A new efficient algorithm to detect Current Transformer saturation

This paper presents an algorithm to precisely detect the saturation of Current Transformers (CTs). The algorithm is based on first difference of magnitudes of Lissajous Curve. These Lissajous curves are generated using secondary current signal and its first derivative. PSCAD was used to generate secondary current signals for various practical cases of fault currents and MATLAB was used to implement the proposed algorithm. The algorithm is tested for various cases of severe and mild CT saturation. Moreover, the effects of various factors, such as remnant magnetic flux density, noise and burden power factor are studied. Test results reflect that the proposed algorithm efficiently detect the start and end instants of CT Saturation for almost all cases.