A Current Transformer (CT) Saturation Detection Method for Bus Differential Protection

The performance of various bus differential protection schemes depends on fast and accurate detection of Current Transformer (CT) saturation during external faults. This paper presents a CT saturation detection method using alienation coefficient of two instantaneous current signals found from the two-terminal equivalent model of the busbar. A simulation study is also presented to validate the performance of the proposed CT saturation detection method. Documented results show that the proposed method detects CT saturation accurately irrespective of saturation severity and saturation starting time (i.e. late or fast CT saturation).