METHOD FOR DETECTING RESIDUAL MAGNETISM OF CURRENT TRANSFORMER BASED ON SMALL-SIGNAL SLOPE MAPPING

摘要

A method for detecting residual magnetism of a current transformer (CT) based on small-signal slope mapping. The derivative (I) of a magnetic flux (Ø b ) of an initial operating point (i µ =0) to an exciting current (i µ ) is calculated by secondarily (S1, S2) applying a small voltage (u) signal to the current transformer (CT), and the residual magnetism (Ø r ) of the iron core of the current transformer (CT) is determined by using a current transformer (CT) iron-core magnetization curve (Øb-iµ) to perform slope mapping. The method enables a current transformer (CT) to generate residual magnetism of different magnitudes by magnetizing an actual current transformer (CT). The validity of the present residual-magnetism detection method and theory and the practicability of a detection system platform are evaluated, and the detection result shows that the magnitude of the residual magnetism (Ø r ) of an iron core of a tested current transformer (CT) can be rapidly and accurately reflected by using the detection platform.