TRANSFORMER INRUSH CURRENT PREDETERMINATION FOR DISTORTED WAVEFORM VOLTAGE SUPPLY

摘要

The magnetization current surged by a no-loaded power transformer at the connection instant has extremely high values. These inrush currents generate a significant electrodynamic and thermal stresses on the transformer windings and could determine the faulty operation of the protecting equipment devices. Moreover, since the majority of power distribution systems are affected by harmonic pollution, the applied voltage at the energizing moment has a non-sinusoidal waveform. Thus, the paper presents a predetermination of both the inrush current peak value and its harmonic spectrum under a distorted supply voltage waveform. Starting from the transient state equations along with a particular description of transformer core H-B nonlinear characteristic and core stacking factor value, the inrush current time evolution is accurately predicted.