Dr Fiona Robinson is principal researcher at Cogent Power Ltd, Tata Steel and her work is focused on improving the magnetic properties of grain-oriented electrical steels primarily for use in transformers.
WHEN buying a domestic appliance one of the selection criteria for us is its energy rating, but do you think about the efficiency of generating and distributing the electricity that powers it?
Transformers are devices that “step up” and “step down” the voltage of electricity; they are used to facilitate the generation, transmission and distribution of electricity for domestic or industrial applications.
Layers of electrical steel are stacked to build transformer cores which form strong electromagnets when AC current is applied, making them extremely efficient while minimising expensive copper usage. Grain-oriented electrical steels have their best magnetic properties in one direction; this attribute is used to build powerful and efficient transformer cores.
My objective is to make the grain-oriented steel used to build transformers easier to magnetise in an electric field and maximise useful energy produced, while minimising wasted heat due to magnetic core losses.
Despite complaining about electricity prices few of us are prepared to give up our addiction to portable electronic devices all requiring regular charging, home entertainment systems or games consoles. Electrical power generation, transmission and distribution can be made more efficient by developing grain-oriented steels with excellent magnetic properties, helping keep electricity affordable and reducing environmental impact.
For transformers to have high energy efficiency, low losses and low noise (the distinctive transformer “hum”) the magnetic properties of the grain-oriented steel used in them must be carefully controlled. They need to have a high permeability which means they are easy to magnetise and demagnetise in an alternating electric current.
High levels of silicon added during steel-making reduce the magnetic losses in the final product although this makes steel brittle and difficult to roll so it is a balancing act between the practical aspects of manufacturing and reducing magnetic loss.
The purpose of my research is to develop electrical steels, with low magnetic losses that are easy to magnetise and with a very thin strip thickness which can be consistently manufactured.
The production process has several heat treatment and rolling steps and takes about two weeks from start to finish, when the magnetic properties can be measured. Each production step impacts on the next and this, together with steel chemistry affects the magnetic quality of the final product; this is particularly evident for thinner steel strip. The objective of my research is to develop a repeatable “recipe” for industrial production of very thin grain-oriented steel strip with low magnetic losses by identifying, understanding and controlling steel chemistry and the parameters at each process stage.
Grain-oriented electrical steel is a long established but continuously evolving product because customers want to construct increasingly efficient transformers; necessitating research to reduce magnetic losses, make magnetisation easier and roll brittle high silicon steels even thinner
Every production facility is different and has been updated as new technology becomes available making practical application of academic theory challenging.
By further improving the magnetic properties of grain-oriented electrical steels we can maintain manufacturing sustainability of this high quality product in Wales.
To contact Fiona please e-mail firstname.lastname@example.org
This article first appeared in the Western Mail‘s Health Wales supplement on 11th February 2013, as part of the Welsh Crucible series of research profiles.