Mourad, Dina2019-11-052019-11-0520190378-77961873-2046https://doi.org/10.1016/j.epsr.2018.10.032https://www.sciencedirect.com/science/article/abs/pii/S0378779618303559One area of the major concern of busbar differential schemes is misoperation due to current transformer saturation through close-in out-of-zone faults. A comprehensive fault discrimination scheme is extremely needed for differential protection algorithms to overcome the CT saturation problem. This paper attempts to introduce a method based on innovative Cos-Sin characteristics that is capable of distinguishing between in-zone and out-ofzone faults of busbar protection. The results covered a wide variety of fault scenarios; these results proved the ability of the proposed algorithm to differentiate between in-zone and out-of-zone faults relating to CT saturation conditions. They further demonstrated the noticeable adaptability and performance of the algorithm since it is not affected by such fault parameters as fault type, fault resistance, and fault inception time. Experimental implementation of the devised Cos-Sin signal was conducted and manifested the capability and simplicity of its experimental constructability.enUniversity for Digital Signal ProcessingBusbar protectionCT saturationRatio identificationCos-Sin transformationArticlehttps://doi.org/10.1016/j.epsr.2018.10.032