Modified method of high alternating current measurement

The conventional current transformers (CTs) in the form of a bar primary and secondary winding on a highly permeable ring core suffer from ratio error and phase angle errors, which are primarily due to the no-load current of the transformer. A modified design of a CT has been described. In this design, a feedback technique has been used in order to reduce the no-load current to a negligibly small value so that the said error may be minimal. Using this technique, a CT has been designed and fabricated with the commercially available material. The performance of the transformer has been tested experimentally and the output and input AC waves have been observed in a storage cathode ray oscilloscope (CRO) and the experimental results are reported.