Transformer impedance is the winding impedance of coil in transformer which include resistance, inductive reactance and capacitive reactance. The transformer has requirement for impedance and loss. Some users raise or reduce the impedance voltage, the loss follow the standard set before may it is unreasonable. If the impedance voltage decrease, the no load loss need to increase, the load loss need to decrease. If the impedance voltage increase, the no load loss need to decrease and the load loss need to increase.
The transformer impedance use percentage to show. The standard values of different transformers are stipulated in the national standard of transformers. But there are errors in the manufacture of transformers. The margin of error is between +7.5% and -7.5%.The short-circuit impedance of transformer is related to many factors of transformer. Such as transformer capacity, loss, internal coil structure and so on. But once the transformer is made, it doesn’t change. The short-circuit impedance of a transformer is its own impedance. The impedance is large, the transformer needs to resist short circuit current multiples are small, relatively strong short circuit resistance. On the contrary, the short circuit impedance is small, the transformer needs to resist short circuit current multiple is large, the transformer is required to have a strong ability to resist short circuit. Of course, the external characteristics of the transformer is good. In addition, short-circuit impedance will affect the cost of transformer manufacturing. It’s not that the bigger the better, or the smaller the better.