In this paper, a new model based on the thevenin equivalent circuit for investigating the ultra-saturation phenomenon during the energization of a loaded power transformer is presented and its effect on the differential protection of the transformer is considered. The ultra-saturation phenomenon causes the mal-operation of the power transformer differential protection. So, the description a...

Power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. Once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. The resonant overvoltages may destroy the insulation between turns and cause to insul...

We present an automatic source-level transformer for DSP applications written in MATLAB. Our transformer is based on a novel approach to specify the transformations in an XML-based language resulting in a simple implementation of the transformer as a rewriting engine. In an earlier study we have identified transformations that pay off handsomely for DSP applications. This paper describes the d...

The modeling of power transformer faults and its application to performance evaluation of a commercial digital power transformer relay are the objective of this study. A new method to build an EMTP/ATP power transformer model is proposed in this paper. Detailed modeling of the transformer relay is also discussed. The transient waveforms generated by ATP under different operating conditions are ...

In transformers the main consequence of harmonic currents is an increase in losses, mainly in windings, because of the deformation of the leakage fields. Higher losses means that more heat is generated in the transformer so that the operating temperature increases, leading to deterioration of the insulation and a potential reduction in lifetime. This paper includes the effects of non-sinusoidal...

DC bias current flowing into the neutral point of power transformer will seriously affect the normal operation of AC power system. In this paper, exciting current, harmonic component of the excitation current, magnetic flux density and noise of transformer were analyzed when the transformer is in the no-load operation state based on field-circuit coupled method. Through the calculation and anal...

Energizing of large power transformers is considered a critical event in the operation of an electric power system. When a transformer is energized by the grid or utility, it takes very high value current known as inrush current, the typical value of this current could be ten times. This inrush causes many problems like mechanical stress on transformer & harmonics injection to generator winding...

In this study, a modified disk-shaped multiple-output piezoelectric transformer operated at the fundamental radial vibration mode has been presented. A derived equivalent circuit for the multioutput piezoelectric transformer was used to analyze the performance. Two piezoelectric transformers, a symmetrically electroded piezoelectric transformer with dual outputs and an asymmetrically electroded...

For flyback coverters, the transformer is the most important factor that determines the performance such as the efficiency, output regulation and EMI. Contrary to the normal transformer, the flyback transformer is inherently an inductor that provides energy storage, coupling and isolation for the flyback converter. In the general transformer, the current flows in both the primary and secondary ...