Optimizing the properties of the optical current transformer with special reference to faster transient response

A current transformer, in general, is a means of measuring a very large electrical current, converting it to a much smaller current, requiring low power equipment as simple as a multimeter to display it. The traditional method is based on the electromagnetic principle of an iron ring around the current conductor, supplied with a secondary transformer winding. The latter will deliver a small current directly proportional to the large current, to be displayed by a small current measuring device. An optical current transformer (OCT) is constructed by winding an optical fibre cable around the current conductor. The phenomenon where the angle of a polarized light beam propagating through the optical cable, is deflected when the magnetic flux lines generated by the large current, are appearing longitudinal in the said cable, are utilized to determine the main current. OCT´s are already well developed, but lack to respond to very fast changing transient impulses. This paper describes a research and developing process to address this problem.