Extended Wing Technique Approach for the Detection of Winding Interturn Faults in Three-phase Transformers Makarand Sudhakar Ballal†, Hiralal Murlidhar Suryawanshi*, and Bhupesh Nemichand Choudhari** †*Department of Electrical Engineering, Visvesvaraya National Institute of Technology, Nagpur, India **Department of Electrical Engineering, P. E. S. College of Engineering, Aurangabad, India

Abstract
This paper presents a novel approach to diagnose interturn insulation faults in three-phase transformers that operate at different loading conditions. This approach is based on the loci of instantaneous symmetrical components and requires the measurement of three input primary winding currents and voltages to diagnose faults in the transformer. The effect of unbalance supply conditions, load variations, constructional imbalance, and measurement errors when this methodology is used is also investigated. Wing size or length determines the loading on the transformer. Wing travel and area determine the degree of severity of fault. Experimental results are presented for a 400/200 V, 7.5 kVA transformer to validate this method.

LINK
http://manuscript.jpe.or.kr/ltkPSWeb/pub/pubfpfile.aspx?ppseq=973

A novel pulsewidth modulation to operate a bidirectional two-stage dc-ac converter with high-frequency isolation in discontinuous conduction mode

A novel pulsewidth modulation to operate a bidirectional two-stage dc-ac
converter with high-frequency isolation in discontinuous conduction mode
for photovoltaic applications
Montserrat Mata Dumenjo (1), Sergi Busquets Monge (2), Jaume Diest Yus (3), Joan
Rocabert Delgado (2), Mireia Barenys Espadaler (2), Joan Nicolás Apruzzese (2), Joan Salaet
Pereira (2)
(1) ALSTOM-ECOTÈCNIA
C/ Roc Boronat 78 Barcelona, Catalunya
Tel. 34 93 2257600 montserrat.mata@power.alstom.com
(2) UNIVERSITAT POLITÈCNICA DE CATALUNYA
Av. Diagonal 647 Barcelona, Catalunya
Tel. 34 934017152 sergio.busquets@upc.edu
(3) DISSENY DIEST
C/ Castillejos 424 Barcelona, Catalunya
Tel 934363999 jd@diestdisseny.com
Acknowledgements

LINK RESUMO:
http://caveromiranda.galeon.com/pulsewidth.pdf

Design of Transformer and Power stage of Push-Pull Inverter

Design of Transformer and Power stage of
Push-Pull Inverter
Milomir Šoja, Slobodan Lubura, Dejan Jokic, Milan D. Radmanovic, Goran S. Dordevic,
and Branko L. Dokic
Abstract—In this paper is presented the example of
construction of push-pull inverter that can be used in two
different topologies, with two input voltages and three
power ratings which can at the same time achieve AVR
function and “power-save” feature. Special attention was
paid to scheme, turn ratio calculation and transformer coil
windings arrangements that with only two types (of
different power ratings) allows realization of large number
of push-pull inverter configurations that can be applied to

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