Rating of the first transformer: 10 mva 110/11 kv, impedance: 10%

Rating second transformer : 10 mva 110/11 kv, impedance: 12%

kindly inform me which one will be the better option

as per my opinion second transformer will be good as its impedance is higher, so fault current will be less.

kindly tell me whether i m right or wrong

 

Sounak Nandi... there is no right or wrong answer. Your question can not be properly answered unless you provide a specific goal:

1) To minimize Short-Circuit Duty? (Hardly a concern for typical switchgear capability)

2) To minimize Voltage Regulation, that is to reduce the voltage-drop between no-load, and rated load? (Actually depends on load power-factor)

3) To maximize Efficiency? (Usually depends on load-profile)

If you need additional information, please try to be more specific as to you requirement.

Regards, Phil