What is Transformer Impedance?

You would have to give a lot more information. What is this in relation to?

Transformer Impedance is an inherent electrical characteristic which opposes the flow and change in current and voltage. It is due to many factors such as winding resistance, inductance and capacitive effect in both windings and core. We can use the impedance value to calculate short circuit current in case of a failure. A related value known as percent impedance can also be used to match transformer performance when operating in parallel.

Do not confuse with Impedance Transformer which is a special type of transformer used to increase the impedance effect of a load in oder to achieve a high impedance input as in a PA system.

Hi,

Short the Secondary of the Transformers. Apply simmulated Volatge (433 V) to HV. The percentage of the rated volatge which applied causes rated current to flow gives the percentage Impedance. This is the simplest way of execution.

Regards,

N.Suresh

"Short the Secondary of the Transformers. Apply simmulated Volatge (433 V) to HV. The percentage of the rated voltage which applied causes rated current to flow gives the percentage Impedance. This is the simplest way of execution."

first,find FLA (full load ampere) of transformer. for example, 10 MVA , 11/33 KV transformer. I FLA in primary side is 524 Amps.

second, apply test voltage when secondary side shorted. apply from 0 Volt, increase to 100 V, 200V,....433 V untill we get current in primary side of transformer reach 524 Amps.

that 433V value devide by 11KV times 100% is the xfmr impedance.

XFMR Z is also critical for figuring voltage drop and flicker calcualtions. If you have conductor length, type of conductor(al or cu), and other characteristics, you can figure the amount of flicker for a load on the circuit.

The answer is very easy in case of an ideal transformer:it just depends from the load in the secondary:If impedance in secondary is Zo,then impedance you see in primary is:Zi=Nr.Zo.In casr Zo be a resistance r,the intensity in the primary is reduced in way to make true that equation (case tanformer voltage reducer) So now, can you get the Nr value?