short circuit calculation.

There is a free modelling software available (ATP-EMTP) that provides modelling solutions for this type of problem. You can find it through Google- I'm sorry I don't have a direct link for this available at present.

Thankyou. But, I need a simple calculation ,which gives me the shortcircuit current for my particular problem.

There is no simple calculation except an estimate based on the voltage ratio of the transformers and the impedance, with broad generalisations for any further complex unknowns.

Try a search of CR4 as this is a common question, and i have answered it numerous times (many with links).

If this is homework, we don't do homework. If this is for a job, you clearly don't understand power transformer theory (as post #2 was the answer), so try asking either a power engineer at work or perform a search on Google or Wikipedia for the detailed math.

Remeber SSCR is based on the weakest link in your system. For example if I have a control panel and all the parts, power supply, UPS, PLC, and circuit breakers have a SSCR of 10,000 Amps and the terminal blocks in the panel have 5,000 Amp then the SSCR for the panel is 5,000 Amps. You wanna protect the weakest chain in your system.

I'm not sure if this even helps, but this is how I determine the SSCR for control panels I design and build. Usually manufactures list the SSCR on parts that are typical UL listed. So I would collect all the data sheets and list them all down.

If this is a UL listed part, UL inspectors will be looking out for this. It has happen to me a couple of times.

Multiply the voltage times the impedance. (Short method). Or take the total connected motor load time 4 and 10 times the current of your primary source.