Electromagnetic Wave Hazard of Power Transformer

Due to the inherent hysteresis of ferromagnetic materials, residual magnetic remanence will remain in the iron core after the operation of the voltage ratio and DC resistance measurement of the power transformer. Because of the existence of remanent magnetism, when the transformer is put into operation, the core remanence makes the transformer core half cycle saturated, and produces a large number of harmonics in the excitation current, which not only increases the reactive power consumption of the transformer. And may cause the relay protector misoperation, resulting in certain economic losses. So we must do degauss work before the transformer put into operation to ensure the transformer safe and normal operation.