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# What are the effects of short-circuit impedance on transformers

2021-04-01

What is the short-circuit impedance? Varelen transformer manufacturer introduced that the short-circuit resistance is the resistance formed by the electrical short circuit, which refers to the equivalent series impedance Zk=Rk+jXk between the terminals of a certain winding in a pair of windings at the rated frequency and the reference temperature. Because its value is determined by load test in addition to calculation, it is customarily called short-circuit voltage or impedance voltage.

Short-circuit impedance means that the secondary side of the transformer is short-circuited and voltage is applied to the primary side. When the current is rated, the voltage applied to the primary side is the percentage of the rated voltage of the primary side. So, what effect does the short-circuit impedance have on the transformer? Next, follow Varelen transformer factory to find out.

If the short-circuit impedance is large, the voltage drop of the transformer will be large, but the short-circuit current will be smaller when a fault occurs.

The short-circuit impedance is small, the voltage drop of the transformer will be smaller, but the short-circuit current will be larger when a fault occurs.

The short-circuit impedance will affect the size, structure, and material of the transformer.

The Varelen transformer factory believes that the short-circuit impedance of the transformer should not be present, because the smaller the short-circuit impedance, the more damage the transformer itself will be, and the short-circuit current tends to be infinite. The output circuit of the transformer is connected in parallel to the output line. the resistance of the parallel circuit becomes smaller and smaller. Therefore, when the load exceeds a certain value, the transformer will heat up severely, and various protections will act in succession to cut off the power supply. , Which protects the transformer from damage.