Design and Testing of Low Loss Distribution Transformer for Non-Linear Loading Current

This paper is a critical review of metasurfaces, which are planar metamaterials. Metamaterials offer bespoke electromagnetic applications and novel properties which are not found in naturally occurring materials. However, owing to their 3D-nature and resonant characteristics, they suffer from manufacturing complexity, losses and are highly dispersive. The 2-dimensional nature of metasurfaces allows ease of fabrication and integration into devices. The phase discontinuity across the metasurface offers anomalous refraction, thereby conserving the good metamaterial properties while still offering the low-loss characteristics. The paper discusses salient features and applications of metasurfaces; wavefront shaping; phase jumps; non-linear metasurfaces; and their use as frequency selective surfaces (FSS).

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Investigation of a sinusoidaly supplied transformer under linear and non-linear loading conditions

TENCON 2008 - 2008 IEEE Region 10 Conference ◽

10.1109/tencon.2008.4766464 ◽

2008 ◽

Cited By ~ 1

Author(s):

M. Salih Taci ◽

M. Hadi Sarul

Keyword(s):

Loading Conditions ◽

Non Linear ◽

Linear Loading

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Ferroresonance in low-loss distribution transformers

2003 IEEE Power Engineering Society General Meeting (IEEE Cat. No.03CH37491) ◽

10.1109/pes.2003.1270502 ◽

2004 ◽

Cited By ~ 3

Author(s):

R.A. Walling

Keyword(s):

Low Loss ◽

Loss Distribution ◽

Distribution Transformers

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Modified Distribution Transformer for Enhancing Power Quality in Distribution Systems

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v7.i4.pp1386-1392 ◽

2016 ◽

Vol 7 (4) ◽

pp. 1386

Author(s):

Preetha P.K. ◽

P.S. Chandramohanan Nair

Keyword(s):

Power Distribution ◽

Distribution Systems ◽

Experimental Studies ◽

Considerable Improvement ◽

Distribution Transformer ◽

Maximum Power Point ◽

Non Linear ◽

Power Point ◽

Day By Day ◽

Harmonic Power

<p>The percentage of non-linear loads in the power distribution sector is increasing day by day. Harmonics injected by these non-linear loads circulate in the delta windings of the conventional distribution transformer thereby increasing the temperature and losses. This reduces the efficiency and life of the transformers. In a modified distribution transformer configuration proposed recently, called star-star-delta_utilized configuration (YYD_utilized), the harmonics circulating in the delta winding was utilized and the drainage power thus recovered was used to power auxiliary loads. This paper presents the experimental studies conducted on YYD_utilized distribution transformer. When compared to conventional star-star, delta-star and star-star-delta transformers, the new configuration of YYD_utilized transformer has shown considerable improvement in transformer efficiency. The results obtained show that when the power from the circulating harmonics is recovered and utilized, it not only improves transformer efficiency but also improves the power factor and reduces the harmonic distortions at the primary side of the transformer. The results obtained also suggest the existence of maximum power point or an optimum loading for the recovered harmonic power.</p>

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Effect of load current harmonics on vibration of three-phase generator

MATEC Web of Conferences ◽

10.1051/matecconf/201819711023 ◽

2018 ◽

Vol 197 ◽

pp. 11023

Author(s):

I Made Wiwit Kastawan

Keyword(s):

Single Phase ◽

Electrical Power ◽

Electrical Power System ◽

Negative Effects ◽

Load Current ◽

Current Harmonics ◽

Three Phase ◽

Non Linear ◽

Electrical Loads ◽

Linear Loading

Almost all today electrical loads are considered non-linear such as switch mode power supply (SMPS) for powering computer and mobile phone or variable speed drive (VSD) for driving home and industrial electric motors. These loads generate ac non-sinusoidal current containing a lot of harmonics as indicated by its high total harmonics distortion (THD) figure. Current harmonics bring negative effects into all electrical power system components, including three-phase generator. This paper provides analysis of load current harmonics effects on vibration of three-phase generator. Three different laboratory experiments have been conducted i.e. three-phase linear resistive loading, non-linear loading with a three-phase ac/dc converter and non-linear loading with three single-phase capacitor filtered ac/dc converters. Results show that the higher load current harmonics content the higher is vibration of the three-phase generator. Non-linear loading with a three-phase ac/dc converter that generate about 24.7% THD gives an increase of 4.3% and 5.5% in average of vertical and horizontal vibrations of the three-phase generator respectively. Further, non-linear loading with three single-phase capacitor filtered ac/dc converters that generate THD as high as 74.9% gives significant increase of 28.1% and 23.6% in average of vertical and horizontal vibrations respectively.

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