Why is transformer rating given in kva?

KVA is AC power, so a certain size transformer can only handle a certain amount of power.

Hi buddy,but I think the answer is related to power factor.as KW is given as VI because o and KVA as VI only.

VA is AC power, which takes PF into account. That is why watts is volts x amps x PF.

If a xfer is rated in watts, it will be only for resistive load with a PF of 1.0 or unity. A xfer rated in VA can provide ac power, with a certain component of lagging PF allowed.

A xfer could handle an increased amount of power relative to the leading PF up to Unity with a purely resistive load, this adds a safety margin when used with the everyday inductive characteristics with typical AC loads.