The transient process of iron core transformer no-load closing

Iron core transformer no-load switching-in of transient process - 2019 03 - 30 15:05:59 single-phase transformer as an example to analyze the transient process of transformer no-load closing. Transformer primary side of the input voltage for the type of Um for voltage amplitude values; ω For the power of angular frequency; α For voltage switching Angle. In transformer no-load closing moment type: R is a lateral loop resistance; L for primary side loop inductance, in ignoring a winding leakage inductance of the case, L approximation for transformer excitation inductance; I for the excitation current. Considering the transformer excitation current of transformer no-load closing time is zero, by type ( 2) Field current can be obtained for the transformer core saturation before, if can get excitation flux for core remanence exists inside, as the core in the transformer magnetic flux as type remanence instantaneous value after closing. References [ 8] , remanent magnetization can be said for type of transformer core remanence initial value. Due to transformer transient flux component and the effect of iron core remanence, under the condition of a variety of switching transformer core within the total magnetic flux to the timeline of a side, the side of the transformer magnetic flux will increase greatly. When the transformer magnetic flux increases to saturate the transformer core, transformer will appear excitation inrush current.