نتایج جستجو برای: ultc transformer

تعداد نتایج: 11492  

Journal: :Genes & development 1991
W Mattox B S Baker

The Drosophila transformer-2 gene uses alternative promoters and splicing patterns to generate four different mRNAs that together encode three putative RNA-binding polypeptides. The transformer-2 products expressed in somatic tissues function to regulate the RNA splicing of the sex determination gene doublesex, whereas products expressed in the male germ line play an unknown, but essential, rol...

2009
M. R. Dolatian A. Jalilian

The behavior of three phase five leg transformer under voltage sag is studied in this paper. This paper proposes a simple, practical model of a three phase-five leg, saturated transformer with accurate performance. Transformer saturation is produced when the voltage sag is recovered and it causes inrush current in transformer. Effects of voltage sag depth, duration and initial point on wave hav...

2003
John H. Brunke Klaus J. Fröhlich

Transformer inrush currents are highmagnitude, harmonic-rich currents generated when transformer cores are driven into saturation during energization. These currents have undesirable effects, including potential damage or loss-of-life to the transformer, protective relay misoperation, and reduced power quality on the system. Controlled transformer switching can potentially eliminate these trans...

Nowadays, multi-winding transformers are widely used in traction systems and steel manufacturer.  Multi-winding transformer that is used in these systems has especial geometry (that is usually called as split-winding transformer) and encounters with serious magnetic and thermal difficulties. According to the special geometry of split-winding transformer, studding the transient thermal behavior ...

2009
Young-Dal Kim Jae-Myung Shim Woo-Yong Park Sung-joong Kim Dong Seok Hyun Dae-Dong Lee

The most common cause of power transformer failures is mechanical defect brought about by excessive vibration, which is formed by the combination of multiples of a frequency of 120 Hz. In this paper, the types of mechanical exciting forces applied to the power transformer were classified, and the mechanical damage mechanism of the power transformer was identified using the vibration transfer ro...

2011
Amit Kumar Yadav Abdul Azeem Hasmat Malik O. P. Rahi

The power transformer is one of the most important equipment in a power system. Optimal design of transformer involves determination of design parameters of a power transformer when a chosen objective is optimized, simultaneously satisfying a set of constraints. In this paper Simulated Annealing (SA) is used for optimization of Power Transformer Design (OPTD).The total mass of core and copper i...

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...

J Gholinezhad Reza Shariatinasab, Z Ejtemaee

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...

Journal: :Journal of Electrical Engineering and Technology 2013

2004
Arun Chauhan Ken Kennedy Arthur Conon Doyle

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...

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