Analytic Computation of Inrush Current and Finite Element Analysis of Magnetic Field in Power Transformers

Energizing unloaded transformers may result in magnetizing inrush current of high amplitude. These currents have many unfavorable effects including differential protection mal-operation, deterioration of the insulation material and mechanical support structure of windings, voltage sag and other power quality issues on the HV, as well as on lower voltage terminal(s). An analytic method is presented for computation of inrush current in transformer. The simulation results obtained by this proposed method are compared with the measured values. A compact three-phase, core-type 132/20 kV, 30 MVA, power transformer is modeled, employing two-dimensional (2-D) FEM, magnetic field analysis is evaluated. Since the inrush current lasts longer, and normally occur more frequent than a short circuit in a power transformer it can be a serious threat to damage of transformer windings.

کلیدواژه ها:

Finite-element ، inrush current ، magnetic field ، power transformer ، short circuit