What Should Be Checked for Transformer Differential Protection When Transformer is Put into No-load Operation?

What Should Be Checked for Transformer Differential Protection When Transformer is Put into No-load Operation?

Transformer differential protection, in the new installation of the transformer must be under rated voltage to do 5 times of no-load test. The secondary wiring should be checked and ensured to be correct before no-load input. The no-load input test should be carried out on the large power supply side and the low voltage side of the transformer, because the system impedance and transformer leakage reactance can limit the excitation inrush current, and the large power supply side system impedance is small, and the transformer low-voltage winding is wound inside, leakage reactance is small, so the inrush current is large when the large power supply and low voltage side input. During the test, the protective device should not operate once, otherwise the action current of the relay should be increased.