA and MVA, firstly multiply the maximum voltage between the lines from line to line, with the maximum current of the phase. If your system is in 3-phase then you will have to multiply it by 1.732. If your system is of single phase, then you just have to multiply the maximum voltage between the line and neutral by the maximum current of the phase. In single phase you do not have to multiply by 1.732. Then you will divide the final result that comes in the last by 1000, then your result will come in KVA and if you do 100,000 then your result will come in MVA.

Mathematical calculation for KVA and MVA for transformer:

This calculation applies to both primary and secondary winding of the transformer.

V = line to line voltage (maximum) or line to neutral maximum voltage,
I = phase current (maximum)

1. KVA calculation

For single phase KVA = (V * I) / 1000
For three phase KVA = (V * I * 1.732) / 1000

2. MVA calculation

For single phase MVA = (V * I) / 1000,000
For three phase MVA = (V * I * 1.732) / 100,000

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