How to calculate the short-circuit impedance of the transformer during the short-circuit test

How to calculate the short-circuit impedance of the transformer during the short-circuit test

The short-circuit impedance of a transformer, also known as the impedance voltage, is an important parameter of a transformer,It reflects the impedance voltage drop of the transformer itself when the rated load is running. The specific calculation method is as follows: Test steps: First, short-circuit the secondary side winding of the transformer. Then, an AC voltage of rated frequency is applied to the primary side winding. Gradually increase the voltage until the primary current reaches the rated value. At this point, record the voltage Uz applied on the primary side winding.

Calculation formula: Finally, according to the recorded voltage Uz and the rated voltage Un of the transformer, the proportion of short-circuit impedance can be calculated.The formula is Uz% = Uz/Un × 100%. This percentage is the short-circuit impedance of the transformer.

In addition, the short-circuit impedance test can not only check the condition of the transformer after the impact of the short-circuit current in operation but also assess whether the internal structure of the transformer is intact, such as whether the winding is deformed or displaced.

In general, through the short-circuit impedance test and calculation, you can have a comprehensive understanding of the performance of the transformer, to ensure its stable operation in the power system.