Transformer Rating

Yes somebody can tell you this.

do you have space limitation? if not then MVA rating of 230/33kV can be varied.

i would say 250 - 350 MVA rating is applicable for such voltage. Bigger MVA can also considered taking into account your space limit & transportation method

The Stepdown voltage directly from 220KV to 33KV to be considered in brief, because the substation class of voltages is not a standard class, but you have such ranges based on requirements. Is this a Distribution Substation transformer directly in the customer premises? , then a lot of Protection requirements have to be considered.

As per the previous comments of 250-350MVA is a huge rating in 33KV side i.e, around 4500-6300A. ABB just manufacture's 3600A circuit breaker for 36KV class, means a Max. of 150MVA can be used for such a voltage range. it will be a complex model to be considered with a serious hand in good substation designers.

Hello Amarnath.sn,

perhaps you can take a look to CG Power Systems capability. They had built 3 nos 250 MVA 17/220kV Tx for Ramagundam Thermal power plant. Their switchgear's plant capability also amazing,but not so sure.

However i am pretty sure that ABB/AREVA has an ability to produce switchgear with very high current to be applied for such specification, but price dependency will play most significant role .

This is a good post.

How about if we calculate manually? I think that power factor should also be taken into account.

This question could mean you have this transformer, in which case the rating will be stamped on it. The maximum will be what it was built for. You dont pick up a trandformer and hope for the best. You order and specify you MVA up front first. ie. your requirements are designed in and then built. BUT if the nameplate disappeared, it will be best to open it up and start from the wire size in the windings, etc.

Of course. It will be on an indelible label permanently attached to it and the circuit protective device(s) will be set to trip if this rating is exceeded.