Study of different grades of CRGO core material for evaluation of power factor

Abstract

Electrical steel is significant material and used as core in the manufacture of electrical devices for power and distribution transformers. The magnetic properties of these steels need to be precisely estimated in order to design an accurate electrical device. Deterioration of the Cold Rolled Grain Oriented (CRGO) electrical steels can severely influence the electrical and magnetic properties and thereby the performance of the devices in which they are integrated. A study was conducted on 20 nos of different thickness grades of CRGO electrical steel of primary, non-prime grade CRGO steel and used core material (removed) from transformer. The thickness grades used for the experimental work are 5 nos. of 0.23 grade, 9 nos. of 0.27 grade, 4 nos. of 0.30 grade and 2 nos. of 0.35 grades. The magnetic properties are evaluated such as core loss, apparent power and power factor was calculated. The power factor values for the prime grades are from 0.75 to 0.4, but where as non-prime and used core steel values are below 0.3.