The losses and temperature comparison in three-phase distribution transformer with various assembly core designs

ABSTRACT

Losses in a three-phase transformer can be minimised to a considerable extent by improving the core design. In this paper, a new proposed model (hexagon and hemisphere) of T-joint designs is presented as one of the solutions to reduce the losses for a three-phase transformer. The behaviours of magnetic flux density, load variation, core and winding temperature have been considered and discussed accordingly in this study. The losses of the core and windings were considered a heat source inside the transformer. A nonlinear behaviour of the core material and a 3D finite-element method were employed for the simulation of the proposed models of the transformer cores. The simulation results of the proposed models showed a reduction of no-load and total losses ranging from 7% to 16% compared with the conventional designs. The verification of the results was compared with the experimental results for the 1 MVA and the 11/0.433 kV distribution transformer. This work confirms that it is still possible to reduce the losses of transformer by reassembling the core, particularly in the joint area.

KEYWORDS:

• Power transformer
• core loss
• flux density
• joint design
• finite-element method

Acknowledgements

The authors would like to thank the Centre for Electromagnetic and Lightning Protection Research (CELP), Electrical and Electronic Engineering Department, University Putra Malaysia, Malaysia, for the support given during this work, and the first author would like to thank Mosul University, College of Engineering, Electrical Department, for the support given during this work.

Additional information

Notes on contributors

Omar Sh. Alyozbaky

Omar Sh. AL-Yozbaky was born in Mosul, Iraq on 17th July 1977. He obtained his Bachelor of Science (BSc) in Electrical Engineering in 2001 from Electrical Engineering Department, College of Engineering, University of Mosul, Iraq. Then he was appointed as an assistant engineer in the same mentioned department. After that, he got MSc in “Overcome the effect of Critical distance in XLPE High Voltage Cables by inductive shunt compensator ”, 2008 from the same mentioned department as well. Upon his graduation, he was appointed as teaching a staff (assistant lecturer) in the Electrical Engineering Department, College of Engineering, University of Mosul. In 2012, he obtained the scientific title (lecturer) and the PhD degree in the Department of Electrical and Electronic Engineering, Faculty of Engineering, University Putra Malaysia in 2017. Since 2014, he was a member in Centre for Electromagnetic and lightning protection research (CELP). The subjects for interest, Electromagnetic field associated with lighting on transformer performance, thermal modeling transformer design and electrical machines.